318

ELECTRICAL APPARATUS

mediate speeds, which are only approximated by the transformer
theory of the single-phase induction motor.

For studying the action of the motor at intermediate and at
low speed, as for instance, when investigating the performance
of a starting device, in bringing the motor up to speed, that is,
during acceleration, this method so is more suited. An applica-
tion to the "condenser motor/' that is, a single-phase induction
motor using a condenser in a stationary tertiary circuit (under
an angle, usually 60°, with the primary circuit) is given in the
paper on "Alternating-Current Motors," A. I. E. E. Transac-
tions, 1904.

P&D 120 110 100 90 80 70 60 50 40 30 20 10

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-650

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-600

SINGLE PHASE INDUCTION MOTOR 400 VOLTS

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—550

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—500

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I .2 .3 .4 .5 .6 .7 .8 .9

100

so

70
60
50
40
30
20
10

TIG. 151.

180. As example are shown, in Fig. 151, with the speed as
abscissae, the curves of a single-phase induction motor, having
the constants:

e0 = 400 volts,

1 = 1 + 10 j ohms,

and:

hence:

ZQ = Zi = 0.1 + 0.3 j ohms;

N
lo = 400 ••:=: amp. ;

N = (s0 + 0.2) + j(10so + 0.6 - 0.6S)-, '
K = (0.1 + 0.3 j) N+ (1 + 10 j)(0.1 + j) (0.3-0.

JD

synchronous kw.