GB386322A - Improvements in and relating to liquid-break electric circuit breakers - Google Patents

Abstract

386,322. Oil-break switches; arcrupturing automatic circuit-breakers. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Prince, D. C. ; 1424, Wendell Avenue, Schenectady, New York, U.S.A. July 10, 1931, No. 19949. Convention date, July 10, 1930. [Class 38 (v).] A switch is provided with means for mechanically separating the oil-immersed contacts and means, movable simultaneously with but independently of the contact operating means, for .producing a pressure in the oil, whereby oil is forced across the arcing surfaces as they separate, and is then directed away from the arcing space by the suitable construction of one of the contacts. Under predetermined circuit conditions an armature 35 of an electromagnet 34 is released and a spring 25<1> overcomes a spring 40 to rotate a latch 25 about its pivot 26 and drag downwards, by means of a lug 41, a link 27, thus lifting the tubular movable contact 3 of the circuit breaker. At the same time as the circuit breaker is opened, a piston 5 is released and is raised by a spring 7, placing the oil in the lower compartment 20 of the switch casing 1 under pressure. The fixed contact of the switch comprises segmental contacts 15 resiliently carried by a retaining structure 14 in a spider 11. The oil under pressure escapes along a path between the fixed and movable contacts when they separate, up through the tubular contact 3 and through openings 21. A plug 23 in the movable contact 3 and a plug 22 in the retaining structure 14 of the fixed contact facilitate the circulation of the oil. In this way the arc between the contacts is entrapped and the arc products forced out of the contact gap by a forced flow of oil in a radial direction across the contacts. To reclose the switch, electromagnets 42, 42<1> are energized, the former acting through a link 43 and a lost motion connection 44, 45, to recharge the spring 7, and the latter effecting the re-engagement of the latch 25 with the piston rod, so that the spring 40 recloses the switch contacts. The Specification as open to inspection under Sect. 91 comprises also the arrangement shown in Fig. 3 (Cancelled) in which a number of breaks in series are provided, the several switch contacts being contained within an insulating bushing 51 and tubular stationary contacts engaging with cone-shaped movable contacts operated by common operating rods 59. The rods 59 are spring biased towards the surfaces of a cam 68, carried by an operating rod 67 so that when the latter is moved upwardly with the pressure producing piston 56, one operating rod 59 is moved to the right to open one set of series contacts, and the other is moved to the left by the spring bias to open the other set of series contacts. The several break points are tapped from a high resistance to ensure an equal distribution of the potential of the interrupted circuit. This subject-matter does not appear in the Specification as accepted.