HARLAND DRIVE

221

gears is driven by means of a belt and cone pulleys from the motor to be
controlled, while the third member of the differential actuates the special shunt
regulator in the motor field.

The speed of the master alternator determines the speed of the paper machine.
It is direct coupled to a small master motor.

As is well known, the speed of the third member of any differential gear
is the resultant of the speeds of the other two shafts. When the first and second

>. Ltd.

FIG. 9a-HAMLAWD DMTTNG UHTT

shafts are running at tibe same speed in opposite rotation, the thkd member,
which is connected to the regulator, will remain stationary. Immediately
there is any difference in the speeds of die first and second shafts, the regulator
will move in die required direction to correct die motor speed. If the load
s—say, increases— the motor wifl tend to run slower, and as soon as this
dbe first and second shafts wiB not be in equilibrium, and the thkd

member will move dhe regulator and weaken the field until the two shafts are
running at d*e same speed again. If load is thrown off, the reverse action
takes place.
The system is absolutely positive, the three members of the differential
gear being iwyJuniraBy kicked together, and the smallest change in speed