GB593250A - Improvements in electrical switch gear - Google Patents

Abstract

593,250. Switchgear structures; latching switches. BRUSH ELECTRICAL ENGINEERING CO., Ltd., and YELLAND, H. F. May 26, 1945, No. 13217. [Class 38(v)] A horizontally withdrawable stepdown transformer has the switches on its high and low-tension sides provided with locks and a common key such that the low-tension side must be opened before the key can be made available to unlock and open the high-tension side. The withdrawal of the transformer effects opening of the hightension side, but is prevented by the hightension lock until the low-tension side is opened. Further, each side is held in locked condition when the key is withdrawn therefrom, so the low-tension side cannot be closed until the high-tension side has, been closed. The arrangement avoids expansive switches on the high-tension side. The transformer 1 is mounted on a carriage 3 having rollers 4 running on rails 2 and is operated by a pair of toggles on each side, one link 14 being pivoted at 17 to rail 2 and the other 15 to the carriage 3 at 18. Contacts 32 provided with fuses 35 enter holes 34 in the h.t. cable-box 9 and engage spring contacts 31 therein, the holes being closed by shutters 37 which are pivoted at 39 and operated by the carriage 3, in its approach, by means of levers 40 and rods 42, 46. The toggles are interconnected by a tube 19 carrying a box 20 for the h.t. lock 21<1>, the latter comprising a pair of rods 28 slidable in the tube 19 and interconnected by a lever operated by the lock 21<1>. In the locking position these rods enter holes in the rails 2 and when they are unlocked and the key trapped, the rod 19 can be pulled to withdraw the transformer. In this position, movement of the key 22 to unlock 21<1> is prevented by springs on the lever 14 snapping into grooves in the rods to retain them in locked position, Fig. 5 (not shown). The shaft 23 of switch 11 has a cam 24 with a lobe 24b which, in the switch-closed position, obstructs a tongue 25 on the lock 21, the tongue 25 being only movable to allow unlocking and extraction of the key when a lobe 24a on cam 24 is opposite to it, namely, in the switch-open position.