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Digitized by VjOOQIC
./ Cmeml AV/Zvvv/, v I fork .
FOR REPAIR MEN, CHAUFFEURS, AND OWNERS; COVERING THE CONSTRUCTION,
CARE, AND REPAIR OF PLEASURE CARS, COMMERCIAL CARS, AND
MOTORCYCLES, WITH ESPECIAL ATTENTION TO IGNITION,
STARTING, AND LIGHTING SYSTEMS, GARAGE DESIGN
AND EQUIPMENT, WELDING, AND OTHER
PnpnnJ hy a Staff of
AUTOMOBILE EXPERTS, CONSULTING ENGINEERS, AND DESIGNERS OF THE
HIGHEST PROFESSIONAL STANDING
lllustnitcd ivttli -7 77- fif'if!)! I ItnuhrJ fu-ravn,
AMERICAN TECHNICAL SOCIETY
Copyright, 1909, 1910, 1912, 1915, 1916, 1917, 1918, 1919, 1920
AMERICAN TECHNICAL SOCIETY
Copyrighted in Great Britain
All Rights Reserved
Authors and Collaborators
CHARLES B. HAYWARD
President and General Manager, The Stirling Press, New York City
Member, Society of Automobile Engineers
Member, The Aeronautical Society
Formerly Secretary, Society of Automobile Engineers
Formerly Engineering Editor, The Automobile
C. T. ZIEGLER
With Inter-State Motor Company, Muneie, Indiana
Formerly Manager, The Ziegler Company, Chicago
M ORRIS A. HALL
Editor, Automotive Engineering
Formerly Managing Editor Motor Life, Editor The Commercial Vehicle, cjc.
Author of "What Every Automobile Owner Should Know"
Member, Society of Automobile Engineers
Member, American Society of Mechanical Engineers
DARWIN S. HATCH, B.S.
Editor, Motor Age, Chicago
Formerly Managing Editor, The Light Car
Member, Society of Automobile Engineers
American Automobile Association
GLENN M. HOBBS, Ph.D.
Secretary and Educational Director, American School of Correspondence
Formerly Instructor in Physics, The University of Chicago
American Physical Society
HERBERT L. CONNELL, B.S.E.
Late Lecturer, Automobile Division, Milwaukee Central Continuation School
Editorial Representative, Commercial Car Journal and Automobile Trade Journal
Member, Society of Automobile Engineers
Member, Standards Committee of S. A. E.
Formerly Technical Editor, The Light Car
Authors and Collaborators— Continued
HUGO DIEMER, M.E.
Professor of Industrial Engineering, Pennsylvania State College
American Society of Mechanical Engineers
HERBERT LADD TOWLE, B.A.
Specialist in Technical Advertising
Member, Society of Automobile Engineers
Formerly Associate Editor, The Automobile
ROBERT J. KEHL, M.E.
Consulting Mechanical Engineer, Chicago
American Society of Mechanical Engineers
EDMOXD M. SIMON, B.S.
Superintendent Union Malleable Iron Company, East Mollne. Illinois
EDWARD B. WAITE
Formerly Dean and Head, Consulting Department, American School of
Member, American Society of Mechanical Engineers
C. A. MILLER, JR.
Associate Editor, American Technical Society
Formerly Managing Editor of Xutianal Jtuildcr
Member, American Association of Engineers
W. R. HOWELL
President, W. It. Howell and Company, London, England
WILLIAM K. GIBBS, B.S.
Associate Editor, Motor Aye. Chicago
JESSIE M. SHEPHERD, A.B.
Head, Publication Department, American Technical Society
THE editors have freely consulted the standard technical litera-
ture of America and Europe in the preparation of these
volumes. They desire to express their indebtedness, particu-
larly, to the following eminent authorities, whose well-known treatises
should be in the library of everyone interested in the Automobile and
Grateful acknowledgment is here made also for the invaluable
co-operation of the foremost Automobile Firms and Manufacturers
in making these volumes thoroughly representative of the very latest
and best practice in the design, construction, and operation of Auto-
mobiles, Commercial Vehicles, Motorcycles, Motor Boats,, etc. ; also
for the valuable drawings, data, illustrations, suggestions, criticisms,
and other courtesies.
CHARLES E. DURYEA
First Vice-President, American Motor League
Author of "Roadside Troubles"
Late Consulting Engineer
Past President of the American Society of Civil Engineers
Author of "Artificial Flight," etc.
E. W. ROBERTS, M.E.
Member, American Society of Mechanical Engineers
Author of "Gas-Engine Handbook," "Gas Engines and Their Troubles," "The
Automobile Pocket-Book," etc.
SANFORD A. MOSS, M.S., Ph.D.
Member, American Society of Mechanical Engineers
Engineer, General Electric Company
Author of "Elements of Gas Engine Design"
GARDNER D. HISCOX, M.E.
Author of "Horseless Vehicles, Automobiles, and Motorcycles," "Gas, Gasoline,
and Oil Engines," "Mechanical Movements, Powers, and Devices," etc.
AUGUSTUS TREADWELL, Jr., E.E.
Associate Member, American Institute of Electrical Engineers
Author of "The Storage Battery: A Practical Treatise on the Construction,
Theory, and Use of Secondary Batteries"
Authorities Consulted— Continued
BENJAMIN R. TILLSON
Director, II. J. Willard Company Automobile School
Author of "The Complete Automobile Instructor"
THOMAS H. RUSSELL, M.E., LL.B.
Editor, The American Cuclopcdia of the Automobile
Author of "Motor Boats/' "History of the Automobile," "Automobile Driving.
Self-Taught," "Automobile Motors and Mechanism," "Ignition Timing and
Valve Setting," etc.
CHARLES EDWARD LUCRE, Ph.D.
Mechanical Engineering Department, Columbia University
Author of "Mas Engine Design"
P. M. HELDT
Editor, Horseless Age
Author of "The (Jasollne Automobile"
H. DIEDERICHS, M.E.
Professor of Experimental Engineering, Sibley College. Cornell University
Author of "Internal Combustion Engines"
JOHN HENRY KNIGHT
Author of "Light Motor Cars and Yoiturettes," "Motor Repairing for Ama-
WM. ROBINSON, M.E.
Professor of Mechanical and Electrical Engineering In University College, Not-
Author of "(las and Petroleum Engines"
W. POYNTER ADAMS
Member, Institution of Automobile Engineers
Author of "Motor-Car Mechanisms and Management"
ROLLA C. CARPENTER, M.M.E., LL.D.
Professor of Experimental Engineering, Sibley College, Cornell University
Author of "Internal Combustion Engines"
ROGER B. WHITMAN
Technical Director, The New York School of Automobile Engineers
Author of "Motor-Car Principles"
Authorities Consulted— Continued
CHARLES P. ROOT
Formerly Edltor> Motor Age
Author of •'Automobile Troubles, and Uow to Remedy Them"
Associate Member, Institute of Electrical Engineers
Author of "Electric Ignition for Motor Vehicles'*
SIR HIRAM MAXIM
Member, American Society of Civil Engineers
Uritish Association for the Advancement of Science
Chevalier Legion d'Honneur
Author of "Artificial and Natural Flight," etc.
Author of "Complete Automobile Record," "A B C of Motoring"
JOHN GEDDES McINTOSH
Lecturer on Manufacture and Application of Industrial Alcohol, at the Poly-
technic Institute, London
Author of "Industrial Alcohol," etc.
FREDERICK GROVER, A.M., Inst.C.E., M.I.Mech.E.
Author of "Modern Gas and Oil Engines"
FRANCIS B. CROCKER, M.E., Ph.D.
Head of Department of Electrical Engineering, Columbia University
Past President, American Institute of Electrical Engineers
Author of "Electric Lighting," Joint Author of "Management of Electrical
Captain and Instructor In the Prussian Aeronautic Corps
Author of "Airships Past and Present"
T. HYLER WHITE
Associate Member, Institute of Mechanical Engineers
Author of "Petrol Motors and Motor Cars"
Authorities Consulted— Continued
ROBERT H. THURSTON, C.E., Ph.B., A.M., LL.D.
Director of Sibley College, Cornell University
Author of "Manual of the Steam Engine," "Manual of Steam Boilers," etc.
Motoring Editor, The London Sphere
Author of "The Amateur Motorist"
HERMAN W. L. MOEDEBECK
Major and Battalions Kommandeur In Badischcn Fussartillcrle
Author of "Pocket-Book of Aeronautics"
EDWARD F. MILLER
Professor of Steam Engineering, Massachusetts Institute of Technology
Author of "Steam Boilers"
ALBERT L. CLOUGH
Author of "Operation, Care, and Repair of Automohiles"
W. P. DURAND
Author of "Motor Boats," etc.
PAUL N. HASLUCK
Editor, Work and Building World
Author of "Motorcycle Building"
JAMES E. IIOMANS, A.M.
Author of "Self-Propelled Vehicles"
R. R. MECREDY
Editor, The Encyclopedia of Motoring, Motor Xeics, etc.
S. R. BOTTONE
Author of "Ignition Devices," "Magnetos for Automobiles," etc.
LAMAR LYNDON, B.E., M.E.
Consulting Electrical Engineer
Associate Member, American Institute of Electrical Engineers
Author of "Storage Battery Engineering"
WAGNER STARTING MOTOR WITH BENDIX DRIVE EXPOSED, DESIGNED
FOR GRANT CARS
Courtesy of WaQner Electric Manufacturing Company, St. Louis, Missouri
WAGNER GENERATOR DESIGNED FOR GRANT CARS
Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri
THE period of evolution of the automobile does not
span many years, but the evolution has been none
the less spectacular and complete. From a creature
of sudden caprices and uncertain behavior, it has become
today a well-behaved thoroughbred of known habits and
perfect reliability. The driver no longer needs to carry war
clothes in momentary expectation of a call to the front.
He sits in his seat, starts his motor by pressing a button
with his hand or foot, and probably for weeks on end will
not need to do anything more serious than feed his animal
gasoline or oil, screw up a few grease cups, and pump up a
tire or two.
C, And yet, the traveling along this road of reliability and
mechanical perfection has not been easy, and the grades
have not been negotiated or the heights reached without
many trials and failures. The application of the internal-
combustion motor, the electric motor, the storage battery,
and the steam engine to the development of the modern
types of mechanically propelled road carriages, has been a
far-reaching engineering problem of great difficulty.
Xevertheless, through the aid of the best scientific and me-
chanical minds in this and other countries, every detail
has received the amount of attention necessary to make it
as perfect as possible. Eoad troubles, except in connection
with tires, have become almost negligible and even the
inexperienced driver, who knows barely enough to keep to the
road and shift gears properly, can venture on long touring
trips without fear of getting stranded. The refinements
in the ignition, starting, and lighting systems have added
greatly to the pleasure in running the car. Altogether, the
automobile as a whole has become standardized, and unless
some unforeseen developments are brought about, future
changes in either the gasoline or the electric automobile
will be merely along the line of greater refinement of the
mechanical and electrical devices used.
^ Notwithstanding the high degree of reliability already
spoken of, the cars, as they get older, will need the atten-
tion of the repair man. This is particularly true of the
cars two and three seasons old. A special effort, therefore,
has been made to furnish information which will be of value
to the men whose duty it is to revive the faltering action of
the motor and to take care of the other internal troubles
in the machine.
d. Special effort has been made to emphasize the treatment
of the Electrical Equipment of Gasoline Cars, not only be-
cause it is in this direction that most of the improvements
have lately taken place, but also because this department of
automobile construction is least familiar to the repair men
and others interested in the details of the automobile. A
multitude of diagrams have been supplied showing the con-
structive features and wiring circuits of the principal sys-
tems. In addition to this instructive section, particular
attention is called to the articles on Welding, Shop In-
formation, and Garage Design and Equipment.
Table of Contents
Electrical Equipment for Gasoline Cars (continued) . .
By Charles B. Haywardt Page *11
Practical Analysis of Electric Starting and Lighting Systems (continued)
— Leece-Neville System: Generator, Regulation, Starting Motor, Instru-
ments. Wiring Diagram. Instructions (Testing Field Winding, Regulat-
ing Brush. Adjusting Third Brush, ^Jrush Replacements. Generator or
Motor Failure) — North East System: Dynamotor, Regulation. Protective
Devices, Wiring Diagrams. Instructions (Battery Cut-Out and Regulator,
Five-Terminal Type Unit. Starting Switch), Switch Testa (Ground Test,
Operation Test. Mechanical and Electrical Characteristics) — Remy Sys-
tem: Two-Unit Type (Generator, Regulation, Starting Motor. Instru-
ments and Protective Devices), Single-Unit Type (Mechanical Combina-
tion, Wiring Diagrams, Instructions) — Slmms-Huff System: Dynamotor,
Regulation, Instruments, Dynamotor Connections. Change of Voltage,
Starting Switch. Wiring Diagram, Instructions (Failure of Cut-Out or
Regulator, Generator Tests) — Splitdorf System: Dynamotor, Wiring Dia-
gram, Control, Regulation, Starting Motor, Instructions (Failure of En-
gine to Start, Oiling of Starting Motor) — U.S.L. System: Variations,
Generator, Starting Motor, Regulation, Instruments and Protective De-
vices. Wiring Diagrams, Instructions (Touring Switch, Starting Switch,
Brush Pressures, Radial and Angular Brushes, External Regulator, Test-
ing Carbon Pile, Battery Cut-Out. Ammeter), U.S.L. Twelve-Volt System,
U.S. Nelson System — Wagner System: Twelve-Volt, Single-Unit, Two-
Wire Type (Dynamotor, Regulation, Wiring Diagram, Control, Trans-
mission, Instructions), Six-Volt, Two-Unit Type (Generator. Regulation.
Starting Motor, Control, Wiring Diagram, Instructions) — Westlnghouse
System: Twelve-Volt, Single-Unit, Single-Wire Type (Dynamotor, Regu-
lation, Control, Wiring Diagram. Instructions), Six-Volt, Double-Unit,
Single-Wire Type (Generators, Regulation, Wiring Diagram, Battery
Cut-Out, Starting Motors, Instructions) — Special Starting and Lighting
Systems for Ford Cars: Ford System: General Instructions, Removal of
Starting Motor, Removal of Generator, Lighting and Ignition — Gray and
Davis System: Installation (Preparing Engine, Mounting Starter-Gen-
erator, Remounting Engine Parts, Starting Switch, Timing Device, Bat-
tery, Final Connections and Adjustments), Instructions, Testing Gener-
ator with Ammeter — Starting and Lighting Storage Batteries: Importance
of Battery — Careful Attention to Battery Necessary — Principles and Con-
struction: Function of Storage Battery, Parts of Cell, Specific Gravity,
Action of Ceil on Charge and Discharge, Battery Capacity. Construction
Details, Edison Cell not Available — Care of Battery: Adding Distilled
Water, Adding Acid, Hydrometer (Hydrometer Tests. Variations in Read-
ing, Frozen Cells, Low Cells), Adjusting Specific Gravity. Gassing,
Higher Charge for Cold Weather, Sulphatlng, Restoring Sulphated Bat-
tery, Specific Gravity Too High, Internal Damage, How to Take Read-
ings, Detecting Deranged Cells, Temperature Variations in Voltage Test.
Joint Hydrometer and Voltmeter Tests, Cleaning Battery. Replacing Jar,
Overhauling Battery (Dismounting Cells, Treating Plates. Reassembling
Battery, Checking Connections, Reconnecting Cells, Renewals), Lead
Burning (Type of Outfit. Methods of Burning, Use of Forms to Cover
Joint, Illuminating Gas Outfit, Hydrogen Gas Outfit). Installing New Bat-
tery, Storing Battery, Charging from Outside Source, Equalizing Charges
Necessary, Methods of Charging (Charging in Series, Motor-Generator.
Rectifiers), Care of Battery in Winter, Testing Rate of Discharge, Test-
ing Rate of Charge, Voltage Tests. Hydrometer and Voltmeter Tests.
Cleaning Repair Parts — Summary of Instructions: Battery: Electro-
lyte. Hydrometer Tests. Joint Hydrometer-Voltmeter Tests, Gassing
Sulphatlng, Voltage Tests, Sediment, Voltage, Charging from Outside
Source, Intermittent and Winter Use. Edison Battery — Generators: Types
and Requirements. Loss of Capacity, Methods of Regulation, Regulators.
Windings, Commutator and Brushes — Wiring Systems: Different Plans,
Faults in Circuit, Proper Conduction — Protecting and Operative Devices:
Fuses, Circuit-Breakers. Battery Cut-Outs. Contact Points. Switches —
Lighting and Indicators: Lamps, Instruments — Electric Gear Shift
Review Questions Page 307
Index Page 313
•For page numbers, see foot of papes.
M-'or professional standing «»f authors, .«
rotors at front of volume.
AUTO-LITE FOUR-POLE STARTING MOTOR
Courtesy of Electric Auto- Liu Company, Toledo, Ohio
AUTO-LITE FOUR-POLE GENERATOR WITH THIRD-BRUSH REGULATION, ARRANGED
TO RUN AT ENGINE SPEED
Courteny of Electric Auto-Lite Company, Toledo, Ohio
ELECTRICAL EQUIPMENT FOR
ELECTRIC STARTING AND LIGHTING
PRACTICAL ANALYSIS OF TYPES— (Continued)
Six-Volt; Two-Unit; Two-Wire
Generator. Standard shunt-wound bipolar type, combined
with ignition timer and distributor driven by a worm gear on the
armature shaft. The generator is mounted on the left side of the
engine and is driven by the pump shaft (Haynes 1913 installation,
and subsequent models to date).
It differs from the standard shunt-wound machine in that the
shunt field is connected to the regulating third brush. This brush
collects current from the commutator and excites the field, so that a
strong shunt field is provided at comparatively low speeds. As the
speed increases, the voltage supplied to the shunt field decreases,
even though the total voltage between the main brushes may have
increased. This weakens the field and prevents the output of the
generator from increasing with the increased speed. At higher speeds
it acts somewhat similarly to a bucking-coil winding in that it further
weakens the field and causes the generator output to decrease still
more. The closer the third brush is set to the main brush just above,
the greater will be the output of the machine; moving it away from
the main brush decreases the output.
Regulation. Generators of the 1915 and 1916 models are con-
trolled by armature reaction through a third brush, the field coils
receiving their exciting current from the armature through this
brush. The position of the latter on the commutator is shown at
B, Fig. 293. A slight rotation of this brush relative to the com-
mutator changes the electrical output of the machine. As adjusted
at the factory this brush is set to give a maximum output of 15
amperes at 7J volts. (All generators
for 6-volt systems are wound to pro-
duce an e.m.f. of 7£ volts, or there-
about, in order that the voltage
of the generator may exceed that of
the battery when the latter is fully
charged. The e.m.f. of generators
for 12-volt and 24- volt systems also
exceeds that of their batteries in
about the same proportion. Other-
wise, the generator would not be able
to force current through the battery.)
Starting Motor. The motor is
of the bipolar series-wound type
driving the engine through a roller
chain and an over-running clutch.
Instruments. An indicating
type of battery cut-out is employed,
thus combining the functions of the
cut-out and ammeter in one device. The details of this device are
shown in Fig. 294. is the winding or coil of the electromagnet
of which the U-shaped bar
8 forms the magnetic circuit.
At 4 is the pivoted armature,
normally held in the OFF
position as shown by a spring,
when no current is passing,
and adapted to be drawn
against the pole pieces of
the magnet when the latter
is excited by the charging
current. As the two-wire sys-
tem is employed, the cut-out
breaks both sides of the battery-charging circuit and it is provided
with six current-carrying contacts on each of the sides of the circuit.
Four of these, which carry most of the current, are copper to bronze,
Fig. 293. Diagram of Arrangement of
Brushes on Leere- Neville
6- Volt Generator
Fig. 294. Details of Leecc- Neville Indicator
ELECTRICAL EQUIPMENT 445
while those that take the spark in breaking the circuit are cophite to iron
and are actuated by a spring. The indicating target 16 is held in the
OFF position by the spring 19 when no current is passing, and
this reading appears in the opening of the panel on the cover.
When the generator starts and the cut-out closes, the target is
moved to bring the word CHARGING in the opening. The
same panel also carries the three-way lighting switch controlled
by buttons. The central button closes the circuit to the head-
lights and tail lights in the usual manner, while the upper button
throws the headlights in series-parallel connection. As this doubles
the resistance, it halves the voltage passing through the lamps, and
they, accordingly, burn dimly. The lower button controls the cowl
light over the instruments on the dash.
Wiring Diagram. Fig. 295 illustrates the Haynes 1915 installa-
tion. WTiile two wires are employed for connecting all the appara-
tus, it will be noted that the storage battery and the dry-cell battery
are grounded by a common ground connection. This is to permit
using current from the storage battery for ignition, the correspond-
ing ground to complete the circuit being noted at the ignition coil,
close to the distributor. The connections G and B on the panel
board are those of the generator and the battery to the indicating
battery cut-out, the connections of three lighting switches being
shown just to the right. In Fig. 296 is shown the Leece-Neville
installation in White cars.
Instructions. Never run the engine when the generator is dis-
connected from the battery unless the generator is short-circuited,
as otherwise it will be burned out in a very short time. This applies
to all lighting generators except those protected by a fuse in the
field circuit, in which case the fuse will be blown. The Leece-Neville
generator can be short-circuited by taking a small piece of bare
copper wire and connecting the two brush holders together with it.
Instructions for short-circuiting other makes are given in connec-
tion with the corresponding descriptions.
Later models of the Leece-Neville generator are provided with a
circuit-breaker. On the Haynes 12-cylinder models, this is mounted
on top of the generator, while in some cases it is combined with the
ammeter on the dash. To protect the generator and battery, there
is a 5-ampere cartridge fuse under the cover of this circuit-breaker
446 ELECTRICAL EQUIPMENT
ELECTRICAL EQUIPMENT 447
When this fuse blows out, both the generator and the circuit-breaker
become inoperative. Any one of the following conditions may cause
Fig. 296. Wiring Diagram of Leece-Neville System on White Cars
Fig. 297. Wiring Diagram of Generator and Circuit-Breaker Circuits for Leece-Neville System
Courtesy of The Leece-Neville Company, Cleveland, Ohio
this fuse to blow out : loose or corroded connections at the battery; an
open circuit in the wiring on the battery side of the cut-out; not
sufficient water in the battery; output of the generator too high;
448 ELECTRICAL EQUIPMENT
allowing the main brush directly above the third brush to stick in its
holder; a loose connection at the point A 2 , Fig. 297; improper insula-
tion between the wires B\ and J3 2 in the connector plug, Fig. 297.
By an open circuit is meant an actual break at a connector or a termi-
nal, or in the wiring itself, while a loose connection signifies an inse-
curely fastened terminal or wire, at a junction box, or at any other part
of the system. If there is a short-circuit in the field winding of the
generator, this also will cause the fuse to blow out.
Testing the Field Winding. While a short-circuit in the field
winding of any generator is a rare fault, there are times when the
trouble cannot be traced to any other part of the system. To test
the Leece-Neville generator for this, connect the negative terminal of
the portable testing ammeter to F\, Fig. 297, while the positive termi-
nal of the motor must be connected to the positive terminal of a 6-volt
storage battery ; the negative terminal of the battery is to be connected
to the third brush when drawn from its holder. If the indication of
the ammeter is above 4 amperes, there is a short-circuit in the field
windings. In such a case, the generator should be returned to the
manufacturers for repairs.
With the engine running, the working of the generator should be
inspected from time to time. In case there is excessive sparking or
"arcing" between the brushes and the commutator, examine the con-
nections at Fi and Ai and see that the screws are perfectly tight,
as these screws sometimes work loose and are responsible for this arc-
ing which is destructive to the commutator. The loosening of the
connections at F\ and A\ will have no effect on the fuse; but if the
connection at A 2 loosens, the fuse will burn out. When inspecting the
operation of the generator, see that the brushes are making good even
contact with the commutator, and wipe away all particles of dust and
grit from around the brushes and their holders. With the engine
stopped, see that the brushes move freely in their holders. This
should always be done where a car has been laid up for some time
(before starting the engine) as the brushes, through disuse, will have
a tendency to stick.
The fuse in the circuit-breaker has no effect whatever on the
output of the generator, so that a larger fuse must not be inserted in
case the generator is not delivering its rated output or more. The
makers supply a 5-ampere fuse for this purpose, and if a fuse of
Lcece-Neville Starting and Lighting System on White Cars, Model G-M
Courtety of Leece- Neville Company, Cleveland, Ohio
ELECTRICAL EQUIPMENT 449
heavier capacity is employed, it will cause both the circuit-breaker
and the generator so burn out. This will be the case also where a
"jumper" is resorted to, i.e., a piece of wire or other metal bridging
the fuse clips so that the fuse is cut out of the circuit. It must be
borne in mind, however, that these fuses are more or less fragile and
are likely to become damaged by careless handling. A fuse whose
connections have been loosened up is likely to blow out on that
account, so before inserting a fuse in the clips of the circuit, it should
be examined to see that the ferrules on each end of the cartridge are
perfectly tight. Where a good fuse has been inserted and it blows out,
the cause should be ascertained before inserting another fuse.
Regulating Brush. In case the generator output falls off as
shown by its inability to keep the battery properly charged, the
battery itself and all connections being in good condition, and a
proper amount of day running being done to provide the necessary
charging current, the trouble may be in the regulating brush of the
generator. Test by inserting an ammeter, such as the Weston
portable or any other good instrument with a scale reading to 30
amperes, in the line between the generator and the battery. Run
the engine at a speed corresponding to 20 miles per hour, at which
rate the ammeter should record a current of approximately 15
amperes. If the ammeter needle butts against the controlling pin
at the left end of the scale instead of showing a reading, it indicates
that the polarity is wrong, and the connections should be reversed.
Should there be no current whatever, the needle will stay perfectly
stationary except as influenced by vibration. If the ammeter shows
a reading of less than 15 amperes, the current output of the gener-
ator may be increased by loosening the set screw holding the third
brush and rotating the brush slightly in the same direction as the
rotation of the armature. This should be done with the generator
running and the ammeter in circuit, noting the effect on the reading
as the brush is moved. To decrease the output, it should be moved
in the opposite direction until the proper reading is obtained, after
which the brush must be sanded-in to a good fit on the commutator.
It may sometimes occur that sufficient movement cannot be given
the third brush without bringing it into contact with one of the
main brushes. This must be avoided by loosening the two set
screws E, Fig. 293, and moving the main brush holder away
450 ELECTRICAL EQUIPMENT
from the third brush until there is no danger of their touching.
After securing the desired adjustment, fasten the third brush in
place again, stop the engine, and then reconnect the generator to the
battery. Do not cut the ammeter out of the circuit while the gen-
erator is running.
To Adjust Third Brush. Before making any adjustment of the
third brush when it is suspected that any trouble with the current
supply is due to the generator, the output of the generator should be
tested. On a car equipped with lamps totaling 250 candle power or
more (this refers to White busses), the generator should produce 20
amperes. Run the engine at a speed sufficient to drive the car 15
o 16 miles per hour on direct drive and note the reading of the dash
ammeter. In case the car has seen considerable service, it may be
well to check the dash ammeter with the more accurate portable
ammeter described in connection with other tests in previous and
subsequent sections. Where the car lighting system totals 250 c.p.
or over, and the ammeter reading shows more than four amperes above
or below 20, the generator should be adjusted to give its rated capacity
of 20 amperes — as every 15 c.p. less than 250 c.p. used on the car,
lower the output of the generator by one ampere. By making the
adjustments in this manner, the storage battery will be amply
Before making any generator adjustments, test the storage bat-
tery with the hydrometer. Do not add any distilled water just pre-
vious to making this test unless the level of electrolyte is right down to
the plates so that sufficient liquid cannot be drawn into the hydrome-
ter ; in this case, add water and charge the battery for at least one hour
before making the hydrometer test. If the specific gravity of the elec-
trolyte is 1,250 or over, and the generator is found to be delivering less
than the rated lamp load, no adjustment of the generator should
To increase the output of the generator, rotate the third brush
in the direction of rotation of the armature; to decrease the output,
move the brush against the direction of rotation. Adjustments
should be made with the engine standing. Loosen the screw at the
rear of the commutator housing shown at the point b\ Fig. 293.
This releases the third brush holder, and the brush may then be moved
in the direction desired. It should be moved only a short distance,
ELECTRICAL EQUIPMENT 451
and the generator then should be tested until the desired output is
secured. In case the third brush should come in contact with the
main brush above in the course of adjustment, it will be necessary to
move the main brushes. To do this, loosen the two set screws E y
Fig. 293, and move the main brush holder far enough away from
the third brush so that there is no possibility of contact between them.
When the desired location is found, sand-in the third brush to the com-
mutator and also clean the commutator with a piece of worn sand-
paper as described in the section on Sanding-In the Brushes (Delco
instructions) ; if it has been necessary to move the main brushes, they
should be sanded-in also. The brush holder screws should be well
tightened after making any adjustments to prevent any possibility of
the vibration and jolting loosening them up and throwing the gener-
ator out of adjustment again.
Brush Replacements. Never replace any of the brushes on
either the generator or starting motor with any but those supplied
by the manufacturer of the system for this purpose. Motors and
generators adapted for use on electric-lighting circuits are usually
fitted with plain carbon brushes. These are not suitable for use on
automobile generators or starting motors owing to their resistance
being much higher. Due to the low voltage of electric apparatus
on the automobile, special brushes of carbon combined with soft
copper are usually employed. Brushes also differ greatly in hard-
ness, and a harder brush than that for which the commutator is
designed will be liable to score it badly besides producing a great deal
of carbon dust, which is dangerous to the windings. This, of course,
applies to all makes of apparatus and not merely to that under
Generator or Motor Failure. For failure of the generator or of
the starting motor, see instructions under Auto-Lite, Delco, and
Gray & Davis, bearing in mind, however, that the system under
consideration is of the two-wire type, so that in using the test lamp
to locate short-circuits a connection to the frame or ground is not
always necessary. The short-circuit may be between two adjacent
wires of different circuits. Given properly installed wires and
cables, there is less likelihood of short-circuits in the wiring of a two-
wire System. Defective lamps will not infrequently prove to be the
cause, as, in burning out, a lamp often becomes short-circuited.
'452 ELECTRICAL EQUIPMENT
NORTH EAST SYSTEM*
Twelve-Volt, Sixteen-Volt, or Twenty-Four- Volt; Single-Unit; Single-
Wire or Two-Wire, According to the Installation
Dynamotor. The dynamotor is of the four-pole type, with both
windings connected to the same commutator. It is designed for
installation either with silent-chain drive-7-as on the Dodge, Fig. 298,
in which case the drive is direct either as a generator or as a motor —
or with a special reducing gear and clutch for driving from the
pump or magneto shaft of the engine. In the latter type, the start-
ing switch is mounted on the gear housing, which is integral with
Fig. 298. North East Dynamotor with Silent-Chain Drive. Starting
Switch Shown at Right
Courtesy of North East Electric Company, Rochester, New York
the bedplate of the dynamotor. In this case the drive as a gener-
ator is 1J times engine speed, while as a starting motor the
reduction through the gear is approximately 40 : 1.
Regulation. The regulation is by means of a differential wind-
ing or bucking coil, in connection with an external resistance auto-
matically cut into the shunt-field circuit by a relay in series with the
battery cut-out. See "limiting relay", Fig. 299. The "master
relay" is the battery cut-out, and the condenser is to reduce sparking
at the contacts of these relays.
Protective Devices. There is a fuse in the field circuit of the
generator, but fuses are not employed on the lighting circuits.
♦The voltage of any system may be determined by counting the number of cells in the
storage battery, and multiplying by 2 in the case of a lead battery, or multiplying by \\i where
an Edison battery is used.
<&/ HAJ1NG 3WJ tCH.
HCSISTTWCE. unrriNG MASTER rcsisthncc
Fig. 299. Diagrammatic Section of North East Dynamotor, Showing Regulator (Limiting
Relay) and O*-0ut (Master Relay)
454 ELECTRICAL EQUIPMENT
Wiring Diagrams. A graphic diagram of the North East
installation on the Dodge is shown in Fig. 300. This is a G-cell or
12-volt system single-wire type. The sDrocket on the forward end
of the machine drives from a similar but much larger sprocket on
the forward end of the crankshaft of the engine through a silent
chain. The wiring diagram of the Krit 1915, Fig. 301, will be
recognized as being the
same as the Dodge, except
for the use of two wires
throughout. Fig. 302
shows the wiring diagram
of an 8-cell or 16-volt
system, but the battery is
divided for the lighting
circuits so that 8$ — 9-volt
lamps are used, whereas
14- volt bulbs are necessary
on the Dodge installation
as the entire battery is
used in series for lighting.
The wiring of the 12-cell
or 24-volt system is shown
in Fig. 303. In this case
the battery is divided for
lighting so that 7-volt
lamps are employed. Such
a system is usually desig-
nated as 24 — 6- volt, while
the previous one would be
a 16— 6-volt. The North
East installation for Ford
i cars is 24 — 14-volt. With
the exception of the Dodge,
the two-wire system is
employed on the instal-
indicator shows when the
battery is charging or dis-
charging and accordingly
should indicate OFF when
Diagram for 16-Volt North East
System Using 8H — 9- Volt Lamps
TWO WHt*9 LCAOtNOnrOM fifCrrO#-eCNCJ**TOX
TO BATTCKYAN& STA*T#*& S¥*fTO*f TO B& *S
Fig. 303. Wiring Diagram for 24- Volt North East System Using 7-Volt Lamps
458 ELECTRICAL EQUIPMENT
the engine is idle and no lamps are lighted. A discharge reading under
such conditions would indicate the presence of a ground, short-circuit,
or failure of the battery cut-out to release. Should the generator fail
to charge the battery, note whether the field fuse has been blown by
short-circuiting the fuse clips with the pliers or a piece of wire while
the engine is running at a moderate speed. Look for cause of failure
before replacing the fuse. If the fuse has not blown, see whether
battery cut-out is operating; look for loose connections at generator,
cut-out, and battery. If the battery is properly charged, loose con-
nections are also most likely to be the cause of failure of the starting
motor; or, any of the instructions covering brushes, commutator, etc.,
as given previously, may apply.
Battery Cvl-Ovi and Regulator (Relays}. In every case where it is
necessary to make repairs on starter-generators equipped with the
earlier type cut-out and regulator (relays), 1283 (12-volt), 1860
(16-volt), 2501 (24-volt), 1900 (16-volt), and 2503 (12 and 24-volt),
it is advisable to replace the cut-out entirely, installing a later and
improved type, 1196 (12-volt), or 1197 (24-volt and 16-volt). In
order to adapt the starter-generator to the 1196 and 1197 cut-out, or
relay units, it is necessary to cut out the bosses on the commutator
end bearing in which the studs holding the original relay were
screwed. This will provide the clearance required to prevent ground-
ing of the nuts which secure the units to their baseboard. As a
further precaution against grounding, it will be necessary to cut away
that portion of the gasket retainer which would be liable to come
into contact with the armature of the master relay.
Fasten down the baseboard which carries the relays by screwing
the resistance unit studs into the holes which were used for the former
resistance studs. Before making connections on the relay, draw
tight all leads which come from inside the starter-generator so as to
take up whatever slack they have; then tie them together with string
to prevent their slipping back. No loose wire must be left inside the
starter-generator, because of its tendency to be drawn in between the
armature and the pole pieces. The connections on the four-terminal
type starter-generator are made as follows:
Looking at the starter-generator from the driving sprocket end,
the main terminals 1, 2, 4, and 3 of the starter-generator are consid-
ered as being numbered in anti-clockwise rotation, Fig. 304. Viewing
the relay unit as mounted on the starter-generator with the larger, or
master relay, at the left, the four binding posts a, 6, c, and d are
designated from left to right in the same illustration. To relay bind-
ing post a, connect lead (red) coming from starter-generator terminal
2. To relay binding post 6,
connect lead (black) coming &****
direct from starter-generator
terminal 3. To relay binding
post c, connect lead (green)
from starter-generator ter-
minal 4. To relay binding
post d, connect lead (yellow)
from starter-generator shunt-
field coils. It is always advis-
able to check the identity of the
leads by inspection and test.
In order to make a posi-
tive distinction between the d
lead and the b lead, both of
which are in electrical connec-
tion with the starter-generator
terminal 3, the following test
should be made: Using the
test-lamp outfit, send current
from starter-generator ter-
minal 3, through each of these
wires in turn, and note appear-
ance of the lamp. When the
direct lead (6 lead) is in circuit,
the lamp will burn with full
brilliance, but when the d lead,
which includes the starter-generator shunt-field coils, is in circuit, the
lamp will be noticeably dimmer.
Five- Terminal Type Unit The connections on the five-terminal
type generator-starter unit are made as follows: Looking at the
starter-generator, Fig. 305, from the driving sprocket end, the main
terminals 1, 5, 2, 4, and 3, respectively, of the unit are numbered in
anti-clockwise rotation (to the left). Viewing the relay unit as
Internal Wiring Diagram for North East
Model "D" Starter-Generator
mounted on the starter-generator with the master relay at the left,
the four binding posts a, 6, c, and d are designated from left to right
as shown in the illustration. Proceed with the instructions as given
for the four-terminal type starter-generator as given. The new type
relays 1196 and 1197 are regularly furnished with local connec-
tions, as shown in Fig. 304,
but it will be necessary to
make the following altera-
tions when applied to the
five-terminal type starter-
generator, so that the relay
connections will conform to
the diagram in Fig. 305.
Remove the jumper lead that
connects the frame of the
master relay to the rear con-
tact terminal on the limiting
relay; remove from relay
binding post a the left-hand
Lengthen this lead by splic-
ing a piece of the same kind
of wire to it, and solder it to
the limiting relay contact ter-
minal, from which the jumper
has been removed. To this
terminal must also be sol-
dered the lead coming from
starter-generator terminal 5.
(In some starter-generators
this lead includes the field
The condenser in the early models is mounted between the field
coils. One condenser lead must either be connected to the relay
binding post a as shown in either Fig. 304 or Fig. 305 or be spliced
to the wire leading to it. The other condenser lead must either be
connected to the relay binding post d or spliced to the shunt-field
wire leading to it.
Fig. 305. Internal Wiring Diagram for
Model "B" Starter-Generator
Starting Suritch. When its operation indicates that the con-
tactor blades have worn, the starting switch should be dismounted,
and, if necessary, new blades should be inserted. To disassemble the
switch, proceed as follows: (1) Remove the spring 2265, Fig. 306, on
the switch case 2365; (2) remove the cotter pin from the collar 2416;
(3) withdraw the shaft and lever 2401, together with the spring
1818; (4) remove the three screws which hold the cover 2404 in place,
and remove the cover;
(5) remove the stop 2457;
and (6) disconnect the
spring 1813 from the arm
of the ratchet and re-
move the contactor mem-
If, upon inspection,
the contacts are found to
be in such a condition
that their renewal is nec-
essary, make a replace-
ment of the entire cover
member 2404 and the
entire contactor 2344.
Before placing these new
parts in the switch, the
following points should
receive careful attention:
the front edges of the contact blocks should be slightly rounded so
as to eliminate the possibility of these edges catching on each other
when the switch is being operated. The supports on the cover
must be adjusted so that they lie parallel with the faces of the
The upper surfaces of the supports must be .010 to .015 inch
lower than the contact surface of the block. Care should be taken
that the upper surface of the contact blocks are A inch above the
inner surface of the cover. A small steel straightedge laid upon
the face of the contact block and extended over the supports,
as shown in Fig. 307 (a), will serve as a means of checking these
up ft** this _ _//** t/r/s
Top+bbttom **+*/ mfstop
Fig. 307. Assembly of Starting Switch
Courtesy of North East Electric Company, Rochester, New York
ELECTRICAL EQUIPMENT 463
Before placing in service, the contact surfaces must be carefully
cleaned and lubricated with a very small quantity of vaseline. To
reassemble the switch: (1) Connect the spring 1813, Fig. 306, to the
arm of the ratchet; (2) place the contactor member 2344 in
the switch case in such a position that the ratchet will lie against the
pawl 1830; and (3) hold the switch case in the left hand, lever side up,
and insert the right forefinger through the hole in the switch case
and introduce the pawl into the first notch of the ratchet, Fig. 307 (6) ;
(4) hold these parts carefully in position and replace the cover 2404,
Fig. 306, fastening it to the switch case by means of the three screws;
(5) insert the stop through the hole in the switch case and replace it
upon the ratchet plate in such a position that the elongated portion
of the stop will lie between the raised projection which is found on
the ratchet plate and the end of the short lever on the pawl as shown in
Fig. 307 (c). It is very important that the stop be placed in the
switch right side up, Fig. 307 (d) illustrating the proper method of
doing this. (6) Place the spring on the shaft and replace the shaft in
the switch, taking care while entering the shaft not to disturb the
arrangement of any of the switch parts; (7) replace the collar and the
cotter pin; and (8) connect the spring 2265 with the lug on the switch
case. A drop of light oil should be applied to the bearing point at each
end of the switch shaft 2401.
Switch Tests. To determine whether the switch has been
assembled correctly, pull the lever through the full length of its stroke
and allow it to return slowly to its initial position. If the switch
is properly assembled, three distinct clicks will be heard while the lever
is being moved through its stroke, and a snap will occur just before
the lever comes back to its initial position. The switch should be
tested electrically, as follows:
Ground Test. Using the lamp-test set as shown in Fig. 263
and following Part V, hold one contact point on the switch case and
then connect the other to the two contact studs. The test lamp will
not light unless there is a ground.
Operation Test. Hold one of the test points in contact with each
of the two studs, and turn the lever through its stroke. If the switch
is in proper working condition, the test lamp will light up just after
the first click of the switch and continue to burn until the final
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Replacing Dodge Chain. When the driving chain on any equip-
ment operated in this manner has worn to a point where it no longer
makes proper contact with the sprockets (the chain being adjusted to
the correct tension), it will be necessary to replace it. While the
following instructions for "fishing" the chain through the housing
apply particularly to the Dodge car, with little modifications
here and there they will be found equally applicable to all similar
Having removed the old chain, pass a short piece of wire through
the end of the new chain, Fig. 308. Then start the chain on the
lower side of the sprocket, as shown in the illustration, hooking the
wire through the sprocket to keep the chain in mesh, and slowly turn
the engine over by hand until the chain appears at the top of the
sprocket. Then remove the wire from the sprocket, hold the end of
the chain, and continue to turn the engine over until the chain is in
v , a position to apply the
Mechanical and Elec-
When it is desired to
make bench tests of any
of the North East appa-
ratus with the aid of the
outfit described in connec-
tion with the Gray &
Davis tests, the data
shown in Table V will
be found valuable for
checking purposes. The
left-hand columns give
the mechanical charac-
teristics, w r ith the aid of
which the unit may be
JBkvf cfar/n #* 4m»w s/tfe of
r +/r**sre t*/tA MbtrAbro
era** ttnttf #MarcA0/rr axp+tfjns **
*y> ofJpr-ocAot. Aoiet +snF*f Vyfer/>r
^tpmsttUn tor a/p/jptny r
Fig. 308. — Diagram Showing Method of Inserting
Chain in North East Equipment on Dodge Cars
identified, while the right-hand columns give the electrical character-
istics, such as the charging rate, torque in foot-pounds with given
current input, cutting-in and cutting-out points of the master relay
(battery cut-out), air gaps for the limitation relay, and the resistance
of the units.
Digitized by VjOOQ 1C
Digitized by VjOOQU
in O U O Ui
ELECTRICAL EQUIPMENT 467
Six- Volt; Two-Unit; Single-Wire
Generator. Of the multipolar (four-pole) shunt-wound type
of generator combined with ignition timer and distributor and
designed to be driven at 1^ times crankshaft speed, several models
are made, of which one is shown in Fig. 309. In this case, both the
regulator for the generator and the battery cut-out are mounted
directly on the generator. On some of the models only the regu-
lator is so mounted, the cut-out being placed on the dash of the car,
while on others no
lating device is
required as the
of regulation is
employed (on bi-
with the model of
generator and the
requirements Of p ig 309 R emy Ignition Generator and Distributor
the e n ff i n e tO Courtesy of Remy Electric Company, Anderson, Indiana
which it is to be fitted, either the constant-voltage method of
regulation using a vibrating regulator mounted on the generator
or the third-brush method is employed.
Constant-Voltage Method. The regulator for the generator is
similar in principle to that described in connection with the Bijur
system. It consists of an electromagnet; two sets of contact points,
two of which are mounted on springs; a pivoted armature which may
move to make or break the circuit; and a resistance unit. When
running at too slow a speed to produce its maximum output, the
generator field is supplied with current passing directly through the
regulator contact points, which are held together by a spring. As
soon, however, as the speed of the generator increases to a point
where it tends to cause its output to exceed the predetermined
maximum, the charging current which is flowing through the coil
of the electromagnet energizes it so such an extent as to cause it to
468 ELECTRICAL EQUIPMENT
pull the armature down. This separates the contacts and causes
the field current to pass through the resistance unit, thus decreasing
the field current and, in turning, decreasing the generator output,
which reduces the exciting effect on the electromagnet and causes
it to release its armature, cutting the resistance out of the field cir-
cuit. The latter immediately builds up again, and the operation is
repeated as long as the speed remains excessive for the generator,
which is thus supplied with a pulsating current to excite its fields,
and its output is held at a practically constant value.
ThirdrBrush Method. The third-brush method of regulation is
based upon the distortion of the magnetic field of a generator at
high speeds. When running at low speeds, the magnetic flux of a
generator is evenly distributed along the faces of its field pole pieces,
but at high speeds there is a tendency to drag it out of line in the
direction of the rotation of the armature. It is then said to be
distorted. The third brush, which supplies the exciting current to
the field winding, is so located with relation to the main-line brush
of opposite polarity that this distortion of the magnetic flux reduces
the current which it supplies to the fields. This decrease in the
exciting current of the field causes a corresponding decrease in
the output of the generator, and as the distortion of the magnetic flux
is proportional to the increase in speed, the generator output falls
off rapidly the faster it is driven above a certain point, so that it is
not damaged when the automobile engine is raced.
Thermostatic Sivitch. More of the current produced by the
generator is used for lighting purposes in winter than in summer/ in
the proportion that the demands for house lighting vary with the
change of the seasons. Added to the decreased efficiency of the stor-
age battery in cold weather, this tends to place a greatly increased
load on the generator in the winter months. If the generator, as
installed, were regulated to produce sufficient current to take care of
this maximum demand, it would keep the storage battery in a con-
stant state of overcharge in summer and would be likely to ruin the
plates through excessive gassing. The Remy engineers have accord-
ingly developed a method of regulation that will automatically com-
pensate for the difference in the demand with the changing seasons,
consisting of a thermostatic switch in connection with the third-brush
control; it will be found, among others, on the Reo 1917 models.
Digitized by VjOOQIC
To gain a clear idea of the action of an electric thermostat, the
heating effect of the current must be kept in mind; also that different
metals have different coefficients of expansion, i.e., some will expand
more than others under the influence of the same degree of h£at.
Electric thermostats have been
in use for years as automatic
fire alarms and as temperature-
controlling devices in incubators
and for residence heating, and
within the past few years they
have come into use on the auto-
mobile to control the circulation ^
of the cooling water and the f c c f \ II
suction of the engine in accord- ^^^^ST^^S^^/ ^^^^Ly
ance with variations in thetem- ' C E y
Details of Remy Thermostatic
ance with variations in the tem-
perature. The device consists
of a thermal member, or blade, of
two different metals riveted together at their ends. This member is
held fast at one end and at the other it carries a contact point,
designed to complete the circuit by touching a stationary contact.
Under the influence of an increase in temperature, one of the metals
Fig. 311. Wiring Diagram of Switch Connections
expands more than the other and thus springs this member, or blade,
away from the stationary contact.
The details of the Remy thermostat are shown in Fig. 310. B is
the thermo-member carrying the silver contact C, and is supported on
470 ELECTRICAL EQUIPMENT
a strip of steel A. A also carries the resistance unit E, which is a
short coil of high-resistance wire wound on heavy mica insulation.
A and B are riveted together at the end D so as to insulate them from
each other. The two metals composing B are spring brass and nickel
steel, the strip of spring brass being placed on the lower side of
the blade. Sufficient tension is placed on this strip, by means of the
adjusting nut F, to keep the points firmly in contact at temperatures
below 150° F. This adjustment is made by the manufacturer and is
As shown in the* wiring diagram, Fig. 311, which illustrates the
relation of the thermo-switch to the third-brush method of regulation,
it will be noticed that the switch is placed near the commutator of the
generator, as that is the hottest part of the machine when it is in
■ fs-om generator- 6ru*h
* 7a fe*r+r*rft>r /re/a*
. J^ojtt generator SrusA
Fig. 312. Photographic Reproductions and Diagrams of Action of Thermostatic Switch
When Closed and Opened
Courteey of Rerny Electric Company, Anderson, Indiana
operation. It will be noticed also that when the contact points of the
thermo-switch are open, as shown in the illustration, the current
supplied to the field by the third brush must pass through the resist-
ance unit of the switch, thus cutting it down. This is the position
for warm-weather running, when not so much of the current is required
for lighting, and when the storage battery is at its best. When the
temperature of the air about the thermo-switch exceeds 150° F., the
movable blade is warped upward, owing to the greater coefficient of
expansion of the brass as compared with that of the nickel steel. The
contact points will accordingly remain open as long as the temperature
exceeds this degree. When it falls below that point, the quicker
contraction of the brass pulls the blade down, and the points again
make contact, cutting out the resistance and increasing the output
Digitized by VjOOQIC
of the generator, diagrams of the thermo-switch in its closed and open
positions being shown at the right, and a halftone of the switch at the
left in Fig. 312, while the curves, Fig. 313, show the increase in the
current output brought about by the closing of the thermo-switch
points. The path taken by the current when the points are open and
when they are closed is
indicated by the dotted
lines in the diagrams, Fig.
312. The curves show
that with the thermo-
switch open, the maxi-
mum current output of
the generator is limited
to 14 to 15 amperes,
while with the switch
closed it rises tO 20 tO ^** ^ 1 ^' O ut P ut Curves of Remy Patented Generator
22 amperes. The switch will normally remain closed after the engine
has been idle for any length of time; but in summer it will open after
driving a few miles, while in winter it will probably remain closed,
no matter how much the car is driven.
Starting Motor. The motor is the 6-volt 4-pole series-wound
type, illustrated in Fig. 314, mounted either with gear reduction
Fig. 314. Remy Starting Motor with Outboard Type Bendix Pinion
and over-running clutch, or with automatically engaging pinion for
direct engagement with flywheel gear, as described in connection
with the Auto-Lite. The latter is known as the Bendix gear. The
control is by independent switch.
Instruments and Protective Devices. An indicator, or telltale,
shows when the battery is charging or discharging, and also serves
472 ELECTRICAL EQUIPMENT
to indicate any discharge, in all except the starting-motor circuit,
due to grounds or short-circuits. All lamp circuits are fused, and a
fuse is inserted in the regulator circuit.
A Mechanical Combination. While termed a single-unit type,
this is actually two independent units combined, mechanically and not
electrically, so that it bears no resemblance to the single unit on which
both field and armature windings are carried on the same pole pieces
and armature core. The field frame for the two units is a single
casting, Fig. 315, but the
magnetic circuits of both
the generator and the motor
are entirely independent, and
each is a separate unit. They
are combined in this manner
solely for convenience in
mounting where space is
limited. The vibrating type
of voltage regulator is em-
ployed in connection with
the generator, while the start-
ing motor operates through
a train of reducing gears
and an over-running clutch.
Apart from the combination
of the two units and the
Fig. 315. Combined Field Frame of Generator method of Starting drive
and Motor for Remy Single-Unit System wh j ch ^ ent& fts f the Sys-
tem is the same in its essentials as where the units are mounted
Wiring Diagrams. Velie. Fig. 316 shows the installation on
Velie, Model 22, and the details will be plain with further explanation.
The "ratchet reversing switch", shown in the diagram, is for
controlling the ignition current, and it is designed to reverse the
direction of this current each time the switch is turned on in order to
prevent the formation of a crater and cone on the ignition interrupter
contacts, as previously described, thus keeping the points in good work-
Digitized by VjOOQIC
PLATE tfr— WESTIHOHOUSE WIRING DIAGRAM FOR LOCOMOBILE ltlf
ELECTRICAL EQUIPMENT 473
474 ELECTRICAL EQUIPMENT
ing order for a much longer period. The dash and tail lights are 3J-
volt lamps, wired in series, so that the failure of one puts the other out,
thus giving an indication at the dash of the failure of the tail light.
Oakland. The Remy installation on Oakland Model 32 is
shown in Fig. 317. The chief distinction between this and the pre-
vious diagram is the employment of a single 10-ampere fuse on the
ligEting circuits instead of independent fuses on each circuit.
"Breaker box" refers to the ignition-circuit contact-breaker, or
interrupter, as it is variously termed. The starting motor in this
case is fitted with the Bendix drive.
Reo. On the Reo installation, Fig. 318, the starting motor is
mounted on the transmission housing and drives to a shaft of the
latter through a worm gear. In this case the starting switch is
mounted directly on the starting motor, and an ammeter is supplied
on the charging circuit instead of a telltale/ or indicator.
National. A typical installation of the single unit, or so-called
double-deck unit, is shown in Fig. 319. This is on the National
six-cylinder model and is a two-wire system. It is not intercon-
nected with the ignition system, so there are no ground connections,
and no fuses are employed.
Instructions. These instructions cover the systems which
include the ignition. For instructions applying to the double-wire
system on cars having an entirely independent ignition system, like
the National, see instructions under Auto-Lite, Delco, Gray &
Davis, and others, for failure of generator or motor, short-circuits,
and the like.
Battery Discharge. In systems of this type, discharge of the
battery may be due to failure to open the ignition switch after
stopping the car. The amount of current consumed is small but
in time it will run the battery down. The indicator or the ammeter,
according to which is fitted, will show a discharge. An entire fail-
ure of the current may indicate: a loose connection at battery ter-
minals, at battery side of starting switch in connection with a blown
main fuse (Oakland), or a loose battery ground connection; a loose
connection at motor side of starting switch or at starting motor,
or a broken wire between the switches. (See previous instructions
on other makes for testing with lamp set for broken or grounded
Digitized by VjOOQ U
Digitized by VjOOQIC _
ELECTRICAL EQUIPMENT 475
| ' UJ
/ ~ i
\ g ~
478 ELLCTRICAL EQUIPMENT
Failure of Lighting, Ignition, Starting. When the lights and
ignition fail but the starting motor operates, it indicates a short
or open circuit between the starting switch and the main fuse (Oak-
land). This fuse should first be examined and, if blown, a search
should be made for the ground or short-circuit causing it, before
putting in a new fuse. The fault will be in the wiring between the
switch, lights, and ignition distributor. See that all connection^
including those on fuse block, are tight. When the lights fail buv
the ignition and starting motor operate, the trouble will be found
either in the circuits between the lighting switch and lamps; in the
lamps themselves, as a burned-out bulb causes a short-circuit; or
from loose connections in these circuits. Failure of the ignition,
with the remainder of the system operating, may be traced to loose
connections at the ignition switch, coil, or distributor; poor ground
ing of the ignition switch on the speedometer support screw; or tu
open or short-circuits between the igniti6n switch and the distributor.
Further detail instructions on ignition are given in Ignition, Part II.
Dim Lights. When all the lights burn dimly, the most prob-
able cause is the battery, but if a test shows this to be properly
charged, a ground between the battery and the starting switch or
between the latter and the generator may be responsible for leakage.
Other causes are the use of higher candle-power lamps than those
specified, the use of low efficiency carbon-filament bulbs, or failure
of the generator to charge properly.
Examine generator-field fuse and if blown, look for short-
circuits before replacing, as previously instructed. A simple test of
the generator may be made by switching on all the lights with the
engine standing. Start the engine and run at a speed equivalent
to 15 miles per hour or over. If the lights then brighten percepti-
bly, the generator is operating properly. This test must be made
in the garage or preferably at night, as the difference would not be
sufficiently noticeable in daylight.
If the generator fuse is intact, examine the regulator relay con-
tacts. If the points are stuck together, open by releasing the relay
blade with the finger. Clean and true up points as previously
instructed and clean out all dust or dirt from relay before replacing
cover. Particles of dirt lodged between the points will prevent
the generator from charging properly.
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Digitized by VjOOQIC
Digitized by "
ELECTRICAL EQUIPMENT 479
The failure, flickering, or dim burning of any single lamp will
be due to a burned-out bulb, to loose or frayed connections at lamp
or switch, to a bulb loose in its socket, or to an intermittent ground
or short-circuit in the wiring of that particular lamp, or to the frame
of the lamp nor being grounded properly. Where dash and tail
lamps are in series, examine both bulbs and replace the one that
has burned out. Test with two dry cells connected in series.
Ammeter. When the indicator, or ammeter, does not register a
charge with the engine running with all the lights out, stop the engine
and switch on the lights. If the instrument gives no discharge
reading, it is faulty. If it shows a discharge, the trouble is in the
generator or connections. In case the ammeter registers a discharge
with all the lights off, ignition switch open, and engine idle, examine
relay contacts to see if they remain closed. If not, disconnect the
battery. This should cause the ammeter hand to return to zero; if
it does not, the instrument is out of adjustment. With the ammeter,
or indicator, working properly, and the relay contacts in good con-
dition, a discharge then indicates a ground or short-circuit. When
examining the relay for trouble, do not change the adjustment of
the relay blade.
Twelve- Volt; Single-Unit; Single-Wire
Dynamotor. The dynamotor is of the multipolar type having
six poles, as illustrated in Fig. 320, which shows the field frame, coils,
and poles. Fig. 322 illustrates the assembled brush rigging, while
Fig. 321 shows the complete unit with the commutator housing plates
Regulation. Regulation is by reversed series field, in connection
with a combination cut-out and regulator. The regulator is of the
constant-potential type and is combined with the battery cut-out.
It is connected in circuit with the shunt field of the generator, and the
vibrating contacts of the regulator cut extra resistance into this circuit
when the speed exceeds the normal generating rate. There is also
a differential compound winding of the fields, the two halves of which
oppose each other at high speeds.
Instruments. An ammeter is supplied, showing charge and
480 ELECTRICAL EQUIPMENT
Dynamotor Connections* The dynamotor has two connections,
one at the bottom of the forward end plate, marked DYN+, and
the other on top of the field yoke designated as FILED. As the
system is a single-wire type, the opposite sides of both circuits are
grounded within the machine itself. The terminals on the cut-
out are marked BAT+, DYN+, and DYN-, BAT-, and FLD.
Fig. 320. Field Frame. Poles, and Windings Fig. 321. Brush Rigging for
for Simms-Huff Dynamotor Simms-Huff Dynamotor
Fig. 322. Simms-Huff Dynamotor with Commutator Housing
Courtesy of Simms Magneto Company, East Orange, New Jersey
BAT+ connects through a 12-gage wire to the negative side of the
ammeter and thence to a terminal on the starting switch. This con-
nects it permanently to +R of the battery through the ammeter.
This wire supplies the current to the distributing panel, from which
current is supplied to the lamps and horn. DYN + connects through
a similar wire to the plus terminal of the dynamo, while DYN— and
n-j-r* T I
Fig. 323. Wiring Diagram for Simme-Huff Starting and Lighting Sys^ms
BAT— connect with the — L terminal of the storage battery through
a wire of the same size.
Change of Voltage. The system is known as 6 — 12-volt type,
signifying that the current is generated at 6 volts, but is employed for
482 ELECTRICAL EQUIPMENT
starting at 12 volts. There are accordingly 6 cells in the storage
battery, and the latter is charged by placing the two halves of it,
consisting of two 3-cell units, in parallel. This is indicated in the
R/G//T HEAD L/JrtP
LEFT HEPD LAMP
Fig. 324a. Complete Wiring Diagram for 1916-17 Maxwell Cars (see Fig. 324b)
«■ Courtesy of Simms Magneto Company, East Orange, New Jersey
upper diagram, Fig. 323, also in the middle diagram, which shows the
connections for charging. In the lower diagram of the figure are
shown the starting connections, the switch being connected to throw
the 6 cells of the battery in series, so that the unit receives current at
ELECTRICAL EQUIPMENT 483
12 volts for starting, thus doubling its power. Six-volt lamps are
employed and are supplied with current from the left-hand section of
the battery, marked 1, as shown in the upper part of the diagram.
Fig. 324b. Complete Wiring Diagram for 1916-17 Maxwell Care, Showing Details of Dash
Panel and Batteries
Courtesy of Simms Magneto Company, East Orange, New Jersey
Starting Switch. This is mounted on the left side of the gear-
box housing (Maxwell) and is so arranged as to connect the entire
battery in series for starting, thus giving current at 12 volts for this
purpose. The same movement of the starting switch also puts the
484 ELECTRICAL EQUIPMENT
battery in circuit with the ignition system so that, as soon as the
engine starts and the switch is released, it automatically disconnects
the battery from the ignition, and the engine then runs on the magneto
(dual ignition system).
Wiring Diagram. Fig. 324a and Fig. 3246 show the wiring
diagram complete of the ignition, starting, and lighting systems as
installed on the 1916 and 1917 Maxwell cars. The heavy lines indicate
the starting-system connections, while the light lines are the wires
leading from the generator to the battery (through the regulator and
cut-out), and the various connections for the ignition and the lamps.
They show very plainly, upon tracing them out, the relation of the
regulator and cut-out to the generator and the battery, as well as the
method of dividing the six cells of the battery into two units for light-
ing service, and the coupling of all the cells in series for starting. It
will be noted also that the storage battery is not utilized for ignition,
as the starting switch closes the circuit of a dry battery of four cells
for ignition when starting the engine. As the starting switch auto-
matically opens this circuit when released, there is no danger of this
battery being inadvertently left in circuit.
At the upper left-hand corner of the diagram, complete details of
the ignition circuit and of the magneto itself are shown. The
magneto (Simms) is of the true high-tension type, having primary
and secondary windings on the armature core, as well as a condenser
incorporated in it. As this sketch shows not only the relation of high-
tension type of magneto to the plugs but also that of the essential
parts of the magneto, as well as the relation of the ignition system to
the starting and lighting systems through the combination starting
and ignition switch, it will repay close study. The number of wires
makes it appear as if this were a two-wire system, but upon noting
the ground connections at the various terminals it will be evident
that it is not.
Instructions. The Simms-Huff system as above described is
standard equipment on the Maxwell cars. The combination cut-
out and regulator is mounted on the rear of the dash panel carrying
the ammeter and switch. It consists of two distinct devices, the
cut-out serving the usual purpose of protecting the battery when
the generator voltage drops, and the regulator limiting the current
output of the dynamo as the engine speed increases. In connection
Simma-Huff Ignition, Starting, and Lighting Installation on Maxwell 1918 Cars
Courtesy of Maxwell Motor Company, Detroit, Michigan
Digitized by VjOOQIC
Wiring Diagram for Simms-Huf! Starting and Lighting Installation on Maxwell 1918 Cara
Courtesy of Maxwell Motor Company, Detroit, Michigan
ELECTRICAL EQUIPMENT 485
with it a special regulator switch is provided. This is located on
the right side of the dash panel and has two positions, HIGH
and IX)W, the latter inserting additional resistance in the field
circuit of the dynamo to further limit its output when the car is
driven steadily at high speed on long runs. This switch is kept in
the HIGH position for all ordinary driving and only shifted to
LOW as above mentioned.
Failure of Cut-Out or of Regulator. Should the ammeter pointer
go to the limit of its travel on the discharge side, this indicates that
the cut-out contact points have failed to release on the slowing
down of the generator. The latter also will continue to run as a
motor after the engine is stopped. Disconnect the two wires from
the terminals on the generator and wrap them with friction tape
to prevent their coming in contact with any metal parts of the car.
Clean and true up contact points as outlined in previous instruc-
tions. An unusually high reading on the charge side of the ammeter
will, indicate a failure of the regulator to work. If an inspection
shows no sign of broken or crossed wires, loose connections, or other
obvious trouble, the manufacturers recommend that the unit be sent
to them. In the case of the owner, it is recommended that no
attempt be made to correct faults in the cut-out or in the regulator,
but that it be referred to the maker of the device or to the nearest
Generator Tests. To determine whether a short-circuit or a
ground exists in the brush holder, pull up all the brushes and with the
aid of the lamp-test set, test by applying one end to the frame and
the other to the main terminal post. The lamp will light if there is a
short-circuit or a ground between the brush holder and the frame.
A similar test may be made for the armature by pulling up all the
brushes (or heavy paper may be inserted between them and the com-
mutator) and placing one point on the commutator and the other on
the shaft. The lighting of the lamp will indicate that the armature is
grounded. In all tests of this nature where the lamp does not light
at the first contact, it should not be taken for granted at once that
there is no fault. Touch various parts of both members on clean
bright metal. See that the points of the test set are clean, that
the lamp filament has not been broken, and that the lamp itself has
not become unscrewed sufficiently to break the circuit between it and
486 ELECTRICAL EQUIPMENT
the socket. A good rule is always to test the lamp itself first; some-
times the connecting plug of the set is not properly screwed into the
While the above test for the armature, if properly carried out, will
show whether the latter is grounded or not, it will not give any indi-
cation of an internal short-circuit in the armature itself. To deter-
mine this, connect the shunt fields and run the unit idle as a motor,
with the portable ammeter in the circuit, using the 30-ampere shunt.
While running without any load the motor should not consume more
than 7 amperes at 6 volts, i.e., using half the battery. Tests for
grounds in the shunt field may be made with the lamp-test set, but to
determine whether there is a short-circuit in the field, it is necessary
to measure the resistance of its windings. If there is neither a short-
circuit nor a ground in the field, the resistance of the windings should
calculate approximately 6£ ohms on units with serial numbers up to
27,000, and approximately 4.8 ohms on starters above this serial
The Simms-Huff is one of the very few, if not the only unit, that
is belt-driven as a generator. Its normal output is 10 to 15
amperes; so when the dash ammeter shows any falling off in this
rate, with the engine running at the proper speed to give the
maximum charging current, the belt drive of the generator should be
inspected. If* the a'tameter reading falls off as the engine speed
increases, it is a certain indication that the belt is slipping and that
the generator itself is not being driven fast enough. Adjust the
tension of the belt and test again. If this does not increase the output
to normal, inspect the commutator and brushes, brush connections
and springs, etc. See that the brushes have not worn down too far,
and if necessary, sand-in. Failing improvement from any of these
expedients, inspect the regulator. This should not be adjusted to give
more current until every other possible cause has been eliminated;
and before making any change in the adjustment of the contacts, see
if cleaning and truing them up will not remedy the trouble. If
necessary to adjust, do so very carefully, as increasing the current
output by this means will also increase the voltage, and if the voltage
exceeds the normal by any substantial percentage, all the lamps will
be burned out at once. Trouble in the electrical unit itself will be
most likely to appear in the brush holder.
ELECTRICAL EQUIPMENT 487
Whenever it is necessary to remove the front end plate over the
commutator to inspect the commutator or the brushes, be sure that
this plate is put back the same way, and not accidentally turned round
a sixth of a revolution, which would cause the motor to run backward.
There is a slot in the front end of this plate to permit the brush holder
to be moved backward or forward so as to give the best brush setting
as a generator and as a motor. On most of the Simms-Huff units, a
chisel mark will be found on each side of the fiber insulator under the
main terminal post, indicating the factory brush setting. Checking
this brush setting should be one of the further tests undertaken before
resorting to adjustment of the regulator. To do this, connect the
portable ammeter in the charging circuit (30-ampere shunt) or, if
one of these instruments is not available, the dash ammeter may be
Run the engine at a speed high enough for the maximum normal
output; loosen the brush holder and move very slowly backward and
forward, meanwhile noting the effect on the reading of the ammeter;
and mark the point at which the best output is obtained. To test
as a motor, connect the ammeter in circuit with half of the battery
and run idle. Move brush holder backward or forward to obtain best
setting point, as shown by the ammeter reading, which, in this case,
will be the minimum instead of the maximum. The unit should not
draw more than 7 amperes when tested in this manner. If the best
points for generating and running as a motor, as shown by these tests,
are separated by any considerable distance, a compromise must be
effected by placing the brush holder midway between them. If the
dash ammeter does not appear to be correct, check it with the portable
instrument or with another dash ammeter.
Twelve— Six- Volt; Single-Unit; Two-Wire
Dynamotor. Both windings are connected to the same com-
mutator on the dynamotor, which is of the bipolar type.
Wiring Diagram. As the lamps are run on 6 volts, the 6-cell
battery is connected as two units of 3 cells each for lighting, and these
units are connected in series-parallel for charging, as the dynamotor
produces current at 6 volts. The remaining details of the connections
will be clear in the wiring diagram, Fig. 325.
Control. Switch. The starting switch is mounted on the
starting motor. This switch automatically breaks the circuit as
soon as the engine starts. The starting gear slides on spiral splines
on the armature shaft, so that when the engine gear over-runs it,
the starting gear is forced out of engagement. This gear is connected
to a drive rod which also engages a switch rod, so that when the
gear is forced out of mesh with the flywheel, it carries the switch
rod with it and automatically opens the circuit. The switch contacts
cannot stick, and no damage can result from holding down the switch
pedal after the engine has started.
Regulation. On the earlier models, a vibrating regulator was
built in the generator, as illustrated in the section on Constant-
ELECTRICAL EQUIPMENT 489
Potential Generators, but in later models an external regulator com-
bined with the battery cut-out is employed. This is a constant
voltage control of the vibrating type, similar to that described in detail
in connection with the Bijur system, i.e., an electromagnet operating
two spring-mounted armatures carrying contacts.
Instructions. Should a discharge of 3 amperes or more be indi-
cated on the ammeter when the engine is idle and all lights are off,
this can be eliminated by slightly increasing the tension of the spring
at the rear end of the cut-in armature.
Too great an increase in the tension of this spring will cause the
cut-in, or charging point, to be raised too high, as indicated by
the ammeter, which should
be noted when making the
The voltage regulator
as set at the factory is
adjusted to limit the output
of the generator to from 7
to 10 amperes. Should it be
necessary to increase this
for winter running or for .KJKKi
any other reason, it may Newark ' Nexo Jeraey
be done by increasing the tension of the spring armature. The
amount of movement of the adjusting screw at the rear end of the
armature that is necessary will be indicated by the reading of
the ammeter. The passage of current at the regulating contacts,
which are in constant vibration while the engine is running above a
certain speed, tends to roughen them. In time this may affect the
charging rate and cause the points to stick together, which will be
indicated by the ammeter showing a permanent increase in the charg-
ing rate. If the latter becomes excessive, the cover of the regulator
should be removed, and a thin dental file passed between the contacts
on the stationary screw R, Fig. 326, and the movable contact on the
regulating armature until both become smooth. In case it is neces-
sary to remove the contact screw R for the purpose of smoothing its
point, be sure to replace it at the same position, taking care that the
ammeter reading does not exceed 7 to 10 amperes and that the lock-
nut N is fastened securely. Under ordinary conditions, these con-
490 ELECTRICAL EQUIPMENT
tacts should not require attention on an average oftener than once
a year, but it would be well to examine them occasionally.
Fig. 327. Wiring Diagram of Splitdorf Lighting Generator and VR Regulator
By referring to Fig. 327, which is a diagram of the wiring of the
generator and battery, the relation of these essentials to the regulator
and cut-out are made clear. The field fuse shown on this diagram is
ELECTRICAL EQUIPMENT 491
also indicated at F in Fig. 326. This fuse is a small piece of soft-alloy
wire mounted between the post F and the contact-breaker. By
referring to the wiring diagram, it will be noted that this fuse is in the
shunt-field circuit, so that if it has been blown, the machine will not
generate. It is designed to blow only at high speed with the battery
off the line and the vibrator contact R stuck. In actual practice,
the regulator cut-out is mounted directly on the generator itself.
The colors mentioned alongside the different w T ires are for purposes of
identification so that there will be no mistakes in making the
Starting Motor. The starting motor is of the series-wound type
and is similar in design to the generator. It is supplied with a Bendix
drive as shown in Fig. 328.
The starting motor has been designed so that when the oper-
ator pushes a foot pedal or pulls a lever, a gear is carried into mesh
Fig. 328. Splitdorf SU Starting Motor
Courtesy of Splitdorf Electric Company, Newark, New Jersey
with a ring gear on the flywheel, and when the engagement is made,
current is supplied to the motor. The gear is movably carried on the
armature shaft by spiral splines. These splines tend to hold the gear
in mesh while the engine is being cranked. As soon as the engine
picks up, it turns faster than the motor pinion which is operated with
the flywheel, and on account of the spiral splines the pinion is forced
out of mesh with the gear on the flywheel. The gear, while being
"drivingly" mounted on the armature shaft, is also mechanically
connected to a connecting rod, which, as will be noted from the
illustration, protrudes from the commutator end of the motor.
The feature of this construction is, that no matter how long the
operator may hold his foot on the starting pedal, the current is broken
when the engine starts, as in the manner previously described. The
492 ELECTRICAL EQUIPMENT
amount of current actually required for turning over the engine is
thus controlled by the engine itself, and on account of the positive
connection between one element of the switch and the starting
gear, all possibility of the jaws of the starting switch sticking is
Instructions. Apart from the special adjustments of the starting
switch, as mentioned in the description of its operation, the instruc-
tions for maintenance are the same as those for other systems. In
case this switch does not operate properly, the sequence of operations
as mentioned should be checked up, and the distances given verified.
In case these distances have become greater through wear, they
should be adjusted. To replace the brushes, remove the cover strap
over the commutator end of the unit, either generator or motor,
put the two screws holding the rocker disc in place, disconnect the
brush leads, and withdraw the brushes from the holders. It is
important that the brushes slide freely in the holders and that the
brush-lead terminals are clean and bright before replacing the
terminal screws. See that the springs rest fairly on the ends of the
brushes and that their tension has not weakened. Follow instructions
given in connection with other systems for care of the commutator.
Failure of Engine to Start. When the starting motor cranks the
engine after the starting pedal is depressed but fails to start the engine
after a reasonable time, release the starting pedal and ascertain the
cause, which may be due to the following: Ignition off, lack of fuel,
fuel supply choked, cylinders needing priming due to weather con-
ditions, or cylinders flooded from too much priming.
Should the starting motor fail to crank the engine when the
starting pedal is fully depressed, there is a possibility that the battery
is run down (which condition will be indicated by an excessive dim-
ming of the lights), that there is a loose connection in the starting
circuit, or that the starting switch is not making proper contact.
The various tests previously given will probably take care of all
Oiling of Starting Motor. The starting motor should be oiled
once every 500 miles with any medium high-grade oil by applying oil
to the cups, switch rods, guide rods, and pawl; also on the compensat-
ing device. Starting motors equipped with the Bendix drive are
fitted with oil cups at each end of the unit.
ELECTRICAL EQUIPMENT 49S
Twenty-Four— Twelve- Volt, and Twelve— Six- Volt;
Variations. The 24 — 12- volt signifies that the starting voltage
is 24 and the generating voltage 12, the battery of twelve cells being
divided into two groups of six each in series-parallel for charging,
while 12 — 6 signifies that the starting voltage is 12 and the generat-
ing voltage 6, the 6-cell battery being divided in the same manner.
The foregoing systems will be found on cars prior to, and includ-
ing, 1915 models. For 1916 and 1917 models, a 12 — 12-volt system
of the same single-unit two-wire type is standard. In this system the
complete battery is used for the lighting as well as the starting, so
that charging, lighting, and starting are all at the same voltage, using
the complete battery of 6 cells for both of the former.
Generator-Starting Motor. The machine is multipolar (either
six or eight poles) and is designed to take the place of the flywheel of
Fig. 329. Details of U.S.L. Flywheel Type Dynamotor with Outside Armature
Courtesy of U. S. Light and Heat Corporation, Niagara Falls, New York
the engine. All but the 12 — 6- volt equipments are made with an
outside armature, Fig. 329, i.e., the armature revolving outside of the
field poles which it encloses; and the 12 — 6- volt with an inside arma-
ture, Fig. 330. As the armature is mounted directly on the end of the
crankshaft, the drive is direct at engine speed whether charging or
One of the advantages of this type of machine, owing to its large
size, is its ability to generate an amount of current far in excess of any
ordinary requirement. This permits the employment in the inher-
U.S.L. Inside Armature Type Dynamotor
ently regulated type of only three brushes, Fig. 331, when the unit is
running as a generator, while all the brushes are employed when it
operates as a starting motor. In the types equipped with an external
regulator, all the brushes are employed
for generating as well as for starting.
Regulation. The 24— 12-voltunit
in the U.S.L. system is made with two
types of regulation, one type using an
external regulator, which is usually
mounted on the dash, and the other
of the inherent type. The 12 — 6-volt
type has an external regulator. These
two types may be distinguished
by the presence of the regulator
in the charging circuit, which, how-
ever, must not be confused with the
automatic switch, or battery cut-
out, which is only employed on the inherently regulated type. The
details of the regulator are shown in Fig. 332, and it will be noted that
the regulator also incorporates the battery cut-out as well as an indi-
cating pointer which shows whether the regulator is working properly
or not. In operation, the regulator cuts into the generator field
3 Generating Brushes
Fig. 331. Location of Generating
Brushes in U.S.L. Dynamotor
ELECTRICAL EQUIPMENT 495
circuit a variable resistance consisting of an adjustable carbon pile.
The connections of the regulator are shown in the ^wiring diagrams.
The regulation of the U.S.L. inherent type is accomplished by
the combination of a Gramme ring armature, a special arrangement
of connections and of the field windings, and the use of only a part of
the armature and fields for generating. This method is, of course,
special on this make and could not be used on other types of construc-
tion. The regulation obtained is based on armature reaction and is
similar to that resulting from the third-brush method, but the machine
Lower Adjusting Plug
Fig. 332. External Regulator of the U.S.L. System
Courtesy of U. S. Light and Heat Corporation, Niagara Falls, New York
reaches its maximum output at a lower speed than would be possible
with the third-brush method and without the employment of a
special brush for the purpose.
.Instruments and Protective Devices. In addition to the indi-
cator, which is combined with the external regulator in the U.S.L. type,
an ammeter is also employed to show the rate of charge and discharge.
Two fuses, mounted in clips on the base which holds the bat-
tery cut-out, or automatic switch, protect all the circuits. The
smaller of these is a 6-ampere fuse and is in the field circuit of
t the generator, while the larger is a 30-ampere switch and is in the
generator charging circuit. This applies only to those inherently
regulated equipments fitted with a special type of automatic switch.
496 ELECTRICAL EQUIPMENT
. Wiring Diagrams. Figs. 333, 334, and 335 show the standard
wiring diagrams of the three types mentioned, being, respectively,
the 24 — 12-volt externally regulated type, the 12 — 6-volt external
regulator and internal-armature type, and the 24 — 12-volt inher-
ently regulated type. In the diagram proper of each of the 24 —
12-volt types is indicated the layout for using 7-volt lamps, while the
extra diagram at the side shows the method of connecting for 14- volt
lamps. The "touring switch" shown on the first two diagrams
is a hand-operated switch in the charging circuit and is designed to
prevent overcharging of the battery when on long day runs. The
inherently regulated type requires very little field current, and on
most of these the touring switch is of the miniature push-button type,
like a lighting switch.
Instructions. Touring Switch. On the types equipped with
the touring switch, this enables the driver to control the charge.
Pulling out the button closes the switch and permits the generator
to charge the battery when the engine reaches the proper speed;
pushing it in opens the circuit. This switch must always be closed
before starting the engine, and it must be kept closed whenever
the lights are on and also under average city driving conditions
where stops are frequent and but little driving is done at speed.
When touring, the switch should be closed for an hour or two and
then allowed to remain open during the remainder of the day, as
this is sufficient to keep the battery charged, and there is no need
for further charging until the lamps are lighted. The best indication
of the necessity for opening the touring switch is the state of charge
as shown by the hydrometer. The driver should not start on a long
day's run with the battery almost fully charged, without first opening
the touring switch, as the unnecessary charging will overheat the
battery. This switch should be inspected at least once a season.
Push in the button to open the circuits, remove the screw at the back
and take off the cover. The switch fingers should be bright and
make good contact with the contact block; if they do not do so,
remove and clean them, as well as the contact pieces on the block.
Do not allow tools or other metal to come in contact with the
switch parts during the operation, for even though the switch is
open, a short-circuit may result; then one of the fuses will blow.
In replacing the fingers, bend sufficiently to make good firm contact.
ELECTRICAL EQUIPMENT 497
/ VOlT iAMPS
Fig. 333. Wiring Diagram for 24 — 12-Volt External Regulator Type, I'.S.L. System
Fig. 334. Wiring Diagram for 12— 6- Volt External Regulator Type, U.S.L. System
Digitized by VjOOQIC J
ELECTRICAL EQUIPMENT 499
1 4- Volt Lamps 7- Volt Lamps
Fig. 335. Wiring Diagram for 24— 12-Volt Inherently Regulated Type, U.S.L. System
500 ELECTRICAL EQUIPMENT
Starting Switch. The starting switch is filled with oil, and this
should be renewed once a year. To do this, the switch must be
disconnected, and the screws A, Fig. 336, removed; in case the box
sticks, insert a screwdriver point between the top of the box and the
bottom of the frame and pry loose. To guard against the switch
dropping when these screws are removed, hold the hand beneath it
while taking them out. Before attempting to remove the switch,
disconnect the positive battery connections B1+ and B2+ at the
battery as shown in. Fig. 335. These are the two main terminals in
the center. It is unnecessary to tape them, as a short-circuit cannot
occur. Pour out the old oil, clean out thoroughly with gasoline,
allow to dry, and refill with transformer oil or light motor oil to the
proper level with the switch box standing plumb. The proper height
on the Type E-2 or E-3 box is If inches, on E-4 box 2f inches. Before
putting in the new oil, however, the
drum and finger contacts should be
examined, and, if pitted or dirty,
should be cleaned with a fine file.
Make sure that all fingers bear
firmly against the drum so as to
Fig. 336. u.s.l. on-Filled starting make good contact; if they do not,
remove and bend them slightly to
insure this. If the starting switch is abused in operation, or if improper
oil containing water or other impurities be used, the contacts will
burn and fail to make good electrical connection. The switch box
is the only place in the system requiring oil.
Brush Pressures. There is only one adjustment on the gener-
ator, viz, the tension of the brush fingers. The brushes should fit
freely in their holders so as to transmit the full pressure of the
spring against the commutator. The adjustment as made at the
factory should not need correction under one or two years of
service. Pressures required on the various machines are as fol-
lows: for Type E-12 external regulator, If pounds on each brush;
If pounds on brushes of all other external-regiilator machines; If
pounds on each of the three lowest brushes on the inherently regulated
type, these being the only brushes used in generating the charging
current; If pounds on each of the remaining brushes of the inherently
regulated generator. Keep commutator cl^an, as the chief cause of
Digitized by VjOOQIC
failure of the inherently regulated type is an excess of oil or dirt or
both accumulating on it.
Radial and Angular Brushes. The brushes employed are of two
types — radial and angular. Radial brushes are used on external-
regulator type generators other than those having "Type E-49" on
the name plate; angular brushes are used on Type E-49 and all inher-
ently regulated generators. Each radial brush should bear squarely
against that side of its holder toward which the commutator rotates.
Each angular brush should
bear squarely against that
side of its pocket away from
which the commutator
rotates. To sand-in old
brushes or fit new brushes
properly, insert a strip of
No. 00 sandpaper (never use
emery, paper, or cloth), be-
tween the commutator and
the brush, press down on
top of brush and draw sand-
paper under it, Fig. 337. If
the brush is radial, draw the
sandpaper in the direction
of commutator rotation; if
angular, draw the sandpaper
in the direction opposite to
that of commutator rota-
tion. No oil is needed on
the commutator as the
brushes themselves contain
all the lubricant necessary.
Fine sandpaper, as mentioned above, may be used for cleaning the
commutator when necessary, the engine being allowed to turn over
slowly during the operation.
External Regulator. Should the automatic-switch (cut-out)
member of the regulator remain closed with the engine stopped,
start the engine at once, and the switch lever should open. If it
does not, remove the regulator cover (with the engine running) and
Fig. 337. Methods of Sanding- In Brushes on
502 ELECTRICAL EQUIPMENT
pull the lever open by hand. When the switch lever is correctly
set, a slight discharge will*be noted on the ammeter the moment
the switch lever opens. This discharge reading should not exceed
4 amperes; if in excess of this, increase the tension of the switch-
lever spring by releasing the lock nut on the left side of the plate
and turning up on the nut at the right until the proper adjustment is
secured, then retighten the lock nut. The indicating pointer is moved
by the switch lever in closing, and when it appears in its upper position
through the sight glass on the cover, the battery is charging; when
the switch lever opens, the pointer drops against its stop by gravity.
When the battery shows a lack of capacity, the battery itself
and all connections and fuses being in good condition, note the
amount of charging current indicated by the ammeter. If the
maximum current (external-regulator type) shown by the ammeter
does not exceed 10 to 12 amperes at full engine speed after the
engine has been running for fifteen minutes, see that the brushes
and commutator are in good condition — wipe off the commutator
with a dry cloth, and, if necessary, sand-in the brushes to a good seat.
If this does not increase the generator output as shown by the
ammeter, test the latter as already noted, i.e., see whether the pointer
is binding and, if not, check with the portable testing instrument
or another ammeter of the dash type. Should none of these reme-
dies correct the fault, screw in the lower adjusting plug of the
carbon-pile lever slowly, noting the effect on the ammeter reading
as the adjustment is made.
With the external regulator, the charging current should not
exceed 18 amperes at the highest engine speed. If, at any time,
the ammeter shows a higher reading than this, screw out the lower
adjusting plug of the carbon-pile lever slowly to decrease the cur-
rent, stopping when the indication does not go above 18 amperes
at full speed.
After making this adjustment of the lower plug, make sure that
the carbon-pile lever air gap does not exceed J inch, and is not less than
re inch when the engine is stopped. If the gap is too small the
switch lever will vibrate rapidly at high engine speeds. WTien
necessary to adjust this gap, screw the upper adjusting plug in or
out, but, after doing so, the current output must be checked and
adjusted by means of the lower adjusting plug. Always tighten
ELECTRICAL EQUIPMENT 503
the adjustment clamping screws after setting either of the adjusting
Testing Carbon Pile. If the automatic-switch unit of the gener-
ator does not cut in with the engine running at speed equivalent to 10
to 14 miles per hour, test the carbon pile by short-circuiting the
terminals F+ and A + of the generator with the blade of a screw-
driver. Speed up the engine slowly and note whether the generator
cuts in much sooner than when the terminals are nctt short-circuited.
Do not run the engine at high speed, nor for any length of time with
the terminals short-circuited, as an excessive amount of current
would be generated. If the generator does cut in much earlier
with the terminals short-circuited than without this, the carbon pile
needs cleaning. Should the generator not cut in earlier or should
it fail to operate altogether, when the carbon pile is short-circuited
the trouble is probably in the brushes of the generator or in the
To clean the carbon pile, proceed as follows: Unscrew the plug
at the upper end of the glass rod and remove the rod ; if any of the discs
are pitted or burned, rub them together or against a smooth board to
make them smooth and flat. Remove the end carbons and clean the
brass plates with fine sandpaper, if necessary. In replacing end car-
bons, make sure that they fit firmly against the brass end plates and
that the screw heads do not project beyond the faces of the carbon
discs. After reassembling the carbon pile, the regulator will need
adjustment for current output, as previously noted.
If for any reason it becomes necessary to disconnect the bat-
tery, either open the touring switch and block it open so that it
cannot be closed accidentally if the car is to be run, or disconnect and
tape the right-hand regulator terminal A+. Otherwise, the machine
will be damaged by operating.
Battery Cui-Out. Should either of the fuses mounted on the
automatic switch of the inherently regulated type blow, immedi-
ately open the touring switch. A loose connection or a short-circuit
is probably the cause, and the touring switch should not be closed
again until the cause has been located.
Ammeter. The ammeter should be checked at least once a year
by comparing it with a standard instrument, such as the portable out-
fit mentioned previously, or any other suitable low-reading ammeter
504 ELECTRICAL EQUIPMENT
of known accuracy. To do this, disconnect the positive wire from
the ammeter on the dash and connect it to the positive terminal of
the standard ammeter used for testing; then connect a wire between
the negative terminal of the standard ammeter and the positive
terminal of the dash ammeter. With the engine running at various
speeds, take simultaneous readings of both instruments; any differ-
fuses, a large one 9 of 30-ampere capacity in the generator-battery
charging circuit, and a smaller one 8 of 5-ampere capacity in the
generator shunt-field circuit. Should either fuse blow, immediately
push in the touring-switch button, as a short-circuit or an open or a
^=g| loose connection is probably the cause. After
| ||2 locating the trouble, remove the generator fuse
block from the instrument board. To do this,
unlock the knob, press it inward, and turn \
revolution to the right or to the left. Replace
with spare fuses carried in the light fuse block,
return the generator fuse block to its original
position, and lock.
The light fuse block, which is shown in
Fig. 342, carries a total of seven fuses, of which
four are in active use, while the remaining three
are spare fuses for use in replacing blown fuses. On the right-side
view of this fuse block there appear two large fuses 6 and 7. Fuse 7
is a protecting link in the ground-return wire of the lighting and horn
circuits. The small fuse 5 is of 10-ampere capacity and, together with
Fig. 341. U.S.L. Gener-
ator Fuse Block
U.S.L. Left-Hand Side and Right-Hand
Side light Fuse Blocks
fuse 6 of 30-ampere capacity, is a spare fuse for emergency use. On
the left side of the block are three active fuses 1 , 3, and 4 of 10-ampere
capacity; and one spare fuse 2 of 5-ampere capacity. Fuse 1 is in the
horn circuit, fuse 3 in the headlight circuit, and fuse 4 is common to the
tail-, dash-, and side-light circuits. Should any of the fuses on this
block blow, the trouble is probably a short-circuit on the frame of the
car which should be remedied before the fuse is replaced. Instructions
ELECTRICAL EQUIPMENT 507
for the use of the touring switch in this system are the same as
U.S. Nelson System. This type has been specially designed for
the Nelson car, which first appeared in 1917, and it differs radically
from those already described in that it is carried on the forward end
of the engine crankshaft instead of at the rear. The brushes bear on
the inside face of the commutator and may be reached through three
openings in the armature support. To clean the commutator in this
type, it is necessary to turn the armature so that three of the six
brushes appear opposite these openings. Fold a small piece of sand-
paper into a square over one of the brushes and allow the engine to
turn over for a few minutes. Stop the engine and remove the sand-
paper through one of the openings. The engine carries a flywheel at
the rear, as usual, and this provision of flywheel weight at both ends
of the crankshaft is said to minimize vibration almost to the vanishing
point while making possible extremely high speeds.
Twelve- Volt; Single-Unit; Two-Wire (Early Model)
Dynamotor. The bipolar-type dynamotor has both the series
and the shunt-windings, i.e., of generator and motor, connected
to the same commutator. It is driven direct as a generator, and
through a special planetary gear when operating as a starting motor.
Regulation. The regulation is of the inherent type, utilizing
the generator winding to weaken the field with increase in speed,
i.e., a bucking coil.
Wiring Diagram. Single-Unit Type. The left side of the
lower half of the diagram, Fig. 343, illustrates the connections when
the unit is being used as a starter, as indicated by the arrow showing
the direction of rotation of the armature. Those at the right are the
running connections, the armature then rotating in the reverse
direction and generating current to charge the battery.
Control; Transmission. Switch. This is a special type of
drum switch mounted directly on the dynamotor on the same base
with the battery cut-out. As shown in Fig. 344, when the lever Q
is thrown to the left for starting, it also serves to tighten the brake
band on the planetary gear. When moved in the opposite direction,
it releases this brake, and another set of contacts on the drum of
the switch connect the generator for charging. Fig. 345 shows the
details of this switch: A, B, and C are the contacts on the starting
side, while H , G, and F are the running-position contacts, as shown
in Fig. 343. The segments E and L on the drum contact with
J L SHtfMT
Fig. 343. Wiring Diagram for Wagner Twelve-Volt Single-Unit Two-Wire
System (Early Model)
the fingers mentioned when the drum is revolved part way in either
direction by the lever, shown at the right, which engages the shaft M.
Battery Cut-Out. This is of conventional design. For description
and explanation of operation, see previous systems in which a battery
cut-out, or automatic switch, is employed. Methods of locating
trouble are given in connection with instructions farther along.
ELECTRICAL EQUIPMENT 509
Fig. 344. Wagner Control Switch of Drum Type. A— Starter Frame; B— Switch Support; C—
Outside End Plate Gear Box; D— Return Spring; F— Oil Hole Screw; G— Self-Closing Oiler;
H— Oil Plug; J— Connecting Rod; K— Brake Band; M— Battery Leads; N— End Plate Screws:
O— Back End Plate Shield; Q— Starting Switch Lever; R— Brake Band Lever; S— Front End
Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri
Fig. 345. Exploded View of Drum Switch. A, B, F, G, H, and K— Contact Screws to Contact;
C— Auxiliary Contact Finger; E — Drum Contact; J— Screw Holding C; L— Auxiliary Drum
Contact; M — Shaft
510 ELECTRICAL EQUIPMENT
Planetary Gear. The external form of the different gear boxes
used on the early-model single-unit Wagner starter is the same, but
Fig. 348. Exploded View of Planetary Gear Transmission. A— Planetary Pinion; B — Rolling
Pawl; C— Center Pinion; D— Planetary Hub; E— Pawl Seat; F— Pawl Plunger; G — Internal
Gear; H— Inside End Plate; J— Outside End Plate; K— Oil Plug; M— Sheet-Steel Disc
Fig. 347. Assembled Planetary Gear. Letters same as Fig. 346
their internal construction differs somewhat. The details of the
two types employed are shown in Figs. 346 and 347. The prin-
ciple employed is that of the planetary gear as used to obtain first,
ELECTRICAL EQUIPMENT 511
or low, and high speeds on early-model light cars. The unit consists
of a central, or sun, gear C, Fig. 347, and three planet pinions A
meshing with the central gear and also with the internal gear ring G.
For starting, the tightening of the brake band on the outer groove
of the internal gear holds it fast, so that the drive is through the
central gear and the reducing pinions in engagement with it and
the gear ring, while, for running, the rollers B in the clutch D lock
the gears together so that when generating the gear revolves idly
as a unit.
Instructions. The instructions previously given in connection
with other systems apply here. For failure to generate, lack of
capacity, grounds, or short-circuits in windings, and for keeping the
Fig. 348. Jig for Holding Armature and Tooling Commutator
commutator and brushes in condition, see instructions already
given, as well as Summary of Instructions, Part VIII.
Method of Tooling Commutator. A different method of under-
cutting the mica of the commutator is recommended from that
already described in connection with the Delco system. This is
illustrated in Fig. 348. The armature is removed from the generator
and mounted in a simple jig, as shown. The jig is made of 1-inch oak,
while ordinary machine screws held in place by lock nuts are utilized
as the centers. The bar, or guide, on which the cutter operates, can
be made of £-inch rolled-steel rod, while the cutter itself should be
made of J-inch drill rod. The point of this cutter is ground sharp, like
the parting tool used on a lathe or planer, to the thickness of the mica
between the commutator bars. The cutter is moved backward and
512 ELECTRICAL EQUIPMENT
forward on its guide in the same manner as a planer or shaper tool,
and the armature is rotated one segment at a time to bring the mica
sections under the tool successively. Where there is not sufficient
work of this nature to make it worth while to build the jig, a simple
11 i hand tool may be used,
r^^/w^w a Fi S- 349 - This can be
^ |— 1 ~^\ £3 made of a discarded
section J& hacksaw blade or a new
Fig. 349. Diagram of Simple Hand Device for Tooling one > &boUt 8 inches long.
Commutator q^ of ^ ^^ j g
ground similarly to the cutter described for the jig, while the other
should be shaped like a hook, having the same kind of point as the
cutter end. Around the center of this tool should be folded a piece of
heavy tin (sheet iron) and the whole wrapped with electric tape. This
will prevent the brittle saw blade from breaking and make it much
easier to handle. The mica is removed by forcing the sharp end of
the tool from the outer edge of the commutator surface to the inner
edge, and the rough cut thus made is finished by drawing the hooked
end of the tool back through the groove in the opposite direction.
To do the job properly, the armature should be held in a vise, other-
wise it is liable to move, or the tool is liable to slip, and the copper
be cut away with very poor results. Fig. 350 shows the commutator
before and after under-
before cutt i n g the mica.
tool should never be used,
as it will simply, make a
V-shaped cut in the mica,
removing too much in
depth and not enough in
AFTER .*, . . e ^
width. The mica must
be cut out clean and
square, and a small mag-
Fig. 350. Diagram Showing Commutator Sections before n j fying g , ass shoul(J ^
used to see that all of the
pieces adjacent to the bars have been removed. After removing the
mica, the armature should be placed in a lathe, and a light cut taken
from the commutators, i.e., just enough to remove all roughness
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 513
and flat spots. The cutting tool employed should be very sharp, so
that the soft copper will not be dragged from one segment to another.
After turning, fine sandpaper should be used to smooth the commu-
tator. Whether the brushes are replaced with new ones or the old ones
are retained, they must be sanded-in to the commutator (see Delco
instructions). The springs also should be tested for tension; they
must never be allowed to become loose enough to permit the brushes
to chatter when the generator is running, as this would interfere
seriously with its output.
Lack of Capacity through Faulty Gear Box. Should the battery
not charge properly, note whether in starting the lights brighten
Fig. 351. Method of Pulling Wagner Gear Box with a "Come Along"
Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri
perceptibly with the car running below 5 miles per hour, while at
high speed they remain dim. This indicates that the brake band of the
gear box does not release, owing either to improper adjustment of
the tightening screw or to something getting between the band and
drum. To remedy, the band adjusting screw should be turned until
the band feels free when the starting lever is in the running position.
If something has caught between the band and the drum, its removal
usually will be the only remedy necessary.
Should the battery show signs of exhaustion, and if there is no
noticeable increase in the brightness of the lamps when the car
reaches a speed of 10 miles per hour or its equivalent, the trouble
probably is in the gear box. Remove the front end plate and note if
the commutator is rotating. If not, and the reason therefor is not
apparent on an inspection of the gears, it may be necessary to remove
the gear box. A "come along", such as is employed for taking off
Ford wheels, is necessary for this, Fig. 351. It may be found that
some of the parts need replacement, or that an entirely new gear
box is necessary.
Failure Due to
Battery Cut-Out. If
the failure to charge
the battery be not
due to the gear box,
remove the cover of
the cut-out and see
if it is operating
properly. When the
engine is running at
a speed equivalent
to 15 miles per
hour, the contact
should spring away
from the adjusting
screw. If it does
not, connect a volt-
meter across the
terminals B and //
of the switch, Fig.
352. Should the
not move, examine
the contact fingers connected to the studs C and F and see that they
make firm contact with the drum of the switch. Place the end of a
pencil on the contact finger D and bear down lightly; if the main
contact maker then springs away from the adjusting screw, the cause
of the trouble is an open circuit at this contact. Bend D so that
it bears down on the drum segments; should the contacts not close
on making this test, the trouble will be an open connection, either in
the generator itself or between the generator and the cut-out (switch).
Fig. 352. Details of Wagner Starting Switch. A and B — Large
Contact Finger; C — Auxiliary Contact Finger; D — Auxiliary
Contact; E— Drum Switch; F, G, and H— Drum Switch Studa;
J — Screw Leading to C; Q — Starting Switch Lever
ELECTRICAL EQUIPMENT 515
Should the voltmeter give a reading of 6 volts while the contacts
do not close, it shows that the shunt coil of the cut-out is open and
indicates that its connections are broken or that the trouble is in the
coil itself. This may be confirmed by operating the contacts by
hand — pushing the contact away from the adjusting screw until it
touches the stationary contact. If it remains in that position, the
generator is charging the battery, but the shunt coil of the cut-out is
out of action and the cut-out will function automatically as it should.
If, under the conditions mentioned in the first paragraph under
this heading, the cut-out closes, connect the voltmeter as described
and accelerate the engine to a speed corresponding to 25 miles
per hour. If the reading is then 15 to 20 volts, the trouble may be
looked for in a break in the generator connection to the cut-out.
Should it not be possible to locate any break, it may be in the series
coil of the cut-out, in which case a new cut-out will be necessary.
Switch or Generator Parts to Be Adjusted. If the starting lever
of the switch is not returning to the proper position for running after
starting the engine, it will be indicated by a low battery and dim
lights. Adjust so that the lever will go to correct, position for running
and see that the contact fingers of the switch are making proper
contact with the drum.
In case the battery does not get sufficient charge, connect an
ammeter to the terminal D of the switch and to W of the cut-out.
At a speed equivalent to 15 miles per hour, the ammeter should read
7 to 9 amperes if the generator is working properly. If it does not,
examine the commutator, brushes, and wiring, as previously described.
Six- Volt; Two-Unit
General Characteristics. This type is similar in characteristics
to most of the other makes of this class already described.
Generator. The generator is the multipolar (four-pole) shunt-
Regulation. The regulation is of the inherent or bucking-coil
type, integral with the field windings of the generator.
Starting Motor. The motor is four-pole and series-wound, driv-
ing through a reducing gear mounted on the motor housing, Fig. 353.
Control. Battery Cut-Out. The complete instrument, minus
its cover, is shown in Fig. 354. It is of standard design and is intended
Digitized by VjOOQIC
516 ELECTRICAL EQUIPMENT
to be mounted in the tool box under the driver's seat. As shown in
the photograph, the upper binding post is the series-coil connection,
the central binding post just below it is the shunt-coil connection,
Fig. 353. Wagner Six- Volt Two-Unit Type Starting Motor. Left— Commutator
End; Right— Gear End
Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri
while the lowest binding post is a connection completing the circuit
through both coils to the battery.
Switch. The switch is of the circular knife-blade type, two sets
of spring contacts close together being pressed down over the sta-
tionary contact against the spring, as shown in Fig. 355 which illus-
trates the parts of the
Wiring Diagram. A
typical wiring diagram of
the Wagner two-unit sys-
tem as installed on the
Scripps-Booth four- and
eight-cylinder models is
shown in Fig. 356. The
only difference in the
wiring of the two models
Fig. 354. Wagner Cut-Out ^ ^ d() ^ ^ ^
tion and merely affects the distributor connections, as illustrated by
the panel in the upper right-hand corner, which shows the distributor
and connections for the four-cylinder car. As the system is a single-
wire type, one side of every circuit is grounded, the spark plugs
themselves representing the grounded side of the high-tension ignition
HATS IM— AUTO-UTE WIMlfO DIAGRAM FOR PEERLESS ItlT CAR8
Remy Ignition and Wagner Starting and Lighting Installations on Studebaker Four and Six, Models
SF and ED. Upper Diagram Shows Junction- Block Wiring Diagram; Lower Diagram
Shows Car Wiring Diagram
Courtesy of The Studebaker Corporation of America, Detroit, Michigan
ELECTRICAL EQUIPMENT 517
circuit. The caution on the diagram — Never run generator with battery
removed from car nor with wire disconnected from generator — applies
not only to the Westinghouse system but to practically every other
system as well.
Instructions. Ground in Starting or in Lighting Circuits. When
the blowing of a fuse on one of the lighting circuits is due to a ground,
or a similar fault is suspected in the starting system, it may be tested
for either with the lamp outfit already described or with the low-
reading voltmeter, as follows:
Disconnect one battery terminal, taping the bare end to prevent
contact with any metal parts of the car, and connect one side of the
voltmeter to this terminal. Attach a length of wire having a bared
end to the other terminal of the voltmeter, as shown in Fig. 357.
Fig. 355. Details of Wagner Switch
Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri
Connect the bared end of the free wire to some part of the car frame;
making certain that good electrical contact is made. Disconnect the
generator and starting motor completely, open all lighting switches,
and be sure that ignition switch is off. If there is no ground in the
circuit, the voltmeter will give no indication. Be sure that none of
the disconnected terminals is touching the engine or frame; to insure
this, tape them.
Should the voltmeter give a reading of 4 volts or more, it indicates
that there is a ground in the wiring between the battery and the
junction box, or in the wiring between the junction box and the gen-
erator or the starting motor. If th^ voltmeter reads less than 4
volts but more than \ volt^ all wiring and connections should be care-
fully inspected for faults. This test should be repeated by reversing
the connections, that is, by reconnecting the wires on the side of
the battery circuit that has been opened and disconnecting the
Localizing Any Ground. To localize any fault that the reading
of the voltmeter may show, reconnect the wires to the starting motor
and close the starting switch; any reading of the voltmeter with
such connections will indicate that the ground is in this circuit.
Should no ground be indicated with these connections, disconnect
ELECTRICAL EQUIPMENT 519
the starter again and reconnect the generator; if the voltmeter
records any voltage, the ground is in the generator circuit. With
both starter and generator disconnected, the voltmeter being con-
nected first to one side
of the battery and then
to the other, operate
the lighting switches, the
ignition switch, and the
horn, one at a time, and
note whether the volt-
meter needle moves upon
closing any of these
switches. A voltage read-
ing upon closing any of
these switches will indi-
cate a ground in that par-
ticular Circuit. Fig 3 . 7 Te9ting for Groundfl ^th Voltmeter in
Short-Circuit Tests. Two-Wire System
To test for short-circuits, substitute the ammeter for the voltmeter, but
do not connect the instrument to the battery. The shunt reading to 20
Fig. 358. Testing for Short-Circuits with Ammeter in Two- Wire System
amperes should be employed, one side of the ammeter being grounded
on the frame as previously described, and the other being connected
with a short wire that can be touched to the open side of the bat-
520 ELECTRICAL EQUIPMENT
tery, Fig. 358. Disconnect the starter and the generator and open
all the switches, then touch the bare end of the wire to the battery
terminal on the open side as shown. Any reading, no matter how
small, will indicate a short-circuit (two-wire system) in the wiring
between the battery and junction box or between the latter and the
starter, or generator. If the ammeter reading shows a heavy current,
there is a severe short-circuit.
Localizing a Short-Circuit The short-circuit may be localized
in the same manner as described for the voltmeter test, i.e., connect
the starter and test; disconnect the starter, connect the generator and
test. A reading on the generator test may be due to the contacts of
the cut-out sticking together. If the cut-out contacts are open and
the ammeter registers, there is a short-circuit in the generator
Disconnect the generator again, remove all the lamps from the
sockets, and turn on the lighting-circuit switches one at a tim% touch-
ing the wire to the battery terminal after closing each switch. A
reading with any particular switch on indicates a short-circuit in the
wiring of the lamps controlled by that switch. Only one switch should
be closed at a time, all others then being open. This test should be
made also with the ignition switch on but with the engine idle. The
ammeter then should register the ignition current, which should not
exceed 4 to 5 amperes. If greater than-this, the ignition circuit should
Cautions. Do not attempt to test the starter circuit with the ammeter
as it will damage the instrument. To test the starter circuit, reconnect
as for operating, removing the ammeter. Close the starting switch ; a
short-circuit in the wiring will result either in failure to operate or in
slow turning over of the engine. See that the switch parts are clean
and that they make good contact. If the short-circuit is in the wind-
ing of the starting motor, there will be an odor of burning insulation
The battery must be fully charged for making any of these
tests. While the effect either of a ground or of a short-circuit will
be substantially the same, its location and the remedy will be more
easily determined by ascertaining whether it is the one or the
other. Instructions for making these tests have already been dis-
cussed in the Gray & Davis section.
Digitized by VjOOQIC
i J *
Weatinghouse Starter Intallation on Pierce-Arrow Scries Four Car& Upper Diagram for Models 38
and 48; Lower Diagram for Model 66
Courtesy of Pierce-Arrow Motor Car Company, Buffalo, New v mk
Digitized by VjOOQ 1C
Courteey of The Locomobile Company of America, Bridgeport, Connecticut
Twelve- Volt; Single-Unit; Single-Wire
Dynamotor. The single unit of the 12-volt system, or the
"motor-and-generator" as the manufacturers term it, is a bipolar,
machine, both the generator and starting-motor windings of which
are connected to the same commutator. Installation is usually by
means of a silent chain, as on the Hupp (1915 and earlier). The
characteristics of this type of machine are such that when running
at a speed equivalent to 9 miles per hour or less, it acts as a motor,
and when the speed increases, it automatically becomes a generator
and begins to charge the battery.
Regulation. The third-brush method of regulation is employed,
the amount of current supplied to the shunt fields by this brush
IL U Horn Hi.
Motor end Generator
Sm'/ch Lh^x f*i-
TolqniHon ["^"FViw Block
Fig. 359. Wiring Diagram for Westinghouse Single-Unit System on Hupmobile
decreasing as the magnetic field of the generator becomes distorted
owing to increased speed.
Control. The switch employed with this type of combined unit
is the regular single-throw single-pole switch used on lighting-
plant switchboards. This switch controls both the ignition and
the starting-motor circuits and, at starting, is thrown on and left
closed as long as the car is running.
Wiring Diagram. The connections of the Hupp installation
are shown in Fig. 359.
Instructions. Battery Charging. As the unit acts as a motor
to drive the engine when the latter is running at a speed of less
than the equivalent of 9 miles per hour on high gear, slow driving
or permitting the engine to idle at a very low speed when the car is
standing will discharge the battery. Where no fault in the wiring
or connections exists and the battery will not stay charged (the
522 ELECTRICAL EQUIPMENT
generator, of course, working properly), this practice may be the
cause of the trouble. If the voltage drops to 10 or 11 volts, with
the headlights on but with the engine stopped, it indicates that the
battery is practically discharged. This voltage reading will be
somewhat higher in summer than in winter. The remedy is to
run with fewer lights at night or to run the engine for longer periods
in the daytime, or at higher speeds. Running solely at night will
not keep the battery sufficiently charged, as most of the generator
output is consumed by the lamps. Should the battery become
discharged to a point where it cannot operate the starting motor,
disconnect the wires C and S at the dynamotor, taping their ter-
minals to prevent contact with any part of the engine or chassis.
Start the engine by hand and, when running at a speed of about
500 r.p.m., reconnect these wires, being sure to connect wire S first,
when the battery will begin to charge.
Fire Prevention. Gasoline or kerosene is frequently employed
to wash automobile engines. Before doing so, be sure that the
starting switch is open, and disconnect the negative terminal of
the battery, taking care that it does not come in contact with any
metal parts of the car. To make certain of this, it is better to tape
the metal terminal. Allow the gasoline to evaporate entirely before
reconnecting the battery, as a flash or spark would be liable to ignite
the vapor. This naturally applies to all cars, although only such as
are equipped with the Westinghouse single-unit or the Dyneto single-
unit have starting switches which remain closed all the time the
engine is running.
Weak Current. If the dynamotor fails to operate when the
starting switch is closed, open the switch and test with the port-
able voltmeter. If it indicates less than 11 volts, the battery is run
down; if it indicates 12 volts or over, look for a loose connection or
an open circuit (broken wire) either in the connection from the
battery to the starting switch, from the switch to the dynamotor,
from the latter to the ground, or from the battery to the ground, in
the order named. Dim burning of the lamps when the engine is
stopped also indicates a discharged battery. When this is the case,
it is advisable to recharge at once from an outside source, if possible.
A quick method of determining whether there is a ground in the
wiring is to disconnect the battery wire and, the engine being stopped
A — Storage Battery F — Ammeter M — Head Lamps
B— Starting 8 witch G — Ignition Switch N — Tail Lamp
C— -Starting Motor H — Lighting Switch O— Instrument Lamp
D— -Generator I — Spark Coil P — Horn Push Buttoa
E — Voltage Regulator K — Atwatcr-Kent Igniter Q — Spark Pluga
L — Horn"
Westinghouse Ignition, Starting, and Lighting Installation on Hupmobile Scries N 1916-17
Cars. Upper Diagram Applies to WestinghouBe Equipment for Numbers
60000 to 75000; Lower Diagram Applies to Cars after 75000
Courtesy of Hupp Motor Car Corporation, Detroit, Michigan
PLATE IIS— REMY STARTING A|ID LIOHTIlfG WIRIHG DIAGRAM FOR
SCRIPPS-BOOTH SIX-CTLOTDBR MODELS
Fig. 360. Westinghouse Bipolar Generator for Six-Volt Double-Unit Single- Wire System
Courtcxy of Westinghouse Electric and Manufacturing Company, East Pittsburgh, Pennsylvania
can be slipped out. Ca^e should be taken to replace brushes in the
same position, and if they do not bear evenly over their entire surface
on the commutator, they should be sanded-in as described in the
Delco instructions. The latter suggestion also applies to new brushes.
Six- Volt; Double-Unit; Single-Wire
Generators. Four types of generators are made, as illustrated
in Fig. 116, Part III; in Fig. 157, Part IV; and in Fig. 360, shown
herewith, the fourth being similar to the unit shown on this page
except for the method of regulation employed, which is of the third-
Regulation. The reverse series-field winding, or bucking-coil,
method is used in the first two types of generator, while a voltage
regulator combined with the battery cut-out is employed on the
t Digitized by VjOOQIC
To Satttiy. B"
Fig. 361. Wiring Diagram for Westinghouae Generator with Self-Contained Regulator
Fig. 362. Closed and Open Position of Westinghouae Cut-Out Switch
ELECTRICAL EQUIPMENT 525
Fig. 363. Wiring Diagram for Westinghouse System with External Regulator
526 ELECTRICAL EQUIPMENT
third, and the third-brush method on the fourth. This regulator is
either self-contained, i.e., built in the generator, or is mounted inde-
pendently. The connections of the built-in regulator are shown in
Fig. 361 . The open and closed positions of the contacts of the exter-
nal cut-out are shown in Fig. 362.
Wiring Diagram. Fig. 363 shows the connections of the separately
mounted regulator together with the charging and lighting circuits.
Fig. 364. Westinghouac Cut-Out Switch of Generator with Third-Brush Regulation
Battery Cut-Out. The type of automatic cut-out used with
the type of generator employing the third-brush method of regu-
lation is illustrated in Fig. 364. This may or may not be combined
with a starting sw T itch mounted on the engine side of the dash or
some similar location. Fig. 365 is a wiring diagram showing the con-
nections of the separately mounted cut-out with the third-brush
generator. The cutting-in speed varies from five to ten miles per
hour on high gear, varying with the gear ratio and wheel diameter of
the car. This speed may be determined by running the car slowly
and speeding up very gradually, meanwhile observing the increase in
speed on the speedometer. The point at which the contacts close
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 527
will be indicated by a slight quick movement of the ammeter needle.
The cutting-out speed is slightly below this to prevent constant
Fig. 365. Diagram of Connections for Complete Westinghouse System
with Separately Mounted Regulator
vibration of the cut-out armature when the car is being driven close
tc the cutting-in speed.
Starting Motors. Variations. Several types are built to meet
varying requirements; i.e., with self-contained reduction gearing,
with single-reduction automatic screw pinion shift (Bendix drive),
and with automatic electromagnetic pinion shift. The first two will
be familiar from the descriptions already given of other makes.
The third is similar in principle to the Bosch-Rushmore, but an
independent magnet is employed instead of utilizing the armature
of the motor itself for this purpose.
Magnetic Engaging Type. This type, as well as the other types
of starting motors mentioned, may be operated either by a foot con-
trolled switch or by a magnetically controlled switch put in action
by a push button. The wiring diagrams, Fig. 366, show the circuits
of both installations and also make clear the operation of the auto-
Sni/tmg Mogntt^Jtorting Motor
Stortin g Mog net^Storting Motor
' -..»_.— . Driving
Fig. 366. Wiring Diagrams of Motor Connections for Automatic Electromagnetic Pinion 8hift
matic engagement. The armature is mounted on a hollow shaft;
and on the end of this shaft is carried a splined pinion designed
to engage the flywheel gear. This pinion is caused to slide along
the shaft by a shifting rod which is attached to the pinion and passes
through the hollow shaft. The other end of this shifting rod acts as
the core of the shifting magnet and will be recognized as the plunger
of a solenoid. When the motor is idle, a spring holds the pinion at
the right-hand end of the shaft and clear of the flywheel gear-
As shown diagrammatically in Fig. 366, when the starting switch
is closed, the circuit is completed from the negative terminal of the
battery, through the switch, the shifting solenoid, the armature, and
the series field of the motor to the frame of the car on which the
positive side of the battery is grounded. The large amount of
current necessary for starting energizes the shifting solenoid suffi-
*uln -nit j.
Wcatinfchouse Ignition, Starting, and Lighting Installation on Marion-Handley Six. 1917
Courteey of The Mutual Motors Company, Jackson, Michigan
ELECTRICAL EQUIPMENT , 529
ciently to overcome the force of the spring so that it draws the shifting
rod to the right through the hollow shaft, meshing the pinion with
the flywheel gear. When the engine speeds up to the no-load speed
of the starting motor, the current in the latter falls off so that the
pull of the solenoid is less than that of the spring, and the pinion is
automatically disengaged, though the motor will continue to revolve
until the starting switch is opened.
Electromagnetic Switch. In principle, the electromagnetic switch
is the same as that of the automatic engaging device for the pinion.
The movable double-pole contact, instead of being attached to a rod
for foot operation, is mounted on the plunger of a solenoid and nor-
mally is held open by a spring. This solenoid requires but a small
amount of current for its operation and is connected on an independent
circuit with the battery. It is controlled by a push button, and when
the circuit is closed by means of the latter, the plunger of the solenoid
is drawn into the coil against the pull of the spring, thus bringing the
contacts together and holding them there as long as the solenoid
Instructions. Regulator. When the generator of the voltage-
regulator type fails to charge the battery properly, all parts of the
circuits and connections having been examined to determine that
they are in proper condition, the regulator may be tested for faults.
With the aid of the portable voltmeter, note at what voltage the
contacts of the cut-out close or cut in, and at what voltage they
cut out or open. See that the contact points are clean and square
so that they make good contact over their entire surfaces when
pressed together with the hand. Insufficient charging may be due
to the voltage regulator keeping the voltage of the generator below
the proper point for this purpose. A voltage adjusting screw is
provided to compensate for this. With the voltmeter in circuit
and the engine running, turn the screw very slowly and note the
effect on the reading. For proper charging the latter should be
approximately 1\ to 8 volts, and the screw should be adjusted very
gradually to bring the voltmeter reading to this value. This screw
is properly set at the factory and is unlikely to need adjustment;
so all other possible causes should be investigated before changing
it. The instructions for the 12-volt system also apply here, except
that for voltage tests the system operates on 6 volts.
530 ELECTRICAL EQUIPMENT
SPECIAL SYSTEMS FOR FORD CARS
FORD SYSTEM f
General Instructions. On the latest model enclosed Ford cars
such as the sedan and the coup£, an electric lighting and starting
system is now being furnished as a regular part of the equipment.
As will be noted by the illustration, Fig. 367, this has been
designed especially for the Ford motor and is combined with it
in a manner that makes it practically integral. The system is a
standard two-unit six-volt single-wire type that is of conventional
design throughout so that any repairman who is familiar with the
other system previously described will at once recognize the layout
of the Ford system and have no difficulty in handling it. The
details of the generator and starting motor are shown in Fig. 36S,
while the complete wiring diagram is illustrated in Fig. 369. The
battery is a 6-volt 13-plate Exide.
The precautions mentioned in connection with other systems
of this type apply to the care and handling of the Ford. If for
any reason the generator is disconnected from the battery, the
engine must not be run unless the generator is grounded as other-
wise it is apt to be burned out. A piece of wire, preferably flexible
copper cable and in no case less than ^-inch in diameter, should be
run from the terminal on the generator to one of the valve cover
stud nuts, making sure that the wire is tightly held at both ends.
Removal of Starting Motor. It is necessary to remove the
starting motor to replace the transmission bands. To do this,
first remove the engine pan on the left side of the engine and then
take out the four small screws holding the shaft cover to the
transmission cover. Upon removing the cover and gasket, turn
the Bendix driveshaft around so that the set screw on the end of
the shaft is in the position shown in the illustration, Fig. 368.
Immediately under the set screw is placed a washer of the locking
type, having lips or extensions oppositely placed on its circumfer-
ence. One of these is turned against the collar and the other is
turned up against the side of the screw head. Bend back the lip
which has been forced against the screw and remove the set screw.
A new lock washer of this type must be used when replacing the
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 531
Pull the Bendix assembly out of the housing, taking care to
see that the small key is not lost. Remove the four screws which
hold the starter housing to the transmission cover and pull out the
starting motor, taking it down through the chassis, which explains
532 ELECTRICAL EQUIPMENT
3 k §
E *> £
P I «
I- £ t
Digitized by VjOOQ IC
Digitized by VjOOQIC
Digitized by VjOOQlC
ELECTRIC AL EQUIPMENT
534 ELECTRICAL EQUIPMENT
the reason for removing the engine pan. In replacing the starting
motor, note that the terminal for the electric cable must be placed
on top. If the motor is placed in any other position, the cable
will not reach to the terminal. In case it is necessary to run the
car without the starting motor in place, transmission cover plates
% supplied for the purpose should be put in place to exclude dirt and
prevent the waste of oil.
Removing Generator. To take the generator off the engine,
first take out the three cap screws holding it to the front end
cover and by placing the point of a screw driver between the gen-
erator and the front end cover, the generator may be forced off
the engine assembly. Always start at the top of the generator
and force it backward and downward at the same time. In case
it is necessary to run the car without the generator in place, a
plate may be had to cover the opening thus left in the timing
gear case. Should the battery be removed, the engine must not
be run without grounding the generator in the manner already
The generator is driven from the large timing gear to wh\ch
the camshaft is attached and is set to cut into the battery circuit
when the speed of the motor is equivalent to 10 miles an hour on
the direct drive, while it reaches its maximum at 20 miles per
hour. Both the generator and the starting motor are lubricated
by the splash system of the engine itself, but an additional oil cup
is placed on the rear end bearing of the generator and should be
given a few drops of oil at short intervals.
Lighting and Ignition. The lighting system consists of two
double-bulb headlights and a small taillight controlled by a com-
bination lighting and ignition switch mounted on the instrument
board and the connections of which will be noted in the wiring
diagram. All of the lamps are connected in parallel, current
being supplied for them by the battery. The lamps should never
be connected to the magneto, as the higher voltage of the latter
will burn out the bulbs and it may discharge the magnets.
Reference to the wiring diagram will show the connection
between the battery and the combination lighting and ignition
switch by means of which the battery current may be sent
through the induction coils for starting. On models equipped with
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 535
starting and lighting systems, the magneto is employed solely for
ignition. Whenever any adjustments or repairs are to be made to
the wiring, the cable leading to the positive side of the battery
should first be disconnected and protected with insulating tape.
Otherwise, the battery current is apt to be passed through the
magnet coils, and this will result in discharging the magnets. -
The operation of the system is checked by means of an
ammeter mounted on the instrument board. When the lights are
burning and the engine is not running at a speed in excess of the
equivalent of 10 miles an hour, the ammeter will show discharge.
At a speed of 15 miles per hour or faster, the ammeter should
show a reading of 10 to 12 amperes, even with the lights burning.
When the ammeter fails to give a charge reading with the engine
running at a speed of 15 miles an hour or better, the generator
should be tested, if an examination fails to reveal any loose con-
nections at the ammeter or on its line. To make the generator
test, the cable is disconnected from its terminal on the generator
and the engine run at a moderate speed. With a pair of pliers,
short-circuit the generator by placing against the terminal stud
and against the housing of the generator at the same time. If the
generator is in good working condition, a bright spark will result.
The engine should at once be stopped, as the generator should not
be run in this condition a moment longer than necessary. An
inspection of the connections and wiring as outlined in previous
sections will be found equally effective in discovering short-circuits
or grounds as in any of the other systems mentioned.
Operating Starter. The management of the starter is simple.
The spark and throttle levers should be placed in the same position
on the quadrant as when cranking by hand, and the ignition switch
turned on. Current from either battery or magneto may be used
for ignition. When starting, especially if the engine is cold, the
ignition switch should be turned to "battery." As soon as the
engine is warmed up, turn switch back to "magneto." The start-
ing motor is operated by a push button, conveniently located in
the floor of the car at the driver's feet. With the spark and throttle
levers in the proper position, and the ignition switch turned on,
press on the push button with the foot. This closes the circuit
between the battery and starting motor, causing the pinion of the
Digitized by VjOOQIC
536 ELECTRICAL EQUIPMENT
Bendix drive shaft to engage with the teeth on the flywheel, thus
turning over the crankshaft. When the engine is cold, it may be
necessary to prime it by pulling out the carburetor priming rod,
which is located on the instrument board. In order to avoicf flood-
ing the engine with an over-rich mixture of gas, the priming rod
should only be held out for a few seconds at a time.
GRAY AND DAVIS
General Instructions. Gray and Davis and some of the other
leading manufacturers who make the starting and lighting equip-
ment for larger cars also manufacture a special type designed for
the Ford. These special Ford systems are simple and compact,
and everything necessary to install them on the machine is pro-
vided by the maker of the apparatus so that they may be installed,
either by the owner of the machine or by the local garage man
whose electrical experience is limited. This necessitates the removal
of the radiator, radiator brace rod, hose connections, fan, fan pul-
leys and belt, cylinder head, and in some cases the timing-gear
housing. The ground connection of the headlights, which is
soldered to the back of the radiator on 1915 and subsequent
models provided with electric headlights supplied by the Ford
magneto, must be discarded altogether, as the lights are to be
supplied by the storage battery. In cases where it is necessary to
remove the timer (this must be done when the timing-gear housing
has to be removed), both the timer and the carburetor should be
adjusted for efficient running before starting to dismantle the
engine, and if the latter is turned over while the timer is off, the
ignition timing must be readjusted when the timer is put back.
As the removal of all the parts mentioned is a simple matter fully
covered in the Ford instruction books and familiar to practically
every garage man in the country, they are not repeated here.
Installation. Preparing Engine. Remove the radiator, discon-
necting the ground wire from it; disconnect the wires from the head
lamps and remove the head lamps and supports. Take off the bracket
and fan, Fig. 370, and turn the engine by hand until the pin 2 in the
fan pulley is straight up and down; remove the pin from the jaw
clutch and remove the starting-crank 4, belt 5, and the cotter pin, 3;
take the pin from the fan pulley and remove the pulley 6. Remove
the second, fourth, and fifth bolts from the crankcase flange 7, the
left and front bolt from the side-water connections 8 and 9, as well
as the second cylinder-head bolt 10. i
Note — The numerals refer to the parts to be removed or replaced, as well
as the sequence in which the operations are to be carried out, as shown on the
sketches. Each illustration, however, has its own series of the same numbers,
which should not be confused with those on other views.
I^ay the chain 1 in the rear of the engine support around the
crank-shaft, Fig. 371, and then place the original starting-crank jaw
Fig. 370. Preparing Engine for Mounting Starting Unit
Courtesy of Gray A Davis, Boston, Massachusetts
clutch 2 inside of the crankshaft sprocket. Place the crankshaft
sprocket 3 on the crankshaft and put the new belt 4 around the pulley
on the crankshaft. Secure the sprocket with the new pin 5 (supplied)
and then connect the starting crank in its original position. Secure
tbe jaw clutch to the starting crank with pin 7.
Mounting Starter-Generator. In Fig. 372 is shown the starter-
generator unit, for which note the following instructions: See that
Fig. 371. Putting Driving Chain on Crankshaft Sprocket in
Gray <fc Da via Ford Installation
Fig. 372. Details of Gray 6 Davis Generator Unit for Ford Starter
ELECTRICAL EQUIPMENT 539
the motor terminal 1 is free from contact with any other metal; also
that»the dynamo terminal 2 and insulation are net injured. Test the
shaft and gears 3 to see that they turn freely, a^d then fill the oil
cups 4 with oil.
Release the top adjusting screw 5, also two lower clamping lock
nuts 6 (front), as well as the two upper clamping lock nuts 7 (rear) and
the singlfe middle clamping lock nut 8 (front). The units must be in
the lowest position possible on the bracket before placing it on the car.
In Fig. 373 is shown the starter-generator unit in place on the engine
with the bolts and nuts all tightened. This is carried out as follows:
Fig. 373. Starter Unit Mounted on the Engine
Courtesy of Oray ic Davis, Boston, Massachusetts
Place three f-inch spacers over the first, second, and third holes in
the crankcase flange 1, and then place the unit on car 2; pass three
f- by 2J-inch bolts through the lower bracket, but do not attach nuts
3. Tip the starter unit forward and pass the chain over the dynamo
sprocket 4; attach the bracket by meams of cylinder-head bolt, but
do not fasten.
Place a M^inch spacer between the bracket and top water con-
nection 7 and attach the bracket with ^- by 2 f-inch bolts, but do not
fasten securely; then place ^-inch spacers 7 A under the bracket
so that the chain will be tight when the units are in the lowest possible
position. Use washers 8 as shims between the bracket and the
cylinder-head link. Secure the three lower bracket bolts 9 with
lock washers and nuts, also secure the water-connection bolts 6 and
7 and the cylinder-head bolt 5. Adjust the bracket stay bolt 10,
adjust the chain 11 to moderate the tension and lock adjustment,
securely tighten five clamping bracket nuts, and then crank the engine
slowly by hand to see that everything turns smoothly. If, through
some irregularity in the engine casting the bracket should not seat
properly, it may be necessary to file the bracket holes to meet this
condition. Be sure that the sprockets are in true alignment, or the
Fig. 374. Installing dray Ac Davie Wiring and lighting Switch on Ford Car
uneven strain may cause injury. If necessary, elongate the holes in
the bracket or shim bracket as needed to insure perfect alignment
When adjusting the bracket stay bolt 10, make sure that it rests
against the engine casting without strain and secure it with nuts on
each side of the bracket. Bend the ignition timing to clear the chain,
if necessary, but after bending, the distance between the ends of the
rod in a straight line must be equal to its original length. Adjust the
chain to moderate tension and secure both the adjustment lock nuts
at the top. If all five nuts holding the adjustable bracket are not
released before adjusting, uneven strain may cause injury. Securely
tighten the sliding-bracket nuts 12 — two at the bottom front side,
two at the top rear, and one at the front end. Test by turning the
engine over by hand slowly.
Remounting Engine Parts. Fit split pulley 1 to the hub of the
fan, Fig. 374, and attach split pulley 2 with four screws; slip a new
belt over the fan pulley, attach the fan, and adjust. Place the radia-
tor 4 on its support and screw the radiator rod into the radiator and
secure with check nut 3; secure the hose clamps at the top and side
water connection 6; place the radiator nuts and secure with cotter
pins. Attach the lighting switch at the cowl (left) with j^-inch screws
and attach three lighting-
cable clips on the rear of
the dash, using |-inch
wood screws; cut the
corner from the toe board
for clearance. Attach
three wire clips 10 to the
left side of the frame and
attach green wire 11 to
the dynamo terminal.
Then connect the short
black and red wire to the
left head lamp. Pass a
long black and red wire
through the radiator tube
to the right head lamp,
then connect the short
wire from each head lamp to the metal of the car frame 14- Attach
the starting cable 15, which has a copper terminal at each end, to the
starting-motor terminal. Refill the radiator and watch carefully for
leaks in the circulation system.
Starting Switch. The location of the starting switch and the
method of installing it are shown in Fig. 375. Take the plate 1 off
the starting switch and use it to mark the holes in the floor strip two
inches in front of heel board and nine inches from the sill, as shown in
the illustration. Make three holes for the starting switch in the rear
floor strip 2 and attach the switch with bolt 3 at the side nearest the
center of the car; then attach the other switch bolt 4, support
Fig. 375. Installation of Starting Switch
Courtesy of Gray & Davis, Boston, Massachusetts
the cable clip holding the two wires, and secure the spring and the
knob with a pin.
Priming Device. Connect the priming device 1, Fig. 376. Drill
a TjF-inch h°' e * n the dash two inches to the right of the coil box and
six inches above the toe board and pass the upper rod through. Con-
nect the lever arm 2 vertically to the foremost exhaust manifold bolt
with stationary member in horizontal position; then connect the lower
rod 3 to the carburetor priming lever. Work it back and forth several
times to make sure that it returns to normal position when released.
Battery. Place the battery box on the right-hand running board,
Fig. 377, to permit easy opening of doors and access to battery box;
Fig. 376. Replacement of Carburetor Timing Rod on Daah
Courtesy of Gray <fr Davis, Boston, Massachusetts
then mark four holes with the center punch. Drill four holes U inch
in diameter in the running board 2, using a jack or prop to support
the running board while drilling. Replace the battery box on the
running board in order to mark the holes in mud guard for insulating
cable bushings 3, then make two holes 1 1 inches in diameter. Insert
insulating-cable bushing 4 in left hole and secure with round wooden
nut; do the same with the right-hand bushing 5. Secure wood nuts 6
with a wire twisted around the thread. A coat of heavy paint will
also hold the nut in place and preserve the insulator. Place the two
flat wood cleats 7 with holes at each end between the battery box and
the running board; then pass four bolts 8, f inch by 1 J inches, through
ELECTRICAL EQUIPMENT 543
the battery box, cleats, and running board, and secure them with
four nuts and lock washers. Place two special-shaped wood cleats 9
inside the battery box, one at each end for the battery to rest upon,
so that holes in the cleats will fit over the bolt heads. Raise springs
10 and hang on the side of the battery box, placing the battery in the
box and inserting two ^-inch wood strips, one each side between the
battery and the battery box. Attach two springs 11 at opposite ends
Fig. 377. Installing Gray & Davis Battery and Wiring
to hold the battery down securely. Inspect the battery and if the
solution does not cover the plates at least \ inch, add pure water,
filling the cells to | inch above the tops of the plates. Water for
battery use should be free from iron or alkali.
Final Connections and Adjustments. Fig. 378 is a plan view of
the chassis, showing the entire system in place. Figs. 379 and 380
show the wiring in plan and in perspective. Drill and attach to the
woodwork on the underside of the body 1 three wire clips holding the
Digitized by VjOOQIC
tail-light wire; see that the wire does not make contact with any metal
edges. Attach the electric light 2. If the tail lamp has a one-point
wire connector, the lamp body must be metallically connected with
Fig. 379. View of Complete Wiring System Simplified
the chassis frame. Be sure the connecting surfaces are clean, free
from paint, and securely connected. Connect the tail-light wire 3
to the tail lamp. Tail lamps are usually made with a single wire
connector, but, if the lamp has two wire connectors, another wire
should run from the .second
terminal of the connector to the
metal framework of the car.
Connect the short starting
cable 4 (negative) and the
green and red wire to the start-
ing-switch terminal nearest the
battery. Then pass the end of
the battery cable through the
foremost insulator in the mud
guard. Attach the end of the
starting cable 5> leading
through the rear hole in the
mud guard, to the second bolt
in the transmission case. Use
a lock washer and a plain
washer under the head of the
bolt to insure permanent con-
tact. This is the positive cable
which connects to the + termi-
nal 9 of the battery . Then pass
the end of the cable through
the rear insulator in the mud
guard and under the exhaust
pipe, which it must not touch.
Attach to the starting-switch
terminal 6, securely, the end
of the cable which runs to the
starter. Support the starter
cable 7 by a clip to the inside
curved edge of the dash. When
connecting cables to the bat-
tery, be sure that the terminals
are securely fastened — firm
contact must be made. The
battery terminals are made of
lead and must be handled care-
fully. Battery-cable terminals
differ slightly in size and correspond to the holes in the battery
terminal, the negative-cable terminal being the smaller. Pass the
foremost cables 8 through the battery-box insulator and connect
them firmly to the negative battery terminal. Do not connect
the positive cable to the .battery or insert the fuses until the instal-
lation has been made in accordance with the instructions and tests
show that wires are not in contact with the frame of the car. Turn
the lighting switch off and touch the positive terminal lightly to the
battery terminal. If there is a spark, it indicates a short-circuit or
a ground, caused by a wire coming m contact with the frame.
Remedy the trouble before connecting up the battery. If there is
no spark, permanent connection may be made. The lamp-test set
may be used to determine
whether there are any
grounds or short-circuits,
before connecting up the
When all indications
show that the installation
has been made properly,
connect the positive start-
ing cable to the positive
terminal 9 of the battery.
Place and secure the
cover 10 on the battery
box. Place fuse 11 in fuse clip of lighting switch. Fig. 381 shows
details of the different types of lamps.
Instructions. Oil the two generator bearings and the two motor
bearings every 200 miles, keeping oil-well covers closed. The chain
must be kept well adjusted. When the unit is first installed or when
a new chain has been fitted, the chain should be adjusted occasionally
during the first 500 miles of travel until all stretch has been taken
out of it. After this distance has been run, the chain stretch will
be slight. Never allow the chain to run slack.
To adjust the chain, release five clamping nuts (2 nuts in the rear
of the bracket at the top, 2 in front of the bracket at the bottom, and
1 at the right-hand side) a few turns to permit the bracket to slide.
Then adjust the chain to moderate tension by turning the adjusting
Fig. 381. Details of Gray & Davis Ford Lamps
548 ELECTRICAL EQUIPMENT
screw at the top of the bracket and tighten the check nut and adjust-
ing screw to lock the adjustment. Then retighten all five clamping
nuts securely. Turn the engine by hand to determine whether the
chain runs smoothly; the chain should not be too tight. After long
service, when all chain adjustment has been taken up, the chain may
be shortened by taking out a pair of links. The latest type of chain is
supplied with a removable pair of links, retained in position by two
removable pins. These pins are a trifle longer than the regular
Where the chain has been shortened, it is sometimes necessary
to lower the supporting bracket slightly by removing some of the
g*y-inch washers under the bracket ort>y filing the spacers slightly, so
that the chain will be tight when the unit is in the lowest possible
Wires are subject to dislodgement and injury, hence they should
be examined carefully to see that they are not resting on sharp edges
of metal and that the insulation is not worn or injured. See that none
of the wires are swinging or rubbing against metal, as this is likely to
injure the insulation. Also examine the x cables leading through the
battery box and mud guards; the bushings must be intact and in place
to protect the cables from short-circuiting. Wherever injury to any
part of the insulation is found, wrap the spot carefully with insulating
tape and bend away from the metal to provide sufficient clearance to
prevent further damage.
If the lamps fail to light when the lighting switch is operated,
the fuse on the back of the lighting switch should be examined ; it may
be burned out, broken, or not properly clamped in its fuse clips.
The wires may not be properly connected (this should be checked by
wiring diagram), the bulbs may be burned out, or the filaments may
be broken. The lamp wiring may be short-circuited or the charging
circuit may be open.
Do not run the engine with the battery disconnected or off the
car without first insulating or removing two of the generator brushes
to prevent the generator from generating a current. To determine
if generator is operating properly, turn on the head and tail lamps
while the engine is idle. Start the engine and accelerate to charging
speed or over; a perceptible brightening of the lamps will indicate
that the machine is generating sufficient current both to charge the
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 540
; battery and to light the lamps. Do not open the charging circuit at
■ any time when the engine is running.
| Testing Generator with Ammeter. A more accurate determina-
j tion may be made by connecting an ammeter in the circuit. Discon-
j nect the red and green wire connected to the fuse terminal on the back
[ of the lighting switch and connect it to one terminal of the ammeter,
f From the other terminal of the ammeter, connect a wire to the fuse
I terminal to which the red and green wire was previously connected.
Turn the lights on with the engine idle. The ammeter should regis-
I ter "discharge", the reading representing the amount consumed by
the lamps turned on, i.e., head and tail lamps, 5 to 6 amperes; side and
tail lamps, 1| to 2 amperes. If the ammeter indicated "charge"
instead of "discharge", with the lamps turned on and the engine idle,
reverse the wires connected to the ammeter terminals. In case the
ammeter does not register, see that the pointer is not jammed, other-
wise, the circuit is open at some point or the battery is exhausted.
Run the engine at a speed corresponding to 12 to 15 miles per
hour, the lights being turned off. If the ammeter registers "charge",
the generator is then charging the battery. Increase the engine speed
to a car speed corresponding to 13 to 18 miles per hour. The ammeter
reading should then be from 12 to 15 amperes. As the engine speed
is increased above 18 miles per hour, the charging rate will decrease
gradually to approximately 10 amperes at very high speed. With the
engine running at 12 miles an hour or faster, turn the lights on;
the charging rate should drop according to the number and size of the
lamps turned on (see current consumed by each lamp as given above).
Turn the lights off and, while permitting the engine to slow down,
observe the ammeter. It should drop to zero at approximately 0-
to 2-ampere charge.
ELECTRICAL EQUIPMENT FOR
ELECTRIC STARTING AND LIGHTING
STARTING AND LIGHTING STORAGE BATTERIES
Importance of the Battery in Starting and Lighting. In the
last analysis, every electric lighting and starting system on the
automobile is necessarily a battery system. An electric starter
is, first and last, a battery starter, since no system can be any more
powerful than its source of energy. In other words, the storage
battery is the business end of every electrical starting and lighting
system. Just as the most elaborate and reliable ignition apparatus
is of doubtful value with poor spark plugs, so the finest generators,
motors, and auxiliaries become useless if the battery is not in proper
Storage Battery Requires Careful Attention. A little experience
in the maintenance of electric starting and lighting systems will
demonstrate very forcibly that the relative importance of the storage
battery is totally disproportionate to that of all the remaining
elements of the system put together. The latter essentials have
been perfected to a point where they will operate efficiently without
attention for long periods. The battery, on the other hand, requires
a certain amount of attention at regular and comparatively short
intervals. Usually, this attention is not forthcoming, or it may be
applied at irregular intervals and with but scant knowledge of the
underlying reasons that make it necessary. Consequently, the battery
suffers. It is abused more than any other single part of the entire
system and, not being so constituted that it can withstand the effects
of this abuse and still operate efficiently, it suffers correspondingly.
Then the entire system is condemned.
552 ELECTRICAL EQUIPMENT
Other things being equal, the successful operation of any starting
and lighting system centers almost wholly in the proper maintenance of
the storage battery. Not all the defections that this part of the elec-
trical equipment of the car suffers are caused by the battery, but unless
properly cared for, it will be responsible for such a large proportion
that the shortcomings of the rest of the system will be entirely for-
gotten. To make it even stronger, it may well be said that unless
the storage battery is kept in good condition, the rest of the system
will not have an opportunity to run long enough to suffer from wear.
In a great many cases that come to the repair man's attention, the
battery is ruined in the first six months' service, usually through
neglect. For this reason, considerable attention is devoted to the
battery and its care in this connection, despite the fact that it is
very fully covered in the volume on Electric Vehicles. The condi-
tions of operation, however, are totally unlike in the two cases.
In one instance, the energy of the battery is called for only at a rate
of discharge which is moderate by comparison with the ampere-hour
capacity, while the battery itself is constantly under the care of a
skilled attendant. In the other instance, the demand for current is
not alone excessive but wholly disproportionate to the total capacity
of the battery when it is used for starting, and intelligent care is
usually conspicuous by its absence.
PRINCIPLES AND CONSTRUCTION
Function of Storage Battery. In the sense in which it is commonly
understood, a battery does not actually store a charge of electricity.
The process is entirely one of chemical action and reaction. A battery
is divided into units termed cells. Each cell is complete in itself
and is uniform with every other cell in the battery, and one of the
chief objects of the care outlined subsequently is to maintain this
uniformity. Each cell consists of certain elements which, when a
current of electricity of a given value is sent through them in one
direction for a certain length of time, will produce a current of
electricity in the opposite direction if the terminals of the battery
are connected to a motor, lamps, or other resistance. The cell will,
of course, also produce a current if its terminals are simply brought
together without any outside resistance. This, however, would
represent a dead short-circuit and would permit the battery to dis-
ELECTRICAL EQUIPMENT 553
charge itself so rapidly as to ruin its elements. This is one of the
things that must be carefully guarded against. When attending
a battery, see that its terminals are not left exposed where tools may
accidentally drop on them. When the current is being sent into the
battery, as mentioned above, it is said to be charging; when it is
connected to an outside resistance, it is discharging.
Parts of Cell. Elements. These are known as the positive
and negative plates and correspond to the positive and negative
electrodes of a primary battery. They consist of a foundation com-
posed of a casting of metallic
lead in the form of a grid, the
outer edges and the connecting
lug being of solid lead, while
the remainder of the grid is like
two sections of lattice work so
placed that the openings do not
correspond. Every manufacturer
has different patterns of grids,
but this description will apply
equally well to all of them. Fig.
382 illustrates the grid of the
Philadelphia battery. The ob-
ject in giving them this form is
to make the active material of _ OQO T An ., w , . . .. v , , . .
Fig. 382. Lead Grid Ready for Active Material
the plates mOSt accessible tO Courtesy of Philadelphia Storage Battery
r # Company, Philadelphia, Pennsylvania
the electrolyte, or solution, of
the battery, and at the same time to insure retaining this active
material between the sides of the grid.
This active material consists of peroxide of lead (red lead) in
the positive plate and litharge, or spongy metallic lead, in the nega-
tive plate. The plates are said to be pasted, to distinguish them
from the old-style plates which were "formed" by a number of charges
and discharges. The active material is forced into the interstices
of the grid under heavy pressure, so that when completed the
plate is as hard and smooth as a piece of planed oak plank. The
positive plate may be distinguished by its reddish color, while the
negative is a dark gray. Each positive plate faces a negative in
the cell, and as the capacity of the cell is determined by the area
o. r ,4 ELECTRICAL EQUIPMENT
of the positive plates, there is always one more negative plate than
positive plates in a cell. The lead connectors of each of the plates
is burned to its neighbor of the same kind, thus forming the positive
and negative groups which constitute the elements of the cell.
Separators. As the elements must not be allowed to come in
contact with each other in the cell because to do so would cause an
internal short-circuit to which reference is made later, and as the
maximum capacity must be obtained in the minimum space, the
plates are placed very close together with wood and perforated
hard rubber separators between them. These are designed to fit
very snugly, so that the combined group of positive and negative
plates is a very compact unit. When reassembling a cell, it is impor-
tant that these separators be properly cared for in accordance with
the directions given later.
Electrolyte. To complete the cell, the grouped elements with
their separators are immersed in a jar holding the electrolyte. This
is a solution consisting of water and sulphuric acid in certain pro-
portions, both the acid and the water being chemically pure to a
certain standard. This is the grade of acid sold by manufacturers as
battery acid and in drug stores as C.P. (chemically pure), while
the water should be either distilled, be cleanly caught rain water,
or melted artificial ice. In this connection, the expression "chemi-
cally pure" acid is sometimes erroneously used simply to indicate
acid of full strength, i.e., undiluted, or before adding water to make
the electrolyte. It will be apparent that whether at its original
strength or diluted with distilled water, it is still chemically pure.
In mixing electrolyte, a glass, porcelain, or earthenware vessel
must be used and the acid must always be poured into the water. Never
attempt to pour the water into the acid, but always add the acid,
a little at a time, to the water. The addition of the acid to the water
does not make simply a mechanical mixture of the two but creates a
solution in the formation of which a considerable amount of heat is
liberated. Consequently, if the acid be poured into the water too
fast, the containing vessel may be broken by the heat. For the same
reason, if the water be poured into the acid, the chemical reaction
will be very violent, and the acid itself will be spattered about.
Sulphuric acid is highly corrosive; it will cause painful burns whenever
it comes in contact (even in dilute solution) with the skin and will
ELECTRICAL EQUIPMENT V*
quickly destroy any fabric or metal on which it falls. It will also
attack wood, for which reason nothing but glass, earthenware, or
hard rubber containers should be employed.
Specific Gravity. The weight of a liquid as compared with
distilled water is known as its specific gravity. Distilled water at
60° F. is 1, or unity. Liquids heavier than distilled water have a
specific gravity greater than unity; lighter liquids, such as gasoline,
have a specific gravity less than that of distilled water. Concentrated
sulphuric acid (battery acid, as received from the manufacturer)
is a heavy oily liquid having a specific gravity of about 1 .835. A
battery will not operate properly on acid of full strength, and it is
therefore diluted with sufficient water to bring it down to 1.275.
This, however, is the specific gravity of the electrolyte only when the
battery is fully charged. The specific gravity of the electrolyte
affords the most certain indication of the condition of the battery
at any time, and its importance in this connection is outlined at
considerable length under the head of Hydrometer Tests. The
following table shows the parts of water by volume, the parts of
water by weight, and the percentage of acid to water to produce
electrolyte of different specific gravities.
Action of Cell on Charge. When the elements described are
immersed in a jar of electrolyte of the proper specific gravity, and
terminals are provided for connecting to the outside circuit, the
cell is complete. As the lead-plate storage battery produces current
at a potential of but two volts per cell, however, a single cell is
rarely used. The lowest number of cells in practical use is the
three-cell unit of the 6-volt battery used for starting and lighting
on the automobile. The different cells of the battery are usually
permanently connected together by heavy lead straps, while detach-
able terminals are provided for connecting the battery to an outside
circuit. When the charging current is sent through the cell, the
action is as follows: The original storage-battery cell of Plants
consisted simply of two plates of lead; when the current was sent
through such a cell on charge, peroxide of lead was deposited on the
positive plate and spongy metallic lead on the negative. This was
termed "forming" the plate. By modern methods of manufacture,
this active material is formed into a paste with dilute sulphuric acid,
and is pressed into the grids. On being charged, this acid is forced
556 ELECTRICAL EQUIPMENT
out of the plates into the electrolyte, thus raising the specific gravity
of the electrolyte. When practically all of this acid has been trans-
ferred from the active material of the plates to the solution, or
electrolyte, the cell is said to be fully charged and should then show
a specific gravity reading of 1.275 to 1.300. The foregoing refers of
course to the initial charge. After the cell has once been discharged,
the active material of both groups of plates has been converted into
lead sulphate. The action on charge .then consists of driving the
acid out of the plates and at the same time reconverting the lead
sulphate into peroxide of lead in the positive plates and into spongy
metallic lead in the negative plates.
Action of Cell on Discharge. The action of the cell on discharge
consists of a reversal of the process just described. The acid which
has been forced out of the plates into the electrolyte by the charging
current again combines with the active material of the plates,
when the cell is connected for discharge to produce a current. When
the sulphuric acid in the electrolyte combines with the lead of the
active material, a new compound, lead sulphate, is formed at both
plates. This lead sulphate is formed in the same w r ay that sulphuric
acid, dropped on the copper-wire terminals, forms copper sulphate,
or dropped on the iron work of the car, forms iron sulphate. In cases
of this kind, it will always be noted that the amount of sulphate
formed is all out of proportion to the quantity of metal eaten away.
In the same manner, when the sulphuric acid of the electrolyte com-
bines with the lead in the plates to form lead sulphate, the volume
is such as to completely fill the pores of the active material when
the cell is entirely discharged. This makes it difficult for the charging
current to reach all parts of the active material and accounts for the
manufacturers' instructions, never to discharge the battery below a
As the discharge progresses, the electrolyte becomes weaker by
the amount of acid that is absorbed by the active material of the
plates in the formation of lead sulphate, which is a compound of
acid and lead. This lead sulphate continues to increase in bulk,
filling the pores of the plates, and as these pores are stopped up by
the sulphate, the free circulation of the acid is retarded. Since
the acid cannot reach the active material of the plates fast enough
to maintain the normal action, the battery becomes less active,
ELECTRICAL EQUIPMENT 557
which is indicated by a rapid falling off in the voltage. Starting
at slightly over 2 volts per cell when fully charged, this voltage
will be maintained at normal discharge rates with but a slight drop,
until the lead sulphate begins to fill the plates. As this occurs,
the voltage gradually drops to 1:8 volts per cell and from that point
on will drop very rapidly. A voltage of 1.7 volts per cell indicates
practically complete discharge, or that the plates of the cell are
filled with lead sulphate and that the battery should be placed on
During the normal discharge, the amount of acid used from the
electrolyte will cause the specific gravity of the solution to drop
100 to 150 points, so that if the hydrometer showed a reading of
1.280 when the cell was fully charged, it will indicate but 1.130 to
1.180 when it is exhausted, or completely discharged. The electrolyte
is then very weak ; in fact, it is little more than pure water. Practically
all of the available acid has been combined with the active material
of the plates. While the acid and the lead combine with each other
in definite proportions in producing the current on discharge, it is
naturally not possible to provide them in such quantities that both
are wholly exhausted when the cell is fully discharged. Toward the
end of the discharge, the electrolyte becomes so weak that it is no
longer capable of producing current at a rate sufficient for any
practical purpose. For this reason, an amount of acid in excess of
that actually used in the plates during discharge is provided. This
is likewise true of the active material.
Capacity of a Battery. The amount of current that a cell will
produce on discharge is known as its capacity and is measured
in ampere hours. It is impossible to discharge from the cell as much
current as was needed to charge it, the efficiency of the average cell
of modern type when in good condition being 80 to 85 per cent,
or possibly a little higher when at its best, i.e., after five or six
discharges. In other words, if 10G ampere hours are required to
charge a battery, only 80 to 85 ampere hours can be discharged
from it. This ampere-hour capacity of the cell depends upon the
type of plate used, the area of the plate, and the number of plates
in the cell, i.e., total positive-plate area opposed to total negative-
plate area. To accomplish this, both outside plates in a cell are
made negative. The ampere-hour capacity of a battery, all the
cells of which are connected up as a single series, is the same as that
of any single cell in the series; as in connecting up dry cells in series,
the current output is always that of a single cell, while the voltage
of the current increases 1 \ volts for each cell added to the series. In
the case of the storage battery, it increases two volts for each cell.
The capacity of the cell as thus expressed in ampere hours is
based on its normal discharge rate or on a lower rate. For example,
take a 100-ampere-hour battery. Such a battery will produce current
at the rate of 1 am-
/■Unacrt* This Cop
pere for practically 100
hours, 2 amperes for 50
hours, or 5 amperes for
20 hours; but as the dis-
charge rate is increased
beyond a certain point,
the capacity of the bat-
tery falls off. The battery
in question would not
produce 50 amperes of
current for 2 hours. This
is because of the fact that
the heavy discharge pro-
duces lead sulphate so
rapidly and in such large
quantities that it quickly
fills the pores of the
active material and pre-
vents further access of
the acid to it. Thus,
while it will not produce
50 amperes of current for 2 hours on continuous discharge, it will be
capable of a discharge as great or greater than this by considerable, if
allowed periods of rest between. When on open circuit, the storage
battery recuperates very rapidly. It is for this reason that when
trying^ to start the switch should never be kept closed for more than
a few seconds at a time. Ten trials of 10 seconds each with a half-
minute interval between them will exhaust the battery less than will
spinning the motor steadily for a minute and forty seconds.
Fig. 383. Section of Willard Starting Battery,
Showing Mud Space
ELECTRICAL EQUIPMENT 559
Construction Details. For automobile starting and lighting
service, the elements of the cells are placed in insulating supports
in the bottom of the hard rubber jars and sealed in place. These
supports hold the plates off the bottom of the jar several inches in
the later types of starting batteries. Figs. .'J8o and 384 showsections
of the Willard starter battery and another standard type This is
known as the mud space and is designed to receive the accumulation
of sediment consisting of the active material which is shaken off the
plates in service. This ac-
tive material is naturally a
good electrical conductor,
and if it were allowed to
come in contact with the bot-
toms of the groups of plates,
it would short-circuit the
cell. Sufficient space is usu-
ally allowed under the plates
to accommodate practically
all of the active material that
can be shed by the plates
during the active life of the
cell. In a battery having
cells of this type, it is never
necessary to wash the cells,
as the elements themselves
would require renewal be-
fore the sediment could
reach the bottom of the Fi « :i84 Typical Starting Battery with Platca Cut
Down, Showing Assembly
In sealing the elements into the jar, a small opening is left for
the purpose of adding distilled water as well as to permit the escape
of the gas when the battery is charging. Except when being used
for refilling the jars, this opening is closed by a soft rubber stopper
which has a small perforation through which the hydrogen passes
out of the cell when the latter is gassing, as explained later. The
different cells of a battery are electrically connected by heavy lead
straps, these strips being usually burned onto the plates by the
Edison Cell Not Available. It will be noted that the foregoing
description has been confined entirely to the lead-plate type of storage
battery and that no mention has been made of the Edison cell. The
latter is not available for starting service on the automobile, because
its internal resistance is too high to permit the extremely heavy
discharge rate that is necessary. In extremely cold weather or where
the engine is unusually stiff for other reasons, this may be as high
as 300 amperes momentarily, while, under ordinary conditions, it
will reach 150 to 200 amperes at the moment of closing the switch.
The efficiency of the Edison cell also drops off very markedly in cold
weather, though this is
also true to a lesser extent
of the lead-plate type.
CARE OF THE BATTERY
The following in-
structions are given
about in the order in
which it is necessary to
apply them in the care of
a storage battery.
Water. In order to func-
tion properly, the plates
in the cells must be cov-
ered by the electrolyte at
all times to a depth of half an inch. Fig. 385 shows a handy method of
determining this definitely. A small piece of glass tube, open at both
ends, is inserted in the vent hole of the battery until it rests on the tops
of the plates. A finger is then pressed tightly on top of the upper end
of the tube, and the tube is withdrawn. It will bring with it at its
lower end an amount of acid equivalent to the depth over the plates.
This should always be returned to the same cell from which it was
taken. The electrolyte consists of sulphuric acid and water. The
acid does not evaporate, but the water does. The rapidity with
which the water evaporates will depend upon the conditions of charg-
ing. For example, if a car is constantly driven on long day runs and
gets very little night use, the storage battery is likely to be contin-
Fig. 383. Diagram Showing Method of Measuring Height
of Electrolyte over Plates *
Courtesy of U. S. Light and Heat Corporation,
Niagara Falls, New York
ELECTRICAL EQUIPMENT 561
ually overcharged and may need the addition of water to the elec-
trolyte as often as every three days, whereas, in ordinary service,
once a week would be sufficient. Even with intermittent use, the
battery should not be allowed to run more than two weeks without
an inspection of the level of the electrolyte and the addition of
distilled water, if necessary. Distilled water is always specified,
since the presence of impurities in the water would be harmful to
the battery, this being particularly the case where they take the
form of iron salts. Where it is not convenient to procure distilled
or rain water in sufficient quantities, samples of the local water sup-
ply may be submitted to any battery manufacturer for analysis.
While it is necessary to maintain the electrolyte one-half inch
over the plates, care must be taken not to exceed this, for, if filled
above this level, the battery will flood when charged, owing to the
expansion with the increasing temperature. The best time for adding
water is just before the car is to be taken out for several hours of use.
It may be done most conveniently with a glass and rubber syringe
of the type used with the hydrometer. Care should be taken when
washing the car to see that no water is allowed to enter the battery
box, as it is likely to short-circuit the cells across their lead connectors
and to carry impurities into the cells themselves.
Adding Acid. When the level of the electrolyte in the cell
becomes low, it is, under normal conditions, caused by the evaporation
of the water, and this loss should be replaced with water only. There
bting no loss of acid, it should never be necessary to add acid to the
electrolyte during the entire life of the battery. When a jar leaks or
is accidentally upset, and some of the solution lost, the loss should be
replaced with electrolyte of the same specific gravity as that remaining
in the cell, and not with full strength acid nor with water alone. The
former would make the solution too heavy, while the latter would
make it too weak. Consequently, unless acid is actually known to
have escaped from the cell, none should ever be added to it. Under
the sections on the Hydrometer and Specific Gravity, further reasons
are given why no acid or electrolyte should be added to the cell
under normal conditions, and the causes which would seem to make
the addition of acid necessary are explained.
Hydrometer. Next to the regular addition of distilled water
to the cells, the garage man will be called upon most frequently to
f>f>2 ELECTRICAL EQUIPMENT
test % the condition of the cells with the hydrometer. This is termed
taking the specific gravity and is one of the most important tests
in connection with the care of the battery. The specific gravity of
a liquid is determined by means of an instrument consisting of a
weighted glass tube having a scale marked on it. This instrument is
the hydrometer, and in distilled water at 00 degrees it should sink
until the scale comes to rest at the surface of the liquid at the division
1.0()0. The lighter the liquid, the further the instrument will sink
in it; the heavier the liquid, the higher the
instrument will float. For constant use in
connection with the care of lighting and
starting batteries, the hydrometer shown in
Fig. 386 will be found the most convenient.
Where the battery is located on the run-
ning board of the car, the test may be made
without removing the syringe from the cell,
but care must be taken to hold it vertical
to prevent the hydrometer from sticking to
the sides of the glass barrel. Wherever pos-
sible, the reading should be made without
removing the syringe from the vent hole of
the cell, so that the electrolyte thus with-
drawn may always be returned to the same
i cell. Where the battery is located in a posi-
tion difficult of access, as under the floor
boards, the syringe may be drawn full of
electrolyte and then lifted out; as the soft
rubber plug in the bottom of the glass barrel
Fi K W, Syrin*e Hydro.n- » S in the form ° f » tra P> when the UiatPU-
etor Set ment is held vertical, the solution will not
run out while the reading is being taken.
Failure to replace the electrolyte in the same cell from which
it was taken w r ill result in destroying the uniformity of the cells.
For example, if electrolyte has been withdrawn from cell No. 1 of
the battery and, after taking the reading, it is put into cell No. 2,
the amount taken from No. 1 must later be made up by adding water,
and the solution will be that much weaker, while the electrolyte
of No. 2 will be correspondingly stronger.
ELECTRICAL EQUIPMENT rm
Hydrometer Tests. In taking a hydrometer reading, first see
that the instrument is not held by the sides of the glass syringe
barrel; then note the level of the instrument in the liquid by looking
at it from below, i.e., hold it up above the level of the eye. Reading
the hydrometer in this way is found to give more accurate results
than looking down upon it. While the hydrometer affords the best
single indication of the condition of the battery — the cells should
test 1.250 to 1.300 when fully charged and 1.150 when fully dis-
charged, below which point they should never be allowed to go —
there are conditions under which the instrument may be entirely
misleading. For example, when fresh distilled water is added to a
cell to bring the solution up to the proper level, the additional water
does not actually combine with the electrolyte until the cell has
been on charge for some time. Consequently, if a hydrometer
reading were taken of that particular cell just after the water had
been added, the test would be misleading, as it would apparently
show the cell to be nearer the fully discharged state than it actually
was, owing to the low specific gravity of the electrolyte. If, on the
other hand, fresh electrolyte or pure acid has been added to a cell
just prior to taking readings, and without the knowledge, of the tester
the reading would apparently show the battery to be fully charged,
whereas the reverse might be the case. In this instance, the specific
gravity would be higher than it should be. To determine accurately
the condition of the cells in such circumstances, the hydrometer
readings would have to be checked by making tests with the volt-
meter, as described later.
Under average conditions, however, the hydrometer alone will
closely indicate the state of charge, and its use should always be
resorted to whenever there is any question as to the condition of
a battery. For instance, an irate owner will sometimes condemn the
battery for failure of the starting motor to operate and will be
absolutely positive that the battery has been fully charged, since he
has been driving in daylight for hours. The hydrometer reading will
show at once whether the battery is charged or not. If it is not, it will
indicate either that the generator, its regulator, or the battery cut-out
are not working properly, or that there is a short-circuit qt a ground
somewhere in the lighting or ignition circuits which permits the
battery to discharge itself. Another more or less common complaint,
564 ELECTRICAL EQUIPMENT
the cause of which may be definitely assigned one way or the other
by the aid of the hydrometer is that "the battery is not holding
its charge" . Except where it is allowed to stand for long periods
without use, as where a car is laid up for a month or more, there is
no substantial decrease in the capacity simply through standing,
unless the battery is allowed to stand in a discharged condition.
Consequently, the owner's impression that the charge of the
battery is mysteriously leaking aw r ay overnight through some short-
coming of the cells themselves is not correct. If there is a fault, it
is probably in the wiring; or a switch may have been left on inadvert-
ently; or, as is very often the case, the car is not driven long enough
in daylight to permit the generator to charge the battery sufficiently.
When driving at night with all lights on, as is commonly the custom,
the generator supplies very little current in excess of that required
by the lamps. As a result, the battery receives but a fraction of
its normal charge, so that one or two attempts to use the starting
motor exhaust it. A hydrometer test made just before using the
starting motor will show that there is only a small fraction of a charge
in the cells, so that they are not capable of supplying sufficient current
to turn the engine over longer than a few seconds. The hydrometer
is equally valuable in indicating when^ battery is being overcharged,
though this is a condition which carries its own indication, known
as gassing, which is described in detail under that head.
Variations in Readings. Specific-gravity readings between
1.275 and 1.300 indicate that the battery is fully charged; between
1.200 and 1.225, that the battery is more than half discharged;
between 1.150 and 1.200, that the battery is quickly nearing a fully
discharged condition and must be recharged very shortly, otherwise
injury will result. Below 1.150 the battery is entirely exhausted and
must be recharged immediately to prevent the plates from becoming
sulphated, as explained in the section covering that condition.
Where the specific gravity in any cell tests more than 25 points
lower than the average of the other cells in the battery, it is an
indication that this cell is out of order. Dependence should not be
placed, however, on a single reading where there is any question as
to the specific gravity. Take several readings and average them.
Variations in cell readings may be caused by internal short-circuits
in the cell; by putting too much water in the cell and causing a loss
ELECTRICAL EQUIPMENT 565
of electrolyte through flooding or overflowing; or by loss of electro-
lyte from a cracked or leaky jar. Internal short-circuits may result
from a broken separator or from an accumulation of sediment in the
mud space of the jars reaching the bottom of the plates.
Quite a substantial percentage of all the troubles experienced
with starting batteries, which are only too often neglected untiF
they give out, is caused by letting the electrolyte get too low in the
jars. The effect of this is to weaken the battery, causing it to dis-
charge more readily, and frequently resulting in harmful sulphating
of the plates and injury to the separators. When such sulphating
occurs, it permits the plates to come into contact with each other,
and an internal short-circuit results. The importance of always
maintaining the electrolyte one-half inch above the tops of the plates
will be apparent from this.
One of the most frequent causes of low electrolyte in a single
cell is the presence of a cracked or leaky jar. If one of the cells
requires more frequent addition of water than the others to maintain
the level of its electrolyte, it is an indication that it is leaking. Where
all the cells of a battery require the addition of water at unusually
short intervals, it is an indication that the battery is being constantly
overcharged. (See Gassing.) Unless a leaky jar is replaced
immediately, the cell itself will be ruined, and it may cause serious
damage to the remainder of the battery. Jars are often broken owing
to the hold-down bolts or straps becoming loose, thus allowing the
battery to jolt around on the running board, or they may be broken
by freezing. The presence of a frozen cell in a battery shows that
it has been allowed to stand in an undercharged condition in cold
weather, as a fully charged cell will not freeze except at unusually
Frozen Cells. In some cases, the cells may freeze without crack-
ing the jars. This will be indicated by a great falling off in the
efficiency of the cells that have suffered this injury, or in a totally
discharged condition which cannot be remedied by continuous
charging. In other words, the battery is dead and the plates are
worthless except as scrap lead. In all cases where cells have been
frozen, whether the jar has cracked or not, the plates must be
replaced at once. It must always be borne in mind that low tempera-
tures seriously affect the efficiency of the Storage battery and that
5G0 ELECTRICAL EQUIPMENT
care should be taken to keep it constantly in a charged condition.
A variation in the temperature also affects the hydrometer readings
themselves. The effect of the temperature on the hydrometer tests
is explained >under Adjusting the Specific Gravity.
Low Cells. When one cell of the battery tests more than 25
points below the specific gravity of the others, as shown by the
average of several readings taken of each, it should be placed on
charge separately from an outside source of current. This may be
done without removing it from the car or disconnecting it from the
other cells, since the charging leads may be clipped to its terminal
posts. If no other facilities are available and direct-current service
is at hand, use carbon lamps as a resistance*in the manner illustrated
on another page. As the normal charging rate of the average starting
battery is 10 to 15 amperes or more, that many 32-c.p. carbon
filament lamps may be used in the circuit. Where only alternating
current is available, a small rectifier, as described under Charging
from Outside Sources, will be found most convenient in garages
not having enough of this work to warrant the installation of a
motor-generator. After the low cell has been on charge for an hour
or two, note whether or not its specific gravity is rising, by taking a
hydrometer reading. If, after several hours of charging, its specific
gravity has not risen to that of the other cells, it is an indication
that there is something wrong with the cell, and it should be cut
out. (See Replacing a Jar and Overhauling the Battery.)
Adjusting the Specific Gravity. Except in such cases as those
mentioned under Hydrometer, where water has been added to the
electrolyte just before testing, or electrolyte has been added without
the knowledge of the tester, specific gravity of the electrolyte is the
best indication of the condition of the cell, and the treatment to be
given should always be governed by it. As explained in the section
on Action on Charge and Discharge, the acid of the electrolyte com-
bines with the active material of the plates to produce the current on
discharge. The further the cell is discharged the more acid there
will be in the plates, and the less in the solution. Consequently,
low-gravity readings practically always mean lack of acid in the
solution, and that implies lack of charge. Unless there is something
wrong with the cell, charging will restore the acid to the electrolyte
and bring the specific-gravity Teadings up to normal. In case a jar
ELECTRICAL EQUIPMENT f><>7
is leaking or has been overturned and lost some of its electrolyte, no
amount of charging will bring its specific gravity up to the proper
The gravity readings of the cells vary somewhat in summer and
winter, and they also decrease with the age of the plates, but the
battery will continue to give good service as long as its specific
gravity rises to between 1.250 and 1.300 when fully charged. In case
it rises above 1.300, there is an indication that excess acid has been
added to the electrolyte, and this must be corrected by drawing off
some of the electrolyte with the syringe and replacing it with distilled
water. A gradually decreasing specific gravity in all the cells
of a battery is an indication that sediment is accumulating in the
bottom of the' jars and that the battery, if of the old type with
low mud space, requires washing; if of the later type with high
mud space, that its elements require renewal. Before accepting
this conclusion, however, make certain that the low reading is not
due to insufficient charging. In actual practice, starter batteries
seldom remain long enough in service without overhauling ever
to need washing.
Many starter batteries are kept in an undercharged condition
so constantly, owing to frequent use of the starting motor with but
short periods of driving in between, that they should be put on
charge from an outside source at regular intervals. In fact, this
is the only method of determining definitely whether the battery
itself is really at fault or whether it is the unfavorable conditions
under which it is operating. Where the cells give a low reading,
no attempt should ever be made to raise the specific gravity of
the electrolyte by adding acid, until the battery has been subjected
to a long slow charge. The maximum specific gravity of the electro-
lyte is reached when all the acid combined in the active material
of the plates has been driven out by the charging current. Adding
acid will increase the specific gravity, but it will not increase the
condition of charge; it will simply give a false indication of a charged
conditidn. For example, if the electrolyte of a cell tested 1.225,
and, without giving it a long charge, acid were added to bring the
specific gravity up to 1.275, it would then rise to 1.325 if put on charge,
showing that 50 points of acid had remained combined in the plates
when the low readings were taken.
568 ELECTRICAL EQUIPMENT
The necessity for adjusting the specific gravity of the electrolyte
in a cell can only be determined by first bringing it to its true maxi-
mum. To do this with a starter battery, it must be put on charge
from an outside source at a low rate, say 5 amperes, and kept on
charge continuously until tests show that the specific gravity of
the electrolyte has ceased to rise. This may take more than twenty-
four hours, and readings should be taken every hour or so, toward
the end of the charge. Should the battery begin to gas violently
while tests show that the specific gravity is still rising, the charging
current should be reduced to stop the gassing, or, if necessary,
stopped altogether for a short time and then renewed.
If after this prolonged charge, the specific gravity is not more
than 25 points below normal, some of the solution may be drawn
off with the syringe and replaced with small quantities of 1.300
electrolyte, which should be added very gradually to prevent bring-
ing about an excess. Should the specific gravity be too high at
the end of the charge, draw off some of the electrolyte and replace
it with distilled water to the usual level of one-half inch over the
plates. A charge of this kind is usually referred to as a conditioning
charge and, given once a month, will be found very greatly to
improve starter batteries that are constantly undercharged in service.
Temperature Corrections. All specific-gravity readings mentioned
are based upon a temperature of 70° F. pf the electrolyte, and as
the electrolyte, like most other substances, expands with the heat
and contracts with the cold, its specific gravity is affected by variations
of temperature. This, of course, does not affect its strength, but
as its strength is judged by its specific gravity, the effect of the
temperature must be taken into consideration when making the tests.
The temperature in this connection is not that of the surrounding
air but that of the electrolyte itself, and as the plates and solution
of a battery increase in temperature under charge, the electrolyte
may be 70° F. or higher, even though the outside air is close
to zero. Consequently, the only method of checking this factor
accurately is to insert a battery thermometer in the vent hole of the
cell. If, on the other hand, the battery has been standing idle for
some time in a cold place, the electrolyte has the same temperature
as the surrounding air, and a hydrometer reading taken without
a temperature correction would be very misleading.
ELECTRICAL EQUIPMENT 569
For example, assume that the car is standing in a barn in which
the temperature is 20° F. and that it has not been running for some
time so that the electrolyte is as cold as the surrounding air. A
hydrometer reading shows the specific gravity of the electrolyte to
be 1.265, which would indicate that the battery was approximately
fully charged. But the correction for temperature amounts to one
point (.001) for each three degrees above or below 70° F., and in this
case a difference of 50 degrees would have to be allowed for. This
amounts to practically 18 points, and the specific gravity of the
cells is 1.265 minus 18, or 1.247. The battery is accordingly three-
quarters charged, instead of fully charged as the uncorrected reading
would appear to indicate. The electrolyte contracts with the drop
in temperature, and its specific gravity becomes correspondingly
higher without any actual increase in its strength. The opposite
condition will be found when the battery has commenced to gas
so violently that the temperature of the electrolyte is raised to
100° to 105° F. At the former figure there would be a difference
of 30 degrees, or 10 points, to allow for, in which case a specific gravity
reading of 1.265 would actually be 1.275. Hydrometer scales, with a
a temperature scale showing at a glance the corresponding correction
necessary, simplify the task of correcting the readings; but to do
this properly a battery thermometer must be employed, as the
temperature of the electrolyte itself is the only factor to be considered.
Gassing. When an electric current is sent through a storage-
battery cell, it immediately attacks the lead sulphate into which
the active material of both the positive and the negative plates
has been converted during the discharge and begins to reconvert
it into peroxide of lead at the positive plate and into spongy metallic
lead at the negative. As long as there is an ample supply of this
lead sulphate on which the current may work, as in a fully discharged
battery, the entire amperage being sent through the battery is restricted
to carrying on this process. In other words, the current will always
do the easiest thing first by following the path of least resistance. When
the cell is in a discharged state, the easiest thing to do is to decompose
the lead sulphate. As there is a comparatively large amount of
this lead sulphate in a fully discharged battery, a correspondingly
large amount of current can be used in charging at the start. But
as the amount of sulphate progressively decreases with the charge,
570 ELECTRICAL EQUIPMENT
a point is reached at which there is no longer sufficient sulphate
remaining to utilize all the current that is passing through the cell.
The excess current will then begin to do the next easiest thing,
which is to decompose the water of the electrolyte and liberate
hydrogen gas. This gassing is not owing to any defect in the battery,
as some owners seem to think, but is simply the result of over-
charging it. In one instance, a car owner condemned the starting
battery with which his machine was equipped, for the reason that
it was "always boiling". In fact, it "boiled" itself to pieces and
had to be replaced by the manufacturer of the car after only a few
months of service; while, as a matter of fact, the conditions under
which the car was driven were wholly responsible. It was used for
long runs in the day time with infrequent stops, and was rarely run
at night; therefore, the battery was continually charging but seldom
had an opportunity to discharge.
This erroneous impression is also closely interlinked with another
that is equally common and equally harmful. This is that one of
the functions of the battery cut-out is to break the circuit and prevent
the battery from becoming overcharged. It is hardly necessary
to add that this is not one of its functions, but that as long as the gen-
erator is being driven above a certain speed, the cut-out will keep the
battery in circuit, and the generator will continue to charge it. Its
only purpose is to prevent the battery from discharging itself through
the generator when the speed of the generator falls to a point where
its voltage would be overcome by that of the battery unless the
battery were automatically disconnected. The cut-out does not
protect the battery from being overcharged; only the driver or the
garage man can do that by noting the conditions under which the
car is operated and taking precautions to prevent the battery
Gassing is simply an indication that too much current is being
sent into the battery. Another indication of the same condition
is the necessity for refilling the cells with distilled w r ater at very
short intervals, as an excess charge raises the temperature of the
electrolyte and causes rapid losses by evaporation. That is the
reason why it is likely to be so harmful to the battery unless remedied,
as if allowed to exceed 1 10° F., the active material is likely to be forced
out of the grids, and the cells to be ruined. While it is essential
ELECTRICAL EQUIPMENT 571
that the battery be fully charged at intervals and that it be always
kept well charged, continuously overcharging it is likely to be as
harmful as allowing it to stand undercharged. Where the conditions
of service cannot be altered to remedy the trouble, the regulator
of the generator should be adjusted to lower the charging rate, or,
if nothing else will suffice, additional resistance, controlled by an
independent switch, may be inserted in the charging circuit. (The
U.S.L. system has a provision to safeguard the battery against
overcharge, termed the touring switch.)
Higher Charge Needed in Cold Weather. While the regulator
of the generator is set by the manufacturer to give *he best average
results, and some makers warn the user against altering its adjustment,
experience has demonstrated that a fixed adjustment of the regulation
will not suffice for cars driven under all sorts of service conditions,
nor for the same car as used at different seasons of the year. The
efficiency of the storage battery is at its lowest in cold weather,
which is the time when the demand upon it is greatest. A battery
that would be constantly overcharged during the summer may not
get more than sufficient current to keep it properly charged in
winter, though driven under similar conditions in both seasons.
On the other hand, a battery. that is generally undercharged under
summer conditions of driving will be practically useless in winter,
as it will not have sufficient current to meet the demands upon it.
It may be put down as a simple and definite rule that if the
battery of a starting system never reaches the gassing stage, it
is constantly undercharged and is rapidly losing its efficiency, as
the sulphate remaining on the plates becomes harder with age
and prevents the circulation of the electrolyte. Even when in the
best condition, the electrolyte cannot reach all of the active material
in the plates, so that any reduction means a serious falling off. Like-
wise, when a battery is constantly gassing, it is in a continuous
state of overcharge and is apt to be entirely ruined in a comparatively
short time. The danger from undercharging is known as sulphat-
ing — the plates become covered with a hard coating of lead sulphate
that the electrolyte cannot penetrate — while that from overcharging
is due to the electrolyte and the plates reaching a dangerous tempera-
ture (105° F. or over) at which the active material is apt to be stripped
from the grids. The conditions of service, on the average, are such
572 ELECTRICAL EQUIPMENT
that a battery can seldom be kept in good condition for any length
of time on the charging current from the generator alone.
The hydrometer should be used frequently to keep track of
its condition and, at least once a month, it should be given a long
conditioning, or equalizing, charge, as it is variously termed.
This charge is required because of the fact that, under ordinary
conditions, a battery seldom receives a complete charge and that
every time it is discharged without this being followed by a charge
which is prolonged until the electrolyte has reached its maximum
specific gravity, more lead sulphate accumulates in the plates. The
object of the long charge is to convert this lead sulphate into peroxide
of lead at the positive plate and into spongy metallic lead at the
negative plate, as explained further under the head of Sulphating.
Sulphating. At the end of a discharge, both sets of plates
are covered with lead sulphate. This conversion of the active material
of the plates into lead sulphate, which takes place during the discharge,
is a normal reaction and, as such, occasions no damage. But if the
cells are allowed to stand for any length of time in a discharged
condition, the sulphate not only continues to increase in bulk, but
becomes hard. It is also likely to turn white, so that white spots
on the plates ota battery when it is dismantled are an indication that
the cells have been neglected. In this condition, the plates have
lost their porosity to a certain extent and it is correspondingly
more difficult for the charging current to penetrate the active material.
When a battery has stood in a discharged condition for any length
of time, it becomes sulphated. The less current it has in it at the
time and the longer it stands, the more likely it is to be seriously
Where a car is used but little in the daytime, and then only
for short runs with more or less frequent stops, the battery never
has an opportunity to become fully charged. The demands of the
starting motor and the lights are such that the battery is never
more than half charged at any time. Consequently, there is always
a certain proportion of the lead sulphate that is not reconverted,
but which remains constantly in the plates. As already mentioned,
this condition does not remain stationary; the sulphate increases
in amount and the older portions of it harden. This represents
a loss of capacity which finally reaches a point where the cells are
ELECTRICAL EQUIPMENT 573
no longer capable of supplying sufficient current (holding enough
of the charge, as the owner usually puts it) to operate the starting
motor. A battery that has been operating under conditions of this
kind is not prepared for the winter's service, which accounts for
the great number of complaints about the poor service rendered
by starting systems in the early part of every winter. As long as
the weather is warm, the battery continues to supply sufficient
current in spite of the abuse to which it is subjected, but when
cold weather further reduces its efficiency, it is no longer able to
meet the demand.
The only method of preventing this and of remedying it after
it has occurred is the equalizing charge metioned in the preceding
section. Long continued and persistent charging at a low rate
will cure practically any condition of sulphate, the time necessary
being proportionate to the degree to which it has been allowed to
extend. It is entirely a question of time, and, as a high rate would
only produce gassing, which would be a disadvantage, the rate of
charge must be low. In case the cells show any signs of gassing,
the charge must be further reduced.
Extra Time Necessary for Charging, The additional length of
time necessary for charging a battery that has been constantly
kept in an undercharged condition is strikingly illustrated by the
following test made with an electric vehicle battery: The cells
were charged to the maximum, and the specific gravity regulated
to exactly 1.275 with the electrolyte just \ inch above the tops of
the plates, this height being carefully marked. The battery was
then discharged and recharged to 1.265 at the normal rate in each
case. The specific gravity rose from 1.265 to 1.275 during the last
hour and a half of the charge. During the following twelve weeks,
the battery was charged and discharged daily, each charge being
only to 1.265, thus leaving 10 points of acid still in the plates. At
the end of the twelve weeks, the charge was continued to determine
the time required to regain the 10 points and thus restore the specific
gravity to the original 1.275. Eleven hours were needed, as compared
with the hour and half needed at first. This test further illustrates
why it is necessary to give a battery an occasional overcharge or
equalizing charge to prevent it becoming sulphated. Had the battery
in question been charged daily to its maximum of 1 .275 and discharged
r>74 ELECTRICAL EQUIPMENT
to the same extent during the twelve weeks, 9J hours of the last
charge would have been saved. These periods of time, of course,
refer to the charging of the electric-vehicle battery, but they indicate
in a corresponding manner the loss of efficiency suffered by the start-
ing battery owing to its being continually kept in an undercharged
Restoring Sulphated Battery. There are only three ways in
which a battery may become sulphated: The first and most common
of these is that it has not been properly charged; second, excess
acid has been added to the electrolyte; third, an individual cell
may become sulphated through an internal short-circuit or by drying
out, as might be caused by failure to replace evaporation with
water, or failure to replace promptly a cracked jar. The foregoing
only holds good, however, where the sediment has not been allowed
to reach the bottom of the plates, and where the level of the electrolyte
has been properly maintained by replacing evaporation with
To determine whether a battery is sulphated or not — it having
been previously ascertained that it does not need cleaning (washing) —
it should be removed from the car (the generator should not be run
with the battery off the car without complying with the manufac-
turer's instructions in each case, usually to short-circuit or bridge
certain terminals on the generator itself) and given an equalizing
charge at its normal rate. The normal rate will usually be found
on the name plate of the battery. If the battery begins to gas at
this rate, the rate must be reduced to prevent gassing, and lowered
further each time the cells gas. Frequent hydrometer readings should
be taken, and the charge should be continued as long as the specific
gravity continues to increase. A battery is sulphated only when there
is acid retained in the plates. When the specific gravity reaches
its maximum, it indicates that there is no more sulphate to be acted
upon, since, during the charge, the electrolyte receives acid from
no other source. With a badly sulphated battery, the charge should
be continued until there has been no further rise in the specific
gravity of any of the cells for a period of at least twelve hours. Main-
tain the level of the electrolyte at a constant height by adding pure
water after each test with the hydrometer (if water were added just
before taking readings, the water would rise to the top of the solution
ELECTRICAL EQUIPMENT f>75
and the reading would be valueless). With a battery on a long
charge, the battery thermometer should be used at intervals to check
the temperature of the electrolyte, and the hydrometer readings
should be corrected in accordance with the temperature.
Specific Gravity too High. Should the specific gravity of any
of the cells rise above 1.300, draw off the electrolyte down to the top
of the plates and put in as much distilled water as possible without
flooding the cell. Continue the charge and, if the specific gravity
again exceeds 1 .300, this indicates that acid has been added during the
previous operation of the battery. The electrolyte should then be
emptied out and replaced with distilled water and the charge con-
tinued. The battery can only be considered as restored to efficient
working condition when there has been no rise in the specific gravity
of any of the cells during a period of at least twelve hours of continu-
Upon completion of the treatment, the specific gravity of the
electrolyte should be adjusted to its proper value of 1.280, using
distilled water or 1.300 acid, as necessary. In cases where one cell
has become sulphated while the balance of the battery is in good
condition, it is usually an indication that there is a short-circuit or
other internal trouble in the cell, though this does not necessarily
follow. To determine whether or not it is necessary to dismantle
the cell, it may first be subjected to a prolonged charge, as above
described. If its specific gravity rises to the usual maximum, the
condition may be considered as remedied without taking the cell
apart. It is the negative plate which requires the prolonged charge
necessary to restore a sulphated battery. When sulphated, the
active material is generally of light color and either hard and dense
or granular and gritty, being easily disintegrated. Unless actually
buckled or stripped of considerable of their active material, the
positive plates are unchanged in appearance and can be restored
to operative condition, though their life will be shortened by this
abuse. Sulphated plates of either type should be handled as little
as possible. By keeping close check with the hydrometer on the
condition of the starting battery and, where it is not being kept in
an overcharged condition constantly, giving it an equalizing charge
once a month, the charge being continued until the cells no longer
increase in specific gravity after a period of several hours, and the
576 ELECTRICAL EQUIPMENT
reading of all the cells being within at least 25 points of each other,
sulphating may be avoided entirely.
Internal Damage. This trouble is usually caused by a short-
circuit, owing either to an accumulation of sediment reaching the
plates or to the breaking of a separator, which may be caused by the
active material being forced out of the grid, usually termed buckling,
which is caused by overheating. It is important to be able to deter-
mine whether or not the low efficiency of a certain cell is caused by
internal trouble without having to dismantle the cell. The repair
man's most important aid for this class of work is the high-grade
portable voltmeter mentioned in connection with other tests of the
starting and lighting system.
Voltage Tests. Under some conditions, the voltmeter will also
indicate whether the battery is practically discharged or not, but,
like the hydrometer, it should not be relied upon alone. To insure
accuracy, it must be used in conjunction with the hydrometer.
Since a variation as low as .1 (one-tenth) volt makes considerable
difference in what the reading indicates regarding the condition of
the battery, it will be apparent that a cheap and inaccurate voltmeter
would be a detriment rather than an aid. The instrument illustrated
in connection with tests of other parts of starting and lighting systems
(see Delco) is of the type required for this service. Complete
instructions for its use will be received with the instrument, and these
must be followed very carefully to avoid injuring it. For example,
on the three-volt scale, but one cell should be tested; attempting
to test the voltage of more than one cell on this scale is apt to burn
out the three-volt coil in the meter. The total voltage of the number
of cells to be tested must never exceed the reading of the particular
scale being used at the time; otherwise, the coil of the scale in question
will suffer, and the burning out of one coil will make it necessary
to rebuild the entire instrument.
Clean Contacts Necessary. Where the voltage to be tested is
so low, a very slight increase in the resistance will affect it considerably
and thus destroy the accuracy of the reading. Make certain that
the place on the connector selected for the contact point is clean
and bright, and press the contact down on it firmly. To insure a
clean bright contact point, use a fine file on the lead connector.
The contact will be improved by filing the test points fairly sharp.
ELECTRICAL EQUIPMENT 577
Even a thin film of dirt or a weak contact will increase the resistance
to a point where the test is bound to be misleading. The positive
terminal of the voltmeter must be brought into contact with the posi-
tive terminal of the battery, and the negative terminal of the volt-
meter with the negative of the battery. If the markings of the cell
terminals are indistinct, connect the voltmeter across any one cell.
In case the pointer butts up against the stop at the left instead of
giving a reading, the connections are wrong and should be reversed;
if the instrument shows a reading for one cell, the positive terminal
of the voltmeter is in contact with the positive of the battery. This
test can be made with a voltmeter without any risk of short-circuiting
the cell, as the voltmeter is wound to a high resistance and will pass
very little current. Connecting an ammeter directly across a cell, how-
ever, would short-circuit it and instantly burn out the instrument.
How to Take Readings. It is one of the peculiarities of the
storage cell that when on "open circuit", i.e., not connected in
circuit with a load of any kind, it will always show approximately
two volts, regardless of whether it is almost fully charged or almost
the reverse. Consequently, voltage readings taken when the battery
is on open circuit, i.e., neither charging nor discharging, are valueless,
except when a cell is out of order. Therefore, a load should be put
on the battery before making these tests. This can be done by
switching on all the lamps. With the lights on, connect the volt-
meter, as already directed, and test the individual cells. If the
battery is in good condition, the voltage readings, after the load
has been on for about ten minutes, will be but slightly lower than
if the battery were on open circuit. This should amount to about
.1 (one-tenth) volt. Should one or more of the cells be completely
discharged, the voltage of these cells will drop rapidly when the
lamps are first switched on and, when a cell is out of order, will
sometimes show a reverse reading. Where the battery is nearly
discharged, the voltage of each cell will be considerably lower than
if the battery were on open circuit, after the load has been on for
Detecting Deranged Cells. To distinguish the difference between
cells that are merely discharged and those that are out of order,
put the battery on charge, either from an outside source or
by starting the engine, which should always be cranked by hand
578 ELECTRICAL EQUIPMENT
when any battery trouble is suspected. Then test again with the
voltmeter. If the voltage of each cell does not rise to approximately
two volts after the battery has been on charge for ten minutes or
more, it is an indication of internal trouble which can be remedied
only by dismantling the cell. (See instructions under that heading.)
Temperature Variations in Voltage Test When making voltage
tests, it must be borne in mind that the voltage of a cold battery rises
slightly above normal on charge and falls below normal on discharge.
The reverse is true of a warm battery in hot weather, i.e., the voltage
will be slightly less than normal on charge and higher than normal
on discharge. As explained in connection with hydrometer tests
of the electrolyte, the normal temperature of the electrolyte may
be regarded as 70° F., but this refers only to the temperature of
the liquid itself as shown by the battery thermometer, and not to
the temperature of the surrounding air. For the purpose of simple
tests for condition, voltage readings on discharge are preferable,
as variations in readings on charge mean little except to one expe-
rienced in the handling of storage batteries.
Joint Hydrometer and Voltmeter Tests. As already explained
above, neither the hydrometer nor the voltmeter reading alone
can always be taken as conclusive evidence of the condition of the
battery. There are conditions under which one must be supple-
mented by the other to obtain an accurate indication of the state
of the battery. In making any of the joint tests described below,
it is important to take into consideration the four points following:
(1) The effect of temperature on both voltage and hydrometer
(2) Voltage readings should be taken only with the battery
discharging, as voltage readings on an idle battery in good condition
indicate little or nothing.
(3) Never attempt to use the starting motor to supply a
discharge load for the battery, because the discharge rate of the
battery is so high while the starting motor is being used that even
in a fully charged battery it will cause the voltage to drop rapidly.
(4) The voltage of the charging current will cause the voltage
of a battery in good condition to rise to normal or above the moment
it is placed on charge, so that readings taken under such circumstances
are not a good indication of the condition of the battery.
ELECTRICAL EQUIPMENT 579
In any battery which is in good condition, the voltage of each
cell at a normally low discharge rate, i.e., 5 to 10 amperes for a starter
battery of the G-volt type or slightly less for a higher voltage battery,
will remain between 2.1 and 1.9 volts per cell until it begins to
approach the discharged condition. A voltage of less than 1 .9 volts
per cell indicates either that the battery is nearly discharged or is
in a bad condition. The same state is also indicated when the
voltage drops rapidly after the load has been on for a few minutes.
The following joint hydrometer and voltmeter tests issued by the
Prest-O-Lite Company of Indianapolis will be found to cover
the majority of cases met with in actual practice.
(1) A voltage of 2 to 2.2 volts per cell with a hydrometer reading of 1.275
to 1.300 indicates that the battery is fully charged and in good condition.
(2) A voltage reading of less than 1.9 volts per cell, with a hydrometer
reading of 1.200 or less indicates that the battery is almost completely discharged.
(3) A voltage reading of 1.0 volts or less per cell, with a hydrometer
reading of 1.220 or more, indicates that excess acid has been added to the cell,
ruder these conditions, lights will burn dimly, although the hydrometer reading
alone would appear to indicate that the battery was more than half charged.
(4) Regardless of voltage — high, low, or normal — any hydrometer reading
of over 1.300 indicates that an excessive amount of acid has been added.
(">) Where a low voltage reading is found, as mentioned in cases 2 and
3, to determine whether the battery is in bad order or merely discharged, stop
the discharge by switching off the load, and put the battery on charge, cranking
the engine by hand, and note whether the voltage of each cell rises promptly to
2 volts or more. If not, the cell is probably short-circuited or otherwise in bad
Cleaning a Battery. Electric vehicle batteries usually receive
such careful and intelligent attention that the life of the battery
is measured by the maximum number of charges and discharges of
which the plates are capable under favorable conditions. To prevent
any possibility of short-circuiting, a cell is cut out and opened after
a certain number of discharges, and if the amount of sediment in
the jar is approaching the danger point, the entire battery is opened
and cleaned. With the old type starter cell, this would be necessary
if the battery received the proper attention; with the modern or
high mud-space type, cleaning is never necessary as the space is
designed to accommodate all the active material that can fall from
the plates without touching their under sides. As a matter of fact,
the batteries of starting and lighting systems never last long enough
to require cleaning out. They are either kept undercharged and
580 ELECTRICAL EQUIPMENT
thus become badly sulphated, or they are overcharged to a point
where the temperature passes the danger mark frequently. When
hot, the acid attacks and injures the wood separators so that the
average life is about one year. Exceptions to this are found in
those cases where the battery has been given proper attention,
which results in unusually long life without the necessity of opening
the cells for either cleaning or the insertion of new separators. These
cases are so in the minority, however, that the battery manufacturers
usually recommend that the car owner have his starting battery
overhauled in the fall to put it in the best of condition for the winter
as well as for the following year. Even where a battery has been
Fig. 387. Drilling Off Connectors
Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania
given conscientious attention, the conditions of charging on the
automobile are likely to vary so radically that it will be found almost
impossible to keep the cells in a good state. Consequently, it is
considered the best practice to give all starter batteries an over-
hauling once a year. The method of doing this is described in
Replacing a Jar. When a cell requires the addition of distilled
water more often than the other cells of the battery, or does not
test to the same specific gravity as the others, it is usually an indica-
tion that there is a leak in the jar. Failure to give the same specific-
gravity reading is not proof of this condition, as the cell may be
ELECTRICAL EQUIPMENT 581
low from other causes, but the loss of electrolyte is certain evidence
of it. The only remedy is to replace the jar at fault.
After locating the cell in question, carefully mark the connectors
so as to be sure to replace them the same way. Disconnect the
cell from the others in the battery. This may be done either with
the aid of brace and bit, which is used to drill down through the
post of the connector, Fig. 387, or with a gasoline torch which should
be applied carefully to the strap at the post. When the metal has
become molten, pry the strap up on the post with a piece of wood.
Do not use a screwdriver or other metal for this purpose as it is
apt to short-circuit one or more of the cells. Care must also be
taken not to apply so much heat that the post itself will be melted as
this would make it difficult to reconnect the cell. For one not
accustomed to handling the
torch, it will be safer to drill out
the post, as illustrated. Lift the
complete cell out of the battery
box and then use the torch to
warm the jar around the top
to soften the sealing compound
that holds the cover, Fig. 388.
Grip the jar between the feet,
take hold of the two connectors
and pull the element almost out
of the jar, Fig. 389. Then grip „. a , . a ,. „ , „ „
J ' e & * Fig. 388. Softening Scaling Compound on Cell
the elements near the bottom
to prevent the plates flaring out while transferring them to the new
jar, taking care not to let the outside plates start down the outside
of the jar, Fig. 390. After the element is in the new jar, reseal the
cell by pressing the sealing compound into place with a hot putty
knife. Fill the cell with 1.250 electrolyte to the proper point, the
old electrolyte being discarded.
Before replacing the connectors, clean both the post and the
inside of the eye of the connector by scraping them smooth with
a knife.* When the connector has been placed in position, tap it
down firmly over the post to insure good contact. To complete
the connection, melt the lead of the connector and the post at the
top so that they will run together, and while the lead is still molten,
582 ELECTRICAL EQUIPMENT
melt in some more lead until the eye of the connector is filled level.
This is termed lead burning and is described at greater length in
a succeeding section. Where no facilities are at hand for carrying
it out, it may be done with an ordinary soldering copper. The
copper is brought to a red heat so that all the tinning is burned
off, and no flux of any kind is used. The method of handling the
soldering copper and the lead-burning strip to supply the extra
metal required to fill the eye is shown in Fig. 391 .
Fig. 380. Lifting Elements out of Jar Fig. 393. Installing Elements
by Hand in Jar
Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania
Put the battery on charge from an outside source, and when
the cells begin to gas freely, reduce the current to half the finishing
rate given on the battery name plate and charge at this rate as long
as there is any rise in the specific gravity of the electrolyte in
this or any of the other cells. The maximum gravity has been
reached when there has been no rise in the specific gravity for a
period of three hours. If the gravity of the cell having the new jar
is then over 1.280, draw off some of the electrolyte and replace it
with distilled water. If the gravity is below 1.270, draw off some of
the electrolyte and replace it with 1.300 electrolyte. If necessary
ELECTRICAL EQUIPMENT 583
to put in 1.300 electrolyte, allow the battery to continue charging
for about one-half hour longer at a rate sufficient to cause gassing,
which will cause the stronger acid to become thoroughly mixed with
the rest of the electrolyte in the cell.
Overhauling the Battery. As already mentioned, it will be
found desirable to overhaul the majority of starter batteries at
least once a year. The expense to the car owner will be less than
Pig. 391. Reburning Battery Connectors with Soldering Iron
Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania
the cost of the frequent attention required by a run-down battery
with complete renewal at no distant date, and the service rendered
by the battery will be much improved. The best time of year to
do this is in the late fall, so that the battery may be at its best during
the cold weather. Before undertaking the work, have on hand a
complete renewal set of rubber and wood separators as well as suf-
ficient fresh acid of 1.300 specific gravity with which to mix fresh
electrolyte. Use the good separators, particularly the rubber ones.
5M ELECTRICAL EQUIPMENT
Dismounting Cells. Remove the connectors by drilling, heating,
or pulling (in the same manner as a wheel is pulled), and loosen
the jar covers by heating or running a hot putty knife around their
edges so that they may be lifted off. The covers should be washed
in hot water and then stacked one on top of the other with heavy
weight on them to press them flat. Lift the jars out of the battery
box and note whether any of them haye been leaking. A cracked
jar should of course be replaced. Treat one cell at a time, by
pulling the element out of the jar with the aid of the pliers, meanwhile
holding the jar with the feet. Lay the element on the bench and
Fig. 392. Removing Old Separators Fig. 393. Pressing Negative Group
Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania
spread the plates slightly to permit removing t he separators, taking
care not to injure the rubber sheets, Fig. 392. Separate the positive
group from the negative. If the active material of the negative
be swollen beyond the surface of the grid, press it back into position
before it has a chance to dry, placing boards of suitable thickness
between the plates and carefully squeezing the group between heavy
boards in a vise or press, as shown in Fig. 393. Boards of sufficient
size and thickness must be used between the plates or breakage
will result. Charged negative plates will become hot in a short
time when exposed to the air and, in this event, should be allowed
to cool before reassembling. Remove any loose particles adhering
Google . J
ELECTRICAL EQUIPMENT 585
to the positive plates by passing a smooth wood paddle over the
surface but do not wash the positive plates.
Treating the Plates. If the positive plates show signs of buckling
or stripping of the active matter, or if the negative plates have the
light spotted appearance indicative of sulphating, it may be necessary
to replace them altogether. In case sulphating appears to be the
only trouble, the groups should be reassembled in an open jar with
distilled water and given a long, slow charge, testing with the hydrom-
eter at frequent intervals to note whether the specific gravity is
rising or not. Twenty-four hours
or more may be necessary for
this charge, and two or three days
will be nothing unusual. This
charging, of course, is carried on
from the lighting mains through
a rectifier or a motor-generator,
unless direct-current service is
available. If it is necessary to
prolong the charge over two or
three days, and the specific grav-
ity still continues to rise slowly,
it may be preferable to replace
Reassembling Battery. Wash
all the sediment out of the jars,
also wash and save the rubber
sheets, unless they happen to be ^. „, J 3 n ^ o
J i F,R - 394 Wood and Rubber Separator
broken, but throw away the old
wood separators. The rubber sheets should be placed in clean
running water for about a quarter of an hour. Reassemble the
positive and negative groups with the plates on edge in order to
insert the separators. Place a rubber separator against the grooved
side of a wood separator, Fig. 394, and insert a positive plate near
the center of the element. The rubber sheet must be against the
positive plate, and the wood separator against the negative plate.
In this manner insert separators in all the spaces, working in both
directions from the center. Care must be taken not to omit a sepa-
rator as that would short-circuit the cell.
586 ELECTRICAL EQUIPMENT
The separators should be practically flush with the bottoms of
the plates to bring their tops against the hold-down below the strap,
and must extend to or beyond the side edge of the plates. Grip
the element near the bottom to prevent the plates flaring out while
placing the element in the jar. Fill the cell to within one-half inch
of the top of the jar, using electrolyte of 1.250 specific gravity. If
the negative plates show signs of sulphating, but not enough to call
for the special treatment mentioned above, use water instead of the
electrolyte. After all of the cells have been given the same treatment
and reassembled, return them to the battery box in their proper
positions, so that the positive of each cell will be connected to the
negative of the adjoining cell and connect temporarily by pressing
the old connecting straps in place by hand.
Checking the Connections. Put the battery on charge at its
finishing rate (usually about 5 amperes) and, after charging about
fifteen minutes, note the voltage of each cell. This is to insure
having reconnected the cells properly with regard to their polarity.
If this be the case, they should all read approximately 2 volts. Any
cell that reads less is likely to haVe been connected backward. When
the cells begin to gas freely and uniformly, take a hydrometer reading
of each cell and a temperature reading of one of them. Reduce the
current to one-half the finishing rate. Should the temperature of
the electrolyte reach 100° F., reduce the charge, or interrupt it
temporarily, to prevent the cells getting any hotter. Both hydrometer
and temperature readings must be taken at regular intervals, say
four to six hours apart, to determine if the specific gravity is still
rising or if it has reached its maximum. Continue the charge and
the readings until there has been no further rise for a period of at
least twelve hours. Maintain the height of the electrolyte constant
by adding water after each reading. (If water were added before
the reading, it would not have time to mix with the electrolyte,
and the reading would not be correct.)
Should the specific gravity rise to about 1.300 in any cell, draw
off the electrolyte down to the level of the tops of the plates and
refill with as much water as possible without overflowing. Continue
the charge, and if the specific gravity again exceeds 1\300, dump
out all the electrolyte in that cell, replace it with water, and continue
the charge. The charge can be considered complete only when
Pig. 305. Wiring Diagram for Discharging
Battery through Rheostat
there has been no rise in the gravity of any of the cells during a period
of at least twelve hours of continuous charging. Upon completion
of the charge, the electrolyte
should have its specific gravity
adjusted to its proper value
(1.270 to 1.280) using water
or 1.300 acid, as may be nec-
essary, and the level of the
electrolyte adjusted to a uni-
form \ inch above the plates.
Discharge the battery at
its normal discharge rate to
determine if there are any
low cells caused by defective
assembly. The normal dis-
charge rate of the battery is
usually given on its name
plate. To discharge the bat-
tery, the current may be
passed through a rheostat, as
in Fig. 395, or if no panel
board of this type be avail-
able, through a water resist-
ance, as shown in Fig. 396.
The resistance of a water rheo-
stat increases with the dis-
tance between its plates and
decreases according to their
proximity and to the degree
of conductivity of the water ^^*™"J y f^
itself. If the resistance is
too high with the plates close
together, add a little acid to
the water. It will be neces-
sary, of course, to have an
fTetfges Ur Holding
Wiring Diagram for Discharging
gh Water Resistance
ammeter in the circuit to show the rate at which the battery is
discharging. In case any of the tells are low, owing to being assem-
bled defectively or connected with their polarity reversed, as shown
588 ELECTRICAL EQUIPMENT
by the voltmeter test (they should all register two volts or slightly
over at the beginning of the discharge and should fall off slowly) such
cells should be remedied at once. Recharge the battery and then
remove the temporary connectors, wipe the inside edges of the jars
dry, and put the rubber covers in place. Heat the sealing compound
which is supplied for this purpose and apply around the edges of the
covers, smoothing it down with a hot putty knife. Care must be
taken not to burn the sealing compound when heating it.
Reconnecting Cells. If the old lead connecting straps have been
removed carefully, they may be used again, though in many cases
it will be found preferable to employ new straps. Before ^putting
the straps in place, scrape the posts clean with a knife and clean
out the eyes of the straps themselves. When the connectors have
been put in place, tap them down firmly to insure good contact.
Before reburning the connectors in place, test each cell with a low-
reading voltmeter to make certain that the cells have been connected
in the right direction, i.e., that their polarity has not been reversed.
It is not sufficient to note that the voltage of each cell is correct,
i.e., 2 volts per cell or over, but care must be taken also to note that
it is in the right direction. With a voltmeter having a needle that
moves in both directions from zero, one polarity will be evidenced
by the needle moving over the scale to the right of the neutral line,
while if the polarity be reversed, the needle will move to the left.
One cell having the proper polarity should accordingly be tested
and then, to be correct, the remaining cells should cause the needle
to move in the same direction and to approximate the same voltage
when the instrument leads are held to the same terminals in the
same way for each. Where the voltmeter needle can move in but
one direction, i.e., to the right, a change of polarity will be indicated
by the needle of the instrument attempting to move to the left
and, in so doing, butting up against the stop provided to prevent
this. Complete the reassembly of the cells by burning the connectors
together, as detailed under the head of Lead Burning.
Renewals. In many cases it will be found necessary upon
overhauling a battery to renew the elements. These may be purchased
either as loose plates or as groups ready to assemble in the battery.
Except in garages doing a large amount of this work, it will not
be advisable to buy the loose plates and burn them into groups.
ELECTRICAL EQUIPMENT 589
The new groups should be assembled with rubber sheets and wood
separators, as directed in overhauling the battery, the jars filled
with fresh electrolyte of the proper specific gravity and the battery
given a test charge and discharge with temporary connections. The
electrolyte should be of 1.250 specific gravity, or seven parts of
water to two of pure sulphuric acid by volume. If the test charge
has been carried to a point where the specific gravity has ceased to
rise for several hours, and the discharge shows no defectively
assembled cells, the cells may be permanently connected.
Lead Burning. Type of Outfit. In the manufacture of storage
batteries, and in garages where a large number of batteries are
fig. 397. Arc-Welding Outfit for Burning Connections
maintained, a hydrogen-gas apparatus is employed for this purpose.
For the electric-car owner or the garage doing a comparatively small
amount of battery repair work, the Electric Storage Battery Com-
pany has placed an arc lead-burning outfit on the market. This
is low in first cost and, with a little practice, good results can be
obtained with it. As the battery itself supplies the power neces-
sary, the only material required is the lead in the form of a flexible
strip or heavy wire. The complete outfit is illustrated in Fig. 397.
At one end is the clamp for making electrical connection, while at
the other is a clamp of different form having an insulated handle
and holding a one-fourth inch carbon rod. The two are electrically
590 ELECTRICAL EQUIPMENT
connected by a flexible cable. This simple outfit can be employed
in two ways, the second being preferable for the beginner, at least
until sufficient amount of skill has been acquired to use the arc
without danger of melting the straps.
. First Method of Burning. In the first method, a potential of
from 28 to 30 volts (12 to 15 cells) is required.* The clamp should,
therefore, be fastened to the positive pole of the twelfth to the
fifteenth cell away from the joint to be burned, counting toward the
negative terminal of the battery. The carbon then forms the negative
terminal of the circuit. Otherwise particles of carbon will be carried
into the joint, as the carbon rod quickly disintegrates when it forms
the positive pole. The carbon should project 3 or 4 inches from the
holder. The surfaces of the parts to be burned should be scraped
clean and bright, and small pieces of clean lead about 1 to J inch
square provided for filling the joint. The carbon is then touched to
the strap to be burned and immediately withdrawn, forming an
electric arc which melts the lead very rapidly. By moving the carbon
back and forth the arc is made to travel over the joint as desired, the
small pieces of lead being dropped in to fill the gap as required.
Owing to the high temperature generated, the work must be carried
out very quickly, otherwise the whole strap is liable to melt and run.
As this method is difficult and requires practice to secure good
results, the beginner should try his hand on some scrap pieces of
lead before attempting to operate on a cell. Its advantages are
that when properly carried out it takes but a short time to do the
work, and the result is a neat and workmanlike joint. It is extremely
hard on the eyes and smoked or colored glasses must be used.
Second Method of Burning. The second method, utilizing the
hot point of the carbon rod instead of the arc, is recommended for
general practice. Scrape the parts to be joined and connect the
clamp between the third and fourth cells from the joint. With this
method it is not necessary to determine the polarity of the carbon.
The latter is simply touched to the joint and held there; on account
of the heavy flow of current it rapidly becomes red and then white
hot. By moving it around and always keeping it in contact with
the metal, the joint can be puddled. To supply lead to fill the joint,
♦This voltage may be obtained from an electric vehicle battery in the garage or from the
lighting mains through a suitable resistance, first converting to direct current where the supply
Digitized by VjOOQ IC
ELECTRICAL EQUIPMENT 591
an ordinary lead-burning strip can be used, simply introducing the
end into the puddle of molten lead, touching the hot carbon. The
carbon projecting out of the holder should be only one inch, or even
less, in length. After the joint has been made, it can be smoothed
off by running the carbon over it a second time.
Use of Forms to Cover Joint. In joining a strap which has been
cut in the center, it is best to make a form around the strap by means
of a piece of asbestos sheeting soaked in water and fastened around
the strap in the shape of a cup, which will prevent the lead from
running down. It will be found that sheet asbestos paper is thick
enough, but it should be fairly wet when applied. By this means a
neat joint can be easily made. The asbestos will adhere very tightly
to the metal owing to the heat, but can be removed by wetting it
again. When burning a pillar post to a strap, a form may be made
around the end of the strap in the same manner, though this is not
necessary if reasonable care is used. Two or three pieces of i^-inch
strap iron about one inch wide, and some iron nuts about one inch
square are also of service in making the joint, the strap iron to
be used under the joints, and the nuts at the side or ends to confine
the molten lead. Clay can also be used in place of asbestos, wetting
it to a stiff paste. As the holder is liable to become so hot from
constant use as to damage the insulation, besides making it uncom-
fortable to hold, a pail of water should be handy, and the carbon
dipped into it from time to time. This will not affect its operation
in any way, as the carbon becomes hot again immediately the current
passes through it.
Illuminating Gas Outfit. Heretofore it has not been possible to
do good work in lead burning with illuminating gas, but a special
type of burner has recently been perfected by the Electric Storage
Battery Company, which permits the use of illuminating gas with
satisfactory results. The outfit consists of a special burning tip and
mixing valve. Sufficient ^inch rubber hose should be provided, and
the rubber should be wired firmly to the corrugated connections, Fig.
398, as the air is used at a comparatively high pressure. A supply of
compressed air is necessary, the proper pressure ranging from 5 to 10
pounds, depending upon the length of hose and the size of the parts to
be burned. When air from a compressor used for pumping tires is
utilized for this purpose, a suitable reducing valve must be introduced
592 ELECTRICAL EQUIPMENT
in the supply line. This outfit is designed for use with ordinary
illuminating gas and cannot be employed with natural gas.
Connect the air hose to the right-hand cock and the gas hose to
the left-hand cock. The leader hose, about five or six feet long, is
connected to the lower pipe and to the upper end of the bjirning tip.
When the air pressure at the source is properly adjusted, close the
air cock and turn the gas cock on full. Light the gas at the tip and
turn on the air. If the flame blows out, reduce the air pressure,
preferably at the source. With the gas turned on full, the flame
Fig. 308. Lead-Burning Outfit for Use with Illuminating Gaa
Courtesy of Electric Storage Battery Company,
will have a ragged appearance and show a waist about \ inch from
the end of the tip, the flame converging there and spreading out
beyond. Such a flame is not good for lead burning.
Slowly turn the gas off until the outer portion at the waist
breaks and spreads with an inner tongue of flame issuing through the
outer ring. The flame will now have a greenish color and is properly
adjusted for burning. If the gas is turned off further or if too much
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 593
air is turned on, the flame assumes a blue color gradually becoming
invisible and is then deficient in heating power. When properly
adjusted, the hottest part of the flame is just past the end of the inner
point. Do not hold the flame too close to the work when burning,
as its heating effect is greatly reduced and the flame is spread so as to
make control difficult. The burning tip has at its lower end an
outer sleeve and lock nut; this sleeve can be taken off in case any
of the holes in the tip become clogged. The position of this sleeve
is adjustable, the best position varying with the pressure of the
flame, and it should be determined by experiment.
Hydrogen Gas Outfit. Hydrogen gas gives a hotter flame and
therefore permits of more rapid work, so that where burning is done
on a large scale, it is still preferred. The essentials of such an outfit
are: first, a hydrogen generator; second, a method of producing air
pressure at approximately 2 pounds to the square inch; and third,
the usual pipe and tips for burning. If hydrogen gas is purchased in a
tank and compressed air is available, only the blowpipe, tips, and a
reducing valve on the air line are necessary. This is an expensive
method to purchase hydrogen, however, so that it is usually generated,
and a water bottle is needed between the generator and the blowpipe
to wash the gas and to prevent the flame from traveling back to the
For this purpose hydrogen gas is generated by placing zinc in a
sulphuric-acid solution. The generator usually employed for vehicle-
battery burning requires 50 pounds of zinc, 2 gallons of sulphuric
acid, and 9 gallons of water for a charge. Where no compressed-air
supply is available, an air pump and an air tank for equalizing the
pressure must be used. An outfit of this kind is shown in Fig. 399.
In preparing the generator for use, connect up as shown in this cut,
taking care that the hose from the generator is connected to the
nipple of the water bottle L. Have the water bottle one-half to
two-thirds full and immerse it in a pail of cold water up to i£s neck.
Replace the water in the pail whenever it becomes warm. Have stop
cock N closed. Put the required amount of zinc, which has been
broken into pieces small enough to pass through the opening C,
into the lower reservoir. Put on cap X and screw down with clamp D,
being sure that the rubber drainage stopper H is well secured in
place. Pour the proper amount of water into reservoir A and then
pour in the acid, taking care to avoid splashing. Always pour the
water in first
In running the hose from K to N, arrange it so that there will
be no low points for the water of condensation to collect in; in other
words, this hose should drain back at every point to the water bottle.
If, however, water should collect in the hose to such an extent as to
interfere with the flame and it cannot readily be drained off, kink the
hose between T and U and detach it from K; close the stop cock at
W and pump until a strong pressure is obtained in the tank; then close
Fig. 391). Diagram of Lead-Burning Outfit, Using Hydrogen Gas
the cock at V, opening those at S and N and, finally, quickly open W;
the pressure in the air tank will then force the water out of the hose.
The length of the hose from T to U should be such that the mixing
cocks at S and N are always within easy reach of the man handling
In preparing the flame for burning, close the air cock at S and
open N wide, hold a match to the gas until it lights, then add air
and adjust the gas cock slowly, turning toward the closed position
until the flame, when tried on a piece of lead, melts the metal and
leaves a clean surface. The tip to be used depends on the work, but
most vehicle-battery work is done with the medium tip. Replenish
ELECTRICAL EQUIPMENT 595
the zinc every few days, keeping it up to the required amount. When
a charge is exhausted or the generator is to be laid up for the night,
the old solution should be drawn off before making up a new charge
and the generator thoroughly flushed out by running water through A.
The new charge should not be put in until the generator is to be used
again. To empty the generator, first pull off the hose at the nipple
K, then at E, and finally the rubber plug at H. Care should be
taken not to allow the solution to splash on anything and not to
dump the generator where the contents will damage cement, asphalt,
or wood walks.
Installing New Battery. In not a few instances, it will be neces-
sary to renew the entire battery. As received from the manufacturer,
the battery is in a charged condition, i.e., it was fully charged just
previous to being shipped, but it must be inspected and tested before
being installed on the car. Care must be taken in unpacking it to
avoid spilling any of the electrolyte. After cleaning off the packing
from the tops of the cells, take out the rubber plugs and see that the
electrolyte is £ inch over the plates. If it is uniformly or approxi-
mately below the proper level in all the cells, this is simply the loss
due to evaporation. But if low in only one. or two cells, this is
evidently caused by loss of electrolyte. In case this loss has resulted
from the case being turned over in shipment, it will be indicated
by the presence of acid on the packing on top of the battery (the
acid does not evaporate), and some of the electrolyte will have
been lost from all the cells. Replace the amount lost by refilling the
cells with electrolyte of 1.250 specific gravity, as already directed.
In case the loss of electrolyte is caused by a cracked or broken
jar, the packing under the battery will be wet. Replace the broken
jar as instructed in the directions under that heading and add sufficient
electrolyte of 1.250 specific gravity to make up for the loss. Should
it be found, after replacing the broken jar and giving the battery
an equalizing charge, that the specific gravity does not reach approxi-
mately 1.275, it is due to not having replaced the same amount of
acid as was spilled. To adjust this, draw off the electrolyte from
the cell with the syringe and add water or 1.300 acid to bring the
specific gravity to between 1.270 and 1.280.
Storing a Battery. There is an amusingly erroneous idea
prevalent to some extent that the charge of a storage battery is
Digitized by VjOOQIC
596 ELECTRICAL EQUIPMENT
represented by its electrolyte; that pouring off the electrolyte takes
the charge with it; that, in case it is desired to store a battery,
all that is necessary is to pour off the electrolyte and store the empty
battery arid the solution separately; and when it is desired to put
the battery back in commission, it is then only necessary to pour
the electrolyte back into the cells and, presto! they are ready to
start the engine right away. Unfortunately for this theory, the charge
is in the active material of the plates and not in the electrolyte.
It is frequently necessary to allow the battery to remain idle
for a considerable length of time, in which case it should be put
out of commission. If the battery itself is in good condition at
the time and if it may be wanted for service again at' short notice,
this need only consist of giving it a long equalizing charge until
the specific gravity has ceased to rise for several hours, then filling
the cells to the top with distilled water and putting the battery away
in a handy place. It should be given a freshening charge every
two weeks or, at least, as often as once a month. If it is actually
to be stored, there are two ways of doing this.
One is known as the wet storage method, and the other as
the dry, the one to be adopted depending upon the condition of the
battery and the length of time it is to be out of commission. The
wet storage method is usually applied to any battery that is to be
out of commission less than a year, provided that it will not soon
require repairs necessitating dismantling it. The dry storage method
is used for any battery that is to be out of commission for more than
a year, regardless of its condition, and it is also applied to any battery
that will shortly require repairs necessitating its dismantling. It
wil^ be apparent that this last-named class includes most starter
batteries after they have seen several months of service, so that the
majority can be placed in dry storage when necessary to put them
out of commission.
Examine the condition of the plates and the separators and
also the amount of sediment in the bottom of the jars. If it is found
that there is very little sediment and the plates and separators are
in sufficiently good condition to give considerable additional service,
the battery may be put into wet storage by giving it an equalizing
charge and covering it to exclude dust. Replace evaporation
periodically to maintain the level of the electrolyte \ inch above the
ELECTRICAL EQUIPMENT 597
tops of the plates. At least once every four months, charge the
battery at one-half its normal finishing rate (see name plate on
battery box) until all the cells have gassed continuously for at least
three hours. Any cells not gassing should be examined, and the
When examination shows that the battery will soon require
dismantling, it should be put into dry storage. Dismantle the cells
in accordance with the instructions already given. If the positive
plates show much wear, they should be scrapped; if not, remove
any loose particles adhering to them by passing a smooth wood
paddle over the surface, but do not wash the positive plates. Charged
negative plates will become hot in a short time when exposed to
the air. They should be allowed to stand in the air until cooled.
Empty all the electrolyte out of the jars into a glass or glazed
earthenware jar or a lead-lined tank and save it for giving the negative
plates their final treatment before storage. Wash all the sediment
out of the jars and wash the rubber separators carefully, then dry
them and tie them in bundles. Place the positive groups together
in pairs, put them in the jars, and store them away. Then put the
negative groups together in the same way, place them in the remaining
jars, and cover them with the electrolyte saved for the purpose,
allowing them to stand in it for five hours, at least. Then pour off
the electrolyte, which may now be discarded, and store away the
jars containing the negatives. If the negative plates show any
bulging of the active material, they should be subjected to the pressing
treatment first, using boards and a vise, as described in a previous
section. All of the jars should be well covered to exclude dust.
Make a memorandum of the amount of material required to
reassemble the battery, and, when ordering this, provide for extra
jara and covers, extra rubber separators, and an entire lot of wood
separators with a sufficient excess to take care of breakage in handling.
Unless the old connectors were carefully removed, order a new set.
When a battery is put in storage, it is well to advise the owner in
regard to the material necessary to reassemble, and to request at least
a month's notice to procure it.
Charging from Outside Source. Theoretically at least, the
starter battery on the automobile should be kept in an ideal condition.
It is constantly under charge while the car is running at anything
598 ELECTRICAL EQUIPMENT
except the lowest starting speeds and should accordingly always
be fully charged. The generator is designed to take care of the
storage battery and usually has sufficient capacity to light all the
lamps in addition. Practice, however, does not bear out this
theoretical view of thie favorable conditions under which the starter
battery is supposed to operate. It will be apparent at the very
outset that the method of charging and discharging is not beneficial.
To insure long life to a storage battery, it should be fully charged
and then discharged to at least seventy-five per cent of its maximum
capacity before recharging. It should never be allowed ^o stand
discharged for any length of time. If exhausted, it should be
recharged immediately. It should not be charged to half its capacity
and then discharged. It should not be overcharged to the point
where it continues to gas violently nor where its temperature exceeds
All of these are things that should not be done to the storage
battery, but it will take only a little experience to enable the garage
man to recognize that all these are things which are constantly being
done to the majority of storage batteries on gasoline automobiles.
Most batteries receive treatment that reaches one extreme or the
other, though it will be apparent that the middle course is almost
as injurious to the battery. Either a battery is constantly kept
undercharged so that it has insufficient charge to spin the engine
more than once, and its operation is accordingly unsatisfactory, or
it. is constantly kept overcharged with the result that the hot acid
makes comparatively short work of the plates, and they must be
renewed in considerably less than a year of service. The mean course
between these two is found in the case of the battery that is only
charged to about half its capacity before being discharged again by
the use of the starting motor. This treatment results in sulphating.
To keep the storage battery of the starting system in anything
like efficient operating condition, it cannot be left on the running
board with nothing but the generator of the starting and lighting
system to charge it. Hydrometer and voltage tests will be valueless
unless the conditions they indicate are remedied, and this cannot
be done with the car generator as the sole source of charging current.
Here is a typical instance: The battery is in good condition and it
is fully charged. On a cold morning, it is drawn on intermittently
ELECTRICAL EQUIPMENT 599
for almost fifteen minutes by the starting motor before the engine
fires. As a result, it is practically discharged. The car is driven only
a few miles, stopped and after a rest started again. What charge
the battery received by the short run is again lost. The car is run
for a little longer time and returned to the garage. The battery
has received about one-fourth its normal charge. It stands this
way for several days.
The weather being warmer, the engine starts in a much shorter
time, but not before the starting motor has exhausted the small
amount of charge in the battery. It is not nm enough that day to
charge the battery nor when taken out again that night, as all the
lights are switched on, and under such conditions the battery receives
very little current. Multiply this treatment by five or ten repre-
senting the number of days the car is driven during the month.
At the end of that time, the battery no longer has sufficient charge
to operate the starting motor at all and is condemned, as usual,
by the car owner as being worthless. This is only one instance of
many that are so similar that a few changes in detail would cover
them all. No battery ever made could possibly operate efficiently
under such conditions. After the car in question had been used a
few days, a hydrometer test of the battery would have indicated
its need of charging.
Equalizing Charges Necessary/ Even where a battery receives
almost 100 per cent of its normal charge before being discharged again,
there will be numerous occasions on which the charge is not carried
to completion. As mentioned under the head of Sulphating,
that means so much acid left in the plates at the end of the charge.
That acid represents lead sulphate which continues to increase in
quantity as long as the acid remains in contact with the active
material. To drive it out of the active material into the electrolyte,
which is the function of charging, the charge must be carried to
completion. This is termed an equalizing charge, and it should be
given not oftener than once in two weeks, but at least once a month.
To do this, it is necessary to charge the battery from an outside
source, as it is seldom convenient to nm the engine for the long
period of time needed to complete such a charge. Except in cases
where the battery is chronically overcharged, as indicated by its
violent and continued gassing, it will usually be found necessary
Digitized by VjOOQIC
600 ELECTRICAL EQUIPMENT
to give it an equalizing charge once a month. The constantly over-
charged condition is quite as injurious as its opposite, and it can be
cured only by cutting down the output of the generator or increasing
the demand upon the battery for current.
Methods of Charging* The apparatus employed for charging
starter batteries will naturally vary in accordance with the number
that are looked after in the garage. It may range from the makeshift
consisting of a bank of lamps up to an elaborate panel board designed
to provide charging connections for a dozen or more batteries at once.
Where direct current is available — and only a few starter batteries
need this attention — a bank of lamps in connection with a fused
double-pole switch will be found to fill all the requirements. Note
the charging rate (finishing) given on the name plate of the battery
and make the number of lamps in accordance. A 32 c.p. in the
circuit is practically the equivalent of one ampere of current entering
the battery, i.e., it requires one ampere to light a lamp of this size
and type (carbon filament) to incandescence. A number of standard
lamp sockets should be mounted on a board, connected in multiple,
and the group connected in series with the switch and the battery.
(See illustration in r£sum£ of questions and answers on the battery.)
As many lamps as necessary may then be screwed into the sockets.
The more current needed, the more lamps and the higher power
lamps will be necessary. Tungsten lamps may be employed as well
as the carbon-filament type, but as they take so much less current,
lamps of higher candle power will be needed. For example, to
replace a 32-c.p. carbon-filament lamp, a 100-watt tungsten lamp
will be required.
Charging in Series for Economy. Where several starter batteries
are to be charged at the same time, it will be found more economical
to connect thenyn series and charge them all at once. The difference
between the 110-volt potential of the lighting mains and the 6 to 8
volts needed to charge a single three-cell battery represents that
much waste, as the drop in voltage has to be dissipated, through a
resistance, to no purpose. In this way, any number of 6-volt storage
batteries, up to twelve, can be charged from a 110-volt circuit (direct-
current) with the same expenditure of current as would be required
for a single battery. This is owing to the fact that, in any storage
battery, the capacity of the battery is the capacity of one cell,
ELECTRICAL EQUIPMENT 601
where all are connected in series. Consequently, it will take 10 to
15 amperes to charge one 6-volt battery from the lighting circuit,
and when several more units of the same size are connected in series
with it, the current consumption will still be the same, but a smaller
part of the voltage will have to be wasted through a resistance.
Motor-Generator. Direct current will be found available in
comparatively few places to-day, so that some means of rectifying
an alternating current, in order to use it for charging batteries, will
be necessary. Where quite a number of batteries are to be cared
for, the motor-generator will be found to give the highest efficiency,
besides proving more economical in other ways. As its name indicates,
it consists of a motor wound for alternating current and fed from
the supply mains of the garage, and a direct-current generator Vhich
is driven at its normal generating speed by the a.c. motor. There is
no electrical connection between the two units. Electrical power
in the form of an alternating current is converted into mechanical
power in the a.c. motor which drives the armature of the d.c. generator
and again converts it into electrical power in the form of a direct
current. The first cost of a motor-generator is such that its use is
usually confined to large establishments handling quite a number of
batteries, though motor generators are now made in much smaller
sizes than formerly.
A.C Rectifiers. Where the amount of charging to be done
does not warrant the investment in a motor-generator, a rectifier
is usually employed. There are several makes of different types on
the market: the chemical type, which employs lead and aluminum
plates in an acid solution; the mercury-arc type, in which mercury
is vaporized in a vacuum by the passage of the current; and others,
in all of which the principle is the same. This consists in utilizing
the current on. but one part of the wave, so that the efficiency of
these rectifiers ranges from 60 to 75 per cent. It is accordingly not
good practice to employ them except in the smaller sizes. While
the mercury-vapor rectifier is made for charging private vehicle
batteries, the other types are ordinarily confined to sizes intended
for charging small batteries.
A recent addition to the list that is available for this purpose is
the Tungar rectifier, made by the General Electric Company. The
principle on which this works is the same, but the medium is a new
602 ELECTRICAL EQUIPMENT
one. This is a bulb exhausted of air and filled with a special gas in
which a heavy tungsten-wire filament is brought to incandescence
by the passage of the alternating current. This filament is very
short and thick, its diameter depending upon the capacity of the
rectifier, and it is placed horizontally. It
constitutes the cathode of the couple.
Directly opposite it, but a short distance
away, is the anode of graphite in the form
of a button, the lower face of which is
presented to the tungsten wire. It is made
in three sizes, the smallest of which has a
capacity of but 2 amperes and is designed
for charging the batteries of small portable
lamps, such as are used by miners; and
for charging ignition, call bell, burglar
alarm batteries, and the like.
Fi * 4 g" e^ubw R^ctifE? 6 ^ ^ n ^ e l ar S er s ^ ze » ^ shown in Fig.
400, the bulb is mounted in an iron case,
on the face of which are mounted the switch for alternating cur-
rent; an ammeter on the d.c. side, showing the charge received
by the battery; and a dial switch for adjusting the voltage to
the number of batteries to be charged. There is a compensator
with 15 taps, and the current is adjustable by steps up to 6 amperes.
Anything from a single three-cell battery up to ten of such units
Fist. 401. Interior View of Small Siie G. E. Tungar Rectifies
Courtesy of General Electric Company, Schenectady, New York
(30 cells in all) may be charged at once. The batteries must be
connected in series and then it is only necessary to turn the switch
of the a.c. circuit. In case the alternating-current supply should fail,
the battery cannot discharge through the rectifier, and the latter
ELECTRICAL EQUIPMENT 603
will assume its task again automatically as soon as the current comes
on. This is the 6-ampere 75-volt size. It is also made in a 6-ampere
15-volt size designed for the charging of a three- or six-cell starter
battery in the home garage. Fig. 401 shows an interior view of this
size, illustrating the position of
the converting bulb, the compen-
sator, the reactance coil, and the
fuses, while Fig. 402 illustrates
the 6-ampere 75-volt size, show-
ing the panel instrument, i.e.,
switch, ammeter, and regulating
handle, as well as the bulb and
fuses. A closer view of the bulb
itself is shown in Fig. 403.
Care of Battery in Winter.
There is a more or less general
impression that special treatment Fig. 402. interior view of Large si»e g.e.
must be given the storage battery im8ar ectl er
during cold weather. This is probably owing to the fact that lack
of attention makes itself apparent much more readily in winter than
in summer because of the lower efficiency of the battery resulting
from the lower temperature. The care necessary in winter does not
vary in any respect from
that which should be given
in warm weather, except
possibly that replacement of
the water due to evapora-
tion is not called for so
often, but unless it is con-
scientiously carried out, the
battery is apt to suffer to a
greater extent. In speak- Fig 403 . Tungar Rectifying Buib-the Heart of^
ing of low temperatures, it
must be borne in mind that this always refers to the temperature
of the electrolyte of the battery, and not to that of the surrounding
atmosphere. The latter may be considerably below freezing, whereas
the liquid in the cells may be approaching 100° F. when the battery
is under charge.
004 ELECTRICAL EQUIPMENT
Make the usual hydrometer and voltage tests, as described
under the headings in question, and see that the battery is constantly
kept more fully charged than would be necessary to render satisfactory
service in wanner weather. This is important for two reasons:
first, because of the greatly increased drain on the battery owing to
the difficulty of starting the engine when cold; and second, because
of the liability of the electrolyte to freeze if the battery is allowed
to stand discharged in very cold weather. There is not the same
excess supply of current available for charging the battery in winter
as there is in summer, as the lights are in use during a much greater
part of the time and not so much driving is likely to be done during
the day. As the lamp ldad consumes almost the entire output of the
generator in the average starting and lighting system, there is very
little left for the battery when all the lamps are in use. The practice
of turning on all the lights on the car — headlights, side lights spot
light, and instrument lights — whether they are necessary or not,
should be discouraged in winter, as it is likely to result in exhausting
the battery. The instrument lights are usually in series with the
tail light, and so cannot be dispensed with, but it is never necessary
to have the headlights and side lights going at the same time, and
this also applies to the spot light, which consumes almost as much
current as one of the headlights and should be restricted to the use
for which it is intended, i.e., reading signs by the roadside.
Unless the lamp load is reduced, it may be necessary to increase
the charging rate of the generator during the cold months, and this
is not beneficial to the battery, as it may cause severe gassing and
injury to the plates when continued too long. In case the car is
not driven enough to keep the battery properly charged, it may be
necessary to charge it from an outside source or, if the latter be not
available, to run the engine with the car idle just for this purpose.
Care must be taken to prevent any danger of freezing, and the best
method of doing this is to keep the battery fully charged, as when in
this condition it will freeze only at very low temperatures. The
more nearly discharged a battery is, the higher the temperature at
which it will freeze, and freezing will ruin the cells, regardless of
whether it happens to crack the jars or not.
Why Starting Is Harder in Cold Weather. The electric starting
and lighting system, or rather the storage battery, which is its main-
ELECTRICAL EQUIPMENT 605
stay, is much more severely taxed in winter than in summer for the
following four reasons:
(1) The efficiency of the storage battery decreases with a
decrease in temperature, because the action of the storage battery is
chemical, and chemical action is dependent upon heat and, therefore,
always decreases as the temperature decreases.
(2) The lower the temperature the stiffer the lubricating oil,
which gums the moving parts together, adding a very considerable
load to the ordinary amount of inertia which the starting motor
must overcome and likewise adding to the difficulty of turning the
engine past compression.
(3) Gasoline will not vaporize readily at a low temperature, so
that it is necessary to turn the engine over a great many revolutions
before the cylinders become sufficiently warmed from the friction
and the repeated compression to create an explosive mixture. The
better the mixture the more readily it will fire, and consequently
a greater heat value is required in the spark to ignite it where the
mixture is poor or only partly vaporized. Anything that reduces
the efficiency of the storage battery likewise reduces the heat value
of the ignition spark.
(4) Low heat value of the spark often makes it difficult to
start an engine when cold. This lack of heat in the spark is caused
by a partially discharged battery as well as the lower efficiency of
the battery caused by the cold weather; also by the necessity for
repeated operation of the starting motor, whereby the voltage of the
battery is temporarily cut down.
Intermittent use of the starting motor with a brief period between
attempts will frequently result in starting a cold engine where
continued operation of the starting motor will only result in exhausting
the battery to no purpose. The longer the starting motor is operated
continuously the lower the voltage of the battery becomes, with a
corresponding drop in the heat value of the ignition spark. Cranking
intermittently a number of times has practically as great an effect
in warming the cylinders and generating an explosive mixture as
running for the same period (actual operating time in each case),
while the brief periods of rest permit the battery to restore its normal
voltage, which increases the heat value of the spark and causes the
engine to fire. Both the storage battery and the remaining essentials
606 ELECTRICAL EQUIPMENT
of the starting and lighting system are designed to give satisfactory
service in cold weather, but as a very low temperature brings about
conditions representing the maximum for which the system is designed,
more skillful handling is necessary in winter than in summer to obtain
equally good results.
To Test Rate of Discharge. If the battery terminals are
removable, take off either the positive or the negative terminal,
and connect the shunt of the ammeter to the terminal post and to
the cable which has been removed, binding or wiring it tightly in
place to insure good contact. Where the battery terminals are
not easily removable, insert the shunt in the first joint in the line,
Fig. 404. Setup for Testing Rate of Discharge of Small Storage
Courtesy of Prest-O-Lite Company, Indianapolis, Indiana
as shown in the illustration, Fig. 404. Then connect the ammeter
terminals to the shunt. In case the instrument shows a reverse
reading, reverse the connections to the shunt. When the ammeter
is connected to test for discharge, the starter must never be used
unless the 300-ampere shunt is in circuit, as otherwise the instrument
is likely to be damaged. If a shunt of smaller capacity or a self-
contained ammeter, i.e., one designed to be connected directly in
the line is employed, and it is necessary to start the engine, either
crank by hand or disconnect the ammeter before using the starting
Digitized by VjOOQIC
„ ELECTRICAL EQUIPMENT 607
When the ammeter is connected to show the discharge and no
lights are on, the engine being idle, no current is being used for any
purpose, and the pointer of the ammeter should remain at zero. If
any flow of current (discharge) is indicated, it shows that there is
a ground or a short-circuit (a leak) somewhere in the system. In
such a case, apply the usual tests described under the appropriate
headings for locating grounds and short-circuits.
With the ammeter connected up as shown in the illustration,
the discharge rate of the battery under the various loads it is called
upon to carry may be checked up, and, if it proves to be excessive
in any case, the trouble may be remedied. For example, with the
300-ampere shunt in the line, the amount of energy consume4 by
the starting motor may be checked. Without knowing how much
current a certain make of starting motor should consume in turning
over a given type of engine, it will naturally be impossible to make
any intelligent comparisons with the result of the tests. This infor-
mation, however, is readily obtainable from the manufacturer of
the starting system, and it will be found advantageous to obtain
details of this nature covering the various systems in general use in
your locality, as it will enable you to make these tests valuable in
correcting faults. While the starting loads imposed on the electric
motor by different engines will vary greatly, the general nature of
the load will be practically the same in all cases. When the starter
switch is closed, there will be an excessive discharge rate from the
battery for a few seconds, the discharge falling off very rapidly as
the inertia of the engine is overcome and it begins to turn over,
with a still greater drop to a comparatively small discharge the
moment it takes up its cycle and begins to run under its own power.
Before undertaking such tests, see that the battery is in good
condition and fully charged. Make several tests. Note in each
case whether the maximum discharge at the moment of closing the
switch exceeds the maximum called for by the maker of the starting
system. If a great deal more current is necessary to turn the engine
over than should be the case, it is an indication either that the
starting motor is in need of attention or that the engine itself is
unusually stiff. Atmospheric conditions will naturally have a decided
effect on the result of such tests, as an engine that has stood overnight
in a cold garage will be gummed up with thick lubricating oil and
608 ELECTRICAL EQUIPMENT
will require more power to move it at first than if it had been running
only a few minutes before. As a general rule, more power will
always be needed in winter than in summer, unless the tests are
carried out in a well-heated garage. The condition of the engine
itself will also have an important bearing on the significance of the
tests, as, if the engine has been overhauled recently, its main bearings
may have been tightened up to a point where the engine as a whole
is very stiff.
Note also whether. the discharge rate falls off as quickly as it
should when the engine begins to turn over rapidly. If it does not,
this also is an indication of tight bearings, gummed lubricating oil,
or similar causes, rendering the engine harder to turn over. In
the case of a cold engine, stiffness due to the lubricating oil may be
remedied by running it for ten or fifteen minutes, and a subsequent
test should then agree with the manufacturer's rating. Where the
discharge rate does not drop to a nominal amperage within a few
seconds from the time of closing the switch, it is simply an indication
that the essentials of the engine are not in the best of working order.
The carburetor may not be working properly, or the ignition may
In case the discharge rate is very much less than that called for
by the manufacturer for that particular engine, it is an indication
that the starting system itself is not in the best condition. Poor
connections, worn brushes, loose brush springs, a dirty switch, or
some similar cause is greatly increasing the resistance in the starting
circuit, thus cutting down materially the amount of current that the
battery can force through it. In such circumstances, the discharge
may not reach so high a rate as that called for by the manufacturer,
but to effect a start, even with the engine in normally good condition,
a high rate will have to be continued longer, to the correspondingly
greater detriment of the battery. In other words, a great deal more
current must be drawn from the battery each time the engine is
started. Thus, testing the rate of discharge may be made to serve
as an indication of the condition of both the starting system and
the engine itself. Should it be necessary to make more than eight
or ten starts to determine definitely the cause of any variation between
the discharge rates shown and those that should be indicated, with
everything in normally good condition, the battery should be fully
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 609
recharged before proceeding any further", as using it for this purpose
when almost exhausted is very likely to damage it. Tests of this
kind show also whether the efficiency of the battery has fallen off
substantially or not, as indicated by its condition after making
several starts in succession. When this has been done, the battery
may be tested with the voltmeter and hydrometer to ascertain how
far it has been discharged. The fact that after having been in service
for some time a starting system will not start the engine so many
times without exhausting the battery as it would when new may
be due either to a loss of efficiency in the battery or to the poor
condition of the other essentials of the system. In the majority of
cases, however, it will be due to the condition of the battery.
By substituting the 30-ampere shunt for the 300-ampere, the
load put on the battery by the lights when switched on in various
combinations may be checked and compared with the manufacturer's
ratings. Where the discharge rate for the lights is less than it should
be, it may be due to the use of bulbs which have seen a great deal
of service, the resistance of the filaments increasing with age, or
other causes which place more resistance in the circuit, such as poor
connections, loose or dirty switches, and the like. Tests may also
be made of the ignition system where the battery is called upon to
supply current to a distributor and coil by putting the 3-ampere
shunt in the circuit. The amount of current required by the ignition
system is very small when everything is in normal working order,
usually not more than 1^ tp 2 amperes. This also can be obtained
definitely from the maker of the apparatus. Any great increase
in the amount of current necessary would usually indicate arcing at
the contact points, which should prove to be in poor condition; a
subnormal discharge would signify a great increase in the resistance
as in the foregoing cases, and should be evidenced by poor ignition
To Test Rate of Charge. To determine the rate at which the
battery is being charged (the small dash ammeters are only approxi-
mately accurate), reverse the ammeter connections and start the
engine by hand. If the car is equipped with a straight 6- or 12- volt
system and a dash ammeter is used, see that its reading agrees
approximately with the portable ammeter. Should the variation
be small, advise the owner so that he may correct his readings
610 ELECTRICAL EQUIPMENT
accordingly when noting the instrument on the road. In case it is
very large, the dash ammeter itself should be adjusted, which can
frequently be done merely by bending the pointer.
With the engine running fast enough to give the maximum
charging rate, which is indicated by the fact that the ammeter
needle stops rising, check the charging rate shown on the portable
ammeter, bearing the following in mind: In the majority of cars,
the generator is regulated to charge the battery at from 10 to 15
amperes. Some are designed to charge at as low a rate as 7 amperes.
Unless the proper charging rate is definitely known, whatever
maximum the portable ammeter shows may usually be assumed to
be correct. Where the rate is less than 7 amperes it may generally
be taken for granted, however, that the battery is undercharging,
and the various tests, described in detail under appropriate headings,
may be applied to locate the trouble either in the generator or in
the automatic cut-out. This applies where the charging rate is too
high as well as where it is too low.
The charging rates mentioned above naturally apply only to a
6-volt battery, or to a battery having a greater number of cells,
which is connected in series multiple so as to charge at 6 volts.
In the case of a six-cell battery permanently connected in series so
that it both charges and discharges at 12 volts, the above figures
must be cut in half. Twelve-cell batteries are employed in some
cases, but the total voltage of the battery is used only for starting,
the cells' being divided into four groups in series multiple so that
each group of three cells charges at 6 volts.
With the generator charging at 10 to 15 amperes, turn on all
the lights. If more current is being drawn from the battery than
is being supplied by the generator, this will be indicated by the
ammeter showing a reverse reading or discharge. It signifies
that there is a short-circuit in the lighting switch or the lamps, or
in the wiring between the switch and the lamps, or that additional
lights, other than those furnished originally with the system, have
been added, or larger candle-power bulbs substituted, thus placing
too great a demand on the battery.
If the system has been out of adjustment for any length of
time, it is quite likely that the battery will shortly need repairs or
replacement, because charging at an excessive rate causes the plates
to buckle and break through the separators, forming an internal
short-circuit, while charging at too low a rate causes a constantly
discharged condition of the battery, due to more current being
normally called for than is put in. This results in injurious sulphating
of the plates.
In case additional equipment has been added, the entire
equipment should be turned on, and the total current required should
be noted when making discharge-rate tests. Where the generator
cannot supply sufficient current to permit the battery to take care
of this extra equipment, the battery should be charged from an
outside source at regular intervals. It is poor practice to increase
Conned 3hunl tf ere For
Test On Charge —
Conned Shunt Mere For
Test On Charge-
Fig. 435. Setup for Twelve-Volt Battery Wired to Charge and Discharge
through Starting Motor at Twelve Volts and through
Lamps at Six Volts
the charging rate of the generator, as it is likely to injure the battery
through overheating. Where it is necessary to have a higher charging
rate than that originally called for by the system, it is preferable to
substitute a larger battery. The charging rate of the generator may
then be safely increased in accordance with the demand.
In cold weather, it may be necessary to slightly increase the
charging rate of the generator in order to compensate for the extra
current the battery is called upon to supply. This is owing, not only
to the fact that there is a much greater demand on the starting
system in cold weather, but also to tfie fact that the battery is less
efficient under winter conditions of operation.
Connections fox Two-Voltage Batteries. Where the battery is of
either three or six cells, all connected permanently in series, the
foicgoing suggestions for connecting the testing instruments apply.
They must be varied, however, where tests are to be made of batteries
connected in series multiple, which may be termed two-voltage
batteries since they supply current at one voltage for lighting and
at another for starting. In Fig. 405 is shown a battery of this type
which is connected so as to charge and discharge through the starting
motor at 12 volts, but which discharges at 6 volts to supply the
lamps through a neutral lead in the center of the battery. The
sketch indicates where to connect the ammeter shunt on charge at
Fig. 400. Twelve-Volt Battery Connected Up to Make Two 6-Volt
Batteries in Parallel
12 volts and on discharge at 6 volts. When testing the starting-motor
discharge, it would be connected for 12 volts.
Test the 12-volt circuit with the engine running to get the
charging rate; stop the engine, reverse the ammeter terminals and
see whether there is any discharge indicating a short-circuit. Also
test the discharge rate on the 6-volt circuit with the lights turned off
and again with all lights on. These tests should show whether or
not there is a short-circuit in the system. Before attempting to
test the discharge rate of the starting motor, be certain that the
300-ampere shunt is in the circuit. A 12-volt battery will discharge
only about half the current necessary to start the engine with a
6-volt battery, but no shunt smaller than the 300-ampere size can
be depended upon to carry the load safely and protect the instrument.
ELECTRICAL EQUIPMENT 613
Fig. 406 shows a 12-volt battery connected up in such a manner
that it is practically two 6-volt batteries in parallel. The battery
is charged at 6 volts, and both the lights and horn are supplied with
current at this voltage, but the discharge through the starting motor
is at 12 volts. Note the two positive cables leading to the center
of the battery. To test the charging rate, the ammeter shunt should
be connected first in one of these cables and then in the other, arid
the two readings added together to obtain the charging rate for the
entire battery. The same locations for the shunt, and the same
method of adding the readings also apply on discharge. Ammeter
readings in the connections shown will indicate whether or not
there are any short-circuits, except, of course, in the starting-motor
Voltage Tests. An equally important instrument for the testing
of the storage battery is the voltmeter. It is chiefly useful in showing
whether a cell is short-circuited or otherwise in bad condition. Under
some conditions, it indicates when the battery is practically
discharged, but, like the hydrometer, it must not be relied upon
alone. It should be used in conjunction with the hydrometer readings
to insure accuracy. Since a variation as low as .1 (one-tenth) of a
volt makes considerable difference in what the reading indicates as
to the condition of the battery, it will be apparent that a cheap
and inaccurate voltmeter is likely to be misleading rather than
helpful. For garage use, a good reliable instrument with several
connections for giving a variable range of readings should be employed.
Instructions furnished with the instrument give in detail the method
of using the various connections, and these instructions should be
followed closely, as otherwise the voltmeter is likely to be damaged.
For example, on the 3-volt scale only one cell should be tested.
Attempting to test any more is likely to burn out the 3-volt coil
in the meter. The total voltage of the number of cells tested must
never exceed the reading of the particular scale being used at the
time, as otherwise the instrument will be ruined.
Always make certain that the place on the connector selected
for the contact of the testing point is clean and bright and that
the contact is firm, as otherwise the reading will be misleading,
since the increased resistance of a poor contact will cut down the
voltage. The positive terminal of the voltmeter must be brought
614 ELECTRICAL EQUIPMENT
in contact with the positive terminal of the battery, and the negative
terminal of the voltmeter with the negative terminal of the battery.
If the markings of the cell terminals are indistinct, the proper terminals
may be determined by connecting the voltmeter across any one cell.
Should the pointer not give any voltage reading, butting up against
the stop at the left instead, the connections are wrong and, should
be reversed; if the instrument shows a reading for one cell, the positive
terminal of the voltmeter is in contact with the positive of the cell.
This test can be made with a voltmeter without any risk of short-
circuiting the cell, since the voltmeter is wound to a high resistance
and will pass very little current. This is not the case with an ammeter,
Fig. 407. Proper Setup for Testing Voltage of Batteries
however, as connecting such an instrument directly across the
terminals of the battery will immediately burn out the ammeter.
Inasmuch as any cell, when idle, will show approximately 2
volts, regardless of whether it is fully charged or not, voltage readings
taken when the battery is on open circuit, i.e., neither charging
nor discharging, are practically valueless, except when a cell is ovt
of order. Therefore, a load, such as switching on the lamps, should
be put on the battery before making voltage tests. With the lights
on, connect the voltmeter as explained above and test the individual
cells, Fig. 407 (Prest-O-Lite). If the battery is in good condition,
the voltage readings after the load has been on for about five minutes
will be but slightly lower (about one-tenth of a volt) than if the battery
were on open circuit. If any of the cells are completely discharged,
ELECTRICAL EQUIPMENT 615
the voltage of these cells will drop rapidly when the load is first
put on and, sometimes when a cell is out of order, even show reverse
readings. Where the battery is nearly discharged, the voltage of
each cell will be considerably lower than if the battery were on open
circuit after the load has been on for five minutes. In the case of an
electric-vehicle battery, the lights alone would not provide sufficient
load for making an accurate test, so that one of the rear wheels may
be jacked up and the brake set lightly until the ammeter on the
dash of the car shows 50 to 70 per cent of the usual normal reading.
To do this, start the motor on first speed with the brakes loose,
and apply the brakes slowly until the desired load is shown by
the ammeter reading. Never, under any circumstances, attempt to
start with the brakes locked or on hard, as both the battery and the
motor will be damaged. In the case of a starting-system battery,
the lights alone are sufficient load, as they consume about 10 amperes.
To distinguish the difference between cells that are merely
discharged and those that are out of order, put the battery on charge
(crank the engine by hand in the case of a starter battery) and test
again with the voltmeter. If the voltage does not rise to approxi-
mately 2 volts per cell within a short time, it is evidence of internal
trouble which can be remedied only by dismantling the cell.
Temperature Variations in Voltage. It must be considered, in
making voltage tests, that the voltage of a cold battery rises slightly
above normal on discharge. The reverse is true of a really warm
battery in hot weather, i.e., it will be slightly less than normal on
charge and higher than normal on discharge. As explained in
connection with hydrometer tests of the electrolyte, the normal
temperature of the electrolyte may be regarded as 70° F., but this
refers only to the temperature of the liquid itself as shown by a
battery thermometer, and not to the temperature of the surrounding
air. For the purposes of simple tests for condition, voltage readings
on discharge are preferable, as variations in readings on charge mean
little except to one experienced in the handling of storage batteries.
Joint Hydrometer and Voltmeter Tests. In making any of the
joint tests described below, it is important to take into consideration
the following four points:
(1) The effect of teniperature on both voltage and hydrometer
G16 ELECTRICAL EQUIPMENT
(2) Voltage readings should only be taken with the battery
discharging, the load being proportioned to the size of the battery,
as voltage readings on an idle battery in good condition indicate
little or nothing.
(3) In the case of a starter battery, never attempt to use the
starting motor to supply a discharge load for the battery, because
the discharge rate of the battery while the starter is being used is so
heavy that even in a fully charged battery in good condition it
will cause the voltage to drop rapidly.
(4) The voltage of the charging current will cause the voltage
of a battery in good condition to rise to normal or above the moment
it is placed on charge, so that readings taken under such conditions
are not a good indication of the battery's condition.
In any battery which is in good condition, the voltage of each
cell at a normally low discharge rate (20 to 30 amperes for a vehicle
battery or 5 to 10 amperes for a starting-system battery) will remain
between 2.1 and 1.9 volts per cell until it begins to approach the
discharged condition. A voltage of less than 1 .9 volts per cell indicates
either that the battery is nearly discharged or that it is in bad
condition. The same state is also indicated when the voltage drops
rapidly after the load has been on a few minutes. The joint hydrome-
ter and voltmeter tests given below will be found to cover the
majority of cases met with in actual practice.
(1) A voltage of 2 to 2.2 per cell with a hydrometer reading
of 1.275 to 1.300 indicates that the battery is fully charged and in
(2) A voltage reading of less than 1 .9 per cell with a hydrometer
reading of 1.200 or less indicates that the battery is almost completely
(3) A voltage of 1.9 or less per cell with a hydrometer reading
or 1.220 or more indicates that excess acid has been added. Under
these conditions, lights will burn dimly, although the hydrometer
reading alone indicates the battery to be more than half charged.
(4) Regardless of voltage — high, low or normal — any hydro-
meter reading of over 1.300 indicates that an excessive amount
of acid has been added.
(5) Where a low voltage reading is found, as mentioned in
cases 2 and 3, to determine whether the battery is in bad order or
Digitized by VjOOQIC
merely discharged, stop the discharge by switching off the load, and
put the battery on charge (crank the engine by hand in the case of
a starter battery) and note whether the voltage of each cell promptly
rises to 2 volts or more. If not, the cell is probably short-circuited
or otherwise in bad condition.*
Cleaning Repair Parts. The advent of electric starting and
lighting systems has added appreciably to the amount of attention
required by machines in the garage, particularly as this essential
is a part of the car about which its owner generally knows little. In
fact, it is not overstating it to say that fully 25 per cent of all the
repair work now carried on in the garage has for its object the keeping
Tank Ho. Z
Caustic 5o± •
Cold Water J
Saw Dust Sox.
Fig. 408. Layout for Battery Cleaning Outfit
of the electrical equipment of the car in good operating condition.
Where many cars are cared for and repairs to their electric systems
are made as far as possible right in the garage, it will be found
advisable to install a method for cleaning parts. Owing to the accumu-
lations of dirt and grease that parts carry after having been in service
for a year or more, cleaning them thoroughly before making any
repairs makes it possible to detect defects which might otherwise
pass unnoticed. The following instructions are reprinted through
the courtesy of the makers of the Delco apparatus, and they strongly
recommend that the solutions mentioned be used in the exact manner
* From instructions issued by the Prest-O-Lite Company, Indianapolis, Indiana.
618 ELECTRICAL EQUIPMENT
directed, as they are the result of several years' experience in this
work, and considerable care has been used in checking them. The
sizes of the tanks given are merely indicative of what a very large
repair shop would require and are comparative only. They will
naturally vary with the amount of work to be done.
Cleaning Outfit. The cleaning outfit should consist of three
sheet-steel tanks, Fig. 408, of suitable size (35 gallons for a large
shop) mounted so that their contents may be kept heated to the
desired temperature, three stone jars of approximately 15 gallons
capacity, and a sawdust box. Two of the steel tanks should be
equipped with overflow pipes so that they can be kept about two-
thirds full at all times. These are tanks No. 1 and No. 2. They are
used for clear hot water for rinsing parts after they have been cleaned.
The third tank does not require a drain nor an overflow pipe and is
used for the potash or caustic soda solution. This can be used for
a long time without changing by simply adding a small amount of
soda as the solution weakens. All three tanks are maintained at a
temperature of 180° to 212° F., or approximately the boiling point.
The three jars mentioned are used for the acid solutions and are
referred to as jars No. 1, No. 2, and No. 3. A wood tank large enough
to hold the three jars and divided into two compartments, as shown
in Fig. 408, should be provided. This is important, as the parts
cannot be rinsed in the same cold water after being immersed in the
different acid solutions. The solutions recommended are in tanks
1 and 2, clear hot water; tank 3, a solution consisting of one pound
of caustic soda per gallon of water. Jar No. 1 is filled with a solution
consisting of four gallons of nitric acid, one gallon of water, and six
gallons of sulphuric acid. The water is placed in the jar first, the
nitric acid is added slowly, and the sulphuric acid is poured in last.
This order must be strictly followed, as it is dangerous to mix a
solution of these acids in any other manner. In jar No. 2, the solution
is one gallon of hydrochloric acid to three gallons of water, while
jar No. 3 contains a solution of one-half pound of cyanide to a gallon
of water. Tank No. 2 should be used only for parts which have
been in the potash solution and for no other purpose. Tank No. 1
is for general rinsing purposes.
Method of Cleaning Varti. Various metals are cleaned as follows :
Steel is boiled in the potash solution until the dirt is removed, which
ELECTRICAL EQUIPMENT 619
should require only a few minutes. The steel part is then rinsed
in tank No. 2 and dried in sawdust. Cast iron parts are boiled
in the potash solution to remove dirt, rinsed in tank No. 2, dipped
in the acid solution in jar No. 1, rinsed thoroughly in cold clear
water, dipped in the cyanide solution, jrinsed again in cold
clear water, then rinsed in tank No. 1 and dried in sawdust. Copper
can be cleaned in the same manner. Polished aluminum should
first be thoroughly washed in gasoline, rinsed in tank No. 1, dipped
in the acid solution in jar No. 1, rinsed thoroughly in cold clear
water, rinsed in tank No. 1, and dried in sawdust. Plain aluminum,
unpolished, should be dipped in the potash solution, rinsed in tank
No. 2, dipped for a few seconds in the acid solution, rinsed in
tank No. 2, dipped for a few seconds in the acid solution in Jar
No. 1, rinsed in cold water, then rinsed in tank No. 1, and dried in
It will be noticed that when aluminum is put into the potash
solution the metal is attacked and eaten away rapidly, so that
polished parts of this metal should not be put into this solution,
and any aluminum parts should not be left in for a moment longer
than necessary. Where the parts are covered with caked deposits
of hard grease, they should first be washed in gasoline. Aluminum
parts should never be put into the potash solution unless they can
be put through the acid immediately after, as the acid dip neutralizes
the effect of the potash solution. Parts should only be held in the
acid for a few seconds. Paint should first be removed with a good
paint or varnish remover unless it is present in very small quantity,
and unless the aluminum parts are to go through the potash solution.
Enameled work should be washed with soap and water, dried
thoroughly, and then polished with a cloth dampened with a good
oil, such as Three-in-One. These cleaning methods apply only
to solid parts and should never be employed on any plated pieces,
as the caustic and acid would immediately strip off the plating.
Such parts can be cleaned only in gasoline. It will be apparent,
however, that cleaning in this manner will be found advantageous
for many parts of the car that have to be repaired other than those
of the electric equipment, and, in view of the increasing cost of
gasoline, will be found much more economical as well as much more
Digitized by VjOOQIC
REMY IGNITION DISTRIBUTOR, MODEL SM-B
Court— y of Remy Electric Comvany. A ifitrton, Indiana
ELECTRICAL EQUIPMENT FOR
ELECTRIC STARTING AND LIGHTING
SUMMARY OF INSTRUCTIONS ON ELECTRIC
STARTING AND LIGHTING
It will be apparent from the foregoing description of the various
systems that while the majority differ more or less in detail all are
based on a comparatively small number of well-defined principles,
and that once these are mastered their application in any system
under consideration will be clear. To avoid unnecessary duplication
in the instructions covering points that are common to all, general
instructions have been given only in connection with one or two
systems, and it will be understood that descriptions of the methods
of locating short-circuits or grounds, of caring for brushes and com-
mutator, and of testing with a portable lamp or with the volt-ammeter
are equally applicable to all. The instructions given with other
systems accordingly are limited to special references to the details
of installation that will make it easier to locate faults in that par-
In order to bring the two together in such form that the par-
ticular information desired may be found instantly, a summary
of all the instructions given in the preceding sections is outlined here
in questions and answers.
Types and Requirements
Q. How many types of generators are used in starting and
lighting service on the automobile?
A. Practically all are of one type, i.e., compound-wound, but
this is subdivided into other types, such as differential compound-
622 ELECTRICAL EQUIPMENT
wound, cumulative compound-wound, and the like, that is, all
lighting generators have a shunt and a series winding on their fields,
but the relation of these windings to one another differs, depending
upon the characteristics of the remainder of the system.
Q. What is a differential compound-wound generator?
A. One in which the series winding is reversed, i.e., wound in a
direction opposite to that of the shunt winding so that its exciting
effect on the field magnets opposes that of the shunt winding. The
series winding is then termed a bucking coil because it bucks,
or opposes, the exciting effect of the shunt winding on the field mag-
nets as the speed increases. The series winding in this case is used
simply for regulating the generator output.
Q. What is a cumulative compound-wound generator?
A. One in which the exciting effect of the series coil is added to
that of the shunt coil, the series coil in this case having no connection
with the regulation of the generator output.
Q. As one of the chief requirements of an efficiently operating
system is the control of the generator output under widely varying
speeds, how is a generator of the cumulative compound-wound type
employed on the automobile?
A. The series winding is in practically an independent circuit
in connection with the lamps of the car so that its exciting effect is not
added to the field magnets except when the lights are switched on.
This automatically increases the generator output in accordance with
the number of lights turned on so that the lights have no effect on the
battery charging rate, which remains the same whether the lights are
on or off. An external regulator is employed to control the battery-
Q. How does the generator differ from the motor?
A. Its essentials are all the same, i.e., it has a wound armature
revolving in a magnetic field, commutator, brushes, etc., exactly the
same as the generator.
Q. This being the case, why are the two not interchangeable?
A. To a certain extent they are, that is, when a current is sent
through the generator from an outside source, it becomes motorized
and will run as a motor. But the two are far from being interchange-
able on the automobile, owing to the widely differing requirements fcr
which they are designed. The generator is wound to produce a cur-
ELECTRICAL EQUIPMENT 623
rent seldom exceeding a value of 20 amperes while being driven over a
wide range of speeds, and it is in constant operation. The starting
motor, on the other hand, is designed to utilize an extremely heavy
current, ranging up to 300 amperes or more at the moment of starting
and is only used for very short periods.
Q. How are these widely varying requirements reconciled in
the single-unit type, in which both the generator and the motor are
combined in one machine?
A. The machine is practically two units in one, i.e., there are
two totally different windings on the same magnet cores, a fine wind-
ing with shunt fields for the generator, and a very heavy simple series
winding for the motor end. In some cases, as in the Delco, the differ-
ent windings on the armature are brought out to independent commu-
tators. While combined on one set of magnet cores, there is no
connection whatever between the two windings in such a machine, so
that when operating as a generator the motor windings are dead, and
the reverse is true when being used as a starting motor.
Q. What are the characteristics of the single-unit type of
machine which is simply placed in circuit with the battery by a hand-
operated switch when starting and left in that relation as long as the
engine is running?
A. This is a variable-potential type in which the relation that it
bears to the battery and to the engine is entirely dependent upon the
speed of the engine, that is, the speed at which the machine is driven.
When the switch is closed, current from the battery operates the
machine as a starting motor; as soon as the engine starts and attains
a certain speed, the voltage of the machine overcomes that of the
battery, the direction of current flow is reversed, and the battery begins
to charge. Whenever the driving speed falls below a certain point,
there is another reversal, and the generator once more becomes a motor
until the engine speed increases.
Loss of Capacity
Q. What are the chief causes for the falling off in output of
A. In about the order of the frequency of their occurrence,
these are as follows : dirty or worn commutator; worn brushes making
poor contact; dirty or loose connections causing extra resistance
624 ELECTRICAL EQUIPMENT
at generator, regulator, cut-out, ground, or battery terminals;
failure of cut-out to operate at proper voltage; worn or pitted con-
tacts in regulator or cut-out; loose connections at brush holders;
short-circuited coils in the armature; some of the armature-coil
connections broken away from the commutator; short-circuited
bars in the commutator.
Q. How can the generator output be tested?
A. The simplest method is to switch on all the lamps with
the engine idle. Start the engine and speed up to equivalent of
15 miles per hour. The lights, should brighten very perceptibly,
the test being made indoors in the daytime with the lights directed
against a dark wall, or preferably at night. A more accurate test
can be made with the portable volt-ammeter, using the 30-ampere
shunt. Most generators have an average current output of 10 to
12 amperes, but the normal output as given by the maker should
be checked before making the test. Generators having a constant-
voltage control will show a greatly increased output if the battery
charge is low, running up to 20 amperes or over. On such machines,
the condition of the battery should be checked either with the
hydrometer or with the voltmeter before making the test. The
charging current should be 10 to 12 amperes with a fully charged
battery, and more in proportion when only partly charged.
Q. What other simple method is there of determining quickly
whether the generator is producing its normal output or not?
A. On generators having an accessibly located field fuse (there
are several makes) lift this fuse out and, with the engine running
at a speed equivalent to 10 miles per hour or more, touch the fuse
terminals lightly to the clips. If the machine is generating properly,
there will be a bright hot spark. Should no spark appear, replace
the fuse and bridge the terminals with a pair of pliers by touching the
jaws to the fuse clips; if a spark appears, the fuse has blown. Before
replacing with a new fuse, find the short-circuit or other cause.
Q. Granting that the fuse has not blown, that the cut-out,
regulator, and wiring are all in good condition, and still the gen-
erator does not produce any current, what is likely to be the cause?
A. One of the brushes may not be touching the commutator,
a brush connection may have broken, or carbon dust may have short-
circuited the armature or field windings. Test for short-circuits.
ELECTRICAL EQUIPMENT 625
Q. If the machine is generating current, and the auxiliary
devices and wiring are in good condition, but the battery does not
charge, what is the cause?
A. Short-circuit in the battery due to active material having
been forced out of the plates, or accumulation of sediment touching
plates at their lower ends. (See Battery Instructions.)
Q. Is the regulator ever responsible for a falling off in the
current or for generation of excessive current?
A. Yes. Any irregularity in the operation of the regulator
will affect the output of the generator.
Q. How can this be overcome?
A. This will depend upon the type of regulation employed
(see Regulation). Where the method of regulation is inherent,
i.e., forming part of the construction of the generator itself, such
as the third-brush method, or a backing coil, it may be remedied
by cleaning and seating the brush properly or by testing the bucking-
coil winding to see if its connections are tight and clean, or if it is
short-circuited (see Windings). If cleaning and sanding-in the
brush do not cause the generator to produce its normal output, the
brush itself may be adjusted by shifting its location. Moving it
backward or against the direction of rotation of the commutator
will reduce the output; moving it forward or in the direction of
rotation will increase the output. This refers specifically to the
Delco regulation already described. To adjust properly, the port-
able ammeter should be put in circuit, and the effect on the reading
noted as the brush is moved, clamping it back in place when the
proper point is found. The brush should then be sanded-in to the
commutator, as it will not have a good bearing if its original location
has been disturbed.
Methods of Regulation
Q. Why is it necessary to control the output of the generator?
A. As explained in the section on electric generators, the
amount of current produced depends upon the excitation of the fields,
and the faster the armature revolves before the pole faces of the field
magnets, the greater the amount of current that is sent through the
windings of the magnets. As the speed of the automobile engine
varies between such extremely wide limits, it will readily be seen that
626 ELECTRICAL EQUIPMENT
it may rise to a point where this increase in the field excitation will
cause so much current to be generated that the armature windings
will be literally burned up. This happened very frequently in the
early attempts to produce a lighting dynamo for automobile sendee.
Regardless of how fast the generator may be driven, it is essential that
its current output does not exceed a certain safe limit.
Q. What is the usual safe limit in the majority of generators?
A. Most automobile lighting-system generators are designed to
produce 10 to 15 amperes at a normal speed, i.e., sufficient to light all
the lamps and still provide a slight excess for charging the battery.
No matter how fast its armature revolves, it must not exceed this by
more than ten to twenty-five per cent, as a rule, this being well within
its factor of safety. In some instances, where a voltage system of
regulation is employed, the output of the generator depends upon the
condition of charge of the battery. If the battery is practically
discharged, the generator will charge the battery at a rate of twenty
amperes or over. As the charge proceeds, the battery voltage
increases and the resistance is increased correspondingly, thus cutting
down the amount of current that the generator can force into the
Q. How is the current generated kept from exceeding this safe
A. Mechanical methods were employed at first, a centrifugal
governor being used to operate a slipping clutch. The generator
was driven through this clutch, and the speed at which the armature
revolved depended upon the engagement of the clutch; at low speeds
both shafts would turn at the same rate. As the driving-shaft speed
increased, the governor decreased the pressure on the clutch spring,
and the clutch faces slipped on one another, so that the driven shaft
turned proportionately slower than the driving shaft. The earliest
types of governors, employed about 1903 to 1905, were not successful,
but about 1908 a type was developed that worked effectively on
thousands of cars. It has since been superseded by electrical methods
of regulation, and practically all of those now in use are electrically
Q. How many electrical methods of regulating the amount of
current generated are in general use?
A. So far as their principle goes, practically all are the same.
ELECTRICAL EQUIPMENT 627
They depend upon weakening the excitation of the fields of the gen-
erator to cut down the output. It is in the methods of accomplishing
this that they differ. In the latter respect they may be divided into
two general classes: those that are inherent in the design of the
machine, i.e., the regulating device is actually a part of the machine
itself; and those in which an external regulator is employed. Those
most commonly employed are, in the first class, the bucking-coil
winding and the third-brush method; in the second, an external
regulator is usually combined with the battery cut-out and designed
to keep either the voltage or the current at a uniform value, usually
Q. What is a bucking-coil winding, and why is it so called?
A. We have seen that in a series-wound machine all of the
current generated in the armature passes through the field windings
and energizes the field magnets; in the shunt-wound machine the wires
carry only a part of the current which is proportional to the resistance
that the shunt winding of the fields bears to the resistance of the out-
side circuit. As this outside resistance (the load) increases, more current
will be diverted through the path of lesser resistance, or the shunt-
wound field, and the output of the machine will increase* accordingly .
In the compound-wound machine, the relation of the series to the
shunt winding is such that it is called upon chiefly to help carry any
extra load. In other words, as the demands upon the machine
increase, the series winding adds its energizing effect to that
of the shunt coil. A generator with a bucking-coil winding is a com-
pound-wound machine, but the series winding is in the opposite
direction from that of the shunt winding. Consequently, instead of
adding to the field excitation caused by the latter, it opposes or bucks it,
and the more current there is produced in the shunt field by the rise
in speed, the more the series winding, or bucking coil, tends to neutral-
ize this excess, thus keeping the amount <|f magnetic effect produced
in the field poles practically uniform, regardless of the speed.
Q. What is the third-brush method of regulation?
A. In a conventional shunt-wound generator, the field windings
are directly in shunt with the armature through the brushes; hence, a
certain proportion of all the current induced in the armature windings
will find its way through the field magnet windings, in proportion
to their relative resistance to the outside circuit at the time. Where a
628 ELECTRICAL EQUIPMENT
third brush is employed, the main brushes are not in shunt with the
fields, and they are not depended upon to supply the exciting current
for the latter. The third brush instead is used for this purpose. As is
well known, the output of a generator depends very largely upon the
position of its brushes. In the immediate vicinity of the proper loca-
tion for a brush, there is a short zone of maximum intensity. As we get
away from this toward the next brush, it decreases until at a point
midway between the two there is a neutral zone. The third brush is
accordingly placed between the two main brushes, and its distance
from the nearest main brush determines the amount of current that it
diverts from the armature to the field windings. See illustration
of Delco generator in section on Methods of Regulation. This
method has the advantage of supplying a strong shunt field at low
speeds. As the speed increases, the voltage applied to the shunt field
decreases, even though that between the two main brushes may have
Q. What is a regulator, and what is its purpose?
A. It is an instrument somewhat similar to a battery cut-out,
and its purpose is to regulate the output of the generator in order that
the latter may not exceed safe limits at high speeds. The regulator
is usually combined with the cut-out.
Q. How does the constant-voltage type of regulator operate?
A. The instrument consists of a magnet winding and a pivoted
armature, normally held open by a spring and a resistance unit.
The winding of the magnet has sufficient resistance to prevent the
core becoming energized to a degree where it will attract the armature,
unless the voltage exceeds the safe limit determined for the circuit
The voltage increases with the speed of the generator, so that when the
latter is driven too fast the attraction of the magnet core for the arma-
ture becomes sufficient to overcome the pull of the spring which
normally holds the contacts apart. (See description of Bijur voltage
regulator.) When the contacts come together, the field circuit of the
generator is shunted through the resistance unit; this cuts down the
amount of current energizing the fields, the voltage falls off, and the
contacts again separate. Unless the speed of the generator is
decreased, this action is rapidly repeated, so that the regulator anna-
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 629
ture vibrates at a high speed as long as the voltage is sufficiently high
to energize the magnet.
Q. What is the principle on which this type of regulator
A. The principle that in a circuit having considerable self-
induction the amount of current which may be sent through the
circuit will decrease if the current be pulsating instead of steady.
Every time the contacts of the regulator open, a pulsation, or surge,
of current is sent through the field windings of the generator; when
they close because of the higher voltage, the current is shunted
through the resistance unit, thus cutting it down. The decrease in
the amount of current is in proportion to the number of pulsations per
minute, i.e., the rapidity with which the vibrating contact operates.
The circuit having considerable self-induction is that of the field
winding of the generator, owing to its heavy iron core. (See Induc-
Q. What is the constant-current type of regulator, and how does
it differ from the constant-voltage, or potential, type?
A. It consists of an electromagnet and a spring-controlled
pivoted armature, so that it is of practically the same construction as
the constant-potential type, but it is connected in circuit with the
armature of the generator and it is wound to operate under the
influence of the current rather than the voltage. Consequently,
the pivoted armature is attracted, opening the circuit when the cur-
rent exceeds a certain predetermined value, usually 10 amperes. In
operation, the armature vibrates the same as in the voltage regulator,
but the condition of the charge of the battery has no effect on it, so
that when set to limit the current to 10 amperes, it will always charge
the battery at approximately that rate regardless of the condition
of the battery. The only practical difference is that it is wound to
actuate under the influence of changes in the current flow and is
connected in the armature circuit, whereas the constant-potential
regulator is influenced by variations in the voltage and is connected in
the field circuit of the generator. The latter has the advantage of
charging the battery at a higher rate when the charge is most needed.
Q. What other forms of regulators are employed on lighting
,A. The foregoing comprise practically all of the principles
Digitized by VjOOQIC
630 ELECTRICAL EQUIPMENT
employed, but the regulators differ more or less in design and opera-
tion. For example, in the Bosch-Rushmore generator, a bucking
coil is employed in connection with what is termed a ballast
resistor, or resistance unit. . This is of iron wire, and it is based on the
' fact that resistance increase* very rapidly with the temperature.
The size of the wire is such that it allows 10 amperes to flow without
undue heating, so that its resistance is practically unchanged; above
this point it heats rapidly and increases in resistance so greatly that all
excess current is shunted through the bucking coil. In the Splitdorf
generator, the regulator is built in, projections of the pole pieces of the
field being utilized in connection with special windings, instead of an
independent electromagnet as in the Ward-Leonard and the Bijur.
In the U.S.L. generator of the inherently regulated type, regulation is
accomplished by the combination of a Gramme ring armature, a
special arrangement of connections and of the field windings, and the
use of only a part of the fields and armature for generating current.
The regulation obtained is based on armature reaction and is similar
in effect to the third-brush method. The U.S.L. external type of
regulator cuts into the generator field circuit a variable resistance
consisting of an adjustable carbon pile. In the Adlake regulator,
which is of the constant-potential type, a solenoid operates a switch
over the contacts of a variable resistance. The plunger of the sole-
noid is counterbalanced by a weight, which must be raised to operate
the switch. It is adjustable by increasing the weight of this counter-
Q. What attention does the regulation of the generator require?
A. This will depend upon the method employed in each case.
Where an external regulator is employed, whether of the constant-
potential or the constant-current type, the attention required is
practically the same as in the case of the battery cut-out. See that
the points are not sticking, $nd when badly burned or pitted, smooth
and true up, taking off as little of the contact point as possible to effect
this. When the points have become so badly pitted that this cannot
be done, new parts will be necessary.
With the third-brush method, the attention required by this
brush is the same as that which must be given the other brushes, i.e.,
sanding-in at intervals and replacement when worn too short to
permit the spring to hold the brush firmly against the commutator.
ELECTRICAL EQUIPMENT 031
Where the generator fails to produce sufficient current to keep the
battery charged, all other parts of the system being in good condition
and the car driven long enough in daylight to charge the battery under
normal conditions, the position of the third brush may be shifted to
increase the output. Care must be taken not to let it come in contact
with the main brush. (See Delco instructions.) In the case of a
bucking-coil winding, no attention is necessary, as this is an integral
part of the machine itself. As the Splitdcrf regulator has moving
contact points, the attention necessary is the same as that required
for an external regulator of this type. Special regulators, such as the
U.S.L. external type, require attention covered by the maker's instruc-
tions. (See U.S.L. system.)
. Q. When the generator fails to keep the battery charged prop-
erly, a normal amount of daylight driving being given the car, is the
fault most likely to be found in the regulator?
A. No. It is much morq likely to be caused by a dirty commu-
tator, worn brushes, loose connections, or some similar cause which
inserts extra resistance in the charging circuit. The movement of
the regulator armature is very slight, and the current handled by the
contact points is small, so that it will seldom be the cause of the
trouble. Other causes, such as those above enumerated, should
always be sought first. (See instructions under Generator.)
Q. Are faults in the generator windings frequent?
A. They constitute one of the least frequent sources of trouble
with the machine.
Q. What is likely to cause them?
A. Dousing the machine with water is likely to be one of the
most frequent causes of short-circuits or grounds in the generator
windings. All electrical machinery is intended to be kept dry.
Except where provided with a field fuse, running the generator when
disconnected from the battery or with the battery removed from
the car is another cause. Excessive speed, in some instances, may
generate sufficient centrifugal force to lift the armature coils out
of their slots so that the insulation becomes abraded by rubbing
against the pole pieces, but this is very unusual. In rare instances,
a hard kink left in the wire when winding may crystallize the metal
632 ELECTRICAL EQUIPMENT
and make it break at that point, due to the vibration. Unless cleaned
out at intervals, fine carbon dust from the wear of the brushes may
accumulate in the interstices of the windings, and, when aggravated
by moisture, this is apt to cause short-circuits.
Q. What are the usual indications of such faults?
A. With a short-circuited generator coil (armature), all other
parts of the apparatus and circuits being in good condition, the
charging rate will be lower than normal. The ammeter needle will
vibrate violently when the engine is running at low speeds, and two
or more adjacent commutator bars will burn and blacken. With
an open armature coil (broken wire), the indications will be prac-
tically the same, and there will be severe sparking at the brushes,
causing serious burning of the commutator bar corresponding to
the open coil. A grounded armature coil will give the same general
indications, and if the machine is a single-unit type, the cranking
ability of the starting motor will be seriously impaired. The
ammeter, however, will not vibrate as in the former cases. There
will be practically no charge from the generator, and the battery
will be discharged very rapidly by the starting motor.
In a single-unit machine,, when the windings of the generator
and the starting motor become interconnected, the indications
will be practically the same as those of a grounded armature coil.
If the motor windings of a single-unit machine become grounded,
there will be an excessive discharge from the battery, while the
motor will develop but little power.
Q. How may such faults be located?
A. With the aid of the testing-lamp outfit. Remove the
brushes (when replacing them later, be sure to put each brush
back in the holder from which it was taken), or the brushes may
be insulated from the commutator by placing paper under them.
For a grounded coil, place one test point on the commutator and
the other on the frame; if grounded, the lamp will light. For inter-
connected motor and generator windings in a single-unit machine
having two commutators, insulate the brushes as mentioned and
place the test points one on each commutator. The light will burn
if the two windings are connected. For a grounded-motor winding,
test from the motor commutator to the frame; the light should
not burn if the insulation is all right. For a break or open circuit
ELECTRICAL EQUIPMENT 633
in the field winding, touch the terminals of the latter with the test
points, the commutator being insulated or the armature removed.
The lamp should light. For a blown field fuse on machines so
equipped, place the points on the clips; if the fuse is intact, the
lamp will light.
Q. Are these tests conclusive?
A. No. They will indicate any of the faults mentioned,
but they will not reveal an internal short-circuit in the windings,
which cuts some of the armature or field turns out of action but
does not break the circuit as a whole. Such a short-circuit reduces
the output of the generator and can be determined definitely only
by measuring the resistance of the windings. This requires special and
expensive testing instruments, such as the Wheatstone bridge, so that
where all other tests fail to reveal the cause of a falling off in the out-
put of the generator, it should be sent to the maker for inspection.
Commutator and Brushes
Q. What does a blackened and dirty commutator indicate?
A. Sparking at the brushes or an accumulation of carbon
dust due to putting lubricant on the commutator.
Q. What is the cause of sparking at the brushes?
A. Poor brush contact, due to worn brushes; brush-holder
springs too loose, so that brushes are not held firmly against the
commutator; excessive vibration, which may be due to a bent shaft,
an unbalanced gear pinion, or improper mounting; using too much
oil, or using grease in the ball bearings, which gets on the commutator
and, acting as a solvent for the binder of the carbon, forms a pasty
mass which prevents proper brush contact; worn or roughened
commutator on which the mica needs undercutting; overload due
to failure of regulator or to grounded coils in armature.
Q. What is the remedy for sparking?
A. Clean the commutator with fine sandpaper and sand-in
the brushes to a true bearing on the commutator as directed in the
Delco instructions. See that the brush springs have sufficient
tension to keep the brushes firmly pressed against the commutator
when the machine is running. If the mica protrudes above the
commutator bars, it must be undercut as directed, and the commu-
tator smoothed down again after the operation to remove any burrs.
634 ELECTRICAL EQUIPMENT
Q. Why do some commutators need undercutting and others
A. Undercutting is required only on machines equipped with
brushes that are softer than the mica. Copper-carbon brushes,
as employed on starting motors to reduce the brush resistance, are
hard enough to keep the mica worn down with the copper of the
Q. If, after smoothing off and undercutting the mica, the
commutator still has an uneven and irregular surface, what is the
A. The armature should be removed from the machine, and
the commutator trued up in the lathe, taking as light a cut as possible
consistent with obtaining a true round and smooth surface.
Q. How can excessive commutator wear be prevented?
A. Inspect at regular intervals and on the first sign of sparking
smooth up the surface and sand-in the brushes. Keep the com-
mutator clean and do not permit carbon dust or oil to accumulate
in the commutator and brush housing. Never replace brushes or
brush springs with any but those supplied by the manufacturer
for that particular model. The machine will work with any old
brush and any old spring that fits, but they will prove detrimental
to its operation in a comparatively short time, and its working under
such conditions will never be satisfactory.
Q. Is discoloration of the commutator ever caused by anything
else than sparking?
A. Not actual discoloration which requires cleaning, but the
normal operation of the machine produces a purplish blue tinge on
the bars, which is sometimes mistaken for discoloration by the
inexperienced. This color, in connection with a high polish of the
metal, indicates that the commutator is in the best of condition.
Once the commutator takes on this high polish, it will operate for
long periods without other attention than the removal of dirt by
wiping with a clean rag. Sanding to remove this purple tinge is a
mistake, as it only destroys the polish without having any beneficial
Q. Is it necessary to lubricate the surface of the commutator?
A. No. The brushes employed are usually of what are termed
a self-lubricating type and require no attention in this respect.
ELECTRICAL EQUIPMENT 635
Q. Will any harm result from putting light grease, vaseline, or
lubricating oil on the surface of the commutator?
A. As all lubricants are insulators to a greater or less extent,
the efficiency of the machine will be reduced and, as the voltage is
very low, but a slight falling off is necessary to represent a very sub-
stantial percentage of the maximum. The use of lubricant of any
nature on the commutator also has another harmful effect in that it
collects the carbon dust resulting from the wear of the brushes, caus-
ing it to lodge against them as well as between the commutator bars.
Q. Why should particular care be taken to remove all carbon
dust from the commutator housing of both the generator and the
motor (two-unit system) or the single unit where both functions are
combined in one machine?
A. Carbon dust is an excellent conductor of electric current
and, when spread over the surface of an insulator, it causes the latter
to become conducting as well. Consequently, it is likely to short-
circuit the commutator bars by lodging between them. It will cause
leakage across fiber or other insulating bushing of brush holders when
a sufficient deposit accumulates on them. It will penetrate the arma-
ture and field windings of the machine and may cause trouble by
grounding or short-circuiting them. Especial care should be taken
to remove all traces of carbon dust after sanding-in the brushes.
Q. How often should the commutator be inspected?
A. The commutator is the most vulnerable part of any direct-
current machine, whether it be a gen^ator or motor, and it should
accordingly be inspected at more frequent intervals than any other
single part of the entire system. The efficiency of both the generator
and the motor depend upon it to a very great extent. Most of the
failures of starting and lighting systems that are not due to poor
condition of the battery may be traced directly to the commutator.
Q. What is the function of the brushes?
A. To conduct the voltage and current induced in the armature
by its revolution through the lines of force created by the magnetic
field, to the outer circuit, in the case of an electric generator; and to
conduct the operating current to the armature windings from the
battery, in the case of the starting motor.
Q. Why must the brushes bear evenly over their entire surface
on the commutator?
636 ELECTRICAL EQUIPMENT
A. Because their current-carrying capacity depends upon their
size, and the latter is based upon the entire surface of the end of the
brush making efficient contact. If the brush does not make uniform
contact, those parts of it that do not touch the commutator will cause
arcing or heavy sparking at the gap thus created, resulting in
damage to both the commutator and the brush.
Q. Why are springs of different strengths used on generators
and motors of different makes to hold the brushes against the commu-
tator, though the machines are of practically the same capacity,
operate at the same voltage, and are in other respects very much alike?
A. The carbon compounds of which the brushes are manufac-
tured differ greatly in their conductivity and resistance offered to the
passage of the current, and these differences call for greater or less
spring pressure to hold the brush against the commutator surface in
order to make efficient contact over the entire surface of the brush.
Every maker has his own standard in this particular respect.
Q. Why is it not advisable to use brushes other than those
supplied by the manufacturer as replacements on a machine?
A. For the reasons jus^ given above. The manufacturer has
adopted certain standards for the operation of his machines, and the
brushes supplied have been made particularly to comply with those
standards. No other brushes will do so well, and some will result in
injury to the machine.
Q. When inspection shows that the brushes have worn down
unevenly, what should be done?
A. They should be sanded-in with a strip of fine sandpaper,
such as No. 00, preferably already worn if the brushes are very soft.
(See instructions for doing this properly in connection with machines
of different makes.) No more should be removed than is absolutely
necessary to bring the end of the brush to a firm contact all over its
bearing surface on the commutator; and the end of the brush, after
the completion of the operation, should not show any deep scratches
or pit marks. Unless the surface is smooth and true, injurious spark-
ing will result, and the efficiency of the machine will be decreased.
Q. If, with a smooth and true surface, the brush still fails to
make good contact, what is the trouble?
A. The brush has probably worn down until it is too short for
the spring to exert sufficient force against it to hold it against the
ELECTRICAL EQUIPMENT 637
commutator properly, or the spring itself may be at fault. Wear of
the brush beyond the point where it is any longer of service will most
often be the cause.
, Q. Where the brushes are true and are making good contact
against the commutator, but the machine is inoperative, all other
parts of the system being in good condition, what is likely to be the
A. One of the pigtails, or short flexible connections, of the
brushes may have shaken out from under its spring clip. This breaks
the circuit, just as a parted wire or a ruptured connection at a terminal
in any other part of the system would.
Q. How often is it necessary to replace the brushes?
A. This differs so much with different makes of machines that it
cannot be answered definitely, even as an average. On two-unit
systems, the generator brushes will naturally require replacements
much sooner than those of the starting motor, as the starting motor is
only in operation for very short periods, while the generator is working
constantly. On single-unit types, this naturally does not apply, as,
whether the armature has one or two sets, they are always in use.
Ordinarily, brushes should not require replacement under a year, and
frequent instances are known of their having lasted for two years or
more. It depends upon the care given the commutator and brushes
quite as much as upon the mileage covered, as, if allowed to run dirty
for any length of time, the brushes will wear away much faster than if
kept in good condition. The best rule for the replacement of the
brushes on all makes of machines is to renew them as soon as they
have worn to a point where the springs no longer hold them firm
against the commutator. When they have reached this condition, the
vibration and jolting of the car is likely to shake them out of contact,
which results in sparking.
Q. What is the "third brush", and what is its function?
A. This is an extra brush used on a generator. Its purpose is to
control the amount of current supplied by the armature to the shunt-
field winding as the speed increases. In other words, it regulates the
output of the machine and prevents it from being burned out when
the speed of the engine becomes very high.
Q. Does it differ from the other brushes in construction or in
the care required?
638 ELECTRICAL EQUIPMENT
A. It is a carbon brush of the same nature as the others used on
the same machine, and the care required to keep it in good condition
does not differ. However, it is mounted in an independently adjust-
able holder so that it may be moved backward or forward with relation
to the main brushes in order to increase or decrease the output of
the generator. (See instructions [Delco] on this point.)
Q. Is it ever necessary to alter the location of the brushes
of a machine?
A. Except on generators fitted with the third-brush method of
regulation, on which it may be necessary to shift the main brushes
slightly to avoid having the third brush come in contact with one of
them when moved to change the output, it should never be necessary
to shift the location of the brushes. Brush location has an important
bearing on the operation of the machine, and, in designing it, the maker
has fixed the location of the brushes to conform to its other charao
teristics. Many machines have no provision for adjusting the
brushes in this respect, while some manufacturers cauticjn the user
particularly against altering their location.
Q. How much spring pressure is usually employed to hold the
brushes of the generator and starting motor against the commutator?
A. This varies with different makes of machines and should be
ascertained from the maker's instructions in every case in order to
check up properly. In the various models of the Gray & Davis
starting motors, this spring pressure ranges from 2\ to 3$ pounds,
which is the minimum necessary. In other words, the brush must be
held against the commutator with this amount of pressure in order to
operate efficiently. While there will be a loss if the pressure drops
below the minimum, there is no advantage in greatly exceeding it, as
excess pressure simply causes greater friction loss without any com-
pensating gain in power. Generator-brush pressures are much less
than those employed on starting motors, owing to the smaller amount
of current handled.
Q. How can the proper spring pressure of the brushes be
A. With the aid of an ordinary spring scale of the direct-pull
type, in which the pull on the hook draws the pointer down over the
scale. A scale reading to five pounds is adequate for the purpose;
one intended for heavy weights is not likely to be so accurate. Attach
Digitized by VjOOQIC
ELECTRICAL EQUIPMENT 639
the hook of the scale to the brush and pull until the brush is just clear
of the commutator. The scale will then register the pull in pounds.
Where there is nothing on the brush to which to attach the hook, such
as a screw, place a thin piece of wood on the brush face before passing
the hook of the scale around it, to prevent injuring the contact face
of the brush. In this case, the spring pressure as shown on the scale
will exceed the necessary minimum, as the spring must be compressed
further than it would be when in operation, in order to operate the
scale. This should be allowed for when taking the reading.
Q. When is it advisable to check the spring pressure of the
A. When there is undue sparking at the commutator, while the
commutator and brushes are all in proper condition, i. e., clean, and
bearing uniformly over their entire surface so that the sparking is not
due to any fault in either of these essentials.
Q. When the brushes and commutator are in good condition
and the spring-scale test shows that the brushes are being held
against the commutator with the necessary amount of pressure, what
is likely to be the cause of the sparking?
A. There may be a short-circuited or open coil in the armature.
Q. In what way does the starting motor of a two-unit system
differ from the generator?
A. It is a simple series-wound machine having but one winding
of coarse wire on the fields, and all the current from the battery
passes through its armature coils and field windings.
Q. Is it subject to electrical faults other than those already
referred to in connection with the generator?
A. No. The care and the nature of the tests required to
locate faults are the same. The commutator should be kept clean,
brushes bearing firmly on commutator, and all connections kept
tight. The same instructions for sanding-in brushes and keeping
the commutator in good condition apply as in the case of the
Q. When the starting motor fails to operate, what is likely
to be the cause?
A. In the majority of instances, a low state of charge or a
640 ELECTRICAL EQUIPMENT
wholly discharged battery will be responsible. If the battery is
all right, a loose connection at the battery, switch, or motor, or a
short-circuit in some part of this wiring may be the cause. Should
the battery be properly charged, all wiring and connections in good
condition, switch contacts clean, etc., the starting gears may be
binding, owing to dirt or lack of alignment between the motor shaft
and the flywheel of the engine. In this case, the motor will attempt
to start when the current is first turned on, but will be held fast.
Loosen the holding bolts and line up the motor, cleaning the gear
teeth if necessary.
Q What is likely to be the cause of the starting motor running
slowly and with very little power?
A. Exhausted battery, poor switch contacts, loose connec-
tions, partial ground or short-circuit in wiring causing leakage,
improperly meshing gears, dirty commutator, brushes making poor
contact owing to weak springs or worn brushes, or a ground in the
motor itself. The remedies for all these faults have been given already.
Q. When the battery and all connections and wiring are in
good condition, but the motor fails to crank the engine, what is likely
to be the cause?
A. The engine may be too stiff. If it has been overhauled
just previously, the main bearings may have been set up too tight.
Test with the starting crank to see if it can be turned over easily
by hand. If unusual effort is required, easing off the bearings should
remedy the trouble. Should the engine not turn over as soon as
the switch is closed, release immediately, as otherwise the battery will
Q. When the engine does not start within a few seconds, why
is it better to use the starting motor intermittently than to run it con-
tinuously until the engine does fire?
A. The intermittent use of the starting motor, say ten seconds
at a time, with a pause of half a minute or a minute between attempts
is easier on the battery. If allowed to rest for a short period, the
storage battery recuperates very rapidly. Consequently, the opera-
tion of the starting motor for two minutes, divided into twelve periods
of ten seconds each, will not run the battery down to anything like the
extent that its continuous operation for the same length of time would.
Moreover, this intermittent method of operation increases the chances
ELECTRICAL EQUIPMENT 641
of starting under adverse conditions, as, in very cold weather, every
time the battery is allowed to rest, it will be able to spin the engine at
its normal starting speed, whereas if the starting motor is operated
continuously, the battery will become so weak that the engine will be
turned over very slowly toward the end of the period in question.
Q. Why is it that a starting motor capable of turning an engine
over at a speed anywhere from 75 to 150 r.p.m. will sometimes fail
to start the engine, whereas hand cranking subsequently resorted
to will succeed?
A. It must be borne in mind that the operation of starting an
engine in cold weather involves several factors. (1) The pistons,
crankpins and crankshaft (bearings) must be broken away, i.e.,
forcibly released from the hold that the gummed lubricating oil has on
them, before they can be moved. The great difference between the
power required to do this in summer and in winter is shown by the
greatly increased amount of current used by the starting motor.
(2) Gasoline and air must be drawn into the cylinders, to effect which
in sufficient quantity to start the engine requires quite a number of
revolutions. (3) The gasoline must be vaporized so that it will mix
with the air, which involves more turning of the engine to create the
necessary heat by compression in the combustion chambers and the
friction of the moving parts. In the application of energy in any
form, two factors are always involved, i.e., the unit, or quantity of
power applied, and the length of time during which it is applied. The
starting motor cranks the engine at a comparatively high speed for a
brief period. In hand cranking, a smaller unit of power is employed,
and the speed of cranking is accordingly less, but its application is
continued for a much longer time. The failure of the starting motor is
not due to its inferiority to hand cranking, but simply to the fact that
the battery has become exhausted. Success in hand cranking where
the starting motor has failed is usually due to the fact that the starting
motor has done all the preliminary work, failing in the end simply
because the storage battery did not have sufficient energy to finish
the task. No electrical starting system can ever be any stronger than
its storage battery, or source of energy.
Q. Why is it not necessary to protect the starting motor or its
circuit by fuses or other protective devices as in the case of the
M2 ELECTRICAL EQUIPMENT
A. A simple series-wound machine (practically all electric start-
ing motors are of this type) is capable of standing exceedingly heavy
overloads for short periods, it being nothing unusual for these small
motors to have a factor of safety of five, or even seven, for a limited
time, that is, they will take five to seven times the normal amount
of current for a brief period without injury. As a matter of fact, the
starting motor can utilize all the current the battery is capable of
supplying, provided the motor is free to move. If the engine is stuck
fast or some part of the starting system has gone wrong so that the
electric motor cannot turn over, then there is danger that the motor
may be damaged unless the switch is opened at once. This, together
with the fact that the maximum load which may be placed on the
motor at different times is such a variable quantity, would make it a
difficult matter to provide a fuse that would not blow unnecessarily.
The only object of the fuse would be to protect the motor windings,
and, as the latter can stand all the current the battery can supply, the
only source of danger is the possibility of the motor being held fast
so that its armature cannot revolve.
Q. What is the difference between the single-wire and the
A. In the single-wire there is but one connection to the operat-
ing circuit by means of a wire or cable, the circuit being completed
in every instance by grounding the other side of the circuit. For
this reason the single-wire is also referred to as a grounded system.
In the two-wire system, copper wires or cables are employed to com-
plete the circuits between the generator and battery and between
the battery and the starting motor, as well as to the lamps.
Q. What forms the return circuit of a single-wire system?
A. The steel frame of the chassis.
Q. How are the various circuits grounded?
A. In the case of the battery, a special ground connection is
usually made by drilling the frame and fastening a clamp to it.
The ground cable from the battery is attached to this clamp. The
generator and starting motor are grounded internally, i.e., the end
of a winding or of a brush lead that would be taken out to form the
ELECTRICAL EQUIPMENT 643
return side of a two-wire system is connected to the frame of the
machine, and the latter completes the connection to the chassis
through its holding bolts or other means of attachment. One side
of all lamp sockets is usually grounded, so that the bulb itself com-
pletes the connection when fastened in place. Sometimes there
is a special ground connection from the battery for the return side
of the ignition or lighting circuits, and this ground wire is fused.
Q. What are the advantages and disadvantages of the single-
A. It greatly simplifies the wiring, as but one wire connection
is necessary to the apparatus for each circuit, but this advantage
renders it more susceptible to derangement through unintentional
grounds or short-circuits, since the touching of any metal part of
the chassis by a bare wire will cause a short-circuit. This depends
to a very great extent, however, on the thoroughness with which
the wiring is protected, and, with the armored cables or loom and
the junction boxes used on modern installations, it is reduced
to a point where both systems are practically on a par in this
Q. What are the advantages and disadvantages of the two-
A. Each circuit is complete in itself thus rendering it easier
to locate faults, while no one connection coming in contact with
a metal part of the chassis will cause a ground. The wiring itself,
however, is much more complicated, and, with the small space
available on the bulb connections, it is more difficult to insulate
Q. Which system of wiring is favored?
A. The single-wire system will be found on the majority of
cars, and the number of makers adopting it is steadily increasing.
Faults in Circuit
Q. What is the difference between a ground and a short-
A. So far as the effect produced is concerned, they are the
same; the difference in the terms referring solely to the method of
producing it. For example, if the cable of the starting motor circuit
becomes abraded and the bare part touches the chassis or some
Digitized by VjOOQIC
644 ELECTRICAL EQUIPMENT
connecting part of metal, this is a ground. But it is also a short-
circuit in that the circuit to the battery is completed through a
shorter path than that intended. On the other hand, if, in a two-
wire system, the two cables of the same circuit become chafed close
together and their bared parts touch, this is a short-circuit, but
it is not a ground. For all practical purposes, however, the two
terms are really interchangeable when applied to faults in the circuit.
(See Gray & Davis instructions.)
Q. How may grounds be located in a single-wire system?
A. In any of the fused circuits, the fuse will immediately
blow out. Remove the fuse cartridge and shake it; if it rattles,
the fuse wire has melted and the fuse is blown. If it does not
rattle, short-circuit the fuse clips with the pliers or a piece of metal;
a spark will indicate the completion of the circuit and will also
indicate that the fuse has blown. If, on bridging the fuse clips,
the lamp lights, or other apparatus on the circuit operates, the
short-circuit was only temporary. This does not mean, however,
that the fault has been remedied; the vibration of the car may
have shaken whatever caused it out of contact and further vibra-
tion sooner or later will renew the contact with the same result.
Inspect the wiring of that particular circuit and note whether the
insulation is intact throughout its length. See that no frayed ends
are making contact at any of the connections and that the latter "
are all tight and clean. In case the lamp does not light on bridging
the fuse clips, see if the bulb has blown out; if not, use the test
lamp by applying one point to the terminal and the other to various
points along the wiring.
Q. Does the blowing of a fuse always indicate a fault in the
A. No. A bulb, in blowing out, frequently will cause a tem-
porary short-circuit that will blow the fuse. To determine this,
apply the points of the test-lamp outfit to the bulb contacts; if the
test lamp lights, the bulb is short-circuited, and a new fuse and bulb
may be inserted without further inspection of the circuit. In case
the test lamp does not light on this test, it does not necessarily
indicate a fault in the wiring of that circuit, though inspection is
recommended before putting in new fuse and bulb. The blowing
out of the bulb may cause a short-circuit, which is ruptured by the
ELECTRICAL EQUIPMENT 645
current burning away the light metal parts that were in contact,
such as a small piece of the filament.
Q. Can a short-circuit or ground occur without blowing a fuse?
A. Yes. No fuses are employed on starting-motor circuits
owing to the very heavy current used and its great variation depend-
ing upon the conditions, such as extreme cold gumming the lubri-
cating oil, tight bearings, binding of the pinion and gear, sprung
shaft, starting motor out of alignment, or the like. On other circuits,
the amount of current leaking through the fault in the circuit may
not be sufficient to blow the fuse, as the capacity of the latter is
such that it wall carry the maximum current which the apparatus in
that circuit will carry without damage — usually 5 or 10 amperes
on lighting circuits and 10 amperes on generator-field circuits.
Q. How can such faults be noted?
A. The ammeter, or indicator, will show a discharge reading
when the engine is idle and all lamps are switched off.
Q. What is the usual nature of such a fault?
A. The battery cut-out may have failed to open the circuit
completely; a frayed end of the stranded wire at one of its con-
nections may be making light contact which will permit a small
amount of current to pass; a particle of foreign matter of high
resistance may be bridging a gap either at the cut-out or some
other part of the circuit; or the ignition switch may have been
left on the battery contact so that current is flowing through the
Q. How may faults be located in a two-wire system?
A. With the aid of the test lamp, placing the points along
the two wires of the circuit at fault from one set of terminal con-
nections to the other, examine all connections in the circuit in
question; note whether any wires have frayed ends and, if so, wind
them tight together and dip in molten solder. See whether any
moving part is in contact with one or both of the wires and whether
the insulation of the latter has been worn off. In some two-wire
systems there is a ground connection to the battery for the ignition
system, in which case tests for grounds in the circuit in question
must also be made. Examine the ignition switch for faults; also
the switch of the circuit under test. This applies to single-wire as
well as to two-wire systems.
646 ELECTRICAL EQUIPMENT
Q. What is one of the most frequent causes of short-circuits
in a two-wire system?
A. The bulbs and their sockets, owing to the very small
amount of space available for the insulation. Dirt or particles of
metal may be bridging the small gaps between their insulated con-
tacts. A blown-out bulb also may be responsible, as previously
Q. Why are different sizes of wire employed in the various
A. To permit the passage of the maximum current necessary
in each circuit consistent with the minimum drop in voltage due
to the resistance of the wire and its connections. The voltages
employed are so low that any substantial drop due to this cause
would seriously impair the efficiency of the system and particularly
of the starting motor. For the latter the cables employed are not
only large, but they are also made as short and direct as possible
to save current as well a* expense in the installation.
Q. What is the smallest wire that should be employed in
A. No. 14 B. & S. gage, and this should be used only for the
tail lamp, dash lamp, primary circuit of the ignition, or similar
purpose. No. 10 or No. 12 is usually employed for the other lighting
Q. When, in making alterations on a car, it becomes neces-
sary to extend a circuit, what should be done?
A. The ends of the wires should be scraped clean and bright
for at least 2 inches, and a lineman's joint made with the aid of
the pliers to insure having it tight. A lineman's joint is made by
crossing the bared ends of the wires at their centers at right angles
to each other, then wrapping or coiling each extending end tight
around the opposite wire; the joint then should be soldered and
well taped. A circuit should be extended only by using wire of the
same size and character of insulation. None of the foregoing applies
to the starting-motor circuit. It is inadvisable to lengthen this
circuit if avoidable, but in the rare instances when it would be
necessary, new cable of the same size or larger and with the same
insulation should be cut to the proper length and the old cable
ELECTRICAL EQUIPMENT 647
discarded. All terminals should be solidly fastened to the new cable
Q. Why is it necessary to use such heavy cable for the connec-
tion of the starting motor to the battery?
A. It is essential that the exceedingly heavy starting current
be transmitted with the minimum of loss.
Q. What is considered the minimum permissible loss in the
A. One maker specifies that the starting cable must be large
enough to transmit a maximum current of 400 amperes with not over
one-fourth volt total loss.
Q. Why is it important to hold the voltage drop down to a maxi-
mum so small as to be negligible in almost any other application?
A. Owing to the heavy current necessary, as a drop of but J
volt in potential with a current of 400 amperes represents a loss of 100
watts, or close to \ horsepower. Of course, the current seldom
reaches such a high value as this except when a motor is exceptionally
stiff, as in severe cold weather or just after its bearings have been set
up very tight; moreover, this loss takes place at the instant of starting
only, but it is just at this time that the highest efficiency and full
battery power is needed to start without spinning the engine too much.
Q. On some of the early systems whose efficiency was not of
the best, how can the proper size of cable to use between the starting
motor and battery be determined?
A. Test the starting motor with a high-reading ammeter (scale
should read to at least 300 amperes) after having made certain by
hydrometer and voltage tests that the storage battery is fully charged.
(See instructions regarding this.) Carefully note ammeter reading
exactly at instant of closing switch, to determine maximum current
flow. Measure the length of cable between the battery and the
starting motor, i.e., both sides of starting switch. Then maximum
starting current times 10.7 times number of feet of cable used, divided
by .25 will give the cross-section of the wire in circular mills. For
example, assume that the starting motor required a maximum of 300
amperes momentarily to break away the engine, and five feet of
cable are employed for the connections. Then
300X10.7X5 10Q>lnn . i .„
— = 128,400 circular mills
648 ELECTRICAL EQUIPMENT
By referring to Table I, Part I, which gives the various size wires in
circular mills and their equivalent in gage sizes, it will be noted that
the closest approach to this is No. 00 cable, which is 133,079 circular
mills, so that the largest size cable would have to be used. If the
starting cable used on an old system which does not show particularly
good efficiency is much smaller than this, it would probably be an
advantage to replace it with larger cable, assuming, of course, that
every other part of the system is in good condition and working
Q. Why should connections be inspected frequently?
A. The vibration and jolting to which they are subjected in
service is so severe that no mechanical joint can be depended upon
to remain tight indefinitely.
Q. What harm does a loose or dirty connection occasion?
A. A loose connection causes the formation of an arc between
its contacts whenever vibration causes the parts to separate tem-
porarily. This wastes current and burns the metal away, leaving
oxidized surfaces which are partially insulating, thus increasing
the resistance at the connection. Dirt getting between the surfaces
of the connector has the same effect; the resistance is increased and
there is a correspondingly* increased drop in the voltage of the
circuit, which cuts down its efficiency.
Q. Why should all terminals be well taped when the battery,
starting motor, generator, or other apparatus is temporarily dis-
connected for purposes of inspection or test?
A. To prevent accidental short-circuits which would be caused
by these terminals coming in contact with any metal part of the
chassis on a single-wire system. Such a short-circuit would ruin
the battery and burn out any lamps that happened to be included
in the circuit. This precaution applies with equal force to the two-
wire systems, as in this case the terminals of the different wires
might come together, or there might be a ground connection in
PROTECTIVE AND OPERATIVE DEVICES
Q. What are the protective devices usually employed on
A. Fuses in the separate lamp circuits, in the ground con-
ELECTRICAL EQUIPMENT 649
nection, and in the field circuit of the generator on some machines;
battery cut-out for the charging circuit; circuit-breaker which
takes the place of the fuses.
Q. What is a fuse and what is its function?
A. A fuse consists of a piece of wire of an alloy which melts
at a low temperature and which will only carry a certain amount of
current without melting, the latter depending upon the diameter
of the wire, i.e., cross-section and the nature of the alloy. The fuse
is usually in the form of a cartridge, the wire being encased in an
insulating tube having brass ends, to which the ends of the wire are
soldered. These brass ends are pressed into spring clips to put the
fuse in circuit. In some cases open fuse blocks are employed, the
wire itself simply being clamped under the screw connectors on the
porcelain block. The function of the fuse is to protect the battery
and the lamps when, by reason of a ground or short-circuit in the
wiring, an excessive amount of current flows.
Q. When a fuse blows out what should be done?
A. Investigate the cause before replacing it with a new one.
(See Wiring Systems.)
Q. Is it permissible to bridge the fuse gap with a piece of
copper wire when no replacements are at hand?
A. Only in cases of emergency and after the short-circuit
which has caused the fuse to blow has been remedied. The finest
size of copper wire at hand, such as a single strand from a piece of
lamp cord, should be used. If this burns out, there being no ground
or short-circuit in the wiring, use two strands. Remove the wire
as soon as a new fuse is obtainable.
Q. Why are fuses not employed in the starting-motor circuit?
A. In the starting circuit the current necessary is so heavy
and varies so widely with the conditions that it would not be
practicable to provide a protecting fuse.
Q. What does the intermittent blowing of the fuse on the same
A. A short-circuit that is caused by the vibration, or jolting, of
the car. The wire, lamp socket, or other part of the circuit that is at
fault is shaken loose at times so that the circuit is operative, and a new
650 ELECTRICAL EQUIPMENT
fuse may be inserted without instantly blowing, as it would do were
the short-circuit constant. This is often the case as the car is stopped
to inspect the wiring and insert the new fuse, and standing still lets the
part drop out of contact; starting up shakes it into contact once
more and blows the new fuse. Loose connections, wires with abraded
insulation, and bulbs loosely inserted in their sockets are apt to cause
trouble of this nature.
Q. Does the blowing out of a fuse necessarily indicate a fault in
the wiring or in some other part of the system?
A. No, since a bulb in burning out will frequently cause the fuse
to blow out. This is due to the fact that in breaking, the end of the
parted filament of the bulb may fall across the other terminal where it
comes through the glass, thus causing either a short-circuit or such a
reduction in the ordinary resistance as to permit a much heavier rush
of current than normal, with the result that the fuse goes. To test,
leave burnt-out bulb in place temporarily; short-circuit fuse clips with
screw driver or pliers, just touching them momentarily; if no spark
results, replace bulb with a new one and test again; if a spark occurs,
remove old bulb and test again with no lamp in place; then if no spark
occurs in bridging the fuse terminals, the circuit is all right, and the
fuse may be replaced.
Q. When all the lighting fuses blow out at once, what does
A. A short-circuit across the lighting-switch terminals would
cause this. In some switches with exposed rear terminals, it is
possible to place a screwdriver or similar piece of metal in such a posi-
tion that it bridges practically all the switch terminals. If the light-
ing switches were all closed at the time, this would short-circuit them.
Q. What is a circuit-breaker, and what is its function?
A. The circuit-breaker is an electromagnet with a pivoted
armature and contacts, similar in principle to the battery cut-out.
All the current used in the various circuits, except that of the start-
ing motor, passes through it, and its contacts normally remain closed.
The winding of the magnet coil is such that the normal current
used by the lamps or ignition does not affect it, but the passage
of an excessive amount of current will energize the magnet, attract
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ELECTRICAL EQUIPMENT 651
the armature, and break the circuit. The spring holding the arma-
ture away from the magnet will again close the circuit, and the
circuit-breaker will vibrate until the cause has been removed. This
is usually a ground or short-circuit. The function of the circuit-
breaker is to protect the battery and lamps in place of the usual fuses.
Q. If the circuit-breaker operates when there are no faults
in the wiring, what is likely to be the cause?
A. Its spring may have become weakened so that the vibra-
tion of the car causes it to operate on less current. The Delco
circuit-breaker is designed to operate on 25 amperes or more, but,
once started, a current of 3* to 5 amperes will keep it vibrating.
If tests show that no faults in the wiring or connections exist,
increase the spring tension with the ammeter in circuit until the
reading of the latter indicates that the circuit-breaker is not operat-
ing on the current of less value than that intended. See that the
contacts are clean and true.
Q. What is a battery cut-out?
A. It is an automatic double-acting switch which is closed
by the voltage of the generator and opened by the current from
Q. Of what does it consist?
A. It is essentially a double-wound electromagnet with a
pivoted armature and a pair of contacts. One winding, known as
the voltage coil, is of fine wire and is permanently in circuit with the
generator. The second winding of coarse wire is termed the current
coil and is put in circuit by the contacts.
Q. Why is a cut-out necessary?
A. To protect the storage battery. When the generator
speed falls below a certain point, it no longer produces sufficient
voltage to charge the battery, and the latter then would discharge
through the generator windings if not prevented. This discharge
would always take place when the generator was idle, except for
Q. How does it operate?
A. When the generator voltage approaches the value nec-
essary for charging, it energizes the magnet through the voltage
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652 ELECTRICAL EQUIPMENT
coil and closes the contacts, cutting in the current coil, which fur-
ther excites the magnet and holds the contacts firmly together.
The closing of these contacts puts the battery in circuit and it
begins to charge. As soon as the generator speed falls below the
point necessary for charging, the battery voltage overcomes that
of the generator and sends a current in the reverse direction through
the current coil, causing the contacts to separate and cutting the
battery out of the charging circuit.
Q. If the generator is run for any length of time at or near
this critical speed, what is to prevent the cut-out from vibrating
constantly instead of working positively one way or the other?
A. The resistance of the windings is so proportioned that
there is a difference of 1 to 2 volts between the cutting-in and the
Q. What is the result when the battery cut-out — which is
variously termed a cut-out, a circuit-breaker, an automatic switch,
and a reverse-current relay or an automatic relay — fails to operate?
A. If it fails to cut in, i.e., the contacts do not come together,
the battery does not charge and will quickly show a falling-off in
capacity, such as inability to operate the starting motor properly oi
to light the lamps to full brilliance. If it fails to cut out, the battery
charge will be wasted through the generator windings with the same
indications of lack of capacity.
Q. What is the most frequent cause of trouble?
A. Automatic cut-outs have been perfected to a point where
but little trouble occurs. Freezing or sticking together of the
contacts due to excessive current will most often be found to be
the cause of the device failing to cut out when the generator is
stopped. The points should be cleaned and trued up as described
in previous instructions. Loose or dirty connections making poor
contact may insert sufficient extra resistance in the circuit to
prevent the device from cutting in at the proper point. Excessive
vibration, particularly when the cut-out is mounted on the dash,
may prevent the contacts from staying together as they should
when the engine is running at or above the proper speed. See that
the cut-out is solidly mounted. Temporary loss of battery capacity
may be due to slow driving over rough roads at about the speed
at which the cut-out is designed to put the battery in circuit. '
ELECTRICAL EQUIPMENT 653
Q. None of the above causes existing, what further tests may
A. The windings may be tested as already described for the
generator windings, but trouble from this source is equally rare.
If the contacts are clean and true and the connections are tight,
look for a loose connection elsewhere, as at the generator or battery
or the ground on the frame. A loose connection vibrates when the
car is moving, constantly opening and closing the circuit and causing
the cut-out to do likewise, so that the battery does not charge. A wire
from which the insulation has been abraded will also vibrate, owing
to the movement, causing an intermittent short-circuit. With all con-
tacts and connections in good condition, failure to cut out indicates a
ground or short-circuit between the battery and cut-out; failure to cut
in indicates similar trouble between the generator and the cut-out.
Q. Is a battery cutout necessary on every electrical system?
A. No. On single-unit systems of the type of the Dyneto,
in which the generator becomes motorized as soon as its speed and
consequently its voltage drops below a certain point, the battery
* is always in circuit. A plain knife-blade switch, which also controls
the ignition, is closed to start and left closed as long as the car is
running. But the engine must not be allowed to run at a speed
below which it generates sufficient voltage to charge the battery,
nor must the switch be left closed when the engine is not running;
otherwise, the battery will discharge through the generator windings.
Q. After having trued up points of a battery cut-out, what pre-
cautions should be taken in adjusting them?
A. To insure proper operation, they must be set to the distances
given in the manufacturer's instructions. This refers not only to the
gap between the contact points themselves, but also to the distance
that the armature must be set from its backstop when the points are
open and to the air gap between the armature and the magnet.
These distances are very small in every case, and it is important that
they be adjusted accurately. They differ slightly on cut-outs of
different makes and also on different models of the same make. For
example, in the Gray & Davis cut-out, the distance between the con-
tact points should be .015, the air gap between the armature and its
backstop not less than .010, and the armature air gap, or distance
between the armature and the magnet face, .030. These dimensions
654 ELECTRICAL EQUIPMENT
refer to the flexible, or spring-arm type, while in the solid-artn type
of the same make, they are .010 for the distance between the contact
points and .015 for the armature air gap, it being necessary that the
armature should be set parallel with the pole face of the magnet.
Q. How can these small distances be accurately determined
with the facilities ordinarily found in a repair shop?
A. The manufacturers usually supply a small adjusting wrench,
the different edges of which have been ground to varying thicknesses
representing the proper distances for the various gaps. Lacking one
of these, small pieces of strip brass or steel may be ground or filed
down to the proper size and gauged with a micrometer, which should
be part of the equipment of every garage. The strips should be
stamped with the dimensions and name of gap for identification.
Q. How often will the point of a battery cut-out need adjust-
ment, or truing up?
A. Service conditions vary so greatly that it is impossible to give
any definite average for this, particularly as the instruments them-
selves also are a variable quantity, but, under ordinarily favorable
conditions, they should not require attention more than once a year.
Q. Why is it necessary to make contact points of such an expen-
sive metal as platinum, and why is the latter sometimes alloyed with
A. There is no other metal which withstands the oxidizing
effect of the electric arc and still maintains a clean and bright con-
ducting surface as does platinum. Irridium is added to make the
platinum harder, so that it will be more durable. On cheaply made
instruments in which no platinum has been used in the contacts,
trouble will be experienced constantly with the contacts.
Q. Is there any substitute for platinum or any metal that
approaches it in adaptability for contact points?
A. There is no substitute for platinum, and the only metal that
approaches it is silver. Where contact points only separate occa-
sionally at intervals, as in the Remy thermoelectric switch, the use of
silver contacts is permissible; but in a battery cut-out, or a regulator
in which the vibration of the points is more or less constant, nothing
will serve so reliably as platinum.
ELECTRICAL EQUIPMENT 655
Q. What is the cause of the platinum contacts burning into such
irregular ragged forms?
A. When a current of electricity passes through a contact of this
nature, the material of the positive electrode (i.e., contact point
connected to the positive side of the circuit) is carried over by the
current in the shape, of metallic vapor, or infinitely fine particles, and
deposited on the negative electrode. The positive consequently takes
on the form of a sharp point, while the negative has a depression
formed in it, usually referred to as a "peak and crater", which the two
points resemble in miniature after long use. This peak and crater
effect is much more noticeable in an old-style carbon arc lamp after
it has been burning only a few hours.
Q. What can be done to prevent this?
A. The passing of the metal from one electrode to the other
cannot be prevented, as it is a function of any arc or spark. It can
be minimized, however, by keeping the contacts in good condition so
that the sparking is reduced to a minimum.
Q. Can the formation of the pack and crater effect, which so
greatly reduces the efficiency of the contacts, be avoided?
A. The use of a reversing switch in the circuit, as in the case of
the magneto or the battery-type interrupter which changes the direc-
tion in which the current flows through the points every time it is
turned on, will overcome this. Where there is no reversing switch
in the ignition circuit or where one cannot be used, attention to the
points at regular intervals will prevent this effect from reaching a
stage where most of the point has to be filed away to true it up.
Q. In the use of the file, sandpaper, or emery cloth in this con-
nection, just what is meant by truing the points up?
A. Their surfaces must be made exactly parallel to one another
so that when the points come together they touch uniformly over
their entire surfaces. In the hands of the unskilled user, there is a
tendency to bear down sidewise with the file, thus forming rounded
edges on the points. In addition to having the faces of the two points
perfectly parallel, the face of each point must be at right angles to its
sides. Otherwise, there is bound to be unnecessary sparking between
the points, and this causes them to burn away again much sooner.
It is scarcely necessary to add that as little as possible of the metal
should be removed. As long as there is enough of the platinum left
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656 ELECTRICAL EQUIPMENT
to make true parallel surfaces, the points need not be replaced if
the means for adjustment permits utilizing them when worn far down.
Q. What is the cause of the points freezing, or sticking,
A. Permitting them to wear down to a point where they are in
very poor condition and where the gap between parts of their surfaces
causes the formation of a heavy arc, or hot flash of current, which
practically welds them together. By giving them the necessary
attention at regular intervals, this may be avoided.
Q. How often should the contact points need attention?
A. When new, they should run for a year or more without any
attention. After they have been trued up, the succeeding interval
will often depend upon the skill and care with which this has been
Q. How do switches as employed on the automobile differ
in principle and operation?
A. Starting-circuit switches are either of the knife-blade or
the flat-contact type, while in the majority of cases the lighting
switches are of the push-button type, though knife-blade switches
are used for this purpose also. In some instances, one of the brushes
of the machine is made to serve as a switch, as in the Delco. Ordi-
narily, the switch is normally held open by a spring and is closed
by foot pressure, the spring returning it to the open position as
soon as released. A variation of this is the Westinghouse electro-
magnetically operated switch in which a solenoid takes the place of
foot operation. The circuit of the solenoid is controlled by a spring
push button, which is normally held out of contact. Single-unit
systems, such as the Dyneto, in which the machine automatically
becomes motorized when the speed drops below a certain point,
are controlled by a standard single-throw single-pole knife-blade
switch which is left closed as long as the machine is running.
Q. What faults may be looked for in switches?
A. Loose connections; weakening of the spring; burning of
the contact faces in the knife-blade type, due to arcing caused by
releasing too slowly; dirt or other insulating substance accumulating
on the contact faces of the flat-contact type; failure to release through
ELECTRICAL EQUIPMENT 657
Q. Why is it important to keep the switch contact faces clean
A. Dirt or burned surfaces increase the resistance and cause
a drop in the voltage at the starting motor. The energy represented
by an electric current is a measure of the volume or amperes times
the voltage or pressure under which it flows, and, as such low voltages
are used, only a slight falling off represents a serious percentage
of the total potential. With a dirty switch or one that makes poor
contact, current that should be utilized in the starting motor is
wasted in overcoming the resistance of the switch.
Q. Why is it inadvisable to insert an extra switch in the start-
ing circuit, as is done in some cases by owners to insure against
A. Because of the drop in voltage. The loss in switches as
designed for lighting circuits is about 1 per cent, or a little over 1
volt. If the same switch is used on the low voltage of the starter
system, the loss is then equivalent to about 10 per cent.
LIQHTINQ AND INDICATORS
Q. How many types of bulbs are there in general use on
A. Four: miniature and candelabra screw base, and single-
and double-contact bayonet-lock base, both of the latter being of
the candelabra size.
Q. Are these types equally favored?
A. No. The screw-base type, particularly in the miniature
size, will be found only on old cars, and this type, generally speaking,
is practically obsolete on the automobile, as the vibration tends to
unscrew the lamp. Of the bayonet-lock type, the single-contact
style is steadily gaining favor. Ten million bulbs for automobile
lighting were produced in 1915 (S.A.E. report) and of these 67
per cent were of the single-contact type.
Q. In how many different voltages are these bulbs made?
A. Four: a 6 — 8-volt bulb for a 3-cell or 6-volt system; 12 —
16-volt bulb for 6-cell or 12-volt systems; and 18 — 24-volt bulbs for
9-cell systems; 3 — 4-volt bulbs for tail-light and dash-light use,
where these lights are burned in series on a 6-volt system.
658 ELECTRICAL EQUIPMENT
Q. Are these the only voltages in which the bulbs are made?
A. No. They are the types that are being standardized
to reduce the stock of replacements that it is necessary for a garage
to carry. It has been customary for the lamp manufacturer to
supply bulbs made exactly for any voltage that the maker of the
electric system ordered. Taking into consideration only the standard
sizes now listed for use on 3-, 6-, and 9-cell systems, and the different
bases regularly used, there are about twenty-four different bulbs
that should be stocked by a garage. In addition, about forty other
sizes are in general use, and if individual voltages had to be sup-
plied, considering the different standard bases, a stock of over
two-hundred different bulb sizes would be required.
Q. Why is the voltage of a bulb expressed as "6 — 8", "12 —
A. Owing to the rise and fall of the battery voltage according
to its state of charge, this variation must be provided for, or the
lamps would be burned out when the battery was fully charged.
Headlight bulbs for 3-cell systems are made for 6£ volts, while the
side, rear, and speedometer lights are made for 6| volts, owing to
the lesser voltage drop in their circuits, but they will all. operate
satisfactorily on a potential that does not exceed 8 volts or does not
drop below 6 volts.
Q. When all the lamps burn dimly, what is the cause?
A. The battery is nearly exhausted, in which case its voltage
will be only 5.2 to 5.5 volts for a 3-cell system. The car should be
run with as few lights as necessary to permit the generator to charge
the battery quickly.
Q. What is the cause of one light failing?
A. Bulb burned out or its fuse blown; examine the fuse before
replacing the bulb and if blown, examine the wiring before putting
in a new bulb. Poor contact; see that the lamp is put in properly
and turned to lock it in place. A double-contact bulb may have
been put in single-contact socket, or vice versa.
Q. Why will one lamp burn much brighter than the other?
A. A replacement may have been made with a bulb of higher
voltage; a 12- volt bulb will give only a dull red glow on a 3-cell
system. Where the difference is not so marked as this, but still
very perceptible, it may be due to the difference in the age of the
ELECTRICAL EQUIPMENT 659
lamps. As a bulb grows old in service, its filament resistance
increases, so that it does not take so much current and will not
burn as brightly as when new.
Q. Will the failure of a bulb cause its fuse to blow though
there is no fault in its circuit?
A. This sometimes happens owing to the breaking down of
the filament, causing a short-circuit when the lamp fails.
Q. Can the proper voltage bulbs needed for any system always
be told simply by taking the total voltage of the battery, i.e., the
number of cells times 2?
A. No. Always examine the burned out bulb and replace
with one of the same kind. Many 6-cell systems use 6-volt lamps
and are known as 12 — 6-volt systems. The battery is divided into
two groups in series parallel for lighting and sometimes for charging,
all the cells being in series for starting. Other arbitrary voltages
are also adopted; for example, 14-volt bulbs are used on 12-cell
systems, the battery being divided in the same manner, so that
this would be a 24 — 12-volt system. The only safe way to order
replacements is to give the voltage on the printed label on the old
bulb and state the make of the system on which it is to be used.
Q. What type of bulb is used where the current is taken from
the magneto, as on the Ford?
A. As supplied by the maker, only the headlights are wired,
and they are in series, and in recent models a 9-volt bulb is used,
but the above instructions for replacements will apply here also.
Ordinarily, double-contact bulbs are required, unless the fixtures
are insulated from one another, in which case the single-contact
type can be used.
Q. Why is a bulb of a voltage lower than that of the system
itself often employed on 6-, 9», and 12-cell systems?
A. The lower the voltage, the thicker the filament can be made.
A short comparatively thick filament concentrates the light and
makes the bulb easier to focus; it is also much more durable than
the thin filament required for higher voltages.
Q. Under what conditions will the best results be obtained
from the head lamps?
A. When the bulbs are in proper focus with the lamp reflectors.
The usual focal length for headlight bulbs is H inch, and the
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660 ELECTRICAL EQUIPMENT
focal length of the reflector is made greater than this to permit of
adjustment. The center of the filament should be back of the focus
of the reflector to spread the beam of light. In this position a
greater number of the light rays are utilized and redirected by the
reflector, producing a higher beam candlepower. If the center of
the filament is forward of the focus, the lower part of the reflector
will produce the most glare and throw it into the eyes of pedestrians
and approaching drivers.
Q. How can the headlights be focused?
A. Place the car in position where light can be directed against
a wall about 100 feet distant. Adjust the bulbs backward or forward
until the spotlight on the wall is most brilliant and free from black
rings and streaks. When this position is found, lock the bulb securely
in place. Focus each headlight separately. See that the lamp
brackets are set so that the light is being projected directly ahead.
Q. How can metal headlight reflectors be cleaned when
A. Wash by directing a gentle stream of cold water against
the surfaces and allow to dry without touching them. The reflectors
should never be rubbed with cloth or paper as it will scratch the
highly polished surfaces. If they become very dull, it will be neces-
sary to have them replated.
Q. What is the meaning of the identification marks usually
placed on bulbs, in addition to the voltage, such as "Q-6"?
A. This refers to the size and shape of the bulb. The diameter
of the glass bulb is expressed in eighths of an inch and its shape by
a prefixed G for round (globular), T for tubular, S for straight-
side, etc. Thus, G-6 is a round bulb f inch or f inch in diameter.
Q. What instruments ordinarily are employed in connection
with electric systems on the automobile?
A. Either a double-reading ammeter, a volt-ammeter, or an
indicator, the first named being employed generally. The ammeter
shows whether the battery is charging or discharging or whether no
current is passing; the indicator reads either Off or On; while the
voltammeter gives the voltage, usually upon pressing a button to
put it into operation, in addition to the readings already mentioned.
ELECTRICAL EQUIPMENT 661
Q. On what circuits are the indicating instruments placed?
A. The charging circuit from the generator to the battery,
and the lamp and ignition circuits.
Q. Why is an ammeter not used for the starting-motor circuit?
A. The current is so heavy and varies so greatly with the
conditions that an ammeter designed to give an accurate reading
of it would not be sensitive enough to indicate the smaller amounts
of current used by the lamps, or produced by the generator for
charging. Furthermore, the starting motor is intended only to
be used for very short periods, while the other circuits are in
Q. Do the small ammeters employed fail very often?
A. Considering the unusually severe treatment to which they
are subjected by the vibration and jolting of the car, their failure
is comparatively rare, but as the conditions are so severe for a
sensitive indicating instrument, too much dependence should not
be placed on the ammeter reading when making tests.
Q. What are the usual causes of failure?
A. Failure to indicate — the generator, wiring, and other parts
of the circuit being in good operative condition — may be caused by
the pointer becoming bent, so as to bind it; the pointer may have
been shaken off its base altogether by the jolting, or one of its connec-
tions may have sprung loose from the same cause.
Q. How can the ammeter reading be checked?
A. By inserting the portable testing voltammeter in circuit
with it, using the 30-ampere shunt and comparing the readings.
The dash ammeter must not be expected to give as accurate a
reading as the finer portable instrument. Failing the latter, a spare
dash ammeter may be employed in the same manner and the spare
may be tested beforehand by connecting to a battery of 4 dry cells
in series; if brand new, they should give a reading of 18 to 20 amperes.
Do not keep the ammeter in circuit any longer than necessary to
obtain the reading, as it only runs the cells down needlessly.
Q. Should an ammeter ever be used in testing the storage
A. No. Because it practically would short-circuit the battery,
burn out the instrument, and damage the battery itself. Nothing
but a voltmeter should be employed for this purpose, as its high
662 ELECTRICAL EQUIPMENT
resistance coil permits only a small amount of current to pass. An
ammeter reading from a storage battery gives no indication whatever
of its condition, whereas the voltage affords a close check on the
state of charge, varying from 1.75 for a completely discharged cell
to 2.55 volts for a fully charged one, the headings always being
taken when the battery is either charging or discharging. The
voltage on discharge will not be as high as on charge, the conditions
otherwise being the same.
Q. Why are indicators employed on some systems instead
A. As the indicator is not designed to give a quantitative
reading, it need not be so sensitive as an ammeter and accordingly
can be made more durable.
Q. What are the most frequent causes of failure of an indi-
A. Usually of a mechanical nature caused, by the jolting, such
as the target being shaken off its bearings, broken wire, etc.
Q. When the engine is running slowly, and the ammeter or the
indicator flutters constantly, going from "On" to "Off" at short inter-
vals, in the case of the indicator, or from a small charging current to
zero, in the case of the ammeter, what does this signify?
A. That the setting of the battery cut-out is very sensitive
and that the engine is then running at or about the speed that the
instrument should cut-in. Since the speed of an engine varies con-
siderably when running slowly, picking up momentarily and then
falling off for a longer period, there is a corresponding variation in the
potential, causing the cut-out to operate intermittently. This is a
condition that seldom occurs and results in no harm when it does.
Q. When the ammeter or indicator flutters in the same manner
with the engine running at medium or at high speed, what does it
A. That there is a loose connection between the generator and
the cut-out, or an intermittent short-circuit or ground caused by a
chafed wire alternately making contact with some metal part owing
to the vibration. It is much more likely to be simply a loose connec-
tion and will be found most often on the back of the cut-out itself.
This should be remedied at once. If neglected, it will cause abnormal
wear of the platinum points in the cut-out.
ELECTRICAL EQUIPMENT 663
Q. When the ammeter does not indicate "Charge" though the
engine is speeded up, but does register a discharge when the lights
are turned on and the engine is idle, what is the nature of the trouble?
A. Either the generator is not producing current or the regula-
tor (where an external type is employed) is not working properly.
The generator brushes may not be making proper contact with the
commutator, or there may be a loose, corroded, or broken connection
in the generator cut-out battery circuit. Where a belt drives the
generator, it may be too loose to run the machine at its proper speed.
Q. When the ammeter gives no charging indication though the
lamps are off and the engine is speeded up, and gives no discharging
indication though the engine is idle and lamps are switched on, what
is likely to be the cause?
A. There is an open or a loose connection in the battery circuit
or in the battery itself. The ammeter may be at fault. See that its
indicating pointer has not become jammed nor dropped off its bearings.
Q. In case the ammeter indicates "Discharge" though the
engine be idle and all lights turned off, what is the trouble?
A. There is a short-circuit or a ground somewhere in the light-
ing circuits or between the battery and the ammeter, as the discharge
reading in such circumstances indicates a leakage of current; or the
cut-out has failed to operate and still has the battery in circuit with
the generator, though the engine is stopped. The ammeter pointer
may be bent.
Q. When the meter indicates a charge though the engine is at
rest, what is the nature of the fault?
A. The ammeter pointer has become bent or deranged so that
it is stuck fast in place, showing a charge.
Q. When the ammeter charge indications are below normal,
what is apt to be the cause?
A. The generator commutator or brushes may need attention,
such as cleaning or sanding-in, or new brushes may be necessary.
The generator speed may be too low; in case of belt drive, it may not
be getting the benefit of the full speed of the engine owing to a slipping
belt. The regulator (external type) may not be functioning properly,
or there may be an excessive lamp load on the generator.
Q. When the ammeter charge reading is above normal, what
is likely to be the cause?
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664 ELECTRICAL EQUIPMENT
A. There may be a short-circuited cell in the battery, or a short
in the charging circuit, or the regulator (external type) may not be
Q. What will cause the discharge reading of the ammeter to
become abnormally high?
A. The lamp load may be excessive, as where higher candle-
power bulbs are used, or more lights than originally intended are put
in the circuit. There may be leakage in some part of the lighting
Circuit, or the cutout contacts may be stuck together, permitting a
discharge through it or through the generator.
Q. What is the operating principle upon which the electric gear-
shifting mechanism is based?
A. That of the solenoid and its attraction for its core when a
current is passed through its winding.
Q. What is the source of current supply for the electric gear-
A. The storage battery of the lighting system. The operation
of gear-shifting is carried out so quickly that only a nominal additional
demand is made on the battery.
Q. How is the electric gear-shift controlled?
A. By a series of buttons corresponding to the various speeds
and located on the steering wheel, and by a master switch.
Q. What is the object of the buttons, and what are they termed?
A. To partly close the circuit to the particular solenoid of the
speed desired. They are termed "selector switches" since they per-
mit selecting in advance the speed desired.
Q. Why is a master switch employed, and why is it so called?
A. To avoid the complication which would otherwise result
from the necessity of providing two switches for each change of speed,
i.e., a selector switch and an operating switch. It is termed a master
switch because it controls the current supply to all of the circuits.
Q. Why is a neutral button provided in addition to the but-
tons for the various speeds on the selector switch?
A. To return any of the selector buttons to neutral without
the necessity of going through that speed in case it is not desired to
engage the speed in question after the button has been pushed Also
ELECTRICAL EQUIPMENT 665
to open any of the selector switches that may be closed when it is
desired to stop.
Q. What is the neutralizing device?
A. It is a mechanism incorporated with the shifting mechanism
to open the master switch automatically after the gears have been
Q. Why is the neutralizing device necessary?
A. If it were not provided, the master switch would remain
closed, causing a constant drain on the battery and rendering the
mechanism inoperative after one shift had been made.
Q. How many solenoids are provided in the standard three-
speed and reverse gear box?
A. One for every movement necessary.
Q. Is the current sent through a solenoid in one direction to
pull the shifting bar into it and then in the opposite direction to move
the bar the other way?
A. No, the current is not reversed through the same solenoid.
After the left-hand solenoid, operating the first-speed gear, for
example, has pulled the shifter bar to the left, a second solenoid,
on the opposite end of the same bar, is energized to pull it back to the
right, to shift to second or intermediate. The current is sent through
a different solenoid by means of the selector switches for each shift
Q. When the electric gear-shift failed to operate, where would
be the most likely place to look for the cause of the trouble?
A. First see that the battery is not exhausted, then that no
connections between the battery and the terminal block have parted,
thus cutting off the current supply. The wiring is so simple and so
strongly protected that it is very unlikely to have anything happen to
it except at the connections. This is likewise true of the solenoids.
Q. In case the battery is amply charged and nothing is wrong
with the connections, what procedure should be followed?
A. Use the lamp-testing set described in connection with the
lighting and starting systems and test out the various circuits as
shown on the wiring diagram. In using this test, it must always be
borne in mind that touching the two points to the same or connecting
pieces of wire or metal will always cause the lamp to light. It is useful
in this way for indicating the continuity of a wire, i.e., that it has not
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666 ELECTRICAL EQUIPMENT
broken under the insulation, but, until experience has been gained in
its use, it will be nothing unusual to find that the points have been
touched to connecting pieces of metal which have no relation to the
circuit. As such metal will complete the circuit through the lamp,
the latter will light, but without indicating anything of yalue to the
trouble hunter. Always test the lamp itself before proceeding. It
may have become partly unscrewed in its socket or its filament may
have been broken.
Q. Why is it necessary to refill the battery jars at regular
A. Because the heat generated in the cells evaporates the
water from the electrolyte, and, if the latter is permitted to fall
below the tops of the plates, they will dry out where they are
exposed, and the heat of charging will then cause thena to disinte-
grate, ruining the battery.
Q. Why should this be done at intervals of not less than
A. Because the limited amount of electrolyte permitted
by the restricted size of the cells over the plates — usually one-half
inch — will be evaporated in that period by a battery that is in
more or less constant use.
Q. Why should water alone and never acid or electrolyte
be used to make up this loss?
A. Only the water evaporates, so that if either acid or fresh
electrolyte is added, it will disturb the specific gravity of the solu-
tion in the cells and totally alter their condition.
Q. What is the reason that battery manufacturers insist
that only distilled water or its nearest equivalent, rain water or
melted artificial ice, be used for this purpose?
A. Because ordinary water contains impurities that are
apt to harm the plates, such as iron salts, or alkaline salts that will
affect both the plates and the electrolyte.
Q. What should be done to a battery that has had its efficiency
impaired by being filled with impure water?
A. The cells should be taken apart, the separators discarded,
the plates thoroughly washed for hours in clean running water
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ELECTRICAL EQUIPMENT 667
without exposing them to the air where they would dry, the jars
washed out, the plates reassembled with new separators, the jars
filled with fresh electrolyte of the proper specific gravity, and the
battery put on a long slow charge from an outside charging source,
i.e., not on the car itself. Unless there are proper facilities for
carrying this out, it will be preferable to ship the battery back to
the maker so that it can be given proper treatment, particularly
as it is necessary to reseal the cells.
Q. How is electrolyte prepared?
A. By adding pure sulphuric acid a very little at a time to
distilled water until the proper specific gravity is reached, and then
permitting the solution to cool before using. The mixture must
always be made in a porcelain, hard rubber, or glass jar; never
in a metal vessel. Commercial sulphuric acid or vitriol should
not be employed, as it is far from pure. Never add water to acid.
When the two are brought together, their chemical combination
evolves a great amount of heat, and the acid will be violently
Q. How often should distilled or rain water be added to the
A. This will vary not alone with different systems but with
different cars equipped with the same system, owing to the difference
in conditions of operation. The only way to determine this definitely
is to inspect the cells at short intervals and note how long they will
operate before the electrolyte gets close enough to the tops of the plates
to require additional water. This may be a week, ten days or two
weeks, or even more, if the car is not run much.
Q. When a battery requires the addition of water at very short
intervals to keep the level of the electrolyte one-half inch above the
plates, what does this indicate?
A. It shows that the battery is being constantly overcharged,
which keeps it at a high temperature', causing excessive evaporation.
This will usually occur where a car is in constant use during the day
but is driven very little at night. It may be remedied by adjustment
of the regulation so as to reduce the output of the generator. Where
this is not possible, as in the case of simple bucking-coil regulation
which is entirely self-contained and permits no variation, additional
resistance may be introduced in the generator-battery circuit. This
668 ELECTRICAL EQUIPMENT
may take the form of a small-resistance unit consisting of German
silver or other high-resistance wire wound on a porcelain tube
and mounted on the forward side of the dash. A single-pole knife
switch should be placed in the circuit with the resistance so that
the latter can be cut in or out of the generator circuit as circum-
stances may require.
Q. With conditions as in the preceding question, how can the
amount of resistance to be inserted in the circuit be figured?
A. By the use of Ohm's law. In this case, it would be R=-~ f
or resistance equals voltage divided by current. How much resist-
ance to use can only be answered by the conditions of operation.
Where a car is used steadily during the day and very seldom at night,
it may be necessary to reduce the charge by two-thirds. In the case
of a 6-volt system normally charging at 12 amperes, the generator
delivers current at 7 to 7* volts in order to overcome the voltage
of the battery when fully charged. Selecting 7 volts, we see that
the resistance in circuit when the current is 12 amperes is 7-5-12, or .6
ohm approximately. Now when the charging current is 4 amperes,
we must have 7-^4, or 1.75 ohms in circuit; that is, to reduce the
current from 12 to 4 amperes, a resistance of 1.75— .6, or 1.15 ohms
must be inserted. The amount of resistance wire necessary to give
this resistance or any other resistance necessary may be found in
tables of wire sizes and resistances of special wire employed for this
purpose. The wire is bare and must be wound on the tube so that
adjacent coils do not touch. An extreme instance is cited here. It
may be necessary in many cases to reduce the charging rate by a
very much smaller fraction. Ordinarily the charging rate should
not be altered.
Q. When the battery is constantly gassing, or "boiling",
as the car owner usually puts it, what is the trouble?
A. It is being constantly overcharged. This will greatly reduce
the life of the battery, and the charging rate should be reduced, as
mentioned in the preceding answer. It is essential that the battery
be kept fully charged; but if it is continually overcharged, this will
keep the cells at an abnormal temperature which is injurious to the
plates. The battery treatment will vary with the season, for the
demand on it is much heavier during cold weather than in summer.
ELECTRICAL EQUIPMENT 669
Q. Why should the battery be tested with the hydrometer
at regular intervals of a week or so?
A. Because the specific gravity of the electrolyte is the most
certain indication of the battery's condition.
Q. What should the hydrometer read when the battery is
A. 1.280 to 1.300.
Q. What point is it dangerous to permit the specific gravity
of the electrolyte to fall below, and why?
A. 1.250; because below this point, the acid begins to attack
the plates and the battery plates sulphate. The lower the specific
gravity, the faster sulphating takes place.
Q. What should be done when the hydrometer reading is
1.250 or lower?
A. The battery should be put on charge immediately, either
by running the engine or by charging from an outside source of
current until the gravity reading becomes normal.
Q. If the hydrometer reading of one cell is lower than that
of the others, what should be done?
A. Inspect the cell to see if the jar is leaking; note whether
electrolyte is over the plates to the depth of \ inch and whether
the electrolyte is dirty. If these causes are not apparent, the cell
will have to be opened and inspected for short-circuits from an accu-
mulation of sediment in the bottom of the jar or from buckling of
Q. Are hydrometer tests alone conclusive?
A. No. To be strictly accurate, they should be checked by volt-
age tests, in addition.
Q. How should these voltage readings be taken?
A. With the aid of a portable voltmeter, using the low-reading
scale, i.e., 0-3 volts, and always with the battery discharging, the load
not exceeding its normal low discharge rate.
Q. Why should the test not be made with the starting-motor
A. Because the discharge rate while the starting motor is being
used is so heavy that even in a fully charged battery in good condition
it will cause the voltage to drop rapidly.
670 ELECTRICAL EQUIPMENT
Q. Why should the voltage readings not be taken while the
battery is charging?
A. Because the voltage of the charging current (always in
excess of six volts) will cause the voltage of a battery in good condition
to rise to normal or above the moment it is placed on charge, such
readings are not a good indication of the battery's condition.
Q. What should the voltage of the cells be?
A. In any battery in good condition, the voltage of each cell at
the battery's normal low discharge rate (5 to 10 amperes, as in carry-
ing the lamp load) will remain between 2.1 and 1.9 volts until it begins
to approach the discharged condition. A voltage of less than 1 .9 volts
per cell indicates either that the battery is nearly discharged or that
it is in bad condition. The same state is also indicated when the
voltage drops rapidly after the load has been on a few minutes.
Joint Hydrometer- Voltmeter Test
Q. What should the hydrometer and voltmeter readings be for a
fully charged battery in good condition?
A. Hydrometer 1.275 to 1.300; voltage 2 to 2.2 volts per cell.
Q. What does a hydrometer reading of 1.200 or less with a
voltage of 1 .9 volts or less per cell indicate?
A. This shows that excess acid has been added to the electro-
lyte. Under these conditions, the lights will burn dimly even though
the hydrometer test alone would appear to show that the battery is
more than half charged.
Q. What does a hydrometer reading in excess of 1 .300 indicate?
A. It indicates that an excessive amount of acid has been added
to the electrolyte, regardless of whether the voltage reading is high,
low, or normal.
Q. Where a low voltage reading is found, how can it be deter-
mined whether the battery is in bad condition or merely discharged?
A. Stop the discharge by switching off the load (lamps) and put
the battery on charge, cranking the engine by hand. After a few
minutes of charging, note whether the voltage of each cell promptly
rises to 2 volts or more. Any cells that do not are probably short-
circuited or otherwise in bad condition.
Q. How can a rough test of the condition of the battery be made
without the use of any instruments?
ELECTRICAL EQUIPMENT 671
.A. On systems fitted with a battery cut-out in the generator
battery circuit, remove the cover of the cut-out (the generator being
stationary) and momentarily close the cut-out points with the finger.
The discharge shown by the ammeter the monent the points are
closed should be anywhere from 10 to 20 amperes, differing, of
course, with different systems. In any case, it should be equal to or
greater than the maximum normal output of the generator, provided
the battery is at least three-quarters charged.
Q. What effect will allowing the electrolyte to fall too low in
the cells have, apart from the damage that it will cause to the plates?
A. It will tend to increase the voltage if the battery is otherwise
in good condition, and this may be carried to a point where it will
burn out the lamps.
Q. What is meant by "floating the battery on the line"?
A. This describes the relation of the battery to the generator
and lighting circuits in systems where the current for lighting is taken
directly from the generator when running, any excess over the require-
ments of the lamps being absorbed by the battery. The moment the
generator speed falls bjelow the point where it supplies sufficient cur-
rent to supply all that is needed for the lamps, the battery automati-
cally supplies the balance. When the generator is idle, the battery,
of course, supplies the current for lighting as well as for starting.
Q. Why should the cell tops be wiped dry from time to time
and the latter as well as the terminals be washed with a weak
solution of ammonia and water?
A. As the charge approaches completion, the cells gas; when
overcharged they gas very freely. This gas carries with it in the
form of a fine spray some of the electrolyte, and the acid of the latter
will attack the terminals and corrode them. Wiping clean does
not remove this acid entirely, so the ammonia solution is necessary
to counteract its effect, the ammonia being strongly alkaline.
Q. Why should an unprotected light, i.e., any flame or spark,
not be allowed close to a storage battery?
A. Because the gas emitted by the battery on charge is hydro-
gen, which is not only highly inflammable but, when mixed in
certain proportions with air, forms a powerful explosive mixture.
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672 ELECTRICAL EQUIPMENT
Q. What is the cause of gassing?
A. When a battery is charged, the water of the electrolyte
is decomposed by the current into gases. During the early part
of the charge these gases unite with the active material of the plates,
but as the charge proceeds, more gas is evolved than the plates
can take care of and it bubbles up through the electrolyte. This
is known as the gassing point, and the temperature of the cell also
begins to rise at that point.
Q. Is gassing harmful to the battery?
A. The greatest wear on the positive plates takes place during
the gassing period, and, if carried too far, they may be injured by
reaching a dangerous temperature (105° F., or over) which will tend
to loosen the active material.
Q. How can gassing be checked?
A. By cutting down the charge. In some systems this can
be effected by the insertion of extra resistance provided for the
purpose. Where this cannot be done and it is necessary to keep
the car running, turn on all the lamps or start the engine once or
twice to reduce the charge of the battery. As the lamps usually
consume 80 to 95 per cent of the generator output, they should be
sufficient to prevent a further overcharge.
Q. Can the generator be disconnected from the battery to
A. Not unless it is short-circuited, as directed in the instruc-
tions covering different systems. Otherwise, it will blow its field
fuse or, where one is not provided, burn out its windings, except
in cases where special provision is made to guard against this.
Q. Why must a battery never be allowed to stand in a fully dis-
A. Because the acid of the electrolyte then attacks the plates
and converts the lead into white lead sulphate which is deposited
on them in the form of a hard coating that is impenetrable to the
electrolyte, so that the plates are no longer active. The battery
then is said to be sulphated.
Q. Can a sulphated battery be put in good condition, and what
treatment must be given it to do so?
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ELECTRICAL EQUIPMENT 673
A. If the sulphating has not gone too far, the battery may
be brought back to approximately normal condition by a long heavy
charge at a higher voltage than ordinary. Where the battery has
become badly sulphated, it is preferable to remove it from the car
and charge from an outside source of current, as it may require
several days to complete the process. (Note instructions regarding
the running of the generator when disconnected from the battery,
as otherwise it may be damaged.) If avoidable, the car should not
run with the battery removed. If the battery has not stood dis-
charged for any length of time, the charge may be given on the
car by running steadily for 8 to 10 hours with all lights off. No
lamps must be turned on, as the increased voltage is liable to burn
Q. What is the purpose of the voltmeter in connection with the
A. It is chiefly useful for showing whether a cell is short-
circuited or is otherwise in bad condition.
Q. Can the voltmeter alone be relied upon to show the condition
of the cells?
A. No; like the hydrometer, its indications are not always con-
clusive, and it must be used in conjunction with the hydrometer to
Q. What type of voltmeter should be employed for making
A. For garage use, a reliable portable instrument with several
connections giving a variable range of readings should be employed.
For example, on the 0-3 volt scale, only one cell should ever be tested;
attempting to test any more than this is apt to burn out the 3-volt
coil in the meter. The total voltage of the number of cells tested
should never exceed the reading of the particular scale being used at
the time, as otherwise the instrument will be ruined.
Q. Must these readings be particularly accurate?
A. Since a variation as low as .1 volt (one-tenth of a volt) makes
considerable difference in what the reading indicates as to the condi-
tion of the battery, it will be apparent that the readings must not only
be taken accurately, but that a cheap and inaccurate voltmeter is
likely to be misleading rather than helpful.
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674 ELECTRICAL EQUIPMENT
Q. What precautions should be taken before using the volt-
A. Always see that the place on the battery connector selected
for the contact is bright and clean and that the contact itself is firm,
otherwise the reading will be misleading since the increased resistance
of a poor contact will cut down the voltage.
Q. How is the instrument connected to the battery?
A. The positive terminal of the voltmeter must be brought in
contact with the positive terminal of the battery and the negative
terminal of the voltmeter in contact with the negative terminal of
Q. In case the markings on the battery are indistinct, how can
the polarity be determined?
A. Connect the voltmeter across any one cell. Should the
pointer not give any voltage reading, butting against the stop at the
left instead, the connections are wrong and should be reversed; if the
instrument shows a reading for one cell, the positive terminal of the
voltmeter is in contact with the positive terminal of the battery.
This test can be made without any risk of short-circuiting the cell,
since the voltmeter is wound to a high resistance and will pass very
little current. Such is not the case with the meter, which should
never be used for this purpose.
Q. When the battery is standing idle, what is the cell voltage
and why is this not a good test?
A. Approximately two volts, regardless of whether the battery
is fully charged or not. Voltage readings taken when the battery is on
open circuit, i.e., neither charging nor discharging, are only of value
when the cell is out of order.
Q. If the battery is in good condition and has sufficient charge,
what should the voltmeter reading show?
A. Using the lamps for a load, the voltage reading after the load
has been on for five minutes or longer should be but slightly lower
(about .1 volt) than if the battery were on open circuit.
Q. When one or more cells are discharged, what will the read-
A. The voltage of these cells will drop rapidly when the load is
first put on and sometimes even show reverse readings, as when a cell
is out of order.
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ELECTRICAL EQUIPMENT 675
Q.» What will the voltmeter indicate when the battery is nearly
A. The voltage of each cell will be considerably lower than if on
open circuit after the load has been on for five minutes or more.
Q. How can the difference be distinguished between cells that
are merely discharged and those that are in bad condition?
A. Put the battery on charge, cranking the engine by hand to
start, and test again with the voltmeter; if the voltage does not rise to
approximately 2 volts per cell within a short time, it is evidence that
there is internal trouble which can be remedied only by dismantling
Q. What effect has the temperature on voltage readings?
A. The voltage of a cold battery rises slightly above normal on
charge and falls below normal on discharge. This last is one of the
chief reasons for its decreased efficiency in cold weather.
Q. What is the normal temperature of the battery and to what
does this refer?
A. The normal temperature of a battery is considered at 70° F.,
but this refers to the temperature of the electrolyte in the battery as
shown by a battery thermometer and not to the temperature of the
surrounding air. If the battery has been charging at a high rate for
some time, it may be normal even though the weather be close to zero
at the time.
Q. What is the cause of sediment or mud accumulating
in the jars, and why must it be removed before it reaches the bottoms
of the plates?
A. This sediment consists of the active material of the plates,
which has been shaken out, due to the loosening caused by the charg-
ing and discharging, and aggravated by the constant vibration. It
must never be allowed to reach the plates, as it is a conductor and
will short-circuit them and thus ruin the battery.
Q. How long will a battery stay in service before this occurs?
A. This depends on the type of jar employed and the treat-
ment that the battery has received. If it has been kept constantly
overcharged, or if discharged to exhaustion in a very short period,
as by abuse of the starting motor when the engine is not in good
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676 ELECTRICAL EQUIPMENT
starting condition, or if it has been subjected to short-circuits by
grounding or by dropping tools on its terminals, the plates will
disintegrate much quicker than where proper treatment has been
given it. With the old-style jar, only an inch or so is allowed to
hold this accumulation of sediment below the plates, while in later
types fully 3 inches or more are allowed in the depth of the cell for
this purpose. A battery with jars of the latter type that has been
cared for properly should not require washing out under two years.
The procedure is the same as that given for removing the effects of
impure water. The plates must never be allowed to dry.
Washing the Battery
Q. What is meant by washing the battery, and why is it
A. Washing a battery involves cutting the cells apart, wash-
ing the elements and the jars, and reassembling with new separators
and new electrolyte. It is necessary to prevent the accumulation
of sediment, consisting of active material shaken from the plates,
to a point where it will touch them and thus cause a short-circuit
Q. How often is it necessary to wash a battery?
A. This will depend on the type of cell in the battery and the
age of the latter. If the battery has the modern-style jar with extra
deep mud space, it probably will not be necessary to wash it
until it has seen two to three seasons' use. With the older form
of cell in which the space allowed for sediment is much less, washing
doubtless will be necessary at least once a season. As the battery
ages, it will be necessary to wash it oftener.
Q. What other causes besides the type of jar and the age of
the battery influence the frequency with which it is necessary to
wash the battery?
A. The treatment the battery has received. If it has been
abused by overcharging and permitting the cells to get too hot,
the active material will be forced out of the grids much sooner.
Q. How can the necessity for washing be determined?
A. The presence of one or more short-circuited cells in a
battery that has not been washed for some time will indicate the
necessity for it. Each cell should be tested separately with the
low-reading voltmeter; a short-circuited cell will either give no
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ELECTRICAL EQUIPMENT 677
voltage reading or one much below that of the others. Cut such
a cell out and open it; if the short-circuit has been caused by an
accumulation of sediment, the others most likely are approaching
the same condition.
Q. How is a battery washed?
A. By cutting the cells apart, unsealing them, and lifting out
the elements which should be immersed immediately in a wooden
tub of clean pure water. The separators then are lifted out and
the positive and negative groups of plates separated, but they must
be marked so that the same .groups may go back in the right cells.
Before disposing of thp old electrolyte, its specific gravity should
be noted, as new electrolyte of the same density must be used.
The plates should be washed in copious running water for several
hours, but their surfaces must never be exposed to the air. Reas-
semble with new separators, fill the jars with fresh electrolyte of
the same specific gravity as that discarded, and keep the elements
under water until ready to place in the jars, which then should be
sealed and the lead connectors burned together again.
Give a long slow charge after reassembling. The battery will
not regain its normal capacity until it has been charged and dis-
charged several times.
Q. Why should lead connectors be employed, and why is
it necessary to burn them together?
A. Any other metal will corrode quickly. Burning is necessary
to make good electrical connection, except where bolted connectors
Q. When connections have become badly corroded or broken,
what should be done with them?
A. They should be replaced with new lead-strap connectors
supplied by the makers. If they are not obtainable and the battery
must be in service meanwhile, the old ones can be cleaned by cutting
away the corroded parts and burning new lead on them to bring
them to normal size. If broken, burn together with lead in the
same way. Heavy copper cable can be used temporarily but must
be removed as soon as possible, as it will corrode quickly. Never
use any other metal except lead or copper and never use light copper
678 ELECTRICAL EQUIPMENT
wire. It will either be burned up in a flash or it will cut down the
amount of current from the battery, thus causing unsatisfactory
Q. What is the cause of badly disintegrated or buckled plates?
A. Sudden discharge due to a short-circuit or to constant
abuse of the starting motor on an insufficiently charged battery.
Q. Is there any remedy for such a condition?
A. If the plates are not badly buckled and have not lost much
of their active material, the cells may be put in service again by
washing and reassembling as described, but if there is 'any con-
siderable loss of active material, new plates will be necessary.
Q. What are the indications of a low battery?
A. The starting motor fails to turn the engine over, or does so
very slowly, or only a part of a revolution. The lights burn very dimly.
The hydrometer shows a specific-gravity reading of 1.250 or less.
Voltmeter test shows less than 5 volts for a 3-cell battery (for greater
number of cells, in proportion), or 1 .75 volts or less for each cell.
Q. What are the causes of a low battery?
A. The electrolyte not covering the plates, or being too
weak or dirty. A short-circuit in the battery due to the accumulation
of sediment reaching the bottom of the plates. An excessive lamp
load, all lights being burned constantly with but little daylight
running the car. Generator not charging properly.
Specific Gravity; Voltage
Q. What are the specific gravity and voltage of fully discharged
and fully charged cells?
A. Total discharge : 1 .140 to 1 .170 on the hydrometer; and 1 .70
to 1 .85 volts on the voltmeter. Fully charged : 1 .276 to 1 .300 specific
gravity; 2.35 to 2.55 volts.
Q. Are these readings always constant for the same conditions?
A. No. The charging voltage readings will vary with the
temperature and the age of the cell; the higher the temperature
and the older the cell the lower the voltage will be. Hydrometer
ELECTRICAL EQUIPMENT 679
readings also depend on the temperature to some .extent. For
every ten degrees Fahrenheit rise in temperature, the specific gravity
reading will drop .003 or three points, and vice versa.
Q. Under what conditions should voltage tests be made?
A. Only when the battery is either charging or discharging.
Readings taken when the battery is idle are of no value.
Q. Under what conditions should hydrometer tests be made?
A. The electrolyte must be half an inch over the plates and
it must have been thoroughly mixed by being subjected to a charge.
Hydrometer readings taken just after adding water to the cells
are not dependable.
Q. When should acid be added to the electrolyte?
A. As the acid in a battery cannot evaporate, the electrolyte
should need no addition of acid during the entire life of the battery
under normal conditions. Therefore, if no acid has leaked or splashed
out and the specific gravity is low, the acid must be in the plates
in the form of sulphate and the proper specific gravity must be
restored by giving the battery an overcharge at a low charging rate.
Q. What does a specific gravity in some cells lower than
in others indicate?
A. Abnormal conditions, such as a leaky jar, loss of acid
through slopping, impurities in the electrolyte, or a short-circuit.
Q. How can it be remedied?
A. Correct the abnormal conditions, and then overcharge
the cells at a low rate for a long period, or until the specific gravity
has reached a maximum and shows no further increase for 8 or 10
hours. If, at the end of such an overcharge, the specific gravity is
still below 1.270, add some specially prepared electrolyte of 1.300
specific gravity. Electrolyte should not be added to the cells under
any other conditions.
Q. Is an overcharge beneficial to a battery?
A. The cells will be kept in better condition if a periodical
overcharge is given, say once a month. This overcharge should
be at a low rate and should be continued until the specific gravity
in each cell has reached its maximum and comparative readings
show that all are alike. To carry this out properly will require
at least 4 hours longer than ordinarily would be necessary for a
full charge. If the plates have become sulphated due to insufficient
680 ELECTRICAL EQUIPMENT
charging, it may be necessary to continue the overcharge for 10 to
15 hours longer. Should the specific gravity exceed 1.300 at the
end of the charge, draw off a small amount of electrolyte with the
syringe from each cell and replace with distilled water. If below
1.270, proceed ds mentioned above for addition of acid.
Charging from Outside Source
Q. What is meant by charging from an outside source?
A. A source of direct current other than the generator on
Q. Why is it necessary to charge the battery from an outside
A. When the battery has become sulphated, has been standing
Idle for any length of time, or has been run down from any other
cause so that it is out of condition, a long charge at a uniform rate
is necessary, and it would seldom be convenient to run the car for
8 or 10 hours steadily simply to charge the battery; frequently, a
longer charging period than this is necessary.
Q. How is charging from an outside source effected?
A. This will depend upon the equipment at hand and the nature
of the supply, i.e., whether alternating or direct current. If the
current is alternating, a means of converting it to direct current is
necessary, such as a motor-generator, a mercury-arc rectifier, chemi-
cal or vibrating type of rectifier. These are mentioned about in the
order of the investment involved. In addition, a charging panel is
needed to complete the equipment, this panel being fitted with
switches, voltmeter, and ammeter, and a variable resistance for regu-
lating the charge. Where direct-current service is obtainable at 110
or 220 volts, the rectifier is unnecessary.
Q. How can a battery be charged from direct-current service
mains without a special charging panel?
A. By inserting a double-pole single-throw switch and 10- or 15-
ampere fuses on taps from the mains and ordinary incandescent
lamps in series with the battery to reduce the voltage, Fig. 409.
Q. How many lamps will be needed?
A. This will depend upon their character and size, as well
as upon the amount of charging current necessary. For a 10-ampere
charge for a 6- volt storage battery, seven 110-volt 100-watt (32
Digitized by VjOOQIC
c.p.) carbon-filament lamps, or their equivalent, will be needed;
i.e., fourteen 110-volt 50-watt (16 c.p.) carbonrfilament lamps;
eighteen 110-volt 40-watt tungsten lamps, or twenty-eight 110-volt
25-watt tungsten lamps. For a
12-volt or 24-volt battery the number
of lamps will have to be decreased
in proportion in order not to cut the
voltage of the supply current below
that of the battery. For 220-volt
d.c. supply mains, if a three-wire
system is employed, the taps should
be taken from the center wire and
one outside wire; this will give 110
volts. If the service is 220-volt two-
wire, more lamps will be needed to
reduce the voltage, which should
exceed that of the battery by only l\
to 2 volts, except where a high volt-
age charge to overcome sulphating
is being given, in which case it may
be slightly higher.
Q. Where no outside source
of current is available, or where no
rectifier is at hand to convert alter-
nating current, how can the battery
be given the long charge necessary?
A. Run the engine. Supply it
with plenty of oil and provide hose
connections from the water supply
to the filler cap on the radiator and
a drain from the lower petcock.
Open the latter and turn on just
sufficient water to keep the engine
reasonably cool; increase if necessary
as it runs hotter.
Q. What precaution must be taken always before putting the
battery on charge from an outside source?
A. The polarity of the circuit must be tested in order to
Fig. 409. Diagram of Connections for
Charging Six-Volt Storage Battery
from Lighting Circuit
682 ELECTRICAL EQUIPMENT
make certain that the battery will be charged in the proper
Q. How can this be done?
A. If a suitable voltmeter is at hand, i.e., one of the proper
voltage for the 110- volt current, connect it to the mains. If the
needle does not move over the scale but shows a tendency to butt
against the stop pin at the left, reverse the connections. The needle
will then give a proper reading and the positive connection to the
meter must be used for the positive side ,of the battery. Should no
voltmeter of the right voltage be available, connect two short wires
with bared ends to the fused end of the switch. Dip the bared ends
of the wire in a glass of water, being careful to keep them
at least an inch apart. When the switch is closed, fine bubbles
will be given off by the wire connected to the negative side. The
battery terminals are stamped Pos. and Neg., and the connec-
tions should be made accordingly.
Intermittent and Winter Use
Q. What should be done with an idle battery?
A. If it is to be idle for any length of time, as where the car
is to be stored, it should be given a long overcharge as described
above before being put out of service. Fill the cells right to the top
with distilled water to allow for evaporation and absorption of
acid by the plates. Give the battery a freshening charge at a low
rate once a month. Discharge the battery and re-charge before
putting it into service again. If it has stood out of service for a
long period, the battery will be found at a low efficiency point and
will not reach its maximum capacity again until it has had several
charges and discharges.
Q. Does cold weather have any effect on the storage battery?
A. It causes a falling off in its efficiency. If not kept charged,
the electrolyte will freeze under the following conditions: battery
fully discharged, sp. gr. 1.120, 20° Fahrenheit; battery three-quarters
discharged, sp. gr. 1.160, temperature zero; half discharged, sp. gr.
1.210, 20 degrees below zero; one quarter discharged, sp. gr. 1.260,
60 degrees below zero. When storing away for the winter, the bat-
tery must either be kept charged or put where the temperature
does not go lower than 20 degrees above zero.
ELECTRICAL EQUIPMENT 683
Q. Is it ever necessary to wash out an Edison battery?
A. No. The cells are permanently sealed, as the active
material cannot escape from its containers.
Q. Do all of the foregoing instructions apply to the Edison
as well as to the lead-plate battery?
A. No. The Edison requires very little attention, practically
the only care necessary being to keep the cars replenished with
distilled water at intervals.
Charging rates for Edison cells are given in the article on
Electric Automobiles. S.A.E.-standard instructions for lead-plate
cells are also given in the same article.
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ON THE SUBJECT OF *
ELECTRICAL EQUIPMENT FOR
1. Explain the action of the regulating third brush as used
in the Leece-Neville system.
2. How may a Leece-Neville generator be short-circuited?
3. What must be done to increase and decrease the output
of the generator in a Leece-Neville system?
4. How m regulation obtained in the North East system?
5. Explain the constant voltage method of regulation used
in Remy systems.
6. What tests should be made in an Oakland when lights
and ignition fail but the motor operates?
7. How may the generator in a 1917 Maxwell be tested?
8. How is regulation obtained in the Splitdorf system?
9. Explain the action of the touring switch in the U.S.L.
10. What starting system is used on the 1917 Mercer?
11. What special features does the U.S.L. "Nelmi" system
12. How may a ground in the starting system be located in a
13. How may an ammeter test for short-circuits be made?
14. What should be done when a generator of the voltage *
regulator type fails to charge the battery properly?
15. Sketch the Hupmobile installation.
16. Explain the action of the Wagner switch.
17. Explain the action of the thermostatic switch as used on
18. On the Maxwell car, what does an unusual high reading
on the charge side of the ammeter indicate?
19. What are the special features of the starter installation
furnished by the Ford Company?
20. Give the action of the system when starting the engine.
21. How would you determine that the regulator was not
working properly in a Gray & Davis installator?
22. What lamps are required in a Gray & Davis Ford instal-
23. Why is no provision made for oiling the Gray & Davis
ON THE SUBJECT OF
ELECTRICAL EQUIPMENT FOR
1. What causes sulphating and what can be done with a
badly sulphated plate?
2. If a battery has been kept in an undercharged condition
for some time, what percentage of the time necessary to charge it
originally will now be required to charge it?
3. What is gassing and what does it indicate?
4. Give the correct method for adjusting the specific gravity
of the electrolyte in a cell.
5. What may be learned from a hydrometer test and how
should the tests be carried out?
6. If, in making a test, a voltage reading of 1.9 volts per
cell and a hydrometer reading of 1.220 or more are obtained,
what does this indicate?
7. Outline the proper method of cleaning a battery and
replacing a broken jar.
8. Show by a sketch the proper method for discharging bat-
tery through a water resistance.
9. Give two methods of lead burning.
10. What is the difference between dry and wet storage?
Outline the proper procedure in each case.
11. When should a battery be given an equalizing charge?
12. Discuss the proper methods of battery charging, includ-
ing descriptions of motor-generators and rectifiers.
13. How should a battery be taken care of in the winter?
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14. Why is it harder to start a car in cold weather than in
15. Why are voltage readings of no value, if taken when the
battery is on open circuit?
16. Why is an Edison cell not used for starting service on an
17. How may two six volt batteries be connected so that the
lights and horn may be supplied with six volt current and the
starting motor with twelve volts?
18. Describe the Tungar Rectifier and discuss its method of
19. Discuss the proper method of installing a new battery.
20. One cell in a battery requires the addition of distilled
water more frequently than the others. What is the cause?
Give -a complete description of the method of remedying the fault.
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The page numbers of this volume will be found at the bottom of the pages;
the numbers at the top refer only to the section.
Charging storage battery
Acid, adding to Btorage battery
from outside source
in series for economy
Battery cut-out 112, 121, 142 :
summary of instructions
in Wagner system 1 12 3
Cleaning repair parts of electrical
in Westinghouse system
Battery in starting and lighting
systems, summary of
method of cleaning parts
Cleaning storage battery
Commutator and brushes,
charging from outside source
mary of instructions
Connectors of battery, summary
Contact points, summary
Control in starting and lighting
intermittent and winter use
systems 88, 111, 121,
joint hydrometer-voltmeter test 292
specific gravity; voltage
Buckled battery plates, summary
Deranged cells, detecting
Discharge, testing rate of
Capacity of battery 179
Cell of storage battery (See Stor-
age battery cell)
175, 177, 178
Charge, testing rate of 231
Charging storage battery 11, 219
equalizing charges necessary 221
Note. — For page number* see foot of pages.
Distilled water, adding to storage
Double-unit Westinghouse system 139
Dynamo tor in starting and light-
ing systems 22, 77, 111, 135
North East 22
Edison ceil 182, 305
summary of instructions 305
Electric gear-shift, summary of
Electric starting and lighting sys-
practical analysis of types 11
Ford system 152
Gray & Davis system for
Ford cars 158
Leece-Neville system 11
North East system 22
Remy system 47
Simms-Huff system 77
Splitdorf system 87
U.S.L. system 95
Wagner Bystem 111
Westinghouse system 135
starting and lighting storage
care of battery 173, 182
importance of battery 173
principles and construction 174
summary of instructions 243
electric gear-shift 286
lighting and indicators 279
protective and operative de-
starting motor 261
wiring systems 264
Electrical equipment, cleaning 239
Electrolyte of storage battery cell
summary of instructions 288
Elements of storage battery cell 175
Equalizing charges of storage
Ford cars, special systems for
Gray & Davis
Ford system (continued)
lighting and ignition
removal of starting motor
Frozen storage battery cells
Fuses, summary of instructions 271
general instructions 152
Note. — For page number* tee foot of page*.
Gassing of storage battery 191, 293
summary of instructions 293
Generator in starting and light-
ing systems 11, 47, 121,
139, 156, 171, 243
removing generator in Ford
summary of instructions 243
commutator and brushes 255
loss of capacity 245
methods of regulation 247
types and requirements 243
testing generator with ammeter
in Gray & Davis system
for Ford cars 171
Generator-starting motor 95, 159
Gray & Davis system for Ford
U.S.L. system 95
Gray & Davis special system for
Ford cars 158
final connections and adjust-
t ments 165
mounting starter-generator 159
preparing engine 158
priming device 164
remounting engine parts 163
starting switch 163
instructions % 158, 169
testing generator with ammeter 171
Higher charge needed in cold
Hydrogen gas lead-burning outfit 215
Hydrometer 183, ?00, 237
frozen cells 187
hydrometer tests 185, 200, 237
low cells 188
variations in readings 186
Hydrometer tests of battery,
summary of instructions 291
Ignition in Ford system 156
Illuminating gas lead-burning
Indicators 12, 55, 77, 97, 282
summary of instructions 282
Installing new storage battery 217
Instructions on individual start-
ing and lighting systems
125, 135, 151, 152, 158, 169
Gray & Davis system for Ford
cars 158, 169
to adjust third brush 20
brush replacements 21
generator or motor failure 21
regulating brush 19
testing field winding 16
North East 26
battery cut-out and regula-
tor (relays) 28
five-terminal type unit 31
starting switch 34
battery discharge 60
dim lights 72
failure of lighting, ignition,
failure of cut-out or of regu-
generator tests* 85
Note — For page number* tee foot of page*.
Instructions on individual start-
ing and lighting systems
failure of engine to start 92
oiling of starting motor 92
battery cut-out 105
brush pressures 102
external regulator 103
radial and angular brushes 103
starting switch 102
touring switch 98
testing carbon pile 105
Wagner six-volt 125
ground in starting or in
lighting circuits 125
localizing any ground 126
localizing short-circuit 128
short-circuit tests 127
Wagner twelve-volt 115
failure due to battery cut-
lack of capacity through
faulty gear box 119
method of tooling commuta-
switch or generator parts to
be adjusted 121
We8tinghouse six-volt 151
Westinghouse twelve-volt 135
battery charging 135
fire prevention 136
weak current 136
Instructions on starting and
lighting systems, sum-
mary of 243
buckled plates 300
charging from outside source 302
Edison battery 305
hydrometer tests 291
Instructions on starting and light-
ing systems, summary of
intermittent and winter use
specific gravity; voltage
commutator and brushes
loss of capacity
methods of regulation
types and requirements
lighting and indicators
protective and operative de-
faults in circuit
Instruments used in starting and
12, 55, 77, 97,
summary of instructions
Joint hydrometer end voltmeter
teste 200, 237, 292
summary of instructions 292
Lamps, summary of instructions 279
Lead burning 211
forms to cover joint 213
hydrogen gas outfit 215
illuminating gas outfit 213
methods of burning 212
type of outfit 211,
Leece-Neville system 11
generator 1 1
regulation 1 1
starting motor 12
wiring diagram 13
Lighting, summary of instruc-
Lighting in Ford system 156
Low battery 300
Low cells 188
Motor-generator as rectifier 223
North East system 22
protective devices 22
switch tests 35
wiring diagrams 24
Overhauling storage battery 205
checking connections 208
dismounting cells 206
reassembling battery 207
reconnecting cells 210
treating plates 207
Note — For page numbers ace foot of pages.
Planetary gear on Wagner starter 114
Protective devices in starting and
lighting systems 22, 55, 97
North East 22
Protective and operative devices
in starting and lighting
systems, summary of in-
battery cut-out 273
contact points 276
Regulation in starting and light-
ing systems 11, 22, 47,
77, 88, 96, 111, 121, 135, 139
Leece-Neville 1 1
North East 22
constant-voltage method 47
thermostatic switch 48
third-brush method 48
Wagner 111, 121
Westinghouse 135, 139
Regulators, summary of instruc-
Remy system 47
mechanical combination 56
wiring diagrams 56
instruments and protective
starting motor 55
Replacing storage battery jar 202
Note. — For page numbers see foot of page*.
Sediment in storage battery 297
Separators of storage battery cell 176
Simms-Huff system 77
change of voltage 79
dynamotor connections 78
starting switch 81
wiring diagram 82
Single-unit systems 22, 56, 77,
87, 95, 111, 135
North East 22
22, 47, 77, 135, 139
North East 22
Westinghouse 135, 139
Six-volt systems 11,47
Leece-Neville 1 1
Sixteen-volt system, North East 22
Specific gravity 177, 188, 197, 300
summary of instructions 300
too high 197
Splitdorf system 87
wiring diagram 87
starting motor 91
Starting and lighting storage
care of battery 173, 182
Starting and lighting storage baU
care of battery
A.C. rectifiers 223
adding acid 183
adding distilled water 182
adjusting specific gravity 188
care of battery in winter 225
charging from outside source 219
charging in series for econ-
cleaning battery 201
cleaning repair parts 239
detecting deranged cells 199
equalizing charges necessary 221
higher charge needed in cold
how to take readings 199
installing new battery 217
internal damage 198
joint hydrometer and volt-
meter tests 200
lead burning 211
methods of charging 222
overhauling battery 205
replacing jar 202
restoring sulphated battery 196
specific gravity too high 197
starting harder in cold
storing battery 217
sulpha ting 194
temperature variations in
to test rate of charge 231
to test rate of discharge 228
voltage tests 235
importance of battery 173
principles and construction 174
action of cell on charge 177
action of cell on discharge 178
capacity of battery 179
construction details 181
Edison cell not available 182
Note. — For page numbers see foot of pages.
Starting and lighting storage bat-
principles and construction
function of storage battery 174
parts of cell 175
specific gravity 177
Starting motor 12, 55, 91, 121,
146, 152, 157, 261
Ford system 152, 157
Leece-Neville system 12
Remy system 55
Splitdorf system 91
summary of instructions 261
Wagner system 121
Westinghou8e system 146
electromagnetic switch 151
magnetic engaging type 146
Starting switch 81, 163
Gray & Davis system for Ford
Sims-Huff system 81
Storage Jmttery (see Starting and
lighting storage bat-
Storage battery cell 175, 177
action on charge 177
action on discharge 178
parts of 175
Storage battery in Gray & Davis
system for Ford cars 164
Storage battery jar, replacing 202
Storing battery 217
Sulphating of storage battery 194, 294
extra time necessary for charg-
restoring sulphated battery 196
summary of instructions 294
Switch tests for North East sys-
ground tests 35
mechanical and electrical char-
replacing Dodge chain 38
operation test 35
Switches, summary of instruc-
Voltage readings, how to take
characteristics of North East
Voltage tests 198, 200,
starting and lighting ap-
summary of instructions
Temperature corrections in ad-
temperature variations in
justing specific gravity
Voltmeter tests 198, 200,
Testing rate of charge
Testing rate of discharge
Thermostatic switch in Remy
Twelve — six-volt systems 87
Twelve-volt systems 22, 77, 111,
Twenty-four — twelve-volt system,
Twenty-four volt system, North
Two-unit systems 11,47,
Two-wire systems 11, 22, 87, 95,
instruments and protective de-
Winter care of storage battery 193, 225
higher charge needed
twelve- volt system
Wiring diagrams for starting and
lighting systems 13
56, 82, 87, 98, 111, 122,
U.S. Nelson system
JNote. — For page numbers t$e foot of page*.
Wiring diagrams for starting and
lighting systems (con-
Remy , 56
Note. — For page number* tee foot of- pages.
Wiring diagrams for starting and
lighting systems (oon?
Wagner 111, 122
Westinghouse 135, 142
Wiring in starting and lighting
systems, summary of in-
different plans 264
faults in circuit 265
proper conduction 268