GB435143A - Improvements in electric oil circuit breakers - Google Patents

Abstract

435,143. Fluid-blast switches. FLURSCHEIM, C. H., Rushmoor, Fleet, Hampshire, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. April 13, 1934, Nos. 11222 and 34982. [Class 38 (v)] Bases and cases.-A switch of the high-tension, liquid-immersed type in which the contacts (or those of each phase) are arranged in a substantially horizontal casing suitably supported, as by a vertical pillar, has an insulating bushing through which passes a conductor associated at one end or at both ends with a contact or contacts, the exterior of the bushing being earthed and the whole of it being located within the horizontal casing. In Fig. 1 the two sides are similar and each contain two breaks. The conductor 2 is surrounded by a condenser bushing, the outer layer 5 of which is conductive and is earthed through the main body 3 which is mounted on a metal pillar 4. Current transformers 6 are also housed in the body 3, to which arc shields 7 and insulating housings 11 are secured, the whole being filled with oil to the level X. Conductor 2 is flexibly connected at 12 to one movable contact 13 which co-operates with a fixed contact 15, to which the other movable contact 18 is flexibly connected, the other fixed contact 19 being connected at 20, 21 to the end cap 8 which carries the terminal 9 and corona shield 10. The fixed contacts 15, 19 are located in insulating bushings 15<a>, 19<a> having cross-jet passages the exhausts from which are provided with shields 29 to protect shields 7. The movable contacts 13, 18 are secured to a pair of insulating rods 14, only one of which is shown, which are guided in plates 14<a>, 14b during operation. The latter is effected by a link 23 connected to contact 18 and an arm 22 on a pivot 25, the latter being rotatable by mechanism which is housed in the body 3 and base of pillar 4 and may be of the character described in Specification 435,419. The blast-producing pump may also be housed in the body 3 and operated by the mechanism in the base of the pillar 4, the flow of oil serving also to wash the bushing. In Fig. 2, only a single break is provided and in order to reduce the head of oil (at level X) above the break point and at the same time maintain the shield 37 and housing 38 full of oil, the whole structure shown is inclined at about 5‹ to the horizontal. The conductor is in the form of a tube 31 in a bushing 32 having an earthed layer 33 in the main body 34. It ends in a conducting bushing 44 or other contact in which, to reduce the length of the structure, the extension 43 of the movable contact 42 slides, being guided on rods 40 and having a corona shield 50. The cross-arm 41 of the contact is connected by insulating rods 51 &c. to an actuating shaft 57, and an actuating shaft 61 and link 59 are provided for the blastpump. The fixed contact 45 is housed on a support 48 screwed to the end of 38 and has cross-jet passages at 49. The first Provisional Specification refers to the use of an oil-filled bushing and of a series arc to produce the blast. The second Provisional Specification refers to the use of carbon tetrachloride as the switch liquid, and to modifications in detail. Switchgear structures.-The three body portions 31 of a three-phase switch may be mounted on a common support, the ends of which are mounted on adjustable supports 63, Fig. 4, with a screw gear or other mechanism for lowering the contacts 64, 67 from contacts 65, 68 for isolation purposes.