GB893287A - Improvements in operating arrangements for on-load transformer tap-changing switches - Google Patents

Abstract

893,287. Regulating switches. GENERAL ELECTRIC CO. Ltd. Dec. 10, 1959 [Dec. 10, 1958], No. 39854/58. Class 38 (5). An operating mechanism for an on-load transformer top-changing switch comprises a driving member 8 connected to a lever 1 which is pivoted at 2 and carries a roller 4 engageable with a slot 14 in a segment 12 of a Geneva mechanism. Movement of member 8 in either direction from the Fig. 1 position causes counter-clockwise movement of lever 1 so that segment 12 and a lever 11 fixed thereto are rotated clockwise about a shaft 10 to stretch a spring 17 connected between lever 11 and a lever 15. The latter is fixed on the shaft 10 which is connected to the contacts. The lever 15 is held against a stop 19 by a latch 21 until, when the segment 12 has moved through 90 degrees, the lever 11 is in line with lever 15 and the spring is in its dead-centre position, and latch 21 is released by lever 11. The spring is then caused to go over centre by (1) the use of spring-loaded contacts, or (2) the use of spring-loaded stops 19, 20 (Fig. 5, not shown). Positive actuation is given, if the spring breaks, by the co-operation of abutments 5, 6 on lever 1, with a roller 27 on an arm 28 fixed to shaft 10. In a modification (Figs. 6, 7, not shown), these abutments are in the form of plungers which are loaded by springs which are stronger than the combined strength of four springs which replace spring 17. In this arrangement, the plunger springs give the kickoff from dead centre, assisted by the four springs.