GB263960A - Electric switch-gear - Google Patents

Abstract

263,960. British Thomson-Houston Co., Ltd., Trencham, H., and Wood, C. W. Oct. 12,1925. Switch gear arrangements; switches, interlocking. - An interlocking arrangement comprising a lever 22 is provided between the isolating switches 13, 14 of alternative circuits, for example those of duplicate bus-bars 11, which prevents both of the isolating switches being moved to open position at the same time while the circuit-breaker is closed but allows one or other or both of them to be put into the closed position. As shown in Fig. 1, the locking lever 22, which can be rotated by hand from the outside of the casing, engages a, shoulder 21 on the operating lever of one of the isolating switches and locks that switch against opening. The other switch, however, can be closed and when both switches are closed the locking lever may be rotated through a position in which it locks both switches closed to the other extreme position in which it locks the free switch and releases the hitherto locked switch. The released switch mav be brought to the open position and this, sequence changes over from one bus-bar to the other without breaking the supply circuit. Both isolating switches cannot be opened at the, same time while the circuit-breaker 15 is closed. To ensure this, the locking lever 22 can only be raised free of both operating levers 18, 19 by means of a lock 25 operated by a key 24 which is normally trapped in the circuit-breaker or its operating mechanism and is releasable therefrom only when the circuitbreaker is open and locked open. When the key is in use to raise the locking lever it can be withdrawn from the lock 25 only after turning the key back to the initial position (in which case the locking lever locks one or other of the isolating switches closed) or after fully operating the lock (in which case an arc member 27 on the locking member engages with notches in the operating levers 18, 19 in the switch open position of the levers). A further interlock is introduced in the form of a synchronizing device which operates a locking quadrant normally in engagement with slots in the operating levers to lock one or both of them in the off-position until the circuits with which they are associated are in synchronism.