GB227320A - Improvements in and relating to electric switches - Google Patents

Abstract

227,320. British Thomson-Houston Co., Ltd., (General Electric Co.). April 2, 1924. Oil switches; fluid actuation. - A fluid-break switch comprises a piston connected on either side with the mechanism for operating the movable contact and arranged to be. affected by the pressure generated by the action of the arc on the fluid on separation of the contacts to accelerate the separation thereof. A tank 2 containing an insulating liquid is secured to a casing 1 wherein an opening 8 is connected to an oilseparating and pressure-relieving device. The movable contacts are carried on an insulating rod 14 guided in a frame 15 and fastened into a cap 17 to which are pivoted the two arms 19 of a bifurcated actuating lever 20 by means of a horizontal pin 18. This lever is fulcrummed at 21 on a pair of links 22 pivoted at 23 and connected by a bridge 24, through which extends loosely a rod 25 pivoted to lever 20 and guiding a spring 26. A link 27 is pivoted to each arm 19 of the lever 20 and to the casing to cause the rod 14 to move in a straight line and each arm has a flange. 28 loosely receiving a rod 29 with a head 30. Each rod 29 is threaded into a cross-bar 32 and abuts the cover 6, which supports a cylindrical bracket 33 carrying a flanged button 34 and felt discs 35 which are adjustably compressed by the crossbar 32 against the button 34. The piston 39 slides in an opening 38 and is connected on one side to lever 20 bv a link 40 and on the other side to an operating lever 41 by a link 42. The lever 41 may be operated by a solenoid or centrifugal device, or manually by means of a rod inserted in a socket 44 therein. Means are provided for retaining the toggle 41, 42 in an underset position when the switch is closed, subject to manual or automatic tripping. To close, the lever 41 is operated, moving the piston 39 and lever 20, and the movement is cushioned by the pin 18 striking the resiliently-retained button 34. When the switch is tripped open, the parts move under gravity and are accelerated by spring 26, the gas-pressure due to the arc acting on the piston 39 to assist the movement. At the full open position, the flanges 28 strike the heads 30 of the rods 29 and the movement is cushioned by the felt discs 35. The invention is applicable to any switch opening in an arc-extinguishing fluid, or in an arc-extinguishing gas not dissociated by the. arc. the pressure in the latter case being due to the expansion resulting from an increase in temperature, Specification 26694/01 is referred to.