DEVICE FOR HEAT PROTECTION OF ELECTRIC MOTOR Russian patent published in 1998 - IPC

FIELD: heat protection. SUBSTANCE: device has capacitor, two diodes, two tuning capacitors, fourth thermoresistor, which is located at magnetic circuit of stator of electric motor 2. Said fourth thermoresistor is connected to free terminal of serial circuit of three thermoresistors and emitter of single-junction transistor and diode input, which cathode is connected to first tuning resistor, cathode of thyristor, first resistor and negative terminal of rectifying bridge. Second terminal of serial circuit of thermoresistors is connected to resistor and capacitor which is connected to anode of thyristor, resistor and positive terminal of rectifying bridge. Resistor is connected to second base of single-junction transistor which first base is connected through terminals of tuning resistor to control electrode of thyristor. Semistor is connected to power supply circuit of contactor of electric motor. EFFECT: increased efficiency, decreased power consumption by measuring circuit. 1 dwg