ELECTRICAL EQUIPMENT GROUND FAULT TEST SYSTEM AND EQUIPMENT OPERATOR PROTECTIVE GEAR Russian patent published in 2007 - IPC H02H3/16 H02H7/09 

FIELD: protective devices for electrical apparatuses and installations of insulated-neutral three-phase (multiphase) mains.

SUBSTANCE: proposed test system has three-pole circuit breaker connected to insulated-neutral power supply between the latter and load as well as metering circuit. Newly introduced in system is additional single-pole circuit breaker incorporating unit affording simultaneous operation of electromagnetic releases and mechanical connection for circuit-breaker cases and ON-operation handles; connected to each phase of supply mains past main three-pole circuit breaker contacts through limiting resistors are diodes; common point of mentioned diode cathodes is connected to one of coil leads in metering circuit relay, its other lead is connected to device ground; noise-suppressing capacitor is connected in parallel with relay coil leads; making contact of additional single-pole circuit breaker is connected by means of one lead to supply mains phase past making contact of main three-pole circuit breaker and by means of other lead, to making contact of metering circuit relay whose other lead is connected through fourth limiting resistor to any of two remaining phases past making contacts of main three-pole circuit breaker; test circuit that has series-interconnected test resistor and TEST button is inserted between ground and any phase of mentioned making contacts.

EFFECT: simplified design and enlarged functional capabilities of system.

2 cl, 2 dwg