Fault current disconnector for power supply - has relay detecting sudden changes in resonant current to trigger cut=out fuse

摘要

The fault-current disconnector, for a power supply, has a winding (N2, N3) for each power line (R, M) and a saturation winding (L) all wound on the same toroidal core (W). The saturation winding is supplied with a constant rectangular-wave voltage and forms a non-linear resonant circuit with a series capacitor (C). This resonant circuit (LC) contains a relay (A1) that detects sudden changes in its resonant current and causes a short circuit between the power lines so that the series fuse (S) on one line opens.