GB426869A - Improvements in or relating to contacts for electromagnetic interrupters - Google Patents

Abstract

426,869. Electromagnetic interrupters. HUNTER, S. A., and ARMITAGE, G. H., Springvale Works, West Kensington, London. Sept. 11, 1933, Nos. 25122/33 and 23523/34. [Class 38 (v)] In a vibrating electromagnetic interrupter, in order to prevent breakdown in operation due to the welding of the contacts, an armature, which is rotatably mounted within poles formed in a closed-core electromagnet, is arranged when such welding temporarily occurs, to impart movement to the relatively fixed contact by means of a cam or equivalent, so producing separation of the contacts. As shown in the interrupter trembled blade 10 carries a contact 8 which is adapted to co-operate with a relatively fixed contact 9 carried by a lever 11 pivoted at 12 and urged towards the trembler contact by a blade spring 13. An insulating lead 16 is placed between the pole end of the lever 12 and a cam member 14 which is carried by an armature 2 pivoted in a gap of the core 1. If the trembler contact 8 becomes stuck or slightly welded to its cooperating contact 9 the increase of current in the primary windings of the transformer causes the rotation of the armature 2, the consequent rotation of the cam member 14, causing a rocking of the contact arm 9 which is usually sufficient to separate the contacts and enable the normal operation of the interrupter to be resumed. If, however, a secure welding between the contacts takes place, the greatly increased current in the operating windings causes a large and decided movement of the armature and cam member so that a pin 20 on the latter engages the trembler blade 10 with a sharp blow and a greatly increased separating force for the contacts is thus available.