THREE-PHASE SWITCHING UNIT Russian patent published in 2002 - IPC

FIELD: electrical engineering. SUBSTANCE: switching unit that may be alternatively made as contactless design version and that is distinguished by more complete voltage transmission to load has power thyristor in each phase being handled (A, B, C) whose cathode is connected to anode of power diode; additional diode whose cathode is connected to anode of power thyristor, the latter being connected in its turn through its cathode to output bus of switching unit and through anode, to cathode of power diode and to terminal for connecting supply mains phase A (B, C); first, second, and third diodes whose cathodes are connected through threshold elements, which are in series opposition to them, to gate electrodes of power thyristors of each phase and through anodes for first and third phases, to first leads of current-limiting resistors and through control switch for second phase, to first lead of current-limiting resistor whose second lead is connected to preceding (first) phase A, second leads of current-limiting resistors of first and third phases A and C being connected to output buses of third and second phases, respectively; fourth, fifth, and sixth diodes connected through their cathodes to anodes of respective power thyristors and through anodes, to first leads of current-limiting resistors. EFFECT: reduced current through control switch; reduced internal noise of switching unit in closed position. 1 dwg