Variable speed motor control circuit

Abstract

A control system and method for controlling the speed of a PSC motor having an auxiliary winding configured to provide torque for initial motor startup and a run winding configured to provide continuous motor operation. The motor is coupled to a capacitor configured to direct a portion of a current through the run winding when the PSC motor reaches its intended speed. The control system includes a speed control unit coupled between a voltage line and the PSC motor and a bypass circuit coupled between the voltage line and the capacitor via a first path. The speed control unit is configured to variably control the speed of the PSC motor. The bypass circuit is configured to receive a control signal from the speed control unit via a second path and to regulate a chopped voltage wave form generated by the speed control unit such that at least a portion of the chopped voltage wave form is not applied to the capacitor.

Dependencies are inferred from the claim text.