Improvements relating to metalclad switchgear having earthing arrangements

摘要

554,452. Switchgear structures. SWITCHGEAR & COWANS, Ltd., and UPTON, A. March 17, 1942, No. 3527. [Class 38 (v)] A withdrawable switchgear structure suitable for use in mines comprises a conducting plate which can be moved so as to cover up exposed live contacts in the fixed gear when the breaker is withdrawn, and also to permit engagement of the breaker, there being also provided means whereby the conductors of the circuit controlled by the breaker can be connected by the latter to sockets on the plate for the purpose of earthing them on to the fixed gear. The plate a is pivoted at b on a long pin on the fixed part c and carries earthing sockets e for the breakercontacts g which normally engage the busbar contacts i. Fig. 3 shows the plate in isolating position covering the contacts i, and by dropping a further pivoted plate k the circuit contacts j can be engaged by breaker contacts h, while contacts e, g are in engagement. The handle n of the earthing switch of the breaker is on the opposite side to the normal handle o, suitable interlocks being provided. In the normal, operative position both plates a, k hang downwards. In a modification, Figs. 6-8 (not shown), a single apertured plate has these operative positions corresponding to the above.