GB593119A - Improvements in or relating to electromagnetic relays - Google Patents

Abstract

593,119. Electromagnetic relays. AUTOMATIC ELECTRIC LABORATORIES, Inc. June 12, 1945, No. 14818. Convention date, June 12, 1944. [Class 38(v)] A relay of the slowrelease type, and with a release time which does not vary with reasonable variation in voltage or contact spring pressure, has a copper sleeve surrounding the core 12 and of such dimensions that if the relay were energized by a voltage of one third the normal operating voltage the current flowing in the copper sleeve immediately after the breaking of the relay winding circuit would be sufficient to saturate the magnetic circuit. The time of release may be varied by rotating a selflocking nut 47 which determines the position of an armature stop spring 29 having a rounded end portion 43 adapted to be engaged by the right hand end of an extension arm 17 of the armature 15. The air gap between armature and core when armature is in the attracted position is thus varied. The extension arm 17 also engages a stud 41 on a contact spring 27 moving two contacts on this into engagement with contacts on a forked contact spring 26. The spring 27 thus serves to bias the armature away from the core and when the relay is de-energized the arm 17 engages a projection on the heel piece 14 which is out of line with the stud 41 so that the armature is subjected to a twisting movement which takes up any play between the armature pivot pin 20 and its bearing surfaces of which the surface 19 is constituted by the bottom plate of the contact spring pile up.