High sensitivity electromagnetic release for contact-breaker - has coil with spring and permanent magnet to actuate plunger

摘要

A sensitive electromagnetic release is used in low voltage contact breaker. It is robust and insensitive to other effects and does not go out of adjustment. The electromagnetic release has a case (1) made of magnetic material with high magnetic permeability and low remanence. The case (1) has a cylindrical recess (2). The recess (2) has an upper face (3) with a circular opening (4) for a plunger core (5). The recess (2) has a winding (6) which also takes the plunger (5). There is also a high permeability and low remanence material polar piece (8) between the winding (6) and a permanent magnet (9). A ring (7) separates the winding (6) and the polar piece (8). A coil spring (11) is fitted inside the plunger (5) and between its core (5) and the polar piece (8). Release is obtained by extension of the coil spring (11) when the winding (6) is energised and demagnitizes the permanent magnet (9). The plunger (5) then moves away from its polar piece (8).