Non-polarised differential relay constituting mechanical actuator for triggering circuit breaker or differential relay - has magnetic circuit formed by ferromagnetic cylinder and movable contact bridge piece disposed parallel to transverse base piece

摘要

The differential relay includes the magnetic circuit formed by the ferromagnetic cylinder (21) comprising at least two lateral sides (22,23) connected by the transverse base (24). The movable contact piece (25) is disposed parallel to the base and rests on free ends of the side branches. A permanent magnet is associated with the magnetic circuit. A coil winding (28) is mounted on the ferromagnetic cylinder and is excited by a signal issued from a differential sensor. An elastic spring acts on the contact piece so that it connects with the free ends of the side branches. When the coil is excited by the current, the contact piece floats above the free ends of the side branches. The spring is disposed between the two side branches to obtain a non-polarised differential relay. ADVANTAGE - Non-polarised differential relay assures function of mechanical actuator irrespective of direction of flow of current through coil.