272

ELECTRICAL APPARATUS

As seen from Fig. 133, the power-factor, p, of such a machine
is very low—does not exceed 40 per cent, in this instance.

Very similar to the reaction machine in principle and character
of operation are the synchronous induction motor, Chapter IX,
and the hysteresis motor, Chapter X, either of which is a gen-
erator above synchronism, and at synchronism can be motor as

133.—Load curves of reaction machine.

well as generator, depending on the relative position between
stator field and rotor.
155. The low power-factor and the low weight efficiency bar
the reaction machine from extended use for large powers. Sf>
also does the severe wave-shape distortion produced by it, and
it thus has found a very limited use only in small sizes.
It has, however, the advantage of a high degree of exactness
in keeping in step, that is, it does not merely keep in synchronism
and drifts more or less over a phase angle with respect to the