Circuit arrangement for self-monitoring of a switching device for a load circuit

摘要

A circuit arrangement is shown and described for self-monitoring of a load-circuit switching device, consisting of a drive switch (1), evaluation logic (3) having a redundant design, and of two output relays (4, 5), the make contacts (6, 7) of which are in series with each other in the load circuit (8). In order to increase safety, each output relay (4, 5) has a break contact (9, 10) located in the secondary circuits (11, 12) of in each case a separate converter (13, 14), and the currents flowing in the primary circuits (15, 16) of the two converters are checked for equivalence in a fault-monitoring circuit (17) which, in the event of a fault, triggers tripping of the relays (4, 5). <IMAGE>