Patent ID: 9518570
Filing Date: 2016-12-13
CPC Classification: F04B,H02K,H02P

Claim Text:
1. A motor winding heater comprising: a motor controller configured to receive an alternating current (AC) power and transmit at least a portion of the AC power during a conduction interval of a cycle of the AC power to a motor, the motor including at least two motor windings; the motor controller including a processor configured to control operation of the motor controller in a first operation mode and a second operation mode; the motor controller further including a heating level input to the second operation mode, the heating level input to set at least one of a heating level and a heating period to control heating of the at least two motor windings, the heating level to control a level of heating current to the at least two motor windings; wherein in the first operation mode, the motor controller operates to transmit a first AC power derived from the AC power to all of the at least two motor windings to cause the motor to rotate; and wherein in the second operation mode, the motor controller operates to transmit a second AC power derived from the AC power to all of the motor windings, the second AC power transmitted at a lower frequency than the first AC power to heat the motor windings without causing the motor to rotate.