206

ELECTRICAL APPARATUS

Fig. 130 during the decrease of magnetism. The current, /,
required to produce the magnetism, <i>, is found from <£ and x in
combination with the cycle of molecular magnetic friction of the
material, and the power, P, is the product, IE. As seen in Fig.

FIG. 131.—Hysteresis loop of reaction machine as generator.

129, the positive part of P is larger than the negative part;
that is, the machine produces electrical energy as generator.
In Fig. 130 the negative part of P is larger than the positive;

FIG. 132.—Hysteresis loop of reaction machine as motor.
that is, the machine consumes electrical energy and produces
mechanical energy as synchronous motor. In Figs. 131 and 132
are given the two hysteretic cycles or looped curves, $, / under
the two conditions. They show that, due to the variation of