202
and:

ELECTRICAL APPARATUS

e = e.m.f. generated in the stator by the mutual inductive
magnetic field, that is, by the magnetic flux corresponding to
the exciting admittance, FI ;
and :

I — total current, or current supplied to the external circuit,
Ji = stator current,
J2 = rotor current.

With series connection of stator and rotor:

I = I, = 72,
with parallel connection of stator and rotor:

Using the equations of the general induction machine, the
slip of the secondary circuit or rotor is :

o = __1 •

A — i ,

the exciting admittance of the rotor is :

^"2 = g - jsb = g + jb,
and the rotor generated e.m.f. :

E'z = se = — e;

that is, the rotor must be connected to the stator in the opposite
direction to that in which it would be connected at standstill,
or in a stationary transformer.

That is, magnetically, the power components of stator and
rotor current neutralize each other. Not so, however, the
reactive components, since the reactive component of the rotor
current :

J2 = ;'2 + ji\

in its reaction on the stator is reversed, by the reversed direction
of relative rotation, or the slip, 5 = — 1, and the effect of the
rotor current, 1%, on the stator circuit accordingly corresponds
to:

J'2 =i'2-#"2;

hence, the total magnetic effect is: