ALTERNATING-CURRENT MOTORS
The power output of the motor is:

317

s0 + ZJ - [Zi (Z + ZO, ZJl

and the torque, in synchronous watts:

D--8-

(62)

(63)

From these equations it follows that at synchronism tor-
que and power of the single-phase induction motor are already
negative.

Torque and power become zero for:

S022 — Zi2 = 0,

hence:

SI i / I \ /' r* A \

= \ ~(z)' ( ^

that is, very slightly below synchronism.

Let z = 10, 21 = 0.316, it is, S = 0.9995.

In the single-phase induction motor, the torque contains the
speed S as factor, and thus becomes zero at standstill.

Neglecting quantities of secondary order, it is, approximately:

Jl =

' Z

/« = + JS$0 •

+ Zi) + 2 Z0£i
______Zi_______

-Zi)+2Z0^

D =

(65)
(66)
(67)
(68)
(69)
(70)
(71)

This theory of the single-phase induction motor differs from
that based on the transformer feature of the motor, in that it
represents more exactly the phenomena taking place at inter-