Motor starting circuit with low cost comparator hysteresis

Abstract From the Canadian patent

A low cost, low part content single phase AC induction motor control starting circuit is provided which is speed sensitive, load sensitive and AC line voltage fluctuation insensitive. A dual comparator chip (20, 22) senses and compares relative magnitudes of AC line and auxiliary winding voltages (48 40) to, de-energize the auxiliary winding (2) at cut-out speed and automatically re-energize the auxiliary winding at cut-in speed to accelerate or restart the motor from an overload or stall condition. Hysteresis circuitry (20 50, 52, 57, 80) provides a lower cut in speed than cutout speed. Simplified power supply and voltage detection circuitry is also disclosed.