GB1296131A - - Google Patents

Abstract

1296131 Switchgear structures; earthing switches SOC COQ-FRANCE 12 Feb 1970 [9 Dec 1969] 6754/70 Heading H1N A circuit breaker for a high voltage switchgear comprises an insulating housing 1 with two fixed contacts 4a, 5a and two movable contact rods 7, 18 connected together by a conducting bridge 8. The two rods 7, 18 normally move together, under control of an insulating rod 11, into engagement with the fixed contacts 4a, 5a. Each rod 7, 18 has a conducting lower portion and an insulating or insulated upper portion 7a. The rod 18 slides in engagement with an earthing contact 14 so that it is earthed in its open position. The rod 18 may be disengaged from the bridge 8 by rotating through 90 degrees to disengage latch 13, 17 and thus engage latch 18, 20 which locks the rod 18 in the open position. Then operation of rod 11 moves only rod 7 to the closed position whereby fixed contact 5a is earthed through the rod 7, bridge 8 and rod 18. The circuit breaker is plug-connected to busbar and cable connections 9, 10. In a simpler embodiment (Figs. 1-4, not shown) earthing can take place only after replacing one contact rod (6) by a completely conducting rod (15). The other rod 7 can also be detached from the bridge 8 and replaced by a test probe (16). In Figs. 17-20 a lower housing contains the fixed contacts 4a, 5a and the moving contact rods 6, 7 coupled by a conducting bridge 8 fixed to one rod while an upper housing contains a spring operating mechanism. There are two operating handles 21, 22 on a common axis 24a-24b. Both handles are disengaged in their fully clockwise position (Fig. 16, not shown) by a clutch (Fig. 21, not shown) but on, initial upward movement, engage with a link 100a driving it downwards to stress a spring 106. At the end of this movement an extension 101 trips a latch 109 allowing spring 106 to close the rod 7 rapidly. Similarly during opening, extension 101 compresses the spring 106 until another latch 113 is released to allow the spring to open the rod 7. One handle 21 also has a cam surface acting on a slide member 103 so that movement of handle 21 moves slide 103 to couple together the two rods 6, 7 so that spring 106 operates both rods together as a circuit breaker. On movement of the other handle 22, however the rod 6 remains locked by a catch 107 and only rod 7 moves to earth the cable connection 10. In another embodiment (Figs. 9- 15, not shown) two separate actuating springs (29, 30) are used the handles being arranged to stress one or both of them.