GB667517A - Improvements in and relating to electromagnetic switches for lighting installations of vehicles especially of automobiles - Google Patents

Abstract

667,517. Electromagnetic switches. BOSCH GES., R. April 6, 1950. [April 9, 1948] No. 8694/50. Class 38 (v). [Also in Group XXXV] In a lighting system for vehicles wherein the lamps are supplied with current, when the vehicle is in motion, from an A.C. generator, an electromagnetic switch, adapted to switch the lighting from the generator to the battery and vice versa, has a 'current' winding 36 and a 'voltage' winding 37 which act conjointly and substantially without opposition on the armature 31. The generator has a winding 11 for charging the battery 13 through a rectifier 12 and a winding 10 which, when the vehicle is in motion, energizes the windings 36 and 37 in series so that the armature 31 is attracted, whereupon if the lighting switch 15 is closed, current also passes from the winding 36 through contacts 33, 32 and the armature to the lamps. The magnetic circuits of the coils 36, 37 are substantially independent of each other and the fluxes are in phase with each other when the lighting circuit is not closed. Falling away of the armature at the zero point is, however, prevented by the short-circuited windings 39. When the lighting circuit is closed, the flux of winding 37 is displaced in phase by about 90 degrees relative to flux of winding 36 and there is no resultant zero force on the armature.