THREE-PHASE SWITCH Russian patent published in 2003 - IPC

FIELD: pulse engineering. SUBSTANCE: each phase of three-phase switch incorporates two thyristors inserted in parallel opposition between input and output leads. Rectifier bridge is formed in phase A by first and second diodes interconnected through anodes with their cathodes connected to gate electrodes of respective thyristors in phase A and also by third and fourth diodes whose cathodes are interconnected. First through fourth diodes of phase B are connected in similar way to gate electrodes and to cathodes of phase B thyristors using fifth diodes; first through fourth diodes of phase C are also connected in this way to gate electrodes and cathodes of phase C thyristors using fifth diode. Phase A light-triggered thyristor of first optocoupler and voltage regulator diode are placed in series opposition between diagonally opposite pair of diode bridge terminals. Circuit set up of optocoupler light-triggered thyristor and voltage regulator diode and similar circuit of light-triggered thyristor and other voltage regulator diode are respectively connected in phases B and C. Proposed design ensures reliable protection of three-phase load and switching device against half-wave power supply in case of damage to valves of open circuit type or failure of their control. EFFECT: enhanced operating reliability of switch. 1 dwg