GB484942A - Improvements in electro-magnetic relays - Google Patents

Abstract

484,942. Electromagnetic relays; electric control systems. GENERAL ELECTRIC CO., Ltd., PUCKETTE, C. C., and HARRISON, W. J. D. Feb. 4, 1937, No. 3260. [Class 38 (v)] [Also in Group XXXVIII] In a relay having a reed 7 adapted to vibrate in response to current of a particular frequency in a coil 2, the reed causes the opening or closing of contact springs 16 mounted on spacers 15, the assembly being freely pivoted at 12. In the form shown the reed carries an extension 17 with a bent-over end which enters between the two contact springs 16. The relay is provided with a permanent magnet 5, an adjustable polepiece 6 and an armature 4 on the reed. The natural frequency of vibration of the contact springs 16 is slow compared with that of the reed, or may be made so by weights, Fig. 2 (not shown), so that when current of suitable frequency energizes the relay winding 2, the rapid vibration of the extension 17 forces the contact springs apart and holds them apart. The relay has a second armature, reed and spring set mounted behind the first. An application of the invention for controlling street lighting is shown in Fig. 3. The relay 1 is here operated by currents on the lines P3, N. Application of current of one frequency causes the one armature 31 to respond and contacts 33 to open and current of another frequency causes the other armature 32 to respond and contacts 34 to open. The contacts 33, 34 respectively control the two windings 35, 36 of a relay which operates to tilt a mercury switch 14 controlling the lamps 42 " on " or " off ". The relay 35, 36 is of the type shown in Specification 354,847.