GB625541A - Improvements relating to electrical relays - Google Patents

Abstract

625,541. Electromagnetic switches. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. Aug. 8, 1947, No. 21857. Convention date. March 21, 1942. [Class 38(v)] A polar relay, the polarized armature 9 of which moves one way or the other according to the direction of current in a winding 15 on a core 1, has a neutral armature 4 responsive to the presence or absence of current in the winding 15 and a permanent magnet 5, 6 connected, intermediate its ends, with the core 1. When the direction of current in the winding 15 is reversed, e.g. by a pole changer P, the flux in the core 1 will pass through zero causing the release of the armature 4 which is pivoted at 4a on the pole 3 of the core 1. Owing to the air gap between the parts 2, 4 the pole 3 now becomes strongly of south polarity, as does the armature 9 pivoted at 9a to it so that the armature 9 is respectively attracted and repelled by poles 11, 10 of the permanent magnet and tilts into its other position operating contacts 14. With the rise of current in the winding 15 after passing zero, the armature 4 picks up again. An additional winding 18 may also be arranged as shown. This normally assists winding 15 but when the current in winding 15 is reversed, it opposes it so that armature 4 is released. Armature a then operates as before but also operates a pole changer that reverses current in winding 18 so that this now assists winding 15 and armature 4 picks up. Should armature 9 not reverse armature 4 will remain released.