CONTROL CIRCUIT FOR TWO-SPEED SINGLE PHASE MOTOR

摘要

A control circuit for a two-speed single-phase motor as used in a hermetic refrigerant compressor which includes a control for preventing welding of the start relay contacts of the start relay means by electrical discharge from the run capacitor. In one aspect of the invention, a discharge path is provided for the run capacitor by switches and an auxiliary contactor. In another and preferred aspect of the invention, a negative temperature coefficient thermistor is used in series with and between the start capacitor and the start relay contacts for limiting the current to the start windings from a source of power and for limiting the current discharged into the start capacitor from the run capacitor after the motor is deenergized.