(under subclass 494) Subject matter in which means are provided for controlling the frequency, or the rate of pulsations, of the current supplied to the armature or primary circuit of the motor.
(1) Note. Where means are provided for merely repeatedly making and braking the armature or primary circuit, see subclass 519, below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
49, for plural motor systems having cascaded or tandem connected motors in which the frequency of the current supplied to the second motor depends on the slip of the first or preceding motor (i.e., the motor having its primary circuit connected to the AC supply circuit).
129, for oscillating or reciprocating motor systems in which the speed of operation of the motors is controlled by controlling the frequency of the current or current pulses supplied to the motors.
148, for generator-fed motor systems which have an alternating current generator, the speed or frequency output of the generator being controlled. 807, for induction motor systems wherein the frequency of the current to the primary circuit is varied.
SEE OR SEARCH CLASS
290, Prime-Mover Dynamo Plants, appropriate subclasses for means for controlling the speed and frequency of alternators by controlling the speed of a nonelectric prime mover which drives the alternator.
322, Electricity: Single Generator Systems, appropriate subclasses for generating systems in which the frequency of the generated current is controlled.
331, Oscillators,
36, for oscillators for supplying alternating current of variable or fixed frequency to circuits of general application.
363, Electric Power Conversion Systems,
157, for frequency conversion systems for controlling the frequency applied to load circuits in general.
