SPEED CONTROL

19

for the values of capacity reactance:

k = 0, 0.012, 0.048, 0.096, 0.192, 0.3, 0.6—denoted respectively

by 1, 2, 3, 4, 5, 6, 7.

The impressed voltage of the motor is assumed to be varied
with the change of capacity, so as to give the same maximum
torque for all values of capacity.

The volt-ampere capacity of the condenser is given, at the
frequency of slip, s, by:

«' - **'•

substituting (3) and (6), this gives:

Oi + sr0)2 + sxi + sx0

k\ '
- -j

SPEED CONTROL OF INDUCTION MOTOR BY CONDENSER IN SECONDARY

Y0=.01-.lj ; Z0=.1+.3j; Z,-,l+.3j
CAPACITY REACTANCE 7c : (1): 0; (2) .012; (3) .048;
(4) .096; (5) .192; (6).3; (7) .6

FIG. 8. — Speed control of induction motor by condenser in secondary circuit.

Speed curves.

and, compared with (7), this gives:

At full frequency, with the same voltage impressed upon the
condenser, its volt-ampere capacity, and thus its 60-cycle rating,
would be;
'