Patent ID: 9076621
Filing Date: 2015-07-07
Classification: H01F,H01H

Abstract:
1. An electromagnetic actuator, comprising: a yoke configured to guide a magnetic flux; a holding plate attached to an actuating member, the holding plate and yoke forming a first magnetic circuit; a pre-tensioning device which exerts a pre-tension force on the holding plate away from the yoke, the pre-tensioning device comprising a device external to the electromagnetic actuator; a magnetic flux generation device configured to generate a magnetic flux in the first magnetic circuit, the magnetic flux generation device comprising an under voltage release coil electrically connected to an auxiliary voltage source, the auxiliary voltage source supplying a voltage value to be monitored, and the under voltage release coil being dimensioned to generate an attraction force holding the holding plate against the yoke; a tripping coil, the under voltage release coil being able to generate a magnetic flux in the first magnetic circuit opposing a magnetic flux generated by the tripping coil; and a closing coil configured to generate a magnetic flux in a second magnetic circuit, the second magnetic circuit being separate from the first magnetic circuit; wherein the attraction force exceeds the pre-tension force when the auxiliary voltage exceeds a predetermined threshold value.