GB455060A - Improvements relating to electric gas-blast circuit-breakers - Google Patents

Abstract

455,060. Fluid - blast switches. RUPPEL, S., 3, Alexander-Ufer, Berlin. July 13, 1935, No. 20097. Convention date, July 13, 1934. [Class 38 (v)] In a gas-blast switch employing gas at lower pressure to extinguish arcs due to normal loads and gas at higher pressure to extinguish arcs due to overloads, the gas at the lower pressure is derived from a mechanical compressor which is actuated when the switch is opened. Air, hydrogen, or carbon dioxide may be employed and may be in liquid or solid state. For the normal-load break handoperated compression means may be employed, whereas for the overload break, the overload electromagnets may drive a reciprocating compressor, or the current may produce gas by chemical reaction. The overload point may be opened by the gas-pressure produced by the arc at the normal-load break. In Fig. 1, the normal break is at 1, 3 and the overload break at 2, 4, the movable pin fitting in a gland 33 in an orifice 34, and the pin 4 closely fitting in contact 2. To open a normal load, the spring 22 acts on a piston 16 which compresses gas in the cylinder 15 and chamber 5 and then releases the opening spring 14. To open an overload, this separation of 1, 3 may be made to occur first. The overload release then moves a slide valve 24 to allow gas from the cylinder 23 to traverse pipe 27 and move the operating piston 29, and also to pass into chamber 5 and act on the arc set up between 2, 4. The current causing the latter arc will already be reduced, due to the are at 1, 3 being cooled by the restriction 34, so the arc at 2, 4 is soon extinguished. The pin 4 may be reclosed by a spring when the gas-pressure subsides. The container 23 may be large enough to serve for several reclosures, or it may be only large enough to serve for one reclosure, in which case it is connected by a pipe 31 with a main container. Gas for closing the switch 2, 4 is admitted to cylinder 28 by way of a pipe 30. In Fig. 2 (not shown), a single break is provided, and is acted upon by gas supplies admitted through separate valves to the switch chamber. A somewhat similar form is shown in Fig. 3 in which, on normal loads, the pin 3 only moves and gas is admitted to chamber 40 by valve 37, whereas on overload the contact 4 is also moved and gas is admitted to chamber 44 by pipe 39 and flows round the pin 4 and also passes inside it through opening 41. The supply from 39 may be omitted and the arc extinguished at 34 due to the blast of heated gas set up by the part of the arc which is located in chamber 44. This action may be increased by pressure set up by vapour or gas given off by substances when heated by the arc.