GB299360A - Improvements in or relating to electromagnetic relays - Google Patents

Abstract

299,360. Associated Telephone & Telegraph Co., (Assignees of Erickson, J.). Oct. 24, 1927, [Convention date]. Electromagnets.-An electromagnetic relay has two cores 8 carrying the energizing windings, the cores being clamped in recesses in one limb of a U-shaped magnetic heel-piece 5, the heel-piece being provided with slot's 26 adjacent each core and the pivoted armature 10 being provided with slots 27, 28 extending from its sides to points above the centres of the core in order to prevent eddy-currents flowing in these members. The cores 8 are formed as shown in Fig. 6 by sheets of soft iron formed with folds of increasing length as they reach the centre so that the sheet may be pressed into a circular cross-sectional form, as shown in Fig. 5. The armature 9, as shown in Fig. 4, is secured by screws 19, 32 to a plate 10 of a resilient non-magnetic material, extensions 16, 17 of the plate 10 being screwed to the upper end of the heel-piece 5. The armature is provided with an adjustable retractive spring 20 and when attracted against this spring causes movable contacts carried on an extension 18 of the plate 10 to break contact with the screw 11 and to make contact with the screw 12. To prevent chattering when the relay is energized by alternating current, one of the series-connected energizing windings is paralleled with a condenser to shift the phase of the current therein. The retractive action of the spring 20 on de-energization of the relay is assisted by the elasticity of the tongue 18 which is stressed during the armature attraction. The relay structure as a whole is carried by a U-shaped frame 2 formed of non- magnetic material.