GB386283A - Improvements in and relating to liquid-break electric switches - Google Patents

Abstract

386,283. Oil-break switches. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Paul, W. E.; 2279, Grand Boulevard, Schenectady, New York, U.S.A.) Sept. 26, 1932, No. 26701. Convention date, Sept. 24, 1931. [Class 38 (v).] Fluid actuation; arc-rupturing devices; contacts.-The arc formed when contacts 7, 8 are separated by lowering the bridging-member 1 is utilized to set up a pressure which separates the contacts 5, 6 and blows out the arc set up between them. Contacts 5, 6 are connected in series with contacts 7, 8 and urged into engagement by the springs 32, 33, but carry pistons 29, 30 whereby separation is effected by the arc pressure. When the contact 8 is lowered, the arc drawn creates a pressure in the oil or other fluid in the chamber 13, which acts on a piston 36 on the contact 7 causing the latter to follow up the contact 8 so as to keep the arc of small length and prevent excessive pressure arising. The pressure acts also on a piston 21, but without effect until a cam surface 28 on the bridge-carrier opens a valve 23, so allowing piston 21 to move to the right and open a valve 18. The chamber 13 is now in communication with chamber 20, so that the pressure can act on the pistons 29, 30 to separate the contacts 5, 6 and the arc formed between them is blown out through passage 31. When the pressure subsides, the contacts 5, 6 re-engage but the circuit is opened at 7, 8. Valve 23 is reclosed when the switch is reclosed. When the contacts 7, 8 are in shunt with main contacts, Fig. 2 (not shown), the contact 7 and piston 36 are relatively movable and a compression spring is fitted between them to maintain 7 in engagement with 8 until after the main contacts are separated. The valve 18 may be dispensed with, and the initial break may be caused by the rupturing of a fuse.