Control circuit for a 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 means 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 auxiliary contactor means. In another and preferred aspect of the invention, a negative temperature coefficient thermistor is used in series with and between the start capacitor means 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 means from the run capacitor after the motor is deenergized.