VOLTAGE-CONTROLLED STARTING RELAY FOR INDUCTION MOTOR Russian patent published in 2004 - IPC

FIELD: electrical engineering; starting gear for single-phase induction motors. SUBSTANCE: proposed relay has power supply in the form of diode bridge for feeding its components with regulated voltage from ac power supply that feeds induction motor, triac for feeding ac power to starting winding of induction motor or to turn off ac power supply, input signal unit for detecting voltage induced in starting winding, hysteresis unit for yielding turn-on control signal during initial starting period that produces switch turn-on control signal when induced voltage detected by sensing element rises to preset reference voltage across switch and also generates turn-on control signal for reclosing the switch when induced voltage decreases below preset reference turn-on voltage during normal operation, and turn-on unit for turning on the switch in compliance with hysteresis unit turn-on and turn-off control signal. EFFECT: enhanced operating reliability of relay. 4 cl, 4 dwg