MULTICHANNEL DEVICE FOR PROTECTING THREE-PHASE POWER INSTALLATIONS AGAINST ABNORMAL OPERATION Russian patent published in 2005 - IPC

FIELD: electrical engineering.

SUBSTANCE: proposed device has first switching unit incorporating control circuit and power contacts for connecting power buses, as well as series-connected variable resistor, thyristor, and final relay coil shorted out by diode and capacitor, all connected to terminals used for connecting first and third phase leads of first power installation; gate electrode of thyristor is connected through anode-cathode circuit of diode and series-interconnected break contacts of auxiliary relays to terminal designed for connection to first phase lead of first power installation. Device is also provided with time relay, reverse-sequence voltage filter, voltmeter, second switching units with power contacts for connecting each separate power installation in compliance with desired process, abnormal operation sensors, phasing unit, auxiliary relays with break contacts, and three-phase full-wave rectifier; parallel-connected to time make-and-break delay relay coil through series-connected make contact of time relay and break contact of final relay is switching unit tripping coil; make contact of final relay and break contact of time relay are interconnected in parallel and inserted in series with START and STOP buttons in power circuit of remote turn-on coil of first switching unit; auxiliary contact of first switching unit functions to short out START button in its control circuit.

EFFECT: enhanced reliability of protective device.

1 cl, 1 dwg