GB191424537A - Improvements in and relating to Electromagnets. - Google Patents

Abstract

24,537. Grob, H. Dec. 23. Electro-magnetic switches.-In an electromagnet for operating switches consisting of two single electro-magnets acting in opposition, in which the movement of the armature or mechanically connected armatures is brought about by a strengthening of one magnet and a weakening of the other, the initial movement of the armature is utilized to effect a still further strengthening and weakening of the magnets. In the construction shown in Fig. 1. the magnets have a common pole D, through which the two fluxes produced by the windings E', E<2> pass in the same direction. The magnets, when excited by the coils E<1>, E<2> only, are of equal strength, so that the armature C is in equilibrium. Its movement is effected by current passing through additional coils F<1>, F<2>, the direction of the current determining the direction of rotation of the armature. Mounted loosely on the axis R of the armature is a controlling-device G carrying contact buttons 1, 2, 3, 4. The initial movement of the armature C in the direction indicated, short-circuits the coil E<2> through a contact plate 5 fixed to the armature, a fixed contact plate 6, and the contact buttons 1, 3. Pins M<1>, M<2> in the plate H limit the rotation of the armature C with respect to the controlling device G. The controlling device may interrupt the circuit of the coil E<2>, instead of shortcircuiting it. The end movement of the armature re-establishes the original connexions of the coils E<1>, E<2>. The main switch operated by the electro-magnet may be mechanically connected to the controlling-device G. Easily interchangeable magnetic pieces may be attached to the pole-pieces A, B, or to the armature, to correct for mechanical differences in the two magnetic circuits and to compensate the resisting effect of friction. The correction may also be effected by differentiating the ampere turns of the coils E<1>, E<2>. The switch operated by the electromagnet may be employed to connect together two current sources, such as a dynamo and battery, when the voltage of one begins to outweigh that of the other, and to break the connexion in the contrary case. In addition to the coils E<1>, E<2> and F', F<2>, coils carrying the main current between the two sources may be provided to maintain the switch firmly in its closed position. The circuit of the coils F<1>, F<2> may be interrupted when the voltage of the dynamo sinks below a certain value. The switch may also be used in connexion with two thermoelectric elements connected together through the - coils F<1>, F<2>, to maintain the temperature in a room constant, the switch controlling a gasstove or water-supply. The switch may be worked with alternating current.