DEVICE FOR SERVICEABILITY CHECK AND PHASE-FAILURE PROTECTION OF THREE-PHASE INSTALLATIONS Russian patent published in 1997 - IPC

FIELD: electrical engineering. SUBSTANCE: device has two differentially series-connected current transformers and converter built around diodes, voltage regulator diodes, resistors, and transistor switches whose outputs are connected to disconnecting signal shaping unit which is connected to relay and control current spruce. Collector of one of switches is connected to base of transistor of same conductivity of mentioned unit, its emitter is connected to control current source, capacitor, and thyristor-relay power circuit, and its collector is connected to that of reverse-conductivity switch and to resistor coupled with opposite capacitor plate, voltage regulator diode connected at unit output to thyristor gate electrode, resistor connected to other pole of control current source through relay break contact; relay also has other contacts in installation disconnecting circuit. EFFECT: improved design. 1 dwg