Method and circuit arrangement for rapidly switching off low-voltage circuit breakers

摘要

A method and a circuit arrangement are disclosed for rapidly switching off low-voltage circuit breakers by impinging a switching element which is operated in a short-circuit mode during normal operation and to which a fast trip magnet is connected in parallel, with a current that is proportionate to the current monitored by the low-voltage circuit breaker while the short circuit of the switching element is bypassed when the current monitored by the low-voltage circuit breaker reaches a set threshold value. The fast trip magnet is at least temporarily short-circuited once again as soon as the monitored current reaches a second given threshold value. A corresponding circuit can be designed such that the switching element is embodied as a switching transistor which can be controlled back into the conducting state by a second monitoring circuit for the current monitored by the low-voltage circuit breaker when a second given threshold value has been reached.