A fault detecting device for electrical installations and equipment

摘要

A fault detecting device for an AC supply includes a current transformer (CT3) having a primary winding comprising at least one supply conductor (L) connecting an AC supply to a load (LD), a secondary winding (W3) into which a current is induced in response to a fault current in the primary winding, and an electrical circuit connecting the secondary winding to an electromechanical actuator (PMR 26). The electrical circuit includes at least a first capacitor (C6) which is progressively charged by components of the induced current of at least one polarity. The electromechanical actuator is operably associated with the first capacitor to disconnect the load when the voltage on the first capacitor reaches a predetermined level.