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LIBRARY

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OCT 113.

STANDARDIZATION RULES

OF THE

AMERICAN INSTITUTE OF
ELECTRICAL ENGINEERS

As approved by the Board of Directors. June 27. 191 1

mi- 99 *• I- e- *•

PRICE. (Paper). 10 CENTS

(Dl»co«ni en Ownttttea)

PRICE. (Cloth). 25 CENTS

(N.t)

Published by

THE AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS

33 West Thirty-ninth Street. New York

Third Edition. December. 1912

STANDARDIZATION RULES

or THE
AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS

HISTORY OF 1 VNDAKDIZATION R<

*lep tak ' the %tandar

al apparatus and method* was a topical discussion on " The Stand-
•cnerators. Motors and Transformers." which took place
.mcously ork and Chit Ago on thr evening of January 26.

1808. The ditctmion appears in t!

rested were generally favorable to

the »• standardisation . • .1 apparatus, although some

members feared that difficulties might ante. As a result of this dis-
cussion, a Committee on Standardization was appointed by the Council
of tl .lowing meml>-

Kit vs. is II ( K.H KI w ( kittrma*.

!h t« IIINSOX CHABLBS P. SinswBTi

LEWIS ! KI.L

JOHN \V LIEU. JR. -it- THOU

il consideration of the matter and consultation with the
members of the Institute and interested parties generally, a " Report
of the Committee on Standardization." was presented and accepted by
me 26. 1899. Those original rules appeared in the In-
stitute TKVN XVI, pages 255 and 268.

As a result of changes and developments in the i was

subsequently found necessary to revise the original report, this work
being car 'he following Committ< lardisation:

MM is B. CtOCKBI. Ckatrma*.
A Kill i K t \RI.E4 P. ST*|N*>

•M \V. I.IEH. JE. LBWIX h SUM. WELL

C. o. N: HOMSOM

This revised report was adopted at the 19th Annual Convention at
Great Harrington, Mats., on June 20, 19O2. and appears in t •
TmAMBAcnoHs. Vd M-^ ; ••^- i""'> to 1092.

. further change and development in electrical

apparatus and methods, it was de nbrr. 1905 that a second

is needed, and the following C remittee was appointed to do
this v

FRANCIS B. CROCKEE. Ca«<>««».

K» NXEU.Y. Stereo
HENRY S. CARHART CHARLES P. SCOTT

ix \V. LlBB. JR <ABLB* P. Sir

C. <

ROBBET R. Owt

STANDARVIZA 1 /• ».Y RULES Of- ////•: A.I.i

Committee h« i^s and carried on ei oorre-

spondcncc with manufacturers, consulting and operating engineers
other interested j> report at tin

Annual Convention, held at Mihvar. v 28-30. 1°XX>

siderable discussion the report was accepted .mi

Committee for amend irrangemenl in form. It was then

to be submitted to the Board of Directors for final adoption. In Si-p1
ber, 1906, the foil- on Committee was apj

\N. is H. <-K<X KI K. Chairman.

A. \V. Hi KKKSFORD CHAKI i »TT

DUGALD C. JACK «'n \KI.I--S l(. SII-.INVI

C. O. MAILLOUX !h-\m G, StOTl

ROBERT B. Owi S. W. STRATI ««\

Kl.MII TlH»V

This Committee held monthly meetings, also sub-committee mee
and earefully referred the rules as a whole, and each part «.f them to

of the Institute. The rule <» entirely rearrai

.:iid put in shape to facilitate ready n-fi-i- 'iein and

visions to : without breaking up the logic;.:

Cement. Thus amended the rules were submit ted to the Board of
Directors and approved by it on June Jl . l'.»()7. The p
that the rules should be presented, as accepted by the Board, at the
Annual Convention held at Niagara Falls. June 24 to -7. I!»n7. whil b
tion was taken by President Sheldon on June 26. I'.MIT. By the Con-
stitution which went into effect on June 10. 1907, his Committee has •
made a standing Committee with the title " Stand « on-

sisting of nine members.

On August 12, 1910 the Board of Directors increased the size of the
committee from nine to twelve members; on October 14 from twelv
fourteen, and on March 10, 1911 from fourteen • n. The coin-

thus constituted is given below.

COMFORT A. ADAMS, Chairman.
AKIHI K K. KBNNELLY, secretary.
II. \V. Hi ( K \v. s. MOODY

GAJ K. A. PHILN-

H. \V. FISHER W. H. Powi

H. B. GEAR CHARLES ROBBI

J. P. JACKSON ii. ROSA

\V. L. MKRRILL CHARLES P. SN.INMI i/

RALPH D. MERSH«.\ CALVERT TOWNLEY

This committee and several sub-committees held numerous m<--
at which the general revision of the Standardization Rules of the Institute
was considered. The complete Standardization Rules as revised by this
committee, were presented to and approved by the Board of Directors on
June 27th, 1911. at the Annual Convention held at Chicago, 111.

TABLE OF CONTENTS

GENERAL PLAN.
>! HMTIONS AND TECHNICAL DATA Paragraph

A. DEFINITION*— CURRENTS AM* i: MP.'S.. 2 to 6

B. DiriNiTiOKt— ROTATING V 7 to 2la

C. DEFINITIONS— STATIONARY INDUCTION APPA* ..' to 29b

D. GENERAL CLASSIFICATION OF APPA»V 30 to M
B. MOTORS— SPEED CLASSIFICATION 45 to 49

49., to 49g

ION AND OF TERMS %0 to 63

rid Factor 50 tO Sib

Load >v.» to ftia

: » Power- Factor and Reactive Factor 54 to 56

Saturation- Factor 57 to 58

(V) Variation and Pulsati • 59 to 63

II PKRPORMANCE SPECIPICA . TESTS

65 to 78*

B. WAVE SHAPK 79 to 80

C. EFFICIENT 84 to IM

Definitions *4 to 88

of Efficiency .80 to 100

• Losses inl :

fTcrent Types of Apparatus UK to 186

(A) Direct current Commutating Machines . .118 to I'M

B) Alternating-Current Commutating Machines. 127 to 135

C) Synchronous Commutating Machines 1 t<> •

D) Synchronous Machines . I4H to 155

itionary Induction Apparatus !'•• t

.on Apparatus 162 to 167

(C) Unipolar or Acyclic Machine 16S to

ng Apparatus 176 t«

Transmission LiMi KM

Phase- Displacing Apparatus 1 ^ i to 186

D. RE*. to 200

ls7 to 203

MS for and Tests of Regulation 204 to 200

E. INSILATI* .MO to 250
(I) Insulation Resistance .MO to 213

'cnKth .M4 to 250

.M4 to 226

(B) Methods of Testing 227 t

hods for Measuring the Test Voltage .'4.' •

Apparatus for Supplying Test Volugr 250 to 259

STANDARDIZATION Kl: :: \ //•:/•:.

p. COM-! cnvm ... -2M

RISE OF TEMPERATURE. . . .261 to 292

(I) Measurement of Temperature .261 to'JTl

(A) Methods .261 to 266

(B) Normal Conditions for Tests.. .267 to 271

(II) Limiting Temperature Rise... ..272 to 292

(A) Machines in General ..274 to 278

(B) Rotary Induction Apparatus.. ..279 to 282
(O Stationary Induction Apparatus ..283 to 286

(D) Rheostats... .287 to 288

(E) Limits Recommended in Special Cases 289 to 292

H. OVERLOAD CAPACITIES. ... .293 to 304

III. VOLTAGES AND FREQUENCIES

A. VOLTAGES... .".or, to 310

B. FREQUENCIES M to 312

IV. GENERAL RECOMMENDATIONS -il.i u

V. APPENDICES AND TABULAR DATA

APPENDIX A. — NOTATION ... 324

APPENDIX B. — RAILWAY MOTORS

(I) Ratine. 325 to 327

(II) Selection of Motor for Specified Service 328 to 340

APPENDIX C. — PHOTOMETRY AND LAMPS... .11 to 357a

APPENDIX D. — SPARKING DISTANCES 358 to 359

APIM-MHX K. IKMIM-KAM KK COEFFICIENT- 360

APIMMMX !-.— HORSE POWER.. 361

PAGE
APPENDIX G. — Ivn K\ \ i I<>N \i. A<.KKKMKNTSOF THE I. E.G. 261 1

(Adopted at the Turin Congress in 1911.)

APPENDIX H. — RATING OF ELECTRICAL MACHINJ I . 2572 t«

(Comparative Rules of Different Countries.)

APPENDIX I. — HEATING AND GUARANTEES 2584 to 2585

(Additional Comparative Rules.)

STANDARDIZATION RULES OF THE A. I. E E.

Ai'i'Mtixi-n 1 1 M '.'7, I'M 1

I DEFINITIONS AND TECHNICAL DATA

1 Af* rftmtions and dassificaUons are intended to be prac-

cientifically rigid.

A. DKF1M

S A DIRECT • ; «s a unidirectional cur:

I A r is a steady, or non-imitating, direct current.

; nt to the superpov

alternating current upon a continuous current.

• An ALTERNATING Ct RRENT OR E.M.F. it a currerr

when plotted .IK' m rectangular coordinates, consists of half-

waves of equal area in successively opposit- us from the tero

•a CYCLE. Two imn. ucceeding half-waves constitute a cycle.

6b Pi KI- ired forth n of a cycle is called a penod

REQUENI • cycles per second is called the frequency

M WAVK-FOEM. Theshajv fe.mf. or current plotted against

time in rectangular coordinates, is ordinarily referred to as the wave-form or
wave-shape. Two alternating quantities are said to nave the same wave-
shape if their corresponding phase ordinates bear a constant ratio. The
wa\ .is ordinarily understood, is thus independent of the scales to

which th

Se SIMTLB A i Unless otherwise specified an alternating

current or e.m.f. is assumed to be sinusoidal, ana the wave a sinusoid,
sine-wave or curve of sines. On this account a complete c
860 degrees, and any j>< ay be expressed in degrees

•, such as the ascending tero-p*
is a non- sinusoidal wave

complex -\f> wave is capable of being resolved into a single

f fundamental f: with superposed odd-frequency

waves, or ripples. Of I . (2 • + !) times the

fundatiK v. each harmonic having constant amplitude

a definite st on to the fundamental sine-wu

custom.. inolvzing a complex wave, to neglect harmonics higher

tha <her than 11 times the fundamental.

i>ecial cases, h itill higher may have to be considered.

In cert : cases cvep harm

6g Rooi K VALUE (sometimes called the Virtual or Efl

Val ss otherwise specified, the rating of an alternating-current or

e.m.f.. in amf>eres or volts, is assumed to be the square root of the mean
square value taken throughout one or more complete cycles. T
sometimes abbreviated to r.m.s. The term root-mean-square it to be
•rrt-d to the terms virtual or effective. The root -mean -square value
is indicated \ ;>erlv calibrated Alternating-current voltmeters and

am: c of a sine-wave, the ratio of the maximum to the

r.m.s. value is \X2.

5

STANDARDIZATION RULES OF Till: 17

•h FORM-FACTOR OF AN ALTERNATING WAVE. The ratio of the root

square to the arithmetical mean ordinate of a wave, taken without regard to
sign, is called its form-factor. The form-factor for a purely rectangular
wave is the minimum, 1.0; for a sine wave it is 1.11, and for a
more peaked than a sine wave it is greater than 111

6i THE EQUIVALENT SINE WAVE is a sine wave having the same frequency
and the same r.m.s value as the actual wave.

.e DEVIATION of wave-form from the sinusoidal is determined py super-
posing upon the actual wave, (as determined by oscillograph), the equiva-
lent sine wave of equal length, in such a manner as to give the least <lif
ference, and then dividing the maximum difference between corresponding
ordinates by the maximum value of the equivalent sine wave.

6k PHASE DIFFERENCE. When corresponding cyclic values of two sinu-
soidal alternating quantities such as two alternating currents or e.m.fs. or
of a current and an e.m.f ., of the same frequency, occur at different instants,
the two alternating quantities are said to differ in phase, their phase dif-
ference being the time interval, expressed in degrees or as a fraction of a
cycle, between the occurrence of their corresponding values; e.g. their
ascending zeros or their positive maxima.

61 EQUIVALENT PHASE DIFFERENCE. If two alternating quantities are
non-sinusoidal, and of different wave shapes, the preceding definition of
phase-difference is inapplicable, and phase-difference ceases to have exact
significance. However, when the two complex alternating quantities
are the voltage E and current / in a given circuit, the effective power P of
which is known, it is customary to define the equivalent phase difference
by the angle whose cosine is the power-factor, P/EI, of the circuit. See
Sections 54 and :VJ \ .

6m SINGLE-PHASE. A term characterizing a simple alternating current
circuit energized by a single alternating e.m.f. Such a circuit is usually
supplied through two wires. The currents in these two wires counted
positively outwards from the source, differ in phase by 180 degrees or half
a cycle.

6n THREE-PHASE. A term characterizing the combination of three circuits
energized by alternating e.m.fs. which differ in phase by one third of a cycle;
i.e.. 120°.

60 QUARTER-PHASE, also called TWO-PHASE. A term characterizing the
combination of two circuits energized by alternating e.m.fs. which differ
in phase by a quarter of a cycle; i.e., 90°.

6p SIX-PHASE. A term characterizing the combination of six circuits ener-
gized by alternating e.m.fs. which differ in phase by one sixth of a cycle;
60*.

6q POLYPHASE is the general term applied to any alternating system with
more than a single phase.

6 An OSCILLATING CURRENT is a current alternating in direction, and of
decreasing amplit

"

H. DEFINITIONS. ROTATING MACHINES.

7 A GENERATOR transforms mechanical power into electrical power.

8 A DIRECT-CURRENT GENERATOR produces a direct current that may or
may not be continuous.

9 An ALTERNATOR is an alternating-current generator, either single-phase
or polyphase.

9a A SYNCHRONOUS ALTERNATOR comprises a constant magnetic field and
an armature delivering either single-phase or polyphase current in syn-
chronism with the rotation of the machine.

10 A POLYPHASE GENERATOR produces currents differing symmetrically
in phase; such as quarter-phase currents, in which the terminal voltages of
th* two circuits differ in phase by 90 degrees; or three-phase currents, in
which the terminal voltages of the three circuits differ in phase by 120
degrees.

1913

STANDARDIIA1U>\ *!/>:.% "A / //> I / 7UL

11 - tipplie* both direct and alternating
c same armature -winding .

1U As i ..; alternator in which both itld and

armature winding* am station .>

lib aathinc structurally identical with an

.iction motor, but .\c synchronous speed a* an alternating-

nt gcnci

12 A MOTOR transforms electrical power into r*tffltftknt power.

lia A DIRECI i MOTOR transforms d ;«ower into me-

12b >ntforms alternating -current

lie A mach urally (dent*

synchronous alternator, but operated a* a motor.

lid A • * s. HRONOUS- PHASE MooiMEE. »omeiim«t called a SyocfefOflmft Con-
rooous motor, running cither idle or underload. wbotefteJd

• >cd to a» . the power-factor of t i

or ihroufh -• influence the voltage of the or

He rent motor, either i

polrphaae, independent orimary and jtcondiry

one of which, usually the »r» • The

secondary winding has n<> .-.!:•:.•• . .,nn.-, non with the np|>
Iff A Ki \IOTOI is an induct . 11 y wnfle phaae. in which

axis of the secondary, (a doted coil winding mounted on the
r). is maintained at a > •! angle with respect to the sUtiooary

primary coil by mean* of a multi«rgmcntal commutator aad ih<
ing brushes.
12g

to a series direct-current t: i»ually |>r n ad-

i series compensating * -ed around the out-

t! in slots in the pole face*, for the poipos* of
leakage react a:

13 A BoosTKE is a mat him- m>erted in MTK-N :n a .:• .11*. to change it*

'.IKC. It mav !.<• <lnvm ':•-. .. . which cate it is termed

a motor-booster) or otherwise.

14 A MOIOK < .> M w M. K is a transforming device consisting of a motor

'•cted to one or more generators.

16 A I1 msforming d< innmg both motor and

general* •• magnet -her with two armatures, or with

one armature having two separate winding- and independent commutator*.

16 ng mechanical rotation in
elr i into another. A converter may
to either of several types, as follows:

17 a. A DiKKt i ('t MKBST CONVERTER converts from a direct current to
a direct current. . 'age.

18 s VERIER (commonly called a rotary converter*
converts from an alternating to a <! or m* rrrju.

19 i. A MOTOR- rnsxkit IKK • a combination of an induction motor with

a synchronous converter, the secondary of the former leeoing UM arma-

iuem > other than the impressed

turc of th nt at

frc' t is a synchronous converter concatenated with an in-

SO **. A FIBQVEM t t'utM.i * • « rts the power of an alternating-current
system from one frequency to another, with or without a change in the
number of phases or in the voltage.

21 t. A ROTARY PHASE CONVERTER cor MI an alternating-current

system of one or more phases to an alternating-current system of a dif-
ferent number of phases, but of the tame frequency.

aia KOI U.I/IM. CONN*:* u. -sx are low resistance connections between
equipotential points of multiple-wound closed-coil armatures to equalise
the induced voltage between brushes.

STANDARDlZArio.\ Ri'l.i HI: A.I /

C, DEFINITIONS. STATIONARY INDUCTION APPARATUS.

22 STATIONAKN IM>I« IION APPARATUS changes electric energy to electric
energy through the medium of magnetic energy. It comprises several
forms, <i <*d as follows:

23 a. TRANSFORMERS, in which the primary and secondary windings are
insulated from one another.

23* A PRIMARY \\IMHM. is that winding of a transformer, or of an

induction motor, which receives power from an external source.

23b A SECONDARY WINDING is that winding of a transformer, or ot an

induction motor, which receives power from the primary by
induction.

Note: The terms " High -voltage winding " and " Low-voltage
winding " are suitable for distinguishing between the windings of a
transformer, where the relations of the apparatus to the source of
power are not involved.

24 6. AUTO-TRANSFORMERS, also called compensators, in which a part
of the primary winding is used as a secondary winding, or conversely.

26 (. POTENTIAL REGULATORS, in which one coil is in shunt and one
in series with the circuit, so arranged that the ratio of transformation
between them is variable at will. They are of the following three classes:

26 1. CONTACT VOLTAGE REGULATORS, also called Compensator Reg-
ulators, in which the number of turns in use of one of the coils is
adjustable.

27 (2) INDUCTION POTENTIAL REGULATORS in which the relative
positions of the primary and secondary coils are adjustable.

28 (3) MAGNETO POTENTIAL REGULATORS in which the direction
of the magnetic flux with respect to the coils is adjustable.

29 d. REACTORS or REACTANCE COILS, also called choke coils, are a form of

lonary induction apparatus used to supply reactance or to produce phase
displacement.

29a f. AN INDUCTION STARTER is a device used in starting induction motors,
converters, etc., by voltage control, consisting of an auto-transformer com-
bined with a suitable switching device.

29b A LEAKAGE REACTANCE or SERIES REACTANCE is a portion of the reac-
tance of any induction apparatus which is due to stray or purely self -in-
ductive flux.

D. GENERAL CLASSIFICATION OF APPARATUS.

30 COMMUTATIM. M Under this head may be classed the follow-
ing: Direct-current generators; direct-current motors; direct-current boost-
ers; motor-generators; dynamotors; converters; compensators or balancers;
closed-coil arc machines, and alternating-current commutating motors.

31 Commutating machines may be further classified as follows:

32 a. DIRECT-CURRENT COMMUTATING MAC MINES, which comprise a mag-
netic field of constant polarity, a closed-coil armature, and a multiseg-
mental commutator connected therewith.

33 /.. Al.TERNATING-Cl RRENT COMMUTATING MACHINES, which Comprise a

magnetic field of alternating polarity, a closed-coil armature, and a multi-
segmental commutator connected therewith.

34 c. SYNCHRONOUS COMMUTATING MACHINES, which comprise synchronous
converters, motor-converters and double-current generators.

33 -•• N< HKONOfs MACHINES, comprise a constant magnetic field, and
tture receiving or delivering alternating-currents in synchron-
ism with the motion of the machine; i.e., having a frequency equal to the
product of the number of pairs of poles and the speed of the machine in
revolutions per second.

36 STATIONARY INDUCTION APPARATUS, include transformers, auto-trans-
formers, potential regulators, and reactors or reactance coils.

37 ROTARY INDUCTION APPARATUS, or INDUCTION MACHINES, include ap
paratus wherein the primary and secondary windings rotate with re-

STANDARl' <>h Hi

(>n motors, induction generators. frequency
lary phase cor

18 i •> m which the

rs maintains the same direction
i respect to those conductors.

39 K J • i n , i -.. ' i . i > <»RNRRATORf

40 I i i • i MI IMA i n .\i-\- \»> as condensers, etc.

41 i

42 I LRC IKOTMKMMAL APPAR

42. i

1- 0 APPARA

43 I K APPAMV i« 2i> fair* breakers, Iifhtniof

44

iay, for convenience, be classified with reference to their speed
characteristics as follows:

46 « Ahich the S;HT,I is either constant or
does not uch as is motors, induction motors

ton.

47 ' OTORS (two-speed. thr< .in be

x- speeds being ;

windings,
or number of poles.

48 i - can be varied grad-
ually over a considerable range; but when once remains prac-

.lly unaffected by the load, such as shunt motors devigned for a con-
siderable r ion.

49 d VAKMN<. -i i i o or motors in which the speed varies with
the load, decreasing when the load increases: such as series motors.

: \STRfMENTS.

49a As AMMI -is . nt-nu-asur licating in amperes.

49b .tge- measuring instrum< *in^ in volts.

>wer. and
•in in w.i

49d KKCUKDING AMMETERS, VOLTMETIK METKRS. etc.. are instru-

•s which record graphically upon a time-chart the values of the qnaa*

tit:

49e A V K METER is an instrum. ng total watt- hours.

This term is to be preferred to the term -ing wattmet<

49f MKTBR COMPENSATOR is a device in connection with a

meter, which causes the latter to indicate the voltage at some otb«-r point of

the circuit.

49g IKOSCOPE is a synch: <• which, in . Mition to

K- synchronism, shows whether the machine to be §yn« hronr

fast or slow.

G. DEFINITION A OP TKP

(I) LOAD FACTOR.

60 The LOAD FACTOR of a machine, plant or system is the rat • '. the
average power to the maximum p< ng a crrtain period of :>me.
The average power is • n period of time, such as a dajr
or a year, and the maximum is taken over .1 iterval of the maxi-
mum load within that

61 In •-.-. h case the interval of maximum load should be definitely speci-
fied. The pn>j»ei tally dependent upon local and
upon the purpose for which the load factor is to be determined.

10 STANDARDIZATION RUI.KS ()/• Till- A.I.I-

17-.K.S7/ ) FACTOR.

61* DIVERSITY FACTOR is the ratio of the sum of the maximum p
demands of the subdivisions of any system or part of a system, to the
mut I of the whole system or of the part of the mder con-

sideration, measured at the point of supply.

(Ill) DEMAND FACTOR.

61b l)i MVM> F M IMK if the ratio of the maximum power demand of

!«• the total connected load of th i or of

•;. under considcraticii.

(ID .VO.V-/A7H LOAD AND INDUCTIVE LOAD.

62 A non-inductive load is a load in which the current is in phase with the
voltage across the load.

63 An inductive load is a load in which tin- current lags behind the voltage
across the load. A load in which the current leads the voltage across the
load is sometimes called a condensive or anti-inductive load.

63a When voltage and curr I arc sinusoidal but not in \>\

the voltage may be resolved into two components one in phase with the
current, and the other in quadrature therewith. The former is called the
effective component (sometimes the energy component), and the latter
the reactive component of the voltage. The current may be similarly
subdivided with respect to the voltage, and the two components similarly-
named.

(V) POWER- FACTOR AND REACTIVE FACTOR.

64 The POWER-FACTOR in alternating-current circuits or apparatus is the
ratio of the effective (i.e. the cyclic average) power in watts to the appar-
ent power in «'olt-ampcres. It may be expressed as follows:

effective po watts effective current

apparent power "total volt -amperes* total cur:

66 The REACTIVE-FACTOR is the ratio of the reactive volt-amp-
the product of the reactive component of current by voltage, or re.
component of voltage by current) to the total volt-amperes. It may be
expressed as follows:

: tivejxmtf _ reactive current _ i oltage

apparent power* total yol s* total current

66 POWER-FACTOR and K FACTOR are related as foll«

If p = power-factor and q = reactive-factor, then with sine waves of voltage
and current.

/>'+<?' -1

With distorted waves of voltage and current, q ceases to have definite
significance.

* ATT RAT 1 , (>R.

67 The SAT i K \im\- F.\< i<>k • f a machine is the ratio of a small p
increase in field excitation to the corresponding percentage i:
voltage thereby produced. The saturation factor is, therefore, a err

of the degree of saturation attained in the magnetic circuit at any ex-

•ion selected. Unless otherwise specified, however, the
factor of a machine refers to the excitation existing at normal rated speed
and voltage. It is determined from measurements of saturation made on
open circuit at rated speed.

68 The PERCENTAGE OF SATI RATION of a machine at any excitation may
be found from its saturation curve of generated voltage as ordinates, against
excitation as abscissas, by drawing a tangent to the curve at the ordinate
corresponding to the assigned excitation, and extending the tangent to
intercept the axis of ordinates drawn through the origin. The rat o ot
the intercept on this axis to the ordinate at the assigned excitation, when
expressed in percentage, is the percentage of saturation and is indepen-

\NDAIU>!ZATrO!9 Kt i.t in i / / 11

and voltage. Th; <*qual

deducted

.ind p the percentage of

•at-

IK/I/:
69 Th. VVHIMIMS is I'KIVU M..\, an an*

ft; engines* is

c.l in degree*. from the \>< \ould occupy with uniform rota-

•i as 300 degn •

60 -K MOVKKS is the ratio of the difference between
the maximum and minimum velocities in an en* -o the average

61 t in* s A tots or alternating in general
it the n lifference in phase of the generated voltage wave from a
wave of absolutely constant frequency of the same average value.
expressed in electrical decrees (one cycle equals 300 degrees) and may
be due to the variation of the prime n,

62 i :.' •! MOBS or alternating-current n gen-
eral, is the ratio of the difference between maximum and minimum fre-

luring an cn^ he average frequency.

S3 I- "i VAKIAIIDS in prime mover and alternator. If p-num-

>f pairs of poles, the variation of an alternator is p times the var

: direct-connected, and p n times the variation of

the prime mover if rigidly connected thereto in the velocity ratio •; so that
the speed of the alternator is * times that of the prime mo .

II. PERFORMANCE SPECIFICATIONS AND TESTS.

TING.

66 k A us,, m < M MM i. All electrical apparatus should be rated by output
and not by input. Generators, transformers, etc.. should be rated by
electrical oir ors by mechanical output, and preferably in kilo-

watts.

66a The following four classes of rating are recognised and recommended:
they do not cover the ratine of railway motors which is treat-
Appendix B. and there are other large though less definitely definable rliasei
of i which each case must be treated by itself. Some of these

may be later reduced to fairly simple terms and introduced into these Rules.

66b i vhich under load there is the attainn

approximately stationary temperature, and no other limit of capac
exce-

66c '2. INTKRMIM > which one minute periods of load and rest

alternate until the attainment of approximately stationary temperature
and no other limit of capacity is exceeded.

66d N the temperature depends upon the losses and the capacity

he appar. it them, a constant load may be sub

load in determining the temperature, provided the losses are

m which under load for one minute, no mechanical.

thermal, magnetic, or electrical limit of capacity is exceeded and no perma-
nent wrought in the apparatus.

66f I \ VKIMMI SKKVICB R\TI i desirable here to recognise this

class of rating which is intended the rating of motors for machine-

tool and similar service, in which the thermal absorptive capacity plays a
pan. The specif: >r this rating have not been fully determined

at the time that this edition of the Rales goes to press.

I _' STA XDA RDIZA TION R VLES OF Til / ,17

•6 K \IIN-. i^ KII.OWAIIV KUvtncal power should be expressed in kilo-
watts, except when otherwise specif;

67 :. ii "\ « i i AMPERES. Apparent power in altrrnaiing-
currcnt • uld be expressed in kilovoft-amperes as distinguished
from effective power in kilowatts. When the power factor is 100 per
cent, the apparent power in kilo volt -amperes is equal to the kilowa?

68 The RATED (PULL- LOAD huh. with the rated
terminal voltage, gives the r.itr<l kilowatts, or the rated kilovolt-amperes.
In machines in which the rated voltage differs from the no-load voltage,
the rated etirretU should refer to the for

•9 DETERMINATION OF RATED CURRKM. The rated current may be de-
termined as follows: If P- rating in watts, or volt-amperes if the power
han 100 per cent, and £ —full-load terminal voltage,
the rated current per terminal
p

70 / = amperes, in a direct -current machine or single-phase alternator.

£

1 P

71 I m ' - i? amperes, in a three-phase alternator.

\ 3 &

\ P

72 / = () amperes, in a quarter-phase alternator.

73 NORMAL CONDITIONS. The rating of machines or apparatus should be
based upon certain normal conditions to be assumed as standard, or to be
specified. These conditions include voltage, current, power-factor, fre-
quency, wave shape and speed; or such of them as may apply in each par-
ticular case. Performance tests should be made under these standard
conditions unless otherwise specified.

74 a. POWER FACTOR. Since the inherent capacity of alternating current
generators, synchronous motors, and transformers, depends upon their
voltage and their current, they should be rated in kilovolt-ampere^ If
the apparatus is rated in kilowatts without specification as to the power
factor, a power factor of 100 per cent shall be understood.

If rated in kilowatts and a power factor other than 100 per cent be
specified, this should be understood as defining only the nature of the load,
and not as implying an increase in the ampere rating of the apparatus, which
should be based upon the kilowatt rating at 100 per cent power factor.
76 b. WAVE SHAPE. In determining the rating of alternating-current ma-
chines or apparatus, a sine wave shape of alternating current and voltage
is assumed, except where a distorted wave shape is inherent to the appar-
atus. See Sees. 79-80.

76 FUSES. The rating of a fuse should be the maximum current which it
will continuously carry.

77 CIRCUIT-BREA'KERS." The rating of a circuit-breaker should be th>
imum current which it is designed to carry continuously.

77m NOTE. In addition thereto, the maximum current and voltage at
which a fuse or a circuit-breaker will open the circuit should be specified.
It is to be noted that the behavior of fuses and of circuit-breakers is much
influenced by the amount of electric power available on the circuit.

78 I sim AUNG METERS should be rated according to their full-scale
reading of volts, amperes, or watts. In wattmeters the rated volts and
rated amperes should also be included; i.e., the volts and amperes which
can be safely and continuously carried by the voltage and current coils
respectively.

78* WATT-HOUR METERS should be rated in volts and amperes.

B. WAVE SHAPE.

79 The SINE WAVE should be considered as standard, except where a de-
viation therefrom is inherent in the operation of the apparatus

80 A MAXIMUM DEVIATION of the wave from sinusoidal shape not exceeding
10 per cent is permissible, except when otherwise specified. See Section 5j.

81,82,83. See Sections 5e to 51.

STANDAR/>IZAT/o.\ jfr/.A.s oh iin A I E.E. 13

BFPIC1

(I) DEFINITIONS.

»4 an appat output to iu input

The output and input may ».r m term* of watt-boor*, wmtu. volt-ampere*.
ampere*, or any •>• of interest, thus respectively defining

energy-enVim. -.. 5.. A,-: r!»i. •,!•.-.. .4;. ;.,--•• ,-•! , : .........

AIM specified, however, the term it ordinarily

i :•.,:• • • • • : - " • -. -.••••. . • • • -

66 An In Apparatus in which a .

inh< -i. apparent enVirnt-y should be

the ratio of net i»« ,\\.

87 .. .oton. synchronous

phase modifiers, >ous converters controlling the voltage of an

alte: d regulator*, open magnetic circuit

Iran

86 • parent efficiency of apparatus delivering electric

pou the load, the apparent emciency.

unless otherwise specified, should be referred to a load power-f actor of unity

MEASUREMENT Oh Eh'hK

89 :nay be determined by cither of two methods,
vts.: by measurement of input and outp -nent of losses.

90 I The input and output may both
be meas •!>•. The ratio of the latter to th- the emciency.

91 .' SES. The losses may be measured either colic

1 losses may be added to the output to derive
nput. or subtracted from the input to derive the output.

92 COMPARISON « The output and input method is preferable

. small machines. When, howevi r. as in the case of large machines,
measure the output and input; or when the per-
'age of power loss is small and the emciency is nearly unity, the method
of determining rtVu u-ncy bv measuring the losses should be followed.

93 i hould be measured at the terminals of the appar-
atus. In te .phase m.. he measurement of power should
not IK* • a single circuit but should be extended to all the cir-
cuits in ord< : 1 errors of unbalanced loading.

N POWER in machines should be measured at the pulley,

gearing, cout thus excluding the loss of power in said pulley,

gearing or coupling. t> ng the bearing friction and windage. The

magnitude of bearing friction and windage may be considered, with con-
stant speed, as independent of the load. The loss of power in the belt and
the increase of !•• -n should be excluded.

is mounted upon the shaft of a prime n

iot be separated therefrom, the fractional

losses in bearings and in windage, which ought, by <: to be included

y. should be excluded, owing to the practical
impossibility of separating them from those of the prime mover.

96 In A APPARATUS, such as an exciter, the power lost in the

auxiliary apparatus should not be charged to the principal machine, but
to the plan* ng of principal machine and auxiliary app.t

taken together. The plant emciency in such cases should be distinguished
from the machine efficiency.

96 .• tests should be made under normal
conditions herein set forth, which are to be assumed as standard.
These conditions include voltage, current, power-factor, frequency, wave
shape, speed, temperature and barometric pressure, or such of th<
may apply in each particular case. Performance tests should be made
under these standard conditions unless otherwise specified. See Sees.

75.

97 a. TEMPERATURE. The efficiency of all apparatus, except such as may
be intended for intermittent service should be either measured at. or re-

14 \\n.\RrHZATION RULES OF Till A.l.E.E.

duced to, the temperature which the apparatus assumes under continuous
operation at rated load, referred to a room temperature of 25 deg. cent.
See Sees. 267-202.

98 With apparatus intended for intermittent service, the efficiency should
be determined at the temperature assumed under specified conditions.

99 b. POWER FACTOR. In determining the efficiency of alternating-current
apparatus, the electric power should be measured when the currnr
phase with the voltage, unless otherwise specified, except when a definite
phase difference is inherent in the apparatus, as in induction motors,
induction generators, frequency converters, etc.

100 c. WAVE SHAPE. In determining the efficiency of alternating-current
apparatus, the sine wave should be considered as standard, except where a
difference in the wave form from the sinusoidal is inherent in the operation
of the apparatus. See Sec. 80.

(Ill) MEASUREMENT OF LOSSES.

101 LOSSES. The usual sources of losses in electrical apparatus and the
methods of determining these losses are as follows:

102 (A) BEARING FRICTION AND WINDAGE.

The magnitude of bearing friction and windage (which may be consid-
ered as independent of the load) is conveniently measured by driving
the machine from an independent motor, the output of which may be
suitably determined. See Sec. 94.
(B) COMMUTATOR BRUSH FRICTION.

103 The magnitude of the commutator brush friction (which may be con-
sidered as independent of the load) is determined by measuring the dif-
ference in power required for driving the machine with brushes on and
with brushes off (the field being unexcited).

(O COLLECTOR-RING BRUSH FRICTION.

104 Collector-ring brush friction may be determined in the same manner
as commutator brush friction. It is usually negligible.

(D) MOLECULAR MAGNETIC FRICTION AND EDDY CURKI

105 These losses include those due to molecular magnetic friction and eddy
currents in iron and copper and other metallic parts, also the losses due
to currents in the cross-connections of cross-connected armatures.

106 In MACHINES these losses should be determined on open circuit and
at a voltage equal to the rated voltage +/ r in a generator, and — / r in a
motor, where / denotes the current strength and r denotes the int
resistance of the machine. They should be measured at the correct
speed and voltage, since they do not usually vary in any definite pro-
portion to the speed or to the voltage.

107 NOTE. The TOTAL LOSSES in bearing friction and windage, brush fric-
tion, magnetic friction and eddy currents can, in general, be determined
by a single measurement by driving the machine with the field excited,
either as a motor, or by means of an independent motor.

108 RETARDATION METHOD. The no-load iron, friction, and windage losses
may be segregated by the Retardation Method. The generator should
be brought up to full speed (or, if possible, to about 10 per cent above
full speed) as a motor, and, after cutting off the driving power and
excitation, frequent readings should be taken of speed and time, as the
machine slows down, from which a speed-time curve can be plotted. A
second curve should be taken in the same manner, but with full field ex-
citation; from the second curve the iron losses may be found by subtracting
the losses found in the first curve.

109 The speed-time curves can be plotted automatically by belting a small
separately excited generator (say 1/10 kw.) to the generator shaft and
connecting it to a recording voltmeter.

(£) ARMATURE-RESISTANCE Loss.

110 This loss mav be expressed by p 7l r\ where r -resistance of one arma-
ture circuit or branch, 7 = the current in such armature circuit or branch,
and p-the number of armature circuits or branches.

\SUARI>17.A1H>X *r/.A.s <» Hit-. .!./ 15

(F) COMULlAlulc. HklMi ASK 1'Kl %H COSTAO I RESISTANCE t.Qjg

111 It if desirable to point out that with carbon brushes these loesee may
be considerable in low-voltage machines.

(G) COLLBCt Mm MI - -Off.

112 .ii is usually negl , m machines of extremely low
voltage or in unipolar machines.

oss,

113 With separately excited field, the los« of power in the resistance of the

. . alone -. --r shunt- or tenev field

windings, however, the lots of power in the accompanying rheostat should
also be included, the said rheostat being considered as an ossntisl pan
of the machine, un<l not as separate auxiliary appara*

114 (/) LOAD Losses.

The load losses m.» . .tdered as the difference between tl.

los*< load and the sum of the losses as above specified an

termined.
116

are and may, therefore, be neglect* r. the

large as in commutaiing-pole machines; or. as is shown,
for • he* between no load and

full
considerable, and «shi In this case the cm-

he load losses may l>< the method of Sec.

116 •• c the load losses cannot well be

be considerable and. therefore, their
1 by oh - This can be done

by operating me on short-circuit and at full-load current, that

is. I called the " short -circuit core loss" With

the low and great lag of current existing in this cav

. : : . .• .-..:.. •' •...•-.• ;

117 core loss may. as an approximation, and
in the absence of more accurate information, be assumed as the load loes.

OF I>If s' OF APfAh

(A) Pi HI . i <'t K.-

118 In DIRKI i i'i Kkt M ('OMMI i MIS.. M v le losses are:

119 : HKAKIM. IK M> WIM>A«.I Icasurement of Losses
(<*

120 •• See
Measurement of Losses (/> & 105.

121 « .\KM\II KI. i K LOSSE^ Measurement of Losses (£).

122 d. COMMUTATOR BKLSH FRICTION. See Measurement of Losses (B).

123 r COMMUTATOR, BlUSfl - IKKMMAMR. See Meas-
urement of Losses (F). S< . Ill

124 /. FIELD Hxcn • v See Measurement of Losses (H). Sec. 113.
126 t. LOAD LOSSES -n of Losses (/). Sec. 1

126 NOTE. 6 and care losses in the armature or " armature losses"; 4 and t
" commutator losses "; / " field losses/'

(B) * RENT COM M INKS.

127 InAi.itKNv s. the losses a:

128 : Hi \KI-... !'. • Measurement of Losses (A).
Sec.

129 6. Ro: »ss, measured with the machine at open circuit, the
brushes on the commutator, and the field excited by alternating cur-
rent when driving the machine by a motor.

130 This loss includes molecular magnetic fnction and eddy currents,
caused by rotation through the magnetic field. /» r losses in cross-con-

16 STANDARDIZATION Kt'/.l // A.I.E.E.

nections of cross-connected armatures, TV and other losses in armature-
coils and armature-leads which are short-circuited by the brushes
as these losses are due to rotation.

131 i. Ai IIKNMIM; or TRANSFORMER Loss. These losses are measured
by wattmeter in the field circuit, under the conditions of test b.
include molecular magnetic friction and eddy-currents due to the alter-
nation of the magnetic field, TV losses in cross-connections of cross-con-
nected armatures, Pr and other losses in armature coil and commutator
leads which are short-circuited by the brushes, as far as these losses are
due to the alternation of the magnetic flux.

132 The losses in armature-coils and commutator leads short-circuited by
the brushes, can be separated in ft, and c, from the other losses, by run-
ning the machine with and without brushes on the commutator.

133 d. 71/? Loss, other load losses in armature and compensating wind-
ing and TV loss of brushes, may be measured by a wattmeter connected
across the armature and compensating winding.

134 f. FIELD Ex< n AIK.N Loss. See Measurement of Losses (//), Sec. 113.
136 /. COMMUTATOR BRUSH-FRICTION. See Measurement of Losses (B),

Sec. 103.

(C) SYNCHRONOUS COMMUTATING MACHINES.

136 1. In DOUBLE-CURRENT GENERATORS, the efficiency of the machine
should be determined as a direct-current generator, and also as an alter-
nating-current generator. The two values of efficiency may be different,
and should be clearly distinguished.

137 2. In CONVERTERS the losses should be determined when driving the
machine by a motor. These losses are:

138 a. BEAR'ING FRICTION AND WINDAGE. See Measurement of Losses (A),
Sec. 102.

139 b. MOLECULAR MAGNETIC FRICTION AND EDDY CURRENTS. See Meas-
urement of losses (D) Sec. 105.

140 c. ARMATURE-RESISTANCE Loss. This loss in the armature is q 72r,
where / = direct current in armature, r = armature resistance and q. a
factor which is equal to 1.47 in single-circuit single-phase, 1.15 in double-
circuit single-phase, 0.59 in three-phase, 0.39 in two-phase, and 0.27 in
six-phase converters.

141 d. COMMUTATOR-BRUSH FRICTION. See Measurement of Losses (B),

103.

142 e. COLLECTOR-RING BRUSH FRICTION. See Measurement of Losses (C),
Sec. 104.

143 /. COMMUTATOR, BRUSH AND BRUSH-CONTACT RESISTANCE Loss. See

urement of Losses (F) Sec. 111.

144 g. COLLECTOR-RING BRUSH-CONTACT RESISTANCE Loss. See Measure-
ment of Losses (C), Sec. 112.

145 h. FIELD-EXCITATION Loss. See Measurement of Losses (//), Sec. 109.
148 i. LOAD LOSSES. These can generally be neglected, owing to the ab-
sence of field distortion.

147 3. i ICIENCY OF Two SIMILAR CONVERTERS may be determined
by operating one machine as a converter from direct to alternating, and
the other as a converter from alternating to direct, connecting the alter-
nating sides together, and measuring the difference between the direct-
current input and the direct-current output. This process may be modi-
fied by returning the output of the second machine through two boosters
into the first machine and measuring the losses. Another modification
is to supply the losses by an alternator between the two machines, using
potential regulators.

(D) SYNCHRONOUS MACHINES.

148 In SYNCHRONOUS MACHINES the losses are:

149 a. BEARING FRICTION AND WINDAGE. See Measurement of Losses (A).
Sec. inj

160 b. MOLECULAR MAGNETIC FRICTION AND HDDY CURRENTS. See Mea-
surement of Losses (/>), Sec. 105.

,. Qt.

STANDARi S Of THh. A I i i:

161 . A KM M t RE-RESISTANCE Lota. See Measurement of Lossn (£). Sec.

162 d COLLECTOR K ts<> BRUSSJ l

163 M TO*. RING BRI-

164 . Lots. Sec Measurement of Lossss (10. Sec. m
166 t L04 r« Measurement of Losses (/). Sec. Ill

(fi) ?t nfcTioN APPARATUS.

166 I- >s APPARATUS the losses are:

167 • measured at
open second.* l, rated frequency, and at rated voltage — / r. where

' - resistance of primar

168 •• LOSSES, the sum of the /' r losses in the primary and
in the M-vondary windings of a transformer, or in the two sections of the

isator or auto-transformer, where /-rated current in
the coil or section of coil, and r » resistance.

169 i» LOSSES, i.r, eddy currents in the iron and especially in the
;-er conductors, caused by the current at rated load. For practical

purposes they may be determined by uting the secondary of

the transformer a; ssing upon the primary a voltage sufficient to

send rated load current through the transformer. The loss in the trans-
• these conditions, measured by wattmeter, gives the load
losses + 7*r losses in .ary and secondary coils.

160 In CLOSED ' in TRANSFORMERS, either of the two circuits
may be used as primary when determining the efficiency.

161 >• should be taken at the max-
imum voltage for which the apparatus is designed, and with non-ind
load, unless otherwise specified.

ROTAR\ >s APPARATUS, or INDUCTION ' ' \- MINES

162 In ROTARY IMKTIION .\IT\K MIS. the losses are:

163 a. BEARING FRI .K. See Measurement of Losses (A).
Sec.

164 b. Mi.- FKICIIOV n iron, copper
and other metallic parts; also I- r losses which may exist in multiple-

ngs. a and 6 together are determined by running the motor
without load at rated voltage, and measuring the power input.
166 t. PRIMARY 7* R Loss, which may be determined by measurement of
the current and the resist. i

166 d. SECOM»AK\ /•* K Loss, which may be determined as in the primary,
when feasible; otherwise, as in squirrel-cage secondaries, this loss is meas-
ured as part of t.

167 f LOAD LOSSES; i.r. molecular magnetic friction, and eddy currents

ron, copper, etc.. caused by the stray field of primary and secondary
currents, and secondary /» R loss when undeterminable under (4). These
• losses may for practical purposes be determined by measuring the total
power, with the rotor she: 1 at standstill and a current in the

primary circuit equal to the primary energy current at full load. The
loss in the motor under these conditions may be assumed 'to be equal to
the load losses + P r losses in both primary and secondary coils.

(G) \R OR A« NES.

168 In UNIPOLAR MAC MINES, the losses are:

169 (a) BEARING FRICTION AM> WIM.\..K See Measurement of Losaci
(A). S<

170 MAGNETIC PRKU -s ^ CURRENTS. See
Measurement of Losese (/ <>d.

171 u i ARMATURE-RESISTANCE LOSSES. See Measurement of Losese (£).
Sec.

172 (d) COLLECTOR -BRUSH FRICTION. See Measurement of Losssi (Q.
Sec. nn

STANDARDIZATION RULES OF Till .\.I.E.E.

173 («) COLLECTOR BRUSH-CONTACT RESISTANCE. See Measurement of
Losses (£), Sec. 1

174 ffl FIELD-EXCITATION. See Measurement of Lossr

176 (t) LOAD LOSSES. See Measurement of Losses (/), Sec. Ill

(//) RECTIFYING APPARATUS, PULSATING-CURRENT GENERATORS.

176 This division includes: open-coil arc machines and mechanical and
other rectifiers.

177 In RECTIFIERS the most satisfactory method of determining the efficiency
is to measure both electric input ana electric output by wattmeter. The
input is usually inductive, owing to phase displacement and to wave dis-
tortion. For this reason the power factor and the apparent

should also be considered, since the latter may be much lower than the
true efficiency. The power consumed by auxiliary devices, such a
synchronous motor or cooling devices, should be included in t
input.

178 In Cos RRENT RECTIFIERS, transforming from constant poten-
tial alternating to constant direct current, by means of constant-current
transforming devices and rectifying devices, the losses in the transforming
devices are to be included in determining the efficiency and have to be
measured when operating the rectifier, since in this case the losses may be
greater than when feeding an alternating secondary circuit. In constant-
current transforming devices, the load losses may be considerable, and
therefore, should not be neglected.

179 In OPEN-COIL ARC Y . the losses are essentially the same
direct-current (closed coil) commutating machines. In this case, how-
ever, the load losses are usually greater, and the efficiency should prefer-
ably be measured by input- and output-test, using wattmeters for m
ing'the output.

179a In alternating-current rectifiers, the output should, in general, be
measured by wattmeter and not by voltmeter and ammeter, since
owing to pulsation of current and voltage, a considerable discre;
may exist between watts and volt-amperes. If, howev t-current

and an alternating-current meter in the rectified circuit (either a volt-
meter or an ammeter) give the same reading, the output ma ;sured
by direct-current voltmeter and ammeter. The type of alternatin
rent instrument here referred to should indicate the effective or root-of-
mean-square value and the type of direct-current instrument the arith-
metical mean value, which would be zero on an alternating-current circuit.

(/) TRANSMISSION LINES.

180 The EFFICIENCY of transmission lines should be measured with non-
inductive load at the receiving end, with the rated receiving voltage and
frequency, also with sinusoidal impressed wave form, except where ex-
pressly specified otherwise, and with the exclusion of transformers or
other apparatus at the ends of the line.

(/) PHASE-DISPLACING APPARATUS.

183 In SYNCHRONOUS PHASE-MODIFIERS and exciters of induction generators,
the determination of losses is the same as in other synchronous machines.

184 In REACTORS the losses are molecular magnetic friction, eddy losses
and 7* r loss. They should be measured by wattmeter. The losses of
reactors should be determined with a sine wave of impressed voltage
except where expressly specified otherwise.

185 In CONDENSERS, the losses are due to dielectric hysteresis and leak-
age, and should be determined by wattmeter with a sine wave of voltage
or by an alternating-current bridge method.

186 In POLARIZATION CELLS, the losses are those due to electric resistivity
and a loss in the electrolyte of the nature of chemical hysteresis. These
losses may be considerable. They depend upon the frequency, voltage
and temperature, and should he de .-rminv 1 with

• pt \vher- i ntheru

S Of THR A./.R.R.

1) kl-:« ILLATION.
(I) DEFINITIONS.

187 The .- .fa machine or apparatus in refard to some
cha: v (such as terminal voltage, current or speed)

of thai quantity from its normal value at rated

load to that normal value. The term " regulation." therefore, has the
same meaning as th< r emulation." occasionally used.

188 • - SM charactenstic quantity is intended to re-
mum constant («.f.. constant voltage, constant speed, etc.) between rated
load and no load, the regi the ratio of the maximum variation

. the rated-load \ he no-load value.

189 tic quantity it intended to vary
in .. t*tween rated load and no load, the regulai:

thr the maximum variation from the specified condition to the

rated-load va!

190 the variation (in voltage, current, speed, etc.)
1 load and no load is not sp< hould be assumed to be

a simple linear relation; i.r.. one undergoing uniform variation between
rated load and no load.

191 IK. The regulation of an apparatus may. therefore differ ac-
cording to its qu. for use. Thus, the regulation of a compound-
wound generator specified as a constant-potential generator, will be dif-

it jM>ssesses when specified as an over -compounded
generator.

192 i KM i AL ! s. the regulation is the ratio of the
maximum difference of terminal voltage from the rated-load value (occur-
ring within the range from rated load to open circuit) to the rated load

193 Ii. MINES, the regulation is the ratio of the
maximum difference of current from the rated-load value (occurring

he range from rated-load to short-circuit, or minimum limit of
op< -ad current.

194 It >WBK APPARATUS, the regulation is the ratio of maxi-
mum difference of power from the rated load value (occurring within the
range of operation specified) to the rated power.

196 I: i ti> DIKK i CURRENT MOTORS and INDUCTION MOTORS
the of the maximum variation of speed from its
rated load value (occurring within the range from rated load to no-load)
to the rated load speed.

198 The regulation of an induction motor re. not identical with

which is the ratio of the drop in speed from syn-
ch r« ronous speed.

197 I: SSFORMERS. the regulation is the ratio of
the rise of secon<: voltage from rated non-inductive load to
no-load (at constant primary impressed terminal voltage) to the secondary
ten; .ige at rated load.

198 In OvER-Court' USES, the regulation is the ratio of the
maximum difference in voltage from a straight line connecting the no-load
and rated-load values of terminal voltage as function of the Toad current,
to the rated-load terminal voltage.

199 . i-kv !>, N \\IOTORS. MOTOR-GENERATORS AND FREQO
CONVERTERS, the regulation is the ratio of the maximum difference «
minal voltage at the output side from the rated-load voltage, to the rated-
load voltage on the output side.

200 In TRANSMISSION LINES. FEEDERS. ETC.. the regulation is the ratio of
the maximum voltage difference at the receiving end. between rated non-
inductive load and no load to the rated-load voltage at the receiving end
(with constant voltage impressed upon the sending end).

201 In STEAM ENGINES, the regulation is the ratio of the maximum varia-
tion of speed in passing slowly from rated-load to no-load (with constant
steam pressure at the throttle) to the rated-load speed. For variation
and pulsation see Sees. 59-64.

20 STANDARDIZATION RULE.^ Of 1'IIE A.I.E.E.

202 In a HVDKAI in ! t RHINE or OTHER WATER-MOTOR, the regulation is
the ratio of the maximum variation of speed in passing slowly from rated-
load to no-load (at constant head of water; i.e.. at constant difference of
level between tail race and head race), to the rated-load speed,
variation and pulsation see Sees. 59-64.

203 In a GENERATOR-UNIT, consisting of a generator united with a prime-
mover, the regulation should be determined at constant conditions of the
prime-mover; i.e pressure, head, etc. It includes the
inherent speed variations of the prime-mover. For this reason the regu-
lation of a generator-unit is to be distinguished from the regulation of
either the prime-mover, or of the generator contained in it, when taken
separately.

(II) CONDITIONS FOR AND TESTS OP REGULATION.

204 SPEED. The REGULATION OF GENERATORS is to be determined at con-

.t speed, and of alternating apparatus at constant impressed frequency.

205 N ON INDUCTIVE LOAD. In apparatus generating, transforming or t:
mitting alternating currents, regulation should be understood to refer to
non-inductive load, that is, to a load in which the current is in phase with
the e.m.f. at the output side of the apparatus, except where expressly
specified otherwise.

206 WAVK FORM. In alternating apparatus receiving electric power, regu-
lation should refer to a sine wave of e.m.f., except where expressly speci-
fied otherwise.

207 EXCITATION. In commutating machines, rectifying machines, and syn-
chronous machines, such as direct-current generators and motors, alter-
nating-current and polyphase generators, the regulation is to be. deter-
mined under the following conditions:

(1) At constant excitation in separately excited fields.

(2) With constant resistance in shunt-field circuits, and

(3) With constant resistance shunting series-field circuits; i.e., the
field adjustment should remain constant, and should be so chosen

give the required rated-load voltage at rated-load current.

208 IMPEDANCE RATIO. In alternating-current apparatus, in addition to the
non-inductive regulation, the impedance ratio of the apparatus should be
specified; i.e., the ratio of the voltage consumed by the total internal im-
pedance of the apparatus at rated-load current, to its rated-load voltage.
As far as possible, a sinusoidal current should be used.

209 COMPUTATION OF REGULATION. In synchronous machines the open-
circuit exciting ampere-turns corresponding to terminal voltage plus arma-
ture-resistance-drop, and the exciting ampere-turns at short-circuit for
rated-load current should be combined vectorially to obtain the r

ant ampere-turns, and the corresponding internal e.m.f. should be taken
from the saturation curve.

1C. INSULATION.

(I) INSULATION RESISTANCE.

210 INSULATION RESISTANCE is the ohmic resistance offered by an insulating
coating, cover, material or support to an impressed voltage, tending to
produce a leakage of current through the same.

211 OHMIC RESISTANT K AND DIKLECTRIC STRENGTH. The ohmic resistance
of the insulation is of secondary importance only, as compared with the
dielectric strength, or resistance to rupture by high voltage. Since the
ohmic resistance of the insulation can be very greatly increased by baking,
but the dielectric strength is liable to be weakened thereby, it is preferable
to specify a high dielectric strength rather than a high insulation resist-
ance. The high-voltage test for dielectric strength should always be ap-
plied.

212 RECOMMENDED VALUE OF RESISTANCE. The insulation resistance of
completed apparatus should be such that the rated terminal voltage of the

apparatus will not send more than j QOO 000 °* the ratcd*loa<i current»

STANDARDIZATION RULES OF Till. A I i

through ation. Where ihe value found to this way exceed* ooc

megohm, it it usually sufficient.

213 INSULATION Hi .ould. if potable. b« made at the
' iturc fur which the apparatus is designed.

CTRIC STRRNCI It
(A) TK»T Voi. i A

214 l>i»r. : he dielectric strength of an mtulating «*ll. cwating
cover or path it mea»>: • -»e voltage which must be applied to

..r.ir: tc •-!!• et a !. .;u;. •!•..• •'. ham ••.,.•• .. -
216 UN :• i ... . TRST V The test voltage which

should be a} insulation for commer-

normal operating v c of the service in wh

used, and the scve: i« mechanical and elect r

h it may be subjected. 1 .;c> and other con

which arc re. <-d have been determined as reasonable and proper

t:reat ma cases and are proposed for general adoption.

;<ccific reasons make a mo :

216 or APPAKATUS TO HE TESTED. Commercial tests shoul
be made with the completely assembled apparatus and no*.

The apparatus should be in good condition and high-
voltage tests, unless otherwise specified, should be applied before the
machine is put into commercial service, and should not be applied when
the insulation resistance is low owing to dirt or moisture. High- voltage
should, in general, be made at the temperature assumed under nor-
mal operation. High-voltage tests considerably in excess of the normal
voltages 'ions are fulfilled are admissable

on new machine** nless otherwise agreed tspon. high-voltage tests

of a machine should be understood as being made at the factory.

217 I'MIM* OF Arn ; ige should be sue-

between each electric circuit and all other electric cir-
cuits including conducting material in the apparatus.

218 The I'i test voltage is, in general,
immaterial within commercial ranges. When, however, the frequency has
an appreciable ef n alternating-current apparatus of high voltage
and considerable capacity, the rated frequency of the apparatus should
be used.

219 TABLE OF '1 >LTAGES. The following voltages are recommended
for testing all apparatus, lines and cables, by a continued application
for one minute. The test should be with alternating voltage having a

(or root mean square referred to a sine wave of voltage)
given in the table, and preferably for tests of alternating apparatus at
the normal frequency of the apparatus.

lUud Terminal Volu«e o( lUt«d Output. T«*un* Votu«*

220 Not exceeding 400 •. icr 10 kw 1.000 volts

kw. and ..-.<- 1.500
400 and over, but less than 800 volts. . Under 10 kw

and over 2.000

MX) - • 1.200 ' 3.500

•0 • - 2,500 ~ »H)

2.500 ' * Any Double the normal rated

•

221 ICxcBPTios.— TtANSFORMiBS. Transformers having primary pressures
of from 560 to 5,000 volts, the secondaries of which at-

nected to consumption circuits, should have a testing voltage of 10.000
volts, to be applied bctw. ry and secondary windings, and

also between the primary winding and the core.

222 KXCEFTION.— FIELD ---sts for field windings should be
based on the rated voltage of the exciter and the rated output of the
machine of which the coils are a part. Field windings of synchronous
motors and converters, which are to be started by applying alter:
current to the armature when the field is not excited and when a high
voltage is induced in the field windings, should be tested at 5.000 volts.

STANDARDIZATION RULES Ol- Till: ,!././

223 RATED TERMINAL VOLTAGE. — DEFINITION. The rated terminal voltage
of circuit in the above table, means the voltage between the conductors
of the circuit to which the apparatus to be tested is to be connected, — for
instance, in three-phase circuits the delta voltage should be taken. In
the following specific cases, the rated terminal voltage of the circuit is
to be determined as specified in ascertaining the testing voltage:

224 (a) TRANSFORMERS. The test of the insulation between the primary and
secondary windings of transformers, is to be the same as that between
the high-voltage windings and core, and both tests should be made simul-
taneously by connecting the low-voltage winding and core together during
the test. If a voltage equal to the specified testing voltage be induced
in the high-voltage winding of a transformer it may DC used f«>r insulation

I instead of an independently induced voltage. These tests should IK-
made first with one ena and then with the other end of the high-tension
\\mdine connected to the low-tension winding and to the core.
226 (6) CONSTANT-CURRENT APPARATUS. The testing voltage is to be
based upon a rated terminal voltage equal to the maximum voltage which
may exist at open or closed circuit.

226 (c) APPARAH - IN SERIES. For tests of machines or apparatus to be
operated in series, so as to employ the sum of their separate voltages the
testing voltage is to be based upon a rated terminal voltage equal to the
sum of the separate voltages except where the frames of the machines
are sepa: ulated, both from the ground and from each other, in
which case the test for insulation between machines should be based upon
the voltage of one machine, and the test between each machine and ground
to be based upon the total voltage of the series.

(B) METHODS OF TESTING.

227 CLASSES OF TESTS. Tests for dielectric strength cover such a wide
range in voltage that the apparatus, methods and precautions which are
essential in certain cases do not apply to others. For convenience, the
tests will be separated into two classes:

228 CLASS 1. This class includes all apparatus for which the test voltage
does not exceed 10 kilo volts, unless the apparatus is of very large static
capacity, e.g., a large cable system. This class also includes all apparatus
of small static capacity, such as line insulators, switches and the like, for
all test voltages.

229 METHOD OF TEST FOR CLASS 1. The test voltage is to be continuously
applied for the prescribed interval, — (one minute unless otherwise speci-
fied). The test voltage may be taken from a constant-potential source
and applied directly to the apparatus to be tested, or it may be raised
gradually as specified for tests under Class 2.

230 CLASS 2. This class includes all apparatus not included in Class 1.

231 METHOD OF TEST FOR CLASS 2. The test voltage is to be raised to the
required value smoothly and without sudden large increments and is then
to be continuously applied for the prescribed interval, — (one minute,
unless otherwise specified), and then gradually decreased.

232 CONDITIONS AND PRECAUTIONS FOR CLASS 1 and CLASS 2. The follow-
ing apply to all tests:

233 The WAVE SHAPE should be approximately sinusoidal and the apparatus
in the testing circuits should not materially distort this wave.

234 The SUPPLY CIRCUIT should have ample current-supply capacity so that
the charging current which may be taken by the apparatus under test
will not materially alter the wave form nor materially affect the test volt-
age. The circuit should be free from accidental interruptions.

236 RESISTANCE OR INDUCTANCE in series with the primary of a raising
transformer for the purpose of controlling its voltage is liable seriously to
affect the wave form, thereby causing the maximum value of the volt-
age to bear a different and unknown ratio to the root mean square value.
This method of voltage adjustment is, therefore, in general, undesirable.
It may be noted that if a resistance or inductance is employed to limit
the current when burning out a fault, such resistance or inductance should
be short circuited during the regular voltage test.

STANDARDIZATION HI /./-.N • •/• //// i / 23

236 The Kit I.AIIUN under test should be in normal condition as to dry-
ness and the temperature should when possible be that reached ia normal
Njrvt <-

237 \ i-i'i i IONAL CONDITIONS AND PRECAUTIONS FOR CLASS 2. The following

:u and precaution*, in addition to the foregoing, apply to tests
of apparatus included in Class 2.

238 SUDDEN INCREMENT or '1 > OLTAGE on the apparatus under teat
should be avoided, particularly at high voltages and with apparatus having
considerable capacity, as a momentarily excessive rise In testing voltage
will result.

239 Si OLTAGE of the circuit supplying the

•>* the test should be avoided as they are likely to set up

240 <>.\* in •. :ig the test voltage are es-
sential in or urtou* high frems ir banco* from

1 by a small water rheostat.

:ig may occur, causing high-frr< turhancet which should be

ully av«*:

241 TKANHFORMBR < c transformers, the low- voltage

.ibly be connected to the core and to the ground when
the high-voltage test i> bring made, in he stress from

low-voltage D h would otherwise result through condenser

action. The various terminals of each winding of the high-tension trans-
former • should be c -get her during the test in order
to prevent undue stress on the insulation between turns or sections of the
winding in case the high-voltage test causes a break-down.

(O METHODS FOR MBA«I-KIM. int. n \GB.

242 FOR MK\M KIM. no ii \«iB, two instruments ar« in common
use. (1) the spark gap and .It meter.

243 1 '. so that it will break down with a
certain pred< and is connected in parallel with the in-
sulal ige applied to the insu.

n the break-down voltage of the spark gap. A given
setting of the spark gap is a measure of one definite voltage, and. as its
operatic- upon t: vim value of the voltage wave.

rm and is a limit on the maximum stress to which
the The spark gap is not conveniently adapted

low voltages.

244 >;ap may be set for th

v apparatus adjusted to give a voltage at

The spark gap should then be

adj 'age. and the auxiliary apparatus

>gc of the former breakdown, which

be the assumed voltage for the test. This voltage is to be maintained
for the required interval.

246 T new sewing needles, supported

axially at the ends of 'or* which are each at least twice the

f the ga; should be no extraneous body near the gap

. radius <•: 'able of approximate striking dis-

This table should be used in connection

with tests n. c spark-gap methods.

246 A N • • \ I M K of about one-half ohm per volt should be
inserted in series with each terminal of the gap so as to keep the discharge
current between the limits of one-quarter ampere and 2 amperes. The pur-
pose of the resistance is to limit the current in order to prevent the surges
which might otherwise occur at the time of break-down.

247 J. The VOLTMETER gives a direct reading, and the different values of the
voltage can be read during the application and duration of the test,
suitable for all voltages, and does not introduce disturbances into the test

-.lit.

248 In VOLTMETER MEASUREMENTS, the voltmeter should, in general, derive
its voltage from the high-tension testing circuit either directly or through

24 STANDARDIZATION RULES Ol I III: ,!././

an auxiliary ratio transformer. It is permissible, however, to measure the
voltage at other places, — for example, on the primary of the transf<
provided the ratio of transformation does not materially vary during the
test; or that proper account is taken thereof.

249 SPARK GAP tND VOLTMETER. The spark gap may be employed as a
check upon the voltmeter used in high-tension tests in order to determine
the transformation ratio of the transformer, the variation from th
wave form and the like. It is also useful in conjunction with voltmeter
measurements to limit the stress applied to the insulating n

(D) APPARATUS FOR SUPPLYING TEST VOLTAGE.

260 The GENERATOR OR CIRCUIT supplying voltage for the test should
have ample current carrying capa* hat the current which

be taken for charging the apparatus to be tested will not mau-ri.-ilh
the wave form nor otherwise materially change the voltage.

The TESTING TRANSFORMER should be such that its ratio of trans-
formation does not vary more than 10 per cent when delivering the charg-
ing current required by the apparatus under test. (This may be deter-
mined by short-circuiting the secondary or high voltage winding of the test-
ing transformer and supplying 1/10 of the primary voltage to the pr
under this condition. The primary current that flows under this condition
is the maximum which should be permitted in regular dielectric test.)

261 The VOLTAGE CONTROL may be secured in either of several inch
in order of preference, are as follows:

262 1. By generator field circuit.

263 2. By magnetic commutation.

264 3. By change in transformer ratio.
266 4. By resistance or choke coils.

266 In GENERATOR VOLTAGE CONTROL, the voltage of the generator si
preferably be about its approximate normal rated load value when the
lull testing voltage is attained, which requires that the ratio of the r
transformer be such that the full testing voltage is reached when the gen-
erator voltage is normal. This avoids the instability in the generator
which may occur if a considerable leading current is taken from it when
it has low voltage and low field current.

267 In MAGNETIC COMMUTATION, the control is effected by shunting the mag-
metic flux through a secondary coil so as to vary the induction through
the coil and the voltage induced in it. The shunting should be effected
smoothly, thus avoiding sudden changes in the induced voltage.

268 In TRANSFORMER VOLTAGE CONTROL, by change of ratio, it is neces-

that the transition from one step to another be made without inter-
ruption of the test voltage, and by steps sufficiently small to prevent
surges in the testing circuit. The necessity of this precaution is greater
as the inductance or the static capacity of the apparatus in the t
circuit under test is greater.

269 When RESISTANCE COILS OR REACTORS are used for voltage control, it
is desirable that the testing voltage should be secured when the controlling
resistance or reactance is very nearly or entirely out of circuit in order
that the disturbing effect upon the wave form which results may be negli-
gible at the highest voltage.

F. CONDUCTIVITY

260 COPPER. The conductivity of copper in annealed wires and in electric
cables should not be less than 98 per cent of the Annealed Copper Stand-
ard, and the conductivity of hard-drawn copper wires should not be less
than 95 per cent of the Annealed Copper Standard. The Annealed
Copper Standard represents a mass-resistivitv of 0.153022 ohm per meter-
gram at 20 deg. cent, or 873.75 ohms per mile-pound at 20 deg. cent.; or
using a density of 8.89, a volume-resistivity of 1.72128 microhm-cm., or
microhms in a cm. cube, at 20 deg. cent, or 0.67767microhm-inch at 20
dee. cent.

STANDARDISATION RULES (Jf- Ulh. A I /UL

RISB OF TEMPERATURE.

(I) MEASUREMENT OP TEUPERATl

(A) METHODS.

361 There are two methods in common use for determining the hse tn tern-
per.* by thermometer, and (2) by increase in resistance of

an r!
262 .Mowing precautions should be obecnred

in the u*c of thermometer*:
-• •< rmometers indicating the room temper-

•hou tn thermal r . heated bodies, or

>porary fluctuations of temper-
be used. In using the thermometer

by applying it i<> a heated part, care should be taken so to prote
as t • radiation (rum it. and. at the tame lime, not to interfere

mal radia the part to which it is applied.

264 icrmometer : . applied to the free surface of a ma-

.at the bulb of the thermometer should be covered
A convenient pad may be formed of cotton

waste in a shullo box about one and a half inches in diameter.

ugh a .slot in the • !-• tn which the thermometer bulb is inserted
the thermometer tend;> .in the n .1

heat from the surface to which the thermometer is applied.
266 The resistance may be measured

louble bridge,
method. If a

ist be as »pper may be

takei "i. 00394 per deg. cei at 20 deg. cent., or 0.00438

:i and at • holds for average com-

:t the 1-05.

coefficient should
be taken, ai explanation and discussion of the temperature

The • rise may be «i 1) by dividing the

per cent increase e coefficient for the

-. it ure expressed in per cer.

resistance :iperature

legrees cent., and then dividing ihe pmdt:

d absolute zero temperature of resistance " and is given in the last
:rnn of the table in Appen -»r average commercial a**t*lt4

copper S).

266 .•;.' COMPARISON or METHODS. In electrical conductors, the rise of tem-
perature should be determined by t: ise of resistance where prac-
ticable. Temperature elevations measured in this way are usually in ex-
cess of temp* :evations measured by thermometers. In very low
resistance circuits, thermometer measurements are frequently more relt-
abl< isurements by the resistance method. Where a thermometer
applied to a coil or winding, indicates a h»»jher temperature ele-.

t> that shown by resistance measurement, the thermon .ilion

should be accepted.

(B) NORMAL CONDITIONS FOR TESTS.

267 1. DURATION OP TESTS. The temperature should be measured after a
run of sufficient duration for the apparatus to reach a practically constant
temperature. This is usually from 6 to 18 hours, according to the wie and
construction of the apparatus It is permissible, however, to shorten the
time of the lest by running a lesser time on an overload in current and
voltage, then reducing the load to normal, and maintaining it thus until
the temperature has become constant.

268 2. ROOM TEMPERATURE. The rise of temperature should be referred to
the standard condition of a room temperature of 25 deg. cent.

269 TEMPERATURE CORRECTION. If the room temperature during the teat

STANDARDIZATION RULES OF THE A.I.E.E.

differs from 25 dcg. cent., correction on account of difference in resistant
should be made by changing the observed rise of temperature by one-half
per cent for each degree centigrade. Thus with a room temperature of 35
deg. cent., the observed rise of temperature has to be decreased by 5 per
cent, and with a room temperature of 15 deg. cent., the observed rise of
temperature has to be increased by 5 per cent. In certain casrs. such
as shunt-field circuits without rheostat, the current strength will he
changed by a change of room temperature. The heat-productioi
dissipation may be thereby affected. Correction for this should be made
by changing the observed rise in temperature in proportion as the
loss in the resistance of the apparatus is altered owing to the difference in
room temperature.

270 3. BAROMETRIC PRESSURE. VENTILATION. A barometric pressure of
760 mm. and normal conditions of ventilation should be considered as
standard, and the apparatus under test should neither be exposed to draught
nor enclosed, except where expressly specified. The barometric pr«
needs to be considered only when differing greatly from 760 mm.

271 BAROMETRIC PRESSURE CORRECTION. When the barometric pressure
differs greatly from the standard pressure of 760 mm. of mercury.

high altitudes, a correction should be applied. In the absence of more i
accurate data, a correction of one per cent of the observed rise in tempera-
ture for each 10 mm. deviation from the 760-mm. standard is recommended.
For example at a barometric pressure of 680 mm. the observed rise of tem-
perature is to be reduced by •• 8per O

(II) LIMITING TEMPERATURE RISE.

272 GENERAL. The temperature of electrical machinery under regular
vice conditions, should never be allowed to remain at a point at which
permanent deterioration of its insulating material takes place.

273 LIMITS RECOMMENDED. It is recommended that the following maximum
values of temperature elevation, referred to a standard room temperature
of 25 degrees centigrade, at rated load under normal conditions of ven-
tilation or cooling, should not be exceeded.

(A} MACHINES IN GENERAL.

274 In commutating* machines, rectifying machines, pulsating-current
erators, synchronous machines, synchronous commutating machines and
unipolar machines, the temperature rise in the parts specified should not
exceed the following:

276 Field and armature, 50 deg. cent.

276 Commutator and brushes, by thermometer, 55 deg. •

277 Collector rings, 65 deg. cent.

278 Bearings and other parts of machine, by thermometer, 40 deg. cent.

279 (B) ROTARY INDUCTION. APPARATUS. The temperature rise should not
exceed the following:

280 Electric circuits, 50 dcg. cent., by resistance.

281 Bearings and other parts of the machine 40 deg. cent., by thermometer.

282 In squirrel-cage or short-circuited armatures, 55 deg. cent., by thermo-
meter, may be allowed.

(O STATIONARY INDUCTION APPARATUS.

283 a. TRANSFORMERS FOR CONTINUOUS SERVICE. The temperature rise
should not exceed 50 deg. cent, in electric circuits, by resistance; ami in
other parts, by thermometer.

284 b. TRANSFORMERS FOR INTERMITTENT SERVICE. In the case of trans-
formers intended for intermittent service, or not operating continuously
at rated load, but continuously in circuit, as in the ordinary case of lighting
transformers, the temperature elevation above the surrounding air-tem-
perature should not exceed 50 deg. cent., by resistance in electric circuits
and by thermometer in other parts, after the period corresponding to the
term of rated load. In this instance, the test load should not be applied

\NDARDIZAT10N RULES OF THh A / E £. 27

until the transformer baa beta • for a sufficient time to attain

the • ire elevation due to core lota. With transformers for com-

mercial lighting, the .!-. -he rated-load test may be taken as three

hours, unless otherwise specified.

KEACTOH ^REGULATORS. EJectnccir

by resistance and other parts by thermometer. 60 deg. cent.

d. l.MM.H Art-Ai. urge generators, motor*, transfonnert. or other

apparatus in which reliability and reserve overload capacity are important,
are frequently specified not to rise in temperature more than 40 da*.
i load and 56 deg. cent, at rated overload !•.:». how-
it narily undesirable to specify lower temperature elevations than
at rated load, measured aa ar>

(£>) RBEOSI

287 HBATIBS and othr: hermal apparatus, no corn-

bus' nflammable part or material, or portion liable to come in

•nth such material, should rise more than 50 deg. cent, above the
surrounding air under the service conditions for which it is designed.
188 j 1' \KTHOF RHEOSTATS. Parts of rheostats and similar apparatus nung
in temperature, under the specified service conditions, more than 60 deg.
ontain any combustible material, and should be arranged
hat neither they, nor the hot air issuing from
them, can come in contact with combustible material.

l.i MI is RECOMMENDED IN SPECIAL CASKS.

269 «; HKAT KEM-I. vi apparatus in which the insu-

lating materials have special heat-resisting qualities, a higher temperature
elevation is permtssi

290 .V iUi.ti AIR TEMPER AT t: RK. In apparatus intended for service in
places of abnormally high temperature, a lower temperature elevation
should be specif i

291 c. APPARATUS SUBJECT TO OVERLOAD. In apparatus which by the

service may be exposed to overload, or is to be used in very

high voltage a small- temperature is desirable than in

apparatus not liable to overloads or in low -voltage apparatus. In ap-

itus built for conditions of limited space, as railway motors, a higher

f temperature must be allowed.

292 d. APPARATUS FOR IMI-KMIIII M SKKVKK In the case of apparatus

r. except railway motors, the temperature

elevation which is attained at the end of the period corresponding to the

he values specified for machines

in general. In such apparatus, including railway motors, the temperature
a lion should be measured after operation, under as nearly as pos-
sible th' ns of service for which the apparatus is intended, and

! be specified.

H *t 'VKKI.OAD CAP.V

293 I'nuokM\st H \\IIH OVERLOAD. AH apparatus should be able to carry
the overload hereinafter specified without sen ng. spark*

ss. etc.. and with an additional temperature rise not
•leg. cent., above those specified for rated loads, the overload
being applied after the apparatus has acquired the temperature corre-
sponding to rated load continuous operation. Rheostats to which no
temperature nse limits are attached are naturally exempt from this addi-
tional temperature rise of 15 deg. cent, under overload specified in these
rules.

294 N . - K M v .id guarantees should refer to normal con-

ns of operation regarding speed, frequency, voltage, etc.. and to non-
inductive ci.t n alternating apparatu where a phase dis-
placement is inherent in the apparatus.

STANDARDIZATION Rl'Ll-

295 OVERLOAD CAPAI in; - KKCOMMENDED. The following overload capaci-

are recommended:

296 a. GENERATORS. Direct-current generators and alternating-current
generators, 25 per cent for two hou

297 />. MOTORS. Direct-current motors, induction motors and synchronous
motors, not including railway and other motors intended for intermittent

ce, 25 per cent for two hours, and 50 per cent for one minute.

298 c. CONVERTERS. Synchronous converters, 25 per cent for two hours,
50 per cent for one-half hour.

299 </. >RMERS AND RECTii it K-. Constant-potential transformers
and rectifiers, 25 per cent for two hours; except in transformers connected
to apparatus for which a different overload is guaranteed in which case the
same guarantees shall apply for the transformers as for the apparatus
connected thereto.

300 e. EXCITERS. Exciters of alternators and other synchronous machines,
10 per cent more overload than is required for the excitation of the syn-
chronous machine at its guaranteed overload, and for the same period of
time. All exciters of alternating-current, single-phase or polyphase gen-
erators, should be able to give at their rated speed, sufficient voltage and
current to excite their alternators, at the rated speed, to the full-load ter-
minal voltage, at the rated output in kilovolt-amperes and with 50 per
cent power factor.

301 /. A CONTINUOUS-SERVICE RHEOSTAT, such as an armature- or field-
regulating rheostat, should be capable of carrying without injury for two
hours, a current 25 per cent greater than that at which it is rated. It
should also be capable of carrying for one minute a current 50 per cent
greater than its rated load current, without injury. This excess of ca-
pacity is intended for testing purposes only, and this margin qf capacity
should not be relied upon in the selection of the rheostat.

302 g. An INTERMITTENT SERVICE OR MOTOR-STARTING RHEOSTAT is used for
starting a motor from rest and accelerating it to rated speed. Under
ordinary conditions of service, and unless expressly stated otherwise, a
motor is assumed to start in fifteen seconds and with 150 per cent of rated
current strength. A motor-starter should be capable of starting the
motor under these conditions once every four minutes for one hour.

303 (a) This TEST may be carried out either by starting the motor
at four-minute intervals, or by placing the starter at normal tem-
perature across the maximum voltage for which it is marked, and
moving the lever uniformly and gradually from the first to the
last position during a period of fifteen seconds, the current being
maintained substantially constant at said 50 per cent excess, by
introducing resistance in series or by other suitable means.

304 (6) OTHER RHEOSTATS FOR INTERMITTENT-SERVICE are employed
under such special and varied conditions, that no general rules are
applicable to them.

%.

III. VOLTAGES AND FREQUENCIES.

A. VOLTAGES.

306 DIRECT-CURRENT GENERATORS. In direct-current, low-voltage gener-
ators, the following average terminal voltages are in general use and are
recommended:

125 volts. 250 volts. 600 volts.

306 LOW-VOLTAGE CIRCUITS. In direct-current low-voltage circuits, the
following terminal voltages are in general use and are recommended:

115 volts. 230 volts. 550 volts.

In alternating-current low-voltage circuits, the following terminal volt-
ages are in general use and are recommended.

110 volts. 220 volts. 440 volts. 550 volts.

STANDAKDIZATJO19 RULES OP Tilt. A I KB.

307 I'kiuAKv I»IM» In Alternating-current.

I, Bfiflsfjry*diitnbui u. an average voltage of 2.200 volts.

with step-down transformer ratios I/ 10 and 1/30. is in general use. and U
ftOOOUBMdtd*

308 TRANSMISSION alternating -current constant -potential

:i emission 4get are recommended.

«,60«' (100 33.000 44.000 ttA.OOOHM.000 110.000

109 i ORMRR K • commended that the standard transformer

•§ should be such as to transform between the standard voltage* above

named. usually be an exact multiple of 6 or

310 KAM.I \'.i In alter nat

systems, a range of terminal voltage should be provided from rated voltage
at no load to 10 per <• »p in transmission.

If a greater range than ten per cent is specified, the generator should be
considered as special.

H FRKQUENCi

311 In ALTERNATING-CURRKS ITS. the* following frequencies are.
standar

25 cycles 60 cycles

312 These frequencies are already in extensive use and it U deemed ad-
visable to adhere to them as closely as possible.

IV. GENERAL RECOMMENDATIONS.

313 NAME PLATES.* All electrical apparatus should be provide*! with a name
plate giving the manufacturers' name, the voltage and the current in
amperes for which it is designed. Where practical) watt capacity,
character of current, speed, frequency, type, designation and serial num-
ber should be added.

314 DIAGRAMS OP Coxst All electrical apparatus when leaving the
factory should be accompanied by a diagram showing the electrical con-
nections and the relation of the different parts in sufficient detail to give
the necessary information for proper installation.

316 RHEOS rheostat should be clearly and permam

marked with the voltage and amperes, or range of amperes, for which
15 design-

316 COLORED I .in-. When using colored indicating lights
on switch-boards, red should denote danger such as " switch closed."
or "; green should denote safety, such as " switch open."

circuit ii

317 When white lights are used a lig^ht turned on should denote danger,
such as " switch closed " or " circuit alive "; while the light out should
denote safety, such as " switch open." or Low-effi-
ciency lamps should be used on account of their lesser liability to acci-
dental burn

318 The use of colored lights is recommended, as safer than white lights.

319 GROUNUING METAL WORK. It is desirable that all metal work near
high potcnti.. be grounded.

320 .DEVICES. The following definitions are recommended.

321 KEAEER is an apparatus lor breaking a circuit at the
highest current which n may be called upon to carry.

322 h. AIM-.. s an apparatus designed to open a circuit
only when carrying little or no cur:

323 c. An AUTOMATIC CIRCUIT- BREAKER is an apparatus for breaking ..

• automatically under an excessive strength of current. It should be
capable of breaking the circuit repeatedly at rated voltage and at the
maximum current which it may be called upon to carry.

STANDARDIZATION RULES Ol 1 III: A.I.E.E.

V. APPENDICES AND TABULAR DATA.
APPENDIX A. NOTATION.

The following notation is recommended:

Name of Quantity Symbol Unit

324 Voltage, e.m.f., potential difference E, e, volt
Current / ». ampere
Resistance R. r. ohm
Reactance A", x.
Impedance /. *,
Admittance Y, y, mho
Conductance G, t,
Susceptance H. o,

Power P, p, watt

Capacity ( '. < . farad

Inductance L, henry

Magnetic flux <t> maxwell

Magnetic density gauss

Magnetic force //. gilbert per cm.

Length L, I, cm. or inch

Mass M, m, gm. or Ib.

Time T, t, second or hour

Em, Im and Bm should preferably be used for maximum cyclic values,
e, i and p for instantaneous values, E and / for r.m.s. values (see
Sec. 5g.) and P for the average value or effective power. These distinc-
tions are not necessary in dealing with continuous-current circuits.
Vector quantities are preferably represented by bold face capitals.

APPENDIX B.— RAILWAY MOTOR

(I) RATING.

325 INTRODUCTORY NOTE ON RATING. Railway motors usually operate in
a service in which both the speed and the torque developed by the motor
are varying almost continually. The average requirements, however,
during successive hours in a given class of service are fairly uniform. On
account of the wide variation of the instantaneous loads, it is impracticable
to assign any simple and definite rating to a motor which will indicate
accurately the absolute capacity of a given motor or the relative capacity
of different motors under service conditions. It is also impracticable to
select a motor for a particular service without much fuller data with regard
both to the motor and to the service than is required, for example, in the
case of stationary motors which run at constant speeds.

326 SCOPE OF NOMINAL RATING. It is common usage to give railway motors
a nominal rating in horse power on the basis of a one-hour test. As above
explained, a simple rating of this kind is not a proper measure of service
capacity. This nominal rating, however, indicates approximately the
maximum output which the motor should ordinarily be called upon to
develop during acceleration. Methods of determining the continuous
capacity of a railway motor for service requirements are given under a
subsequent heading.

327 The NOMINAL RATING of a railway motor is the horse-power output at
the car-axle, that is, including gear and other transmission losses, which
gives A rise of temperature above the surrounding air (referred to a room
temperature of 25 deg. cent.) not exceeding 90 deg. cent, at the
commutator and 75 deg. cent, at any other part after one hour's con-
tinuous run at its rated voltage (and frequency, in the case of. an alter-
nating-current motor) on a stand, with the motor-covers removed, and
with natural ventilation. The rise in temperature is to be determined
by thermometer, but the resistance of no electrical circuit in the motor
shall increase more than 40 per cent during the test.

\M>.\Rl>l/..\llt>S RULES OF TV/A A I E.E.

(II) SELECTION Of MOTOR FOR SPECIFIED SERVICE.

328 GENERAL REQUIREMEMTS. The futubthiy of • railway motor for a
specified service depends upon ibe following considerations:

329 ; Mechanical ability to develop the requisite torque and

its speed- torque c :

330 fc. / te successfully the current A»mftMH

331 t Ahihty to ojK-rMr in service without occasioning a

l endangr

332 | operating conditions which
are importan ,f a motor include the weight of load, the
schedule speed, the -I. stance between stops. tl. n of stops, the

of acceleration and of braking retardation, the grades and the curve*.
with these data at hand, t) re required of the motor may

be determined, provided the srr mis are within th-

•petd-toraue curve of the motor. These outputs may be nip rusted
Of curves givin* the instantaneous values of current and of
nt be applied to the motor -» may b<

line, hut they are usually - 1 only for ft O

average or typical run. which it fairly representative of the conditions of
service. To determine whether the motor has sufficient capacity to per-
form the service safely, further tests or investigations must be made.

333 IK is M The capacity of a
railway -he necessary output may be determined by
measurement of its temperature after it has reached a maximum in ser-

• a running test cannot be made under the actual conditions of
service, an t lest may be made in a typical run back and forth,

under such conditions of schedule speed, length of run. rate of acceleration.

• the test cycle of motor losses and conditions of ventilation are
essentially the same as would be o1 a the specified serv

334 MKIH-' v« \\\ ui in SERVICE REQUIRE-

• is not convenient to test motors under actual service
•is or in an equivalent typical run. recourse may be had to one of the
two following methods of determining temperature rise now in general
use:

336 1 in !.os,. \PAcm ri-RVB*. The heat de-

railway motor is carried partly by conduction through the
several parts rough the air to the motor-frame

whence it is distributed to the outside air. As the temperature of the
several parts is thus dependent not only upon their own internal losses
but also upon the temperature of neighboring parts, it becomes necessary
to determine accurately the actual value and distribution of losses in a
railway motor for a given service and reproduce them in an equivalent
run. The results of a series of typical runs expressed in the form of
thermal capu • the relation between degrees rise per watt

loss in the armature and in the field for all ratios of losses between them
met with in the commercial application of a given motor.

336 1 his method consists, therefore, in calculating the several internal
motor losses in a specified scr\ nperature rise
with these losses from thermal capacit -:g the degrees rise
per watt loss as obtained in experimental track tests made under the same
conditions of ventilation.

337 The following motor losses cause its heating and should be carefully
determined for a given s<r R in the field: 71 R in the armature:
/' R in the brush contacts, core loss and brush fn

338 The loss in the bearings (in the case of geared motors) also adds some-
what to the motor- heating, but owing to the variable nature of such
losses they are generally neglected in making calculations.

339 MOD uv < M VMM OF MOTOR. The essential losses
in the motor, as found in the typical run. are in most cases those in the

STANDARDIZATION RULES OF THE A.I.E.E.

motor windings and in the core. The mean service conditions may be
expressed in terms of the current which would produce the same losses
in the motor windings and the voltage which, with that current, would
produce the same core losses as the average in service. The continuous
capacity of the motor is given in terms of the amperes which it will
when run on a testing stand — with covers on or off, as specified — at dif-
ferent voltages, say, 40, 60, 80 and 100 per cent of the rated voltage—
with a temperature rise not exceeding 90 deg. cent at the commutator and
75deg. cent at any other part, provided the resistance of no electric circuit
in the motor increases more than 40 per cent. A comparison of the equiva-
lent service conditions with the continuous capacity of the motor will de-
termine whether the service requirements are within the safe capacity of
the motor.

340 This method affords a ready means of determining whether a specified
service is within the capacity of a given motor and it is also a convenient
approximate method for comparing the service capacities of different
mot

APPENDIX C. PHOTOMETRY AND LAMPS.

341 CANDLE-POWER. The luminous intensity of sources of light is expressed
in candle-power. The unit of candle-power is the international candle
maintained by the Bureau of Standards at Washington, D. C. The
Hefner unit is 0.90 of the international candle.

342 LUMEN. The total flux of light from a source is equal to its mean spherical
intensity multiplied by 4 7T. The unit of flux is called the lumen. A

lumen is the th part of the total flux of light emitted by a source

having a mean spherical intensity of one candle-power.

344 ILLUMINATION. The fundamental physical unit of illumination is the
centimeter-candle, or lumen per square centimeter of incident surface.
This is a very intense illumination. It is, therefore, convenient to express
illumination practically in thousandths of the fundamental unit; i.r.. in
millilumens per sq. cm. In English-speaking countries, the unit of il-
lumination commonly employed is the foot-candle or lumen per square
foot. A foot-candle is nearly the same illumination as a millilumen per
sq. cm. and is actually the more intense in the ratio 1.0764; so that n foot-
candles =1.0764 Xn millilumens per sq. cm. A meter candle or lumen per
square meter, is called a " lux ". A foot-candle is 10.764 lux, and a milli-
lumen per sq. cm. is exactly 10 lux.

346 The EFFICIENCY OF ELECTRIC LAMPS is properly stated in terms of
lumens per watt at lamp terminals. This use of the term efficiency is to
be considered as special, and not to be confused with the generally ac-
cepted definition of efficiency in Sec. 84.

347 a. EFFICIENCY, AUXILIARY DEVICES. In illuminants requiring auxiliary
power-consuming devices outside of the luminous body, such as steadying
resistances in constant potential arc lamps, a distinction should be made
between the net efficiency and the gross efficiency of the lamp. This
distinction should always be stated. The gross efficiency should include
the power consumed in the auxiliary resistance, etc. The net efficiency
should, however, include the power consumed in the controlling mech-
anism of the lamp itself. Comparison between such sources of light
should be made on the basis of gross efficiency, since the power con-
sumed in the auxiliary device is essential to the operation.

348 A STANDARD CIRCUIT VOLTAGE of 110 volts, or a multiple thereof may
be assumed, except where expressly stated otherwise.

349 WATTS PER CANDLE. The specific consumption of an electric lamp is
its watt consumption per mean spherical candle-power. " Watts per
candle " is the term used commercially in connection with incandescent
lamps, and .lenotes. watts per mean horizontal candle-power.

' S Or THh. .\ I K.R.

360 i HOIOMKIMK TEST* . the results are stated in candle-powtr

should be made at such a distance from the source of light that the latter

may be retarded at practically a point. Where tests art made at shorter

inccs, as for example in the measurement of lamps with reflectors, the

results should always be given as " apparent candle-power " at the distance

should always be specifically staled.

861 HA«IS FOR < a flu* ofhght in lumen*, or the

mean spherical candle-power, should always be used as the basis for com*
paring various luminous sources with each other, unless there it a dear
understanding or itatemen- .try.

362 l.\« AMifcM KM I. AW i customary to rate

]>* on the basis of their mean horizontal can hut tn c

• lamps in which the . lumii

inter, lie comp.i: tie based on • .'. flui

ligl lumens, or on their mean spherical candle-power.

362a LIFE TESTS. Similar filaments may be assumed to operate at the
when their lumens per watt consumed are the i
tests are compar.t similar conditions

as to filam« :.i lures.

363 The SPHERICAL REDLCTION-PACTOR of a lamp

mean spherical candle- pox-
me

364 x of light in lumens < y a lamp • 4 V X mean
M! candle-power X spherical redu

366 The- Si K should only be used when properly

determined : 1 characteristics of cacn lamp.

The spherical reduction-factor permits of substantially accurate com-
parisons being made between the total lumens, or mean spherical candle-
powers of different types of incandescent lamps, and may be used in
the absence of proper facilities for direct measurement of the total lu-
•is, or mean spherical candle-po.

366 " RBAI K." Where standard photometric measurements
are impracticable, approximate measurements of illmmnants such as
street lamps may be made by comparing their " reading distances.

by determining alternately the distances at which an ordinary size of
reading print can just be read, by the same person or persons, when all
other light is screened. The angle below the horizontal at which the meas-
u-nt is made should be specified when it exceeds 15 degrees. Reading-
distance methods usually involve the comparison of very faint illuminations
and hence the results may be seriously affected by th< • effect.

367 In COMPARING DIFFERES SOURCES not only should their
candle-power be compared, but al lalive form, brightness, dis-
tribution of illumination and character of light.

367s The following symbols are recommended in connection with photometry:

Pholonwlnc magnitude Symbol

Intensity of light. / International candle.

Luminous flux. Lumen

Illumina* £ Lumen/cm.1, foot-candle.

/? Foot-candle.

Brightness. * :n.«

Qi: 0 Candle.

Lighting. L Lumen-second, lumen-boor.

AI < 1). SPARKING DISTANCES.

368 Table of Sparking Distances in Air between Opposed Sharp Needle*
Points, for Various Root-Mean-Sauare Sinusoidal Voltages, in indie*
nnd in centimeters. The table applies to the conditions specified in Sees.

STANDARDIZATION RULES OF THE A.I.E.E.

369

UH

I:;, he.

;ance.
Cm.

KilovolU
M.S.

(I •J'J.'i

0.67

1 10

0.47

1.19

150

0.725

1.84

Kill

1.0

•2 54

170

l :<

3.3

180

1.625

4.1

190

2.0

5.1

•joo

2.45

6.2

210.. ..

2.95

7.5

220

3.55

9.0

230

4.65

11.8

240

5.85

14.9

250

7.1

18.0

260

8.35

21.2

270

9.6

24.4

2 so

27.3 '-Mm .

11.85

30.1 300..

12.90

32.8

Distance.

KilovolU

R M S.

5...

10...

20...

25...

30...

35...

40...

45...

50...

60...

70...

80...

90...
100...
110...
120. . .
130.

APPENDIX E. TEMPERATURE COEFFICIENT OF COPPER

360 The fundamental relation between the rise of temperature and the
increase of resistance of copper may be expressed thus:

Inchet

Cm.

.13.95

35.4

.15.0

38.1

.16.05

40.7

.17.10

43.4

.18.15

46.1

.19.20

48.8

51.4

54.1

•2-2 :<:>

56.8

59.4

.24.45

62.1

.25.50

64.7

,26.80

67.3

.27.50

69.8

28.50

72.4

.29.50

74.9

30.50

77 4

where Rt is the resistance at any temperature / deg. cent.; #/, is the re-
sistance at any " initial temperature " (or " temperature of reference ")
ti deg. cent.; and Ott is the temperature coefficient from and at the initial

temperature t\ deg. cent. Obviously the temperature coefficient is dif-
ferent for different initial temperatures, and this variation is shown in
the horizontal rows of the table below. Furthermore, it has b
that the temperature coefficient is different for different conduct!
and that the temperature coefficient is substantially proportional to the
conductivity. The results of this simple law are shown by t:
columns of the table below.

TEMPERATURE COEFFICIENTS OP COPPER FOR DIFFERENT INITIAL
TEMPERATURES AND DIFFERENT CONDUCTIVITIES

Ohms per
meter-
paa

deg. cent

Per
cent
con-
due
tivity

«„

«,.

«JO

- T
" Inferred

/v r* ni ab
#J& <*» zero '

0.16108

M

0.00405

0.00381

0.00374

0.00367 0.00361 0.00336

0.15940

M

0.00409

0 00386

0 00378

0.00371 0.00364 0.00340

0.15776

97

0.00414

0.00390

0.00382

0.00375 0.00368 0.00343

0.15727

•97.3

0.00415

0.00391

0.00383

0.00376 000369 000344 -2409

0.15614

M

0.00418

0.00394

0.00386

0.00379 000372 000346

0.15457

99

0 00423

0.00398

0.00390

0.00383 0 00375 0 00349 -236 4

0.153022

100
101

0.00428
0.00432

0 00402
0.00406

0.00394

0.00386 0.00379 0.00352
000390 0.00383 0.00333 -fl

0.15151

0.00398

STANDARDIZATION RULES OF TV/A .4 / R.E. 35

.uuntuy - y >:•-..-:. :n the last column of the above table
calt .iture on the centigrade scale at which copper of the par-

concerned would have aero electrical resist a nr«
-tweenOdeg. cent and 100 deg. cent,
applied .-.ly down to the absolute sero. The usefulneas c:

erred absolut- :»peruture of resistance" in calculating tem-

perature rise is evident from the following formula:

*/-*/

- ., ' <T

presentation of the above table is intended to emphasise the de-
sirability of determining the temperature coefficient rather than assuming

Actual experimental determination i* facilitated by the proportional
relation between the t- nt and the condu mea-

sun r quantity gives both. if a temperature coeffi -

• must be assumed, the best value to take for average commercial
annexed copper wire is that given in the table for 100 per cent cor.

a. -0.00428, a,, -0.00394, a,, -0.00386

This is the value recommended for wire wound on instruments and ma-
they are generally wound with annealed wire and ex peri -

•its have show: ns due to the winding of the wire do

not appreciably affect the temperature coefficient.

If a value must be assumed for kard-drawn copper wire, the value
commended is that given in the table for 97.3 per cent conduct:

a. -0.00415. Of,, -0.00383. a,, -0.00370

The temperature coefficients in fahrenheit degrees are given by dividing
any a above by 1.8. Thus, the 20 deg. cent, or 68 deg. fahr. temperature
coefficient for copper of 100 per cent condu 0.00394 per deg.

cent., or 0.00219 per deg. fahr.

API P. HORSEPOWKK.

361 v of the fact that a horsepower defined as 550 foot-pounds per

second represents a power which varies slightly with the latitude
altitude (from 743.3 to 747.6 watts) and also in view of the fact that dif-
:it authorities differ as to the precise value of the horsepower in watts.
Ikt Standards Commtllee kas adopted 746 raits ax tkt ra/«* of Ikt korsttmctr.
The number of foot-pounds per second to be taken as one horsepo*
therefore such a value at at lace as is equivalent to 746 watts; the

number varies from 552 to 549 foot-pounds per second, being 550 at 5<>
latitude (London), and 550.5 at Washington. The Standards Comm
however, recommends that the kilowatt instead of the horsepower be used
generally as the unit of power.

ADDENDA

TO THE

A. I. E. E. STANDARDIZATION RULES

G. Official Actions of the Turin Congress

AND

H. Rating of Electrical Machinery in
Different Countries

Printed by order of the Board ol Director* in Accordance with the
Following Resolution Adopted October I 3. 19 1 I .

Resolved, that the Secretary be authorized to publnh with the Standard-
ization Rules ol the Institute the decisions ol the International EJectrotednical
Commission at Turin in regard to standard symbology and the direction for
indicating advancement of phase in graphic diagrams of alternating current
quantities, and a resume of the principal features of the rating ol electrical
machinery of the leading foreign

'///(/.!

The following appendix, G, coven Che principal official actions of the
Turin Congress in 1911

APPi:

folio win,- he official action* of the Intern*-

'mission at Tunn in Ittll

<«) / '.

1 I nsUntaneous values of : quantum* which vary with the

time art* to be represented by small If

conitant values <»! « to be represented

quantities to be represented
by » he subscript " m "

be represented
• T* of cither . -faced, or of any

.HIM values of magn< • be repr*

letters of cither svmit. gothic, heavy-faced, or of any special type,
followed by the subschi

6. The following quantities to be repress he following I«

rce

Magnetic force
Magnetic flu

s'th
Mass

: K ««•:•-• to represent, respec-

force, and the resistance, in the
: Ohm's law.

8. I; .ts. the expression

" Rca . ; adopted to designate VI sin f .

(6) IU.\(,R.\MS H)R A

he graphical representation of alternating electric and ma.
n phase shall be represented in the counter >cl<

E. The impedance of a reactive coil, of resistance R. and induct
* /? + \/ ; :-.J that of a condenser of cap;.

1 *

/- qual to 2 JT X frequen

phase tnple alt-

containing an improsse<! •• force O E and a

01 (

UACIUM KY .I.V/J At';
vissels con* n regard to rating were

adopted without :-. n as follows:

itors is defined as thr i>ower

available at the terminals.

he output of electnc motors is defined as the mechanical power
tble at the si

nc and mechanical powers to be expressed in inter

— __-

<• --induct;
tA» exampW* o-

40 RATING OF ELECTRICAL MACHINERY

Appendices H and I give compaiisons of methods of rating electrical
machinery, and particularly of D-C. machinery, in different countries,
as compiled by the Secretary of the International Electrotechnical Com-
mission. See Publication No. 9, " Rating of Electrical Machinery," of
the I. E. C. August, 1911.

APPENDIX H.— RATING OF ELECTRICAL MACHIM-KY
The following are the comparative rules on the rating 01 irrcnt

generators and motors as compiled by the General Secretary of the
International Electrotechnical Commission from the National Rules of
six countries as in force in 1911. These comparative rules have been
appended to the Standardization Rules by order of the Board of Directors
ol the American Institute of Electrical Engineers, in order to present the
extent of agreement or diversity existing on these nil- l''ll, among

the leading electrical engineering societies of the world.

List of documents from which extracts have been made:

BELGIUM. " Prescriptions normales " for the reception of electrical
machines and transformers issued by the " Chambre syndicate des
Electriciens Beiges " in 1908.

FRANCE. General instructions for the delivery and reception of elec-
trical machines and transforrm : by the " Union des Syndicats
de I'Electricite* " in 1910.

Regulations for tenders, supply and testing of electrical machines and
transformers issued by the " Association Alsacicnne des Proprie*taires
d'Appareils * Vapeur," 1906.

GERMANY. Standard rules for the utilization and testing of electrical
machines and transformers issued by the " Verband Deutscher Elektro-
techniker " in 1910.

GREAT BRITAIN. Report of the British Engineering Standards
Committee on " Electrical Machinery " issued in 1907.

SWEDEN. Rules for the testing and reception of electrical machines
and transformers issued by the " Association of Swedish Engineers "
in 1909.

UNITED STATES. Standardization Rules of the American Institute
of Electrical Engineers as contained in its PROCEEDINGS, August, 1911.

ANALYSIS OF THE RULES

POWER

Method of Expressing the Power of Electrical Machines
BELGIUM.

Generators. Kw. at the machine terminals.

Motors. ;anical horse power at the shaft (75 kg-m. per sec.)

FRANCE.

Generators. Kw. at the machine terminals.

Motors. Kw. or horse power at the shaft (75 kg-m. per sec.).

GERMANY.

Generators. Kw.

Motors. Horse power (75 kg-m. per sec. —736 \Y

GREAT BRITAIN.

Generators. Kw.

Motors. B.h.p. (1 Brake horse power -746 W.).

SWEDEN.

Generators. Kw.

Motors. Horse power (75 kg-m. per sec.).

TED STATES.

Generators. Kw. at the machine terminals.

Motors. B.h.p. (746 W.) Preferably in kilowatts.

NOTES. — BELGIUM. Motor* usually have their power indicated as " H.P.." with
consequent confusion as to which is intended; the English b.h.p. being 746 watts, the
" cheval-vapeur " being equivalent to 736 watts.

PRANCE. Toe Association Alsacienne still allow* the Poncelet of 100 kg-m. per sec.

RATING Of ELECTRICAL MACHINERY 41

RA TING

BBLC.I

i /niermiitr- In which the periods of work and re«t alter-

nale in minutes.

In *hi Aork of sufidently short

nary trm|x-r.r reached are folio*

periods of rest long enough f- ill to »pj

h i he prno*U of work are roffi.
id to the esu
perat

FIANCE.

: tuoMJ temte.

1 nlfr mtl'.rn! jfrvii >•

(1) • 'life. In which the periods of work and rest altet-

. tramways, and similar ap-
paratus.)

VAor/ period service. In which the periods of work are not sunV

.: for the final (rated) temperature to be reached, whi
- of rest are long enough for the temperature to fall to approxt-
mat« f the surrounding air.

In which the periods of work are suffi<
r the final temperature (rated) to DC attained.

GBEAT B*n MS

nttous working. The -rs and motors for

king shall be the output at wi. can work con-

tinuously for six hours and conform to the prescribed tests, and th-

1 as the Rated Load.

Iniermtitent working. The output of motors for intermittent
output at which they can work for one hour and
prescribed tests, and this output shall be defined as the
Rated Intern; id.

SWEDEN.

In which ti. iture reaches stationary

In which the working periods do not exceed
one hour or alternate with intervals of rest of a similar length.

KS.

1 < > ttnuous ru/iMf. In wrmh. under load, there is the attainment

nary tern per at

Intermittent rating. In which one minute periods of load and rest
ite until the attainment of approximately stationary conditions

(3) Minute rating. In which, under load for one minute, no limit of
capacity is exceeded, and no permanent change is wrought in the apparatus
Variable service, rating. Not yet defined.

Noras.— PBAMCB. The A*

BRITAIN. The reajon for thr " vi hour* " in the

workmt " i« due to the fact that the CoJnmtttec
>cv, 2 i •«•' •** il a»tbai ipactei

ftandardiutton b*inf to aaaUt the manularturr'

d >r* pot include nMrhiaa* ninmnc from •Mfc.ead u

H M mf : • - -

itpot radar cxmtia^oaa atrrice is deftaed aa that o«t

do *o abor*» I

on brim to MriM the maoof* • voold •rartetr par to

.000 kw.

SAT1

rated ovtpat

ined continoootlr for aa hour without the tavavmttnv

u RATING OF ELECTRICAL MACHINERY

NA ME-PLA TES
Information to be Stated on the Name-plates

BELGIUM. Service recognized (intermittent, momentary, for
hours, or continuous). The rated values of the power, the pressure, the
current and the angular speed.

FRANCE. The power for which the machine has been sold.

It is expressed thus: For generators, in kilowatts at the
for motors, in kilowatts, or horse power of 75 kg-m. per second, available
at the shaft.

Additional information to be stated: For continuous working, the
rated values of the speed in revolutions per minute, the pressure, and
the current; for variable working, the limits of pressure and current;
for intermittent working (traveller, crane, lift, etc.) the power for a period
of one hour, mentioning " intermittent working."

GERMANY. The power for generators to be stated in kilo\\.
Mechanical power to be stated in kilowatts or in horse power

In addition, the name-plate on which the power is stamped, or a special
name-plate, must indicate the rated value of the number of revolutions,
the pressure and the current.

The name-plate must also indicate the rating: " Intermittent," or
" For hours," or " Continuous."

GREAT BRITAIN. Unless otherwise stated, the output is to 1>-
sidered to apply to continuous working. In the case of intermit tint
rating the word " Intermittent " is to be added.

The name-plate shall also indicate: For generators: K\v.,
amperes, rev. per min. For motors: B.h.p., volts, amperes, rev. per
min.; B.h.p (Intermittent), volts, amperes, rev. per min.

SWEDEN. Unless otherwise stated, the output shall be considered as
applying to continuous working.

The values stated on the name-plate shall be in conformity with the
rules, except it bear the indication " For special purposes."

The following information to be stated: For generators: the kilowatts,
volts, amperes, and revs. per minute. For motors: the mechanical power,
the volts, amperes, and revs, per minute.

N. B. — The speed shall be the speed with the machine hot. and a tolerance of ± 7% shall
be allowed.

The service, adding the words: " For continuous service." " For
Intermittent service."

For variable service, the respective limits shall be given.

UNITED STATES. Name of the maker, volts, amperes.

When practicable, the kilowatts, the revs, per minute, the type, the
character of current, designation and serial number.

COMMUTATION

BELGIUM. Under all conditions not exceeding the rated load, the
commutator of a machine shall not require to be cleaned or given other
attention more than once a day, with the brushes remaining in the most
favorable position.

FRANCE.

Union dfs Syndicate de L'ElectriciU. Under all loads included in
running free up to the rated load, the brushes being ground and fixed
in the most favorable position by means £>f a previous run, machines with
a commutator must be capable of working for the period of the test
(specified under Heating: Duration of Test,) without it being necessary
to glass-paper the commutator or resort to any other method of cleaning.
Association Alsacienne. Unless otherwise specified, when once the
brushes have been adjusted in the most favorable position, machines
with commutators shall be capable of working, without appreciable
sparking or adjustment of brushes, at all loads from no load to rated
load, even with sudden changes of current.

RATING OF ELECTRICAL A/.U 7//.\ h.RY

Und« lous workinf. »nJ at any load within the prescribed

hail be such as to require at ten*

r lubric.r r vaU of twelve hour*. Thit

cleaning 'y at i

•» also applies to collector rings.

Oik "nder all conditions of load from one quarter up to the

load, and wit
ng produced must be so negl

-ing attention. The
brushes to be gr»un<l m in the most favorable position.

VI lUlI MS

Swi : rwise specified, the commutation is to U

out appreciable «p»r • overload, and with*

brushes bring alt- •

In the case of ma. 1 :>g. the position of the brashes

may be altered. The working j>« rushes is to be indicated.

ist carry the specified overload
us sparking or mechanical weakness.

OVERLOAD

percentages given below imply an overload in excess of the rated
load marked on the name-plate.

BEL- -r continuous service. 20 per cent of the rated load for

<>d equal to one-fifth of the duration of the heating test, with a
max i nun: .ur.

unttent service. 20 per cent of the rated load for one-fifth
of an hour.

For momentary service. 20 per cent of the rated load for a period
equal to or marked on the name-plate. 40 per cent of

ted load for 3 inn.

• t to be applied at the close of the rated load test.

All mat '• • be capable of withstanding, without deterioration

or au{ .f the rated load for one-tenth of

M of the test for continuous working; 30 per cent of the rated

load for 5 minutes.

•tent service: 25 per cent of the rated load :
minutes; 30 per cent of the rated load for 5 minutes.

GERMANY. For generators and motors: 25 per cent of the rated
load for half an hour.

>n (constant potential) : 40 per cent of the rated loa :
minutes.

M HKI i MS , , 11 f Mint <^ Conclusion of OttrtoaJ 1
SWEDEN. 25 per cent in excess of the rated current without injurious
sparking. Adjustment of brushes permitted.

i ED STATES. For generators: 25 per cent of the rated load
'. u

motors (continuous working): 25 per cent of the rated load for
2 hours; 50 per cent of the rated Toad for 1 minute.

Norss.— Bsumrn. Tbt machine matt b* capable of •MUbrintf tk una«

UN MtiUd pori I --.•..,-, • • • . --.,••. • . .

•-.• cloM of UM rmted load te.t . In which c**» UM rtor te temperature mat act eareed
the limits pmcnbed for UM rated IOM! by nor* than 10 d««. e««U

For motors intended to work for prolonged period*. M owrload ir»t of 40 pv <«rt for
three mtouu».

All motor* mart be ctptbte of withMaMJat M iocrr**. of 90 ptr
for .period of fiv» mioatM.

The owrkMd twt b to be •pplted without rvferm
n*e. And it r^iifl be commenced with ttM nit^fne At toch a tejnponk

" — mil ••Trill innil. gwamln mi In niiiMi uf •

with an overlo»d oTlS percent

n RATING OF ELECTRICAL MACHINERY

VARIATION OF PRESSURE AND SPEED

BELGIUM.

Generators. The pressure variation of a generator is 1 by

the greatest difference observed, at constant speed, between any two
values of the pressure corresponding with loads, the current of which
does not exceed that defined by the rated load, the ; la-ing regu-

at this current, to the rated load value. The brushes to remain
adjusted in the working position.

i . — The excitation of a generator, intended to work at constant pr«
mu*t be capable of maintaining the rated value of the pressure under normal en:
of angular speed, at all loads from no load up to and including l.l.'i times the rated load

Motors. The speed variation is defined as the difference in angular
speed at rated load and at no load at normal working pressure, and with-
out a "f field rheostats adjusted for the rated load.

FK\XCE.

ne rotors. The pressure variation shall be measured in passing
from the rated load to no 1« nt speed, in the case of self-

S machines, whilst maintaining constant the resistance in the field
circuit; in the case of separately excited machines, whilst maintaining
constant the exciting current. During this test, and unless oil.
specified, the brushes shall remain fixed in the rated load sparkless position.
Motors. The speed variation shall be measured in passing trom the
rated load to no load, with constant pressure at the terminals.

GERMANY. At constant rated load speed and excitation, the pressure
to be observed at, at least, four points practically equidistant on the
load curve. The greatest difference between the observed press^:
a measure of the variation. In regard to the adjustment of brushes, the
conditions are to be governed acco-ding to the rating.
GREAT BRITAIN.

DEN. At constant rated load speed an<! itio of

the increase in pressure at raUd load and the pressure at no load, shall
be taken:

(1) By observing the values of the pressure at no load and at rated load:

(2) By observing the values of the pressure with increasing val
the field current, both with no load on the armature and with tht
load current in the ermature. Tolerance allowed ±2 per cent.

I" MI i I. STATES.

Generators. Ratio of maximum variation of terminal pressure from
the normal (occurring between rated load and no load) to the rated
load pressure.

Motors. Ratio of maximum variations in speed from the normal
(occurring between rated load and no load) to the rated load spe<

HEA TING
General Notes

BELGIUM. The test is to be carried out as nearly as possible under
ordinary working conditions. An overload may be applied at th<
mencement of the test in order to attain more rapidly the final conditions
of temperature.

The maximum temperature is to be compatible with the
employed. Special precautions are to be taken when employing ther-
mometers. Unless otherwise specified, apparatus for variable speed and
pressure shall be tested under the most severe conditions.

FRANCE. The maximum temperature is to be compatible with the
insulation employed.

GERMANY. The tests are to be carried out under the conditions of
service specified. Any ventilation which would naturally be produced
under ordinary working conditions and which was provided for in the
design may be imitated during the test. If a thermometer is employed,

RATING OP ELECTRICAL M U HISERY 45

it is recommended that the bulb be covered with tinfoil and every pre-
caution taken to prevent loss of beat.

The temperature allowed depends on the character
of the in

The temperature !

paper, and itt preparations, linen, or similar materials are used solely
as vehicles for insulation varnishes, or enamels, capable of continuously
•>g temperatures above 125 def . cent. Machines in which such
materials are employed are dealt with separate

A much higher tcmjx-ruiure rise than that specified on PA,
may be permitted in machines in w is secured by meant

of special materials designed to resist high temperatures, but the amount
of permit Must depend on the properties of the

insulating materials and the method of construction and most be settled
specially for each clas*

SWEDEN : out as nearly as possible under

ordinary working conditions.

•.<•rnp.-r.i-ur. allowed must not be such as to
be detrimental to the insulation under ordinary working conditions.

An overload may be a; horten the duration of the test.

BELGIUM. By increase in resistance, if this method is practicable.
Otherwise by means of thermometers.

PRANCE. Temperatures ascertained by means of thermometers,
placed in the hottest pan accessible; nevertheless, in the case of

• •» and all stationary windings, the temperature may be
by increase in resistance.

GBK ng coils and stationary windings by increase in

resistance, other parts by thermomf

GREAT BRITAIN. Stationary windings by increase in resistance.
Moving coils by increase in resistance, if possible, otherwise by ther-
mometer or thermo-couple. Commutators, brushes, bearings by ther-
mometer.

SWEDEN. Windings by increase in resistance, if possible, otherwise
by thermometer. Other parts by thermometer.

i ED STATES. By thermometer. Conductors by rise in resistance,
when possible.

Duration of Test

Continuous service. A period of sufficient duration to attain a prac-
tically constant temperature: ordinarily 5 hours up to 20 kilowatts. 8
hours above 20 kilowatts.

Intermittent servic*. One hour.

Momentary tervice. The number of hours indicated on the name-plate.

PRANCE.

Continuous working. \ period sufficiently long to attain a prac1
constant temperature. ',S«

Intermittent servtte. One !

Tb* periods art tivm. to * t*ocr*l m*ao«r. by Uw foOowtaf labto:

K m Volti X Ampcr*.

K ' Rrr.prr :

10... 2 hour.

10-30.. • m

TUO-l.OOO .

100-200.. i.ooo-i.aoo . 10

Abor. l.io <tettte*tk» <rf UM

RATING OF ELECTRICAL M .1(7/7 \KRY

GERM

Intfrmitltnt service. One hour.

Momentary service. The number of hours indicated on the name-plate.

Continuous service. Ten h<

In the case of small m • he duration of test may be reduced.

GREAT BRITAIN

Continuous working. Six hours (up to 1,000 kw.).

Intermittent working. One hour (under revision).

Continuous service. A period sufficiently long to attain a pract
constant temperat

KS.

•inuous sfn-itc. .\ period suftuimtly long to attain a practically
constant temperat r

Intermittent srrrnr. Affording to the conditions <•:' -pecified.

Limtts of Temperature Kt.^c in Deg. Cent.

BELGIUM.

(i) Permissible limits. (11) Recommended limits. (i)

ulated with cotton 50 45

paper 60 i:.

* mica, asbestos or similar preparations. . . 80

Commutators, brushes . 60 50

Bearings, terminals and connections 35 30

For permanently short-circuited windings, 5 degrees rise in excess
of the above limits is permi*
FRANCE.

Continuous service. For stationary windings, 10 deg. cent, in excess
of the limits for moving coils,
ng coils:

Insulated with cotton ."•()

paper

a mica, asbestos or equivalent preparations 80

Iron and ^are conductors 90

Commutators • ' '

Bearings

Intermittent service. In conformity with the regulations of tin- Milan
Congress (see Appendix /).

Uninterrupted service. For commutating machines destined for an
uninterrupted day and night service, the permissible temperature
shall be in accordance with those for continuous service, reduced by 5 deg.
cent.

Association Alsacienne.

(a) For field windings traversed by a continuous current:

By resistance

By thermometer ! '

(6) For all other windings and the iron in which the windings are

embedded. . -l "•

For permanently short-circuited windings 55

(d) For comrruitators, brushes 50

(e) For bearings, terminals and connections

N. B. — For enclosed machines, an extra rise of 5 degrees may be permitted.
For commutating machines destined to work day and night continuously the above
limits of temperature shall be reduced by 5 degrees.

GERMANY. For stationary windings 10 deg. cent, above the limits for
moving coils is permitted.

moving coils as well as the iron in which the windings are embedded:

Insulated with cotton 50

" under oil and paper ... .60

• enamel, mica, asbestos or equivalent prepara-
tions 80

RATING OP ELECTRICAL MACHINERY

Commutators . . 60

Bearings

ton. paper and its preparation*. Uoeo.
'.c or similar material*:

stance). 60

Moving coiU no-couple) . . .

SWEDEN. For stationary windings. 10 per cent above the limit* (or

.

In^ i ton BO

• paper '*>

• mica, asbestos .

O rtpUtt • •

mmtator* . . . '•"

Bearing •

I KH.

•nature windings.

Commutators an«l brushes .'»."•

Bearings and other parts . 40

~Porlar*«maohhM».a Umpwatar* limit of 404*. cart, wrtw rated Ioa4
condition* and 55 d»«. «*m. muter ovwtoad u (r*qo»ntly K~ct<U.1.

5* rro* «</!«{ dir Ttmptrature

(At th« oooMMMMMnt of «*ch p»ra<r«ph th« ft«ur« in d«. c«tt. tedfealM tW
•tandard adopted a* the room tempcrmturc.)

35 deg. cent. Thr temperature to be adopted is the mean of the thcr-

momo • at regular intervals during the last quarter of the

n the currents of air passing to the apparatus, or. in default, at the

.;ht round the apparatus; in any case, as near as possible at

a minimum distance to ensure safety from the effects of direct radiation.

FIANCE.

35 deg. cent. The thermometer indicating the surrounding air shall be
placed in the line of -;ts at about one metre from the machine and

red from all external influence. The mean value of the figures
during the last quarter of the test shall be adopted.

35 deg. cent. The temperature of the surrounding air shall be ta/
: rents of air arriving, or, if there is no well-defined current of a
value shall be taken of the air surrounding the machine at the
middle height and at about one metre distant from the machine. The
mean value of the figures during the last quarter of the test shall be
.1 top* 1
GREAT BEIT A:

25 deg. c
SWEDEN.
35 deg. cent.

i ED STATES.

25 deg. cent. The surrounding air of the test room is to be ascer-
tained by means of several thermometers protected from direct radiation
and air currents.

'if at Cornel ustom of Overload Ttst

BELGIUM. After the application of an overload of 20 per cent for one-
fifth of the specified test period and of 40 per cent for three minutes, the
prescribed limits of temperature must not be exceeded by more than
10 deg. cent.

FRANCE. No conditions as to heating.

48 RATING OF ELECTRICAL MACHINERY

GERMANY. The temperature limits specified for the rated load must
not be exceeded, therefore the overload must be applied for a sufficiently
short period and at a time when the temperature of the machine is
sufficiently low in order to insure that the permissible limits of temperature
cannot be exceeded.

GREAT BRITAIN. Under no conditions must the temperature exceed
85 deg. cent.

» DBN.

UNITED STATES. When the overload test is applied directly after the
rated load test under continuous service conditions, an allowance is per-
mitted of 15 deg. cent, above the limits specified for the rated loa<l.

Surrounding Air Temperature Corrections

BELGIUM. If the surrounding air is likely to exceed 35 deg. cent., the
temperature limits must be reduced by an amount equivalent to the excess.
FRANCE. If the test is carried out with a surrounding temperature
below 35 deg. cent., the temperature limits shall be reduced in the fol-
lowing ratio:

1

1 + 0.005 (35-0) .

0 being the temperature of the surrounding air during the t<

If the machine is intended for a locality in which the surrounding' air
exceeds 35 deg. cent., the temperature limits shall be reduced in the
following ratio:

1

1 +0.005 (0'-35)

f)' being the presumed temperature of the surrounding

Association Alsacienne. If the temperature of the surrounding air
ordinarily exceeds 35 deg. cent., the temperature limits must be reduced
by an equivalent amount.

GERMANY.

GREAT BRITAIN. If the surrounding air in actual service is likely to
exceed 25 deg. cent., the observed temperature rise shall be reduced
by one degree for each degree of difference between the surrounding air and
25 deg. cent.

Swti

UNITED STATES. The observed temperature shall be reduced or
increased one-half per cent for every degree cent, difference between the
surrounding air and 25 deg. cent.

RESISTIVITY OF COPPER
Variation with Temperature

Unless otherwise specified, the following values have been adopted:

BELGIUM. 0.004 per degree cent.

FRANCE. 0.004 per degree cent.

GERMANY. 0.0040 per degree cent.

(IREAT BRITAIN. 0.42 per cent per degree cent, from and at 0 deg. cent.
•\ EDEN. 0.004 per degree cent.

UNITED STATES. 0.428 per cent per degree cent, from and at 0 deg.
cent, for annealed copper of 100 per cent standard conductivity (see
Appendix E).

ATMOSPHERIC PRESSURE

UNITED STATES. 760 mm. of mercury.

The observed temperature rise shall be reduced by 1 per cent for every
10 mm. deviation below 760. This correction is only to be applied when
the atmospheric pressure differs greatly from the standard pressure of
760 mm. of mercury.

RATING OF ELECTRICAL AM< ///.YA*K

MECHASICAL TESTS

BEI )« capable of withstanding for five minutes,

at no load with and •••

•he maximum speed specif><
nature or method of using the ma.

ceeding this figure, in which case the excess must be 100 per •
PRANCE. Generators must be capable of withstanding a morm
••a«e in speed to | ase. according

not or* n.

standing, during five minutes, a speed of 20 per cent in excess of the r
.,,-, i

• •tors must be capable of withstanding,
a speed of 3<> in excess of the rated apted.

Gut" .led to work ,. ally con-

must be cap * during five minute*, a Speed <

in excess of the rated speed, first *

. \r Hkii N

SWEDEN. Machines must be capable of withstanding a speed of 20
per cent in excess of • speed. Generators driven by hydraulic

turbines, unless otherwise specified, must be capable of withstanding a
•peed of 00 per \cess of the rated speed.

t MTBD STATES.

El cT

*dtttO*S

BELGIUM. The n determination is to be specified. Unless

« to be ascertained at rated load and under
the corresponding conditions as to temperature.

liower absorbed in the i. • .its of a machine is to be included

as part of the power • the machine. In the case of a

of the machine and that « •
exciter, shall be separately stated.

PRANCE. The eft. us should be made at. or reduced to. the

temperature attu: >se of the working test. The efficiency

shall be state rated load, three-quarters and half load, and is to

include the !•••—• line •• •' :y apparatus such as ex -tla-

tion. :ig pumps, forming an integral portion of the plant.

GBRV ,-tit as to U. y applies to the rated

load and the s of serv rs ts to be mentioned.

The power absorb- a and in ihe rheostats must be consid*

as losses for • •• of the unless otherwise stated the

power absorbed in cooling the machine must also be considered as a loss,

Por which are specially excited, the efficiency of the two

machines must be stated separat.

GREAT BRII ••

SWEDES. The losses in excitation and in the rheostats are to be in*

Friction losses are only to be included in the case of machines with
automatic lul

Losses due to an el are to be excluded.

The cfliv ts are to be made <* mperaturv

attained by the machine at the close of the rated load test and referred
to a surrounding air temperature of 20 deg. cent.

t'siuj) Si MRS. The test is to be carried out under ordinary work-
ing conditions and with the surrounding air at standard temperati:

In the case of belt-driven machines, the loss of power in belts and the
increase of bearing friction, due to the increase of belt tension, is to be
excluded.

RATING OF ELECTRICAL MACHINERY

In the case of a generator inseparable from its prime mover, bearing
friction is to be excluded.

The losses in exciters or in auxiliary apparatus are to be considered
separately, and charged t<> the plant consisting of the machine toge'
;>pnratus.

The plant efficiency is to be distinguished from the efficiency of the
machine alone. The of a machine is to be me >

reduced to, the temperature which the machine assumes under i
load conditions, referred to a surrounding air temperature of 25 deg. cent.

Method

ALL Cot SIKH.-. D i< tly by input output, where possible.
Indirectly by losses, if the direct method is not possil

Enumeration of Losses
BELGIUM.

FRANCE.

^inical. (a) Bearing friction and ventilation.

(6) Friction of brushes on commutators and collecting

rings.
Electrical. (c) Hysteresis and Foucault currer

(d) Joule effects in the circuits.
GERMANY. The losses are not enumerated in tabular form.

GREAT BRITAIN.

SWEDEN.

(a) Bearing, brush and air friction.
(6) Hysteresis and Foucault currents.

(c) Ohmic losses in armature.

(d) Ohmic losses in brushes.

(e) Ohmic losses in exciting coils.
UNITED STATES.

(a) Bearing friction and windage losses.

(b) Molecular magnetic friction and Foucault current losses.

(c) Armature resistance losses.

(d) Commutator-brush friction loss.

(e) Brush and brush-contact resistance losses.
(/) Field excitation loss.

(g) Load losses.

NOTES. — FRANCE. Association Alsatienne includes under electrical losses brush con-
tact resistance.

UNITED STATES. (/) Losses may be considerable with carbon brushes in low voltage
machine*. <<> Difference between total lostes under load and sum of losses as here
specified.

DIELECTRIC TESTS
General Conditions of Test

• iiUM. Dielectric tests take the place of insulation tests unless the
machine is intended for localities in which special conditions are imposed.

The test is to be carried out before the machine is put into actual
service. The repetition of the test is to be avoided.

The test is to be carried out hot.

The windings of machines and transformers must be capable of with-
standing, for a period of half an hour, a working pressure of 30 per cent
in excess of the highest pressure of the service.

FRANCE. The test of the insulation is to be carried out hot, when
possible, and shall only be made in the works of the manufacturer.

The test pressure is to be applied gradually. The circuits of ma-
chines and transformers shall be capable of withstanding, without undue
strain, for a period of three minutes, a pressure 30 per cent in excess of
the ordinary working pressure, provided no mechanical or electrical
considerations are against it.

RM1XG OF ELECTRICAL MACHINERY 51

GERMANY. The tests, when possible, are to be carried out at the works
of the manufacturer. They are not to tw repeated e*cept in very e».
nal cases. For large machine* the test is to be repeated, tm >i/».
•h. ma. ; actual servtce.

tie carried out h«.r M

capable of withstanding, dunng fivr minutes, a pressure JO per c
excess of the rated pre»

M llMIMIN. — —

SWRI>RK. The test to be earn. •! ..tii

IN In gnu : • Ihr

.ul ami »
Msembl<

!ry and free from «!

/j of Application of Iht Vrt>\*rt

N IKIES. The various rules spc teat pro*

cd between windings and the frame and between all electric

•,r» of tkf 1

But VMCB. (U •• WKIIKS. The values of the tact pres-

m«ltcated are appl cases in •••

is sin

t* mtrn.i :>t work !

;>rc*sure shall be u specified.

riding* it .nng current work »*e

itinuous current, the test pressure shall be 1.4 times that
spa Uk •'.

.tor employed for the test shall be as
m-.irlv .is pCM toll I lM 99199

GREAT BRITAIN.

is. The test is to be carried out with alternating t *
at the normal frrqm-ncy «-f the aupar.i

The values herein given are the root mean square values of the test
pressure r< a sine wave form.

The wave shape of the test pressure should be as nearly as possible
sinusoidal, and should not be materially distorted by the testing .

BELGIUM.

king Pressure. Test Pressure.

I..- th.i:. 300 v. 4 times the working pressure + 300

300- 600 v. - + GOO v.

600- 1.200v. 2,400 v.

<K>- 5,000 Twice the working pressure.

5,000-10,00" The working pressure + 6.000

At 10.000 v. l.A times the working pressure.

FRANCE.

Rated Pressu Tot

Up to 5,000 v.

Prom 5,000-10.000 v.
Aln KK)v.

Up to 5.000 v.

From 5.000-10.000 v.
Above 10,000 v.

(Twice the rated pressure
minimum of IK'
«ure + 5.000

1.5 times rated presst:

(Three times the rated pressure with
minimum of 500
Rated pressure + 10.000 v.
Twice the rated

52 RATING OF ELECTRICAL MACHINERY

GERMANY.

Rated Pressure. Pressure.

Above 10 \. At least 110 v.

Prom 5,000- 7,500 v. The workim: DO T,

Above 7,500 v. Twice the working

GREAT BRITAIN.

SWEDEN.

Working Pressure

Up to 3,300 v. .'t times tin- working with a mini-

mum nf 7<M) v.

•vc 3,300 v. tin irorli

UNITED STATES OF AMERICA.

^ure.
Not exceeding 400 v. Hel..w 10 kw. 1,000 v.

kw, and above. 1, :,<><) v.

400 v. and above, but less than MM) v. Under 10 kw. 1 :.<)0 v.

10 kw. and over. »0 v.

800 v. and above, but less than I.Jnov Any po ") v.

1,200 v. and above, but less than 2,500 v. 5,000 v.

2,500 v. and over. Double the normal

rated voltage.

Length of Test

BELGIUM. 30 minutes.

FRANCE. 30 minutes (hot) ^ j (Associtllillt, Ahaficttnrt ;, minutes).

GERMANY. 1 minute.

GREAT BRITAIN.

SWEDEN. At least 1 minute.
UNITED STATES. 1 minute.

APPENDIX I.
HE A TING (see p. 43).

STIPULATION OF THE MILAN CONGRESS (September, 190G).
The heating of a motor is to be considered as excessive when, starting
from a surrounding air temperature equivalent to 25 deg. cent., the motor,
after 10 hours' working at its permanent power or after one hour working
at its normal power, attains a final temperature exceeding that of the
surrounding air by the following values:

(a) For windings insulated with cotton 70 deg

For windings insulated with paper 80 "

For windings insulated with mica, asbestos or m
substances presenting the same qualities of in-
sulation and incombustibility H»> "

(6) For commutators . . 80 "

(c) For metallic portions in which the windings are cm-
bedded, the value corresponding to that indicated
for the windings, according to the insulation em-
ployed for the latter.

When the windings are in - ith a combination of insulating

materials, the lower limit will be taken. ... By permai r and

normal power of a motor is to be understood that power which, the current
being furnished at the normal pressure of supply, can be developed by
the said motor during 10 consecutive hours, in the first case, and during
an uninterrupted period of one hour, in the second case, without the
heating being excessive in the sense indicated under the paragraph as
to " Heating."

RATING OF ELECTRICAL MACHINERY

i REGARDS GUARANTEES

Us: it OK !/Ki.Ki me

The following table fixes:

i ' Tolerance allowed for error*
A in, h i he question a* to re<!u

ut I..-N..M! »hi. h thr ,,«.--• . the material not

vmg with the *jx-i ifu ation may arise.

I

KM**.

I tf«f. OMt

"-.-—•.-—

Aulor««uUUo«.

10% of UM «UB of UM toul or
I M UMCM*

m*y b«.

>, -

ASSOCIATION ALSACIBNKI

As acceptance of the various guarantees given, it i» usual to fix *.«•<
limits, the first representing the permissible tolerance to allow for inex-
: ies and errors of measurement, the second giving to the buyer the
right to reject the material. Between these two limits it is usually a
question of penalties in proportion to the deviation from the
The penalties for the different guarantees are cumula

The following values are to be recommended:

M to

:.-,.-.-. ^ .

4 dcf . emu above limit*
nf. ftied (for rMJitinrn 10
only).

' . -

16% of UM

Auto- tuanuiuod by DM

;-w teH

40%ofUM

* rr ; '• ' 4»'

16% of UM MUB of tkt 40% of UM
Bfldncy. IOOM*. total or

»bl«. »i thr CAM m*> b*

PLEASE DO NOT REMOVE
CARDS OR SLIPS FROM THIS POCKET

UNIVERSITY OF TORONTO UBRARY

IM

A

134