THREE-PHASE SWITCH Russian patent published in 2002 - IPC

FIELD: pulse engineering; on/off switching of three-phase loads. SUBSTANCE: three-phase switch has first diode and thyristor optocoupler interconnected in parallel opposition and inserted in each phase of supply mains in series with load; two control buttons; two resistors; second diodes connected in phases A and C through their anodes to output lead of respective phase and through cathodes, to anodes of light-emitting diodes in thyristor optocouplers of next phase. Cathode of second diode in phase A is also connected to cathode of additional diode whose anode is connected through first control button to input lead of mentioned phase. Anodes of third diodes for phases A and B are connected to output lead of respective phase and their cathodes for phase A, to cathode of light-emitting diode in thyristor optocoupler of mentioned phase and to first lead of first resistor. Cathode of third diode of phase B is connected to anode of light-emitting diode in thyristor optocoupler of phase C whose cathode is connected through second control button to cathode of light- emitting diode in thyristor optocoupler of mentioned phase and to first lead of second resistor. Second leads of mentioned resistors are connected to output lead of respective next phase. Thyristor switch has only five diodes and two resistors, time of current flow through second control button is reduced to 120 electrical degrees. Load is immediately turned off upon occurrence of open circuit in any of power (first) diodes. EFFECT: simplified design, enhanced reliability. 1 dwg