GB404497A - Improvements in and relating to electric switches operated by gas under pressure - Google Patents

Abstract

404,497. Arc-rupturing in switches. AKT.-GES. BROWN, BOVERI, ET CIE, Baden, Switzerland. March 16, 1933, No. 8053. Convention date, March 16, 1932. [Class 38 (v).] Pneumatic-actuation ; retarding devices.-In pressure-gas operated switches, in which, in opening, the distance between the contacts is rapidly increased until that required for extinguishing the arc is reached, and, after the extinction is completed, the distance is again increased to that requisite for permanently insulating the voltage, the movable contact has an oscillating motion imparted to it such that it reverses its direction of motion at least once within the extinguishing zone. Thus, pressure-gas is applied to the upper face of piston 6 carrying the movable contact, so that, the valve 8 being opened just previously, the piston moves rapidly down in the cylinder 7 and strikes a disc 11 urged upwards by a spring 12. The gas beneath the disc 11 is unable to escape through the space 10 to a sufficient extent, so it becomes compressed and finally reverses the motion of the piston. During the slow final opening stage, the gas leaks through the clearance 10, or a valve may be provided to let it out. In another form, Fig. 3 (not shown), a heavy mass is supported on a gas cushion and /or spring, with a buffer to bring the mass to rest at the end of its down stroke. The Specification also refers to the dimensioning of the outlet 8 and inlet 13 whereby the existing cylinder can be utilized for providing a gas cushion to effect the recoil.