Time-delayed fault current isolator with electronic switch - incorporates thyristor for delayed shorting of output from DC supply circuit to polarised holding magnet trip

摘要

A holding magnet trip device (22) is connected by a capacitor (34) to the sec. winding (28) of a summation current transformer (24). A DC supply circuit (40) is connected to two main lines (P1, N1) for excitation of the trip device (22) by DC in the same direction through diodes (46, 48). A tert. winding (60) feeds an amplifier (54) associated with an electronic delay (56) in application of a short-circuit (50) to the output terminals.