Device for protecting from fault currents

摘要

A device for protecting from fault currents, in which a first subunit (1) which acts as a fault-current protection switch for protecting from fault currents of a first gating is combined with a second subunit which acts as a differential-current switch for protecting from fault currents of a second gating. Both act on a common tripping relay (5). To this end, the tripping relay (5) is arranged in the secondary circuit of a summation current transformer (3), in parallel with which relay the second subunit is coupled, the latter having a circuit (14) for alternating magnetisation and evaluation electronics (38). In detail, the following are provided: - a diode network (12), similar to a bridge rectifier circuit, is used for the coupling; - the tripping relay (5) is connected on one diagonal of this network, and in the other diagonal thereof there is located, on the one side, a terminal (13) of the circuit (14) for the alternating magnetisation and in each of the wires before the other bridge corner (15) a controllable valve (16) is arranged; - this bridge corner (15) is connected to the second terminal of the circuit (14) for the alternating magnetisation and, on the other side, via a resistor (17) to a first terminal of the secondary winding (18) of a summation current transformer (19) for the second subunit which acts as a differential current protection switch; - behind the resistor (17) there is a connection to the control terminal (20) for the valves (16); - the second terminal of the ... Original abstract incomplete. <IMAGE>