PROTECTIVE GEAR FOR ELECTRIC AND AUXILIARY PIECES OF EQUIPMENT Russian patent published in 1998 - IPC

FIELD: protection of electrical equipment against abnormal and emergency operation caused by abnormal increase or decrease in temperature or any other physical quantity. SUBSTANCE: control and protective gear has two thyristors connected in parallel opposition, their gate junctions being shorted out by resistors and in opposition, by diodes. Thyristor gate electrodes are connected through parallel-interconnected current-limiting resistor and capacitor to rectifier bridge. Collector-emitter circuit of first transistor is connected to rectifier output through resistor and that of second transistor, directly. Base-emitter junction of one of transistors is shorted out by posistor. Base circuit of first transistor is connected through resistor to voltage regulator diode and the latter is connected through resistor to collector-emitter circuit of transistor whose base is connected through resistor to transistor collector. EFFECT: enlarged functional capabilities, simplified design , and improved operating reliability of protective gear. 3 dwg