Circuit for starting single-phase AC induction motor.

摘要

A circuit for starting a single-phase AC induction motor (11) having a main winding (12) and an auxiliary winding (13), which is so constructed that a PTC element (16) and a triac (17) are connected in series with the auxiliary winding (13) and a gate voltage of the triac (17) is reduced to turn a portion between main terminals of the triac (17) off after a predetermined time period has elapsed since the motor (11) was started, and can effectively lower the power consumption without degrading starting characteristics and can shorten return time required until the motor (11) is restarted and lengthen the life of the PTC element (16). <IMAGE>