Fault current protective device for protecting electrical systems against e.g. ignited fires, has transformer for detecting low and high fault currents, and protective circuitry switched parallel to winding and acting as crowbar circuit

摘要

The device has a summation current transformer (2) for detecting low and high frequency fault currents and comprising a secondary winding (3) to monitor primary power lines (1) and connected with an electronic circuit (5). A release relay (6) allows interruption of primary power lines parallel to the secondary winding. A protective circuitry (4) is switched parallel to a secondary winding, and acts as a crowbar circuit. The protective circuit is interconnected in series with a crowbar circuitry for over voltage protection.