FESTKÖRPERÜBERSTROMRELAIS

摘要

A self-powered multiple phase circuit protection device including a plurality of current transformers connected in parallel with each other and associated with one phase of a multiple phase load for providing signals representative of the current flowing in an associated phase. A switch can be actuated to interrupt power to the multiple phase load, and a fault determining circuit is connected to the circuit transformers and to the switch for actuating the switch during at least one predetermined condition of the current signals. The fault determining circuit has digital pulse extender circuitry for converting the current signals into DC signals, and a digital timer for delaying actuation of the switch.