GB462893A - Improvements in and relating to electric power switches in series with isolating switches - Google Patents

Abstract

462,893. Air-break switches. BRITISH THOMSON-HOUSTON CO., Ltd. Nov. 25, 1936, No. 32279. Convention date, Nov. 25, 1935. [Class 38 (v)] In a circuit-breaker having isolating contacts 7, 8 in series with power interrupting contacts 2, 5, the disengagement of the latter taking place within an arc extinguishing chamber 1 made of, or lined with, insulating material capable of giving off extinguishing gases or vapour when exposed to an arc, the movable contact 2 of the interrupter is connected to the movable contact 7 of the isolating switch through a slotted link 21 so arranged that the contacts are moved together to the " on " position, while lost motion is permitted on opening, so that the isolating contact 7 is temporarily retained in its closed position against the action of a spring 35 until the circuit has been broken between the contacts 5, 2, the continued movement of the contact 2 then causing the link 21 to release the contact 7 and allow it to move suddenly to its open position. In the construction shown, the contact 2 is in the form of a rod with an insulating extension 3 carrying a member 4 provided with a pin 22 engaging a slot 20 in the link, and the contact 7 has a pin 27 engaging another slot 50 in the link, the contact 7 being carried by one arm 15 of a two-armed lever pivoted at 17. The other arm 151 of the lever engages the spring 35 and places this in compression when the switch 7, 8 is closed. A spring-controlled catch 16 holds the isolating switch closed until the catch is released by a nose piece 24 on the link 21. The contacts 7, 5 are interconnected by a flexible conductor 25. At its upper end, the contact rod 2 passes through a cooler 6 and is connected to an operating arm 51, which can be held in the closed position, against the action of a spring 52, by a catch 60.