OFF-OPERATION PROTECTIVE GEAR FOR POWER INSTALLATIONS IN SINGLE-PHASE LINE WITH SOLIDLY GROUNDED NEUTRAL Russian patent published in 2002 - IPC

FIELD: electrical engineering; automatic electric-shock and fire-hazard protective devices for apartment houses. SUBSTANCE: off-operation protective gear has circuit-opening device with its input connected to phase lead L and to operating neutral lead N of supply mains and its output, to load; it also has bridge rectifier. Phase lead running from output of circuit-opening device L1 is connected to bridge rectifier through coil of independent release of circuit-opening device that has voltage regulator and thyristor switch both connected across diagonally opposite terminals of rectifier bridge, differential current sensor, and amplifier. Protective gear is provided with additional diode arm of bridge rectifier for connecting ground wire PE, in-service inspection device (TEST button), varistor inserted between lead L1 and wire PE, integrating RC circuit connected to output of voltage regulator using compensation circuit arrangement around field-effect transistor. RC circuit capacitor leads are connected to amplifier power circuit; output of mentioned voltage regulator is connected through current-setting resistors to thyristor switch and to TEST button, second lead of the latter being connected to wire PE. EFFECT: enhanced reliability, reduced power requirement of protective gear. 1 dwg