GB261014A - Improvements in and relating to electric relays - Google Patents

Abstract

261,014. British Thomson-Houston Co., Ltd., (Assignees of Schilling, W. W.). Nov. 4, 1925, [Convention date]. Electromagnetic switches. - The inverted T-shaped armature 10, 11, Figs. 2 and 3, is polarized by an energizing winding 12, co-operating with which is a magnetic circuit having poles 13, 14, which may be poles of permanent magnets 15 or of definitely polarized electromagnets. The magnetic circuit is completed through members 16, plate 17 and bushing 17<1> and is protected from external fields by the plate 17, and bottom and side plates 18 - - 20. The armature is rotatable on bearings, one 26 of which is adjustable, whereas the other 27 is carried by a plate 28 which also carries a plate 29 on which is mounted a terminal 30. A torsion spring 31 is connected at one end to the plate 29 and at the other to a movable contact 32 on the armature, said contact 32 co-operating with two spring contacts to control two circuits according to the position of the armature. Assuming the poles 13, 14 are respectively south and north and the armature 11 is polarized by the winding 12 so as to be a north pole, then the armature will move over to the poles 13, stress the spring 31 and cause the contact 32 to engage the back spring contact. On reversal of current in the winding 12, the armature will move back, aided by the spring, so that the contact 32 will engage the front spring contact, but if the spring is initially sufficiently stressed this change will be brought about by a decrease, instead of reversal, of current. The coil 12 mav be used as a series or shunt coil to cause the relay to respond to increase, decrease, or reversal, of current or voltage. The relay is slightly modified when required for A.C. circuits, Fig. 5, there being pole-pieces 37 mounted on the side plate 19. These pole-pieces mav have projecting portions 38 for shading the flux into the armature so that there may be a definite minimum range between the pick-up and drop-out values of current. The part 10 of the armature comprises two parts of magnetic material which are rolled in the form of a cylinder and mounted on a centre. Then two parts are separated by a part of non-magnetic material to increase the reluctance, but one long section may be used instead of the two. The coil may be series- or shuntconnected, so as to cause the relay to respond to increase or decrease of current or voltage.