POL rPH ABM CURRENTS.

49

motor having two independent energizing coils or sets of coils,r r'. One of the circuits from the generator, as s' s', includesone set, r' r', of the energizing coils of the motor, while theother circuit, as s s, includes the primary coils of the regulator.The secondary coil of the regulator includes the other coils, r k,of the motor.

While the secondary coil of the regulator is in its normal posi-tion, it produces its maximum current, and the maximum rotaryeffect is imparted to the motor; but this effect will he diminishedin proportion to the angle at which the coil f of the regulator isturned. The motor will also be reversed by reversing the posi-tion of the coil with reference to the coils c c, and thereby re-versing the phases of the current produced by the generator. Thischanges the direction of the movement of the shifting poles whichthe armature follows.

One of the main advantages of this plan of regulation is itseconomy of power. When the induced coil is generating itsmaximum current, the maximum amount of energy in the prim-ary coils is absorbed; but as the induced coil is turned from itsnormal position the self-induction of the primary-coils reducesthe expenditure of energy and saves power.

It is obvious that in practice either coils o a or coil r may beused as primary or secondary, and it is well understood that theirrelative proportions may be varied to produce any desired differ-ence or similarity in the inducing and induced currents.