GB818577A - Improvements relating to electromagnetic switching relays - Google Patents

Abstract

818,577. Electromagnetic relays. UHER, E. Aug. 22, 1957 [Sept. 1, 1956 ; June 25, 1957], No. 26566/57. Class 38 (5). An electromagnetic relay particularly for the control of a car lighting dynamo and similar to that of Specification 704,412, [Group XXXV], has a magnetic shunt 33, 34 (Figs. 3 to 5) between the pole 9 and armature 35 and arranged so that a part 34 thereof, of a ferromagnetic alloy having a temperature-dependent permeability, lies outside the relay case 30, 32 so as to be subject to the external temperature, in order that the relay may operate at lower current and voltage values at higher ambients. The armature 35 has a contact 15 normally engaging a fixed contact 14 under the bias of the armature mounting spring 12. The combined effect of the voltage and current coils 6, 7 moves the armature so that first the contacts 14, 15 part and later the contact 15 engages a second fixed contact 16. The members 33, 34 pass through a rubber muff 37 in the relay cap 32 and are arranged with a constant gap z between the armature part 36 and part 34 in all armature positions, alternative arrangements being shown in Figs. 3 and 5. In Fig. 11 the part 34 of ferromagnetic alloy is fixed between two iron members 33, 40, the latter having a narrow neck y to saturate and limit the by-pass effect of the magnetic shunt path at higher operating values. The end of the member 40 is bent at 41 to be parallel with an upturned end 42 of the armature 35 and arranged so that the gap z is approximately constant as the armature is moved angularly. The end 42 may be parallel to the pole 9 with no upturned end to the armature (Fig. 14, not shown) but in this case the gap z is variable, or the end 42 may be perpendicular to the pole and co-operate with an armature end constructed similar to 36 in Fig. 5 (Fig. 15, not shown).