GB297895A - Improvements relating to electro-responsive indicating apparatus - Google Patents

Abstract

297,895. British Thomson-Houston Co., Ltd., and Lawes, W. H. July 4, 1927. Moving coil and wound armature indicators; tell-tale apparatus .-A two-position indicator, more particularly for indicating the positions of a circuit breaker, comprises a magnetizable member which is adapted to be moved to two positions alternately by closing the same circuit in succession. As shown in Fig. 1, a magnetizable member 4 is pivotally mounted in the field of an electromagnet or permanent magnet 3 and carries a coil 9 which may be wound round the member 4 or, as shown on a magnetic extension 10. The coil is connected to brushes 13, 14 which are fixed relatively to the member 4 and are adapted to co-operate with fixed contacts 16, 17, 18 connected in circuit with the operating contact 20 and a circuit breaker 21. When the circuit breaker changes its position, the coil 9 is excited by the momentary closure of the contacts 20 and the member 4 is magnetized and, by the repulsive action of the pole piece 7, is thrown over to its other extreme position adjacent the pole piece 8. During operation the connections to the coil 9 are reversed to prepare the apparatus for operation to its original position upon a subsequent change of position of the circut breaker. Stops 11, 12 are provided for limiting the movement of the bar 4. Fig. 2 shows a modification wherein the member 4 is pivoted centrally and the connections to the exciting coil 9 are made either at contacts 28 or 29 according to the position of the member 4. Any suitable form of indicating means may be associated with the apparatus. For example, an indicator of the " minnie " two-bar type, in which a movable line is shown in the gap of or out of alignment with a broken line may be employed.