GB244591A - Improvements in electro-magnetic relays - Google Patents

Abstract

244,591. Western Electric Co., Ltd., (Western Electric Co., Inc.). Dec. 30, 1924. Alternating-current relays comprise a reed armature 13, situated at the centre of a magnetic field formed by a permanent magnet having two N pole and two S pole extensions, and one or more coils energized by alternating current which cause the armature to vibrate at the same frequency and actuate a loose contact device on the armature. According to the construction shown in Figs. 1 and 4, a magnet 9 has adjustable extensions 18 - - 21 fixed on its poles, and a single coil 22 provides the alternating field. The armature 13 is adjustably clamped at 15 so that its free vibrating end may have a natural frequency equal to that of the alternating current, and carries a support 26 which loosely supports one end of a tubular contact 27, the other end of which is loosely linked to a fixed eye-member 28. A circuit normally established through members 26, 27, 28 is thus broken or interrupted when the armature vibrates. According to a modification, Fig. 7, the magnet 9 has magnetic members 21, 22 projecting from its poles, and each of these members carries two projecting pole pieces 26, 27 between which the armature 13 vibrates. Coils 25 connected in series are mounted on the members 27 which serve as cores for them. The reed armature 13 of this modification is channelled and its effective length is determined by a clamp adjusted by a screw.