GB841214A - Improvements relating to electromagnetic relays - Google Patents

Abstract

841,214. Electromagnetic relays. BRISTOL CO. April 26, 1957 [May 1, 1956], No. 13341/57. Class 38 (5). A polarized relay with change-over contacts has a shunt magnetic circuit arranged to bias the contact-carrying armature to one of its two positions, and a coil to deflect the armature to its other position on energization. In Fig. 5 the armature 101 is deflected to the N pole 104, to engage contact 102, by the flux from the permanent magnet 106 passing through the shunt path 110, as shown by the broken lines and arrows. The gap between members 105 and 110 is adjusted to set the amount of bias on the armature. In Fig. 6 (not shown), the gap between the shunt path and the S pole is omitted. In Fig. 7 the armature is off-set and the magnetic casing 107 forms the shunt path. Fig. 1 is an exploded view of a relay constructed as in Fig. 5 with two permanent magnets 39, 40 with laminated soft iron assemblies 35, 36 defining a gap 37 in which the resilient armature 25 moves. A non-magnetic metallic member 21 has a stem 22 which supports the armature by means of screws 47<SP>1</SP>, 481 which also hold the magnetic shunt 27 which passes on the outside of the operating coil 31 near to the assembly 35. The insulated movable contact 26 is carried by the armature and adjustable fixed contacts 43, 44 are mounted on a block 41. The relay may be mounted in a sealed casing which may be evacuated or filled with gas. Specifications 703,772 and 802,758 are referred to.