GB1246434A - Electrical switches - Google Patents

Abstract

1,246,434. Fluid pressure operated switches. SIEMENS A.G. 13 May, 1970 [13 May, 1969], No. 23089/70. Heading H1N. An electric switch, especially a high voltage switch, is operated by means of fluid under pressure, controlled by a valve 17, acting on one or both faces of a differential piston 10 and causing a movable contact rod to assume one of its two positions, an insulating rod 22 actuating the valve. A motor 41 and a compressor 40 maintain the fluid in the reservoir 36 and the line 35 at a high pressure. Changeover valve 30, which may be electromagnetically operated, connects the lower face of the piston 27 with the line 35 causing insulating rod 22 to move valve 17 into the position shown. In this position, smaller piston face 10 is at high pressure, whereas large face 11 is connected to low pressure insulator chamber 26. The contact rod 3 is thus moved down, opening the contacts (not shown) in the switching chamber 2. For the closing operation, rod 22 is lowered by disconnecting line 29 from the high pressure line 35 by means of the valve 30. The valve 17 now closes plate 21 against seat 25, exposing both piston faces 10, 11 to the high pressure fluid, e.g. oil. The lower face 11 being larger, due to the area of rod 3, causes rod 3 to rise, closing the contacts. The column insulator 12 is secured to the earthed metal truck 14, on which are also mounted some of the switch control parts.