ARCLESS-SWITCHING DC CONTACTOR Russian patent published in 1996 - IPC

FIELD: electrical engineering. SUBSTANCE: arcless-opening DC contactor is built up of two series-connected power contacts 1,2, both shorted out by main thyristor 4, and contact 2 shorted out by nonlinear resistance unit 3, such as varistor, which is, in its turn, connected to gate junction of thyristor 4. Contact 2 is first to open causing turn-on of thyristor 4, then contact 1 opens. After power contacts 1 and 2 fully open, thyristor 4 is cut off by forced switching unit (elements 6,7,8,9) which turns on after contacts 17 of limit switch close and pass positive potential from precharged capacitor 7 to gate electrode of thyristor 6 through voltage regulator diode 14, resistor 15, and diode 16. Capacitor 7 is charged from power supply 7 through resistor 11 and thyristor 10 controlled by circuit of elements 18,19,20. EFFECT: improved safety in operation and reliability of contactor. 1 dwg