(under subclass 767) Subject matter wherein the primary member comprises a plurality of windings or winding portions and the circuit includes means connected to the windings or winding portions to cause the motor to rotate at several nominal discrete speeds.
(1) Note. The speeds here are not limited to the synchronous speeds of the motor.
(2) Note. Speed of the motor can be controlled by change of frequency of the power supply, change in the number of poles, or a change in the slip of the motor. Only the change in the number of poles is included in this group of subclasses.
(3) Note. Generally, the speed selected is determined by changing the connections between the winding portions or the number of the winding turns energized.
SEE OR SEARCH THIS CLASS, SUBCLASS:
773+, for poles changing systems to change the speed of the motor.
807+, for frequency control systems to change the speed of the motor.
821+, for impedance control of the motor secondary to change the speed of the motor.