GB1477711A - Electric circuit breaker - Google Patents

Abstract

1477711 Gas blast circuit breakers BROWN BOVERI & CIE AG 16 Sept 1974 [1 Oct 1973] 40298/74 Heading H1N A gas-blast circuit breaker with a nozzle movable contact has secondary contact means arranged on contact opening to produce a rotating secondary arc which increases the temperature and pressure within a gas filled quenching chamber in which the main contacts separate. In the Fig. 1 arrangement, as the main movable nozzle contact 13 is moved to the right, to open the contacts the movable secondary contact assembly 12, 6, 7, 8, 9 moves with it under the influence of a bias spring 11 and a secondary arc rotates between the wound turns of electrodes 56 to produce temperature and pressure increases in the gas (preferably SF 6 ) within a chamber 1. When the secondary contact assembly engages a plate 15c the main contacts 12, 13 separate and the gas is forced through radial ducts 15b into the nozzle contact 13 across the arc formed between the main contacts. In the Fig. 4 arrangement the secondary contacts 47, 50 seperate before the main nozzle contacts 43, 45 and the arc between contact 50 and extension 49 of contact 47 rotates within the chamber 40 to increase the temperature and pressure before the main contacts separate. In the Fig. 6 arrangement the resiliently mounted. fixed contact 61 moves with the nozzle contact 62 whilst secondary contacts 67, 68 separate to produce a rotating arc. The contact 61 may also be a nozzle contact (Figs. 8 and 9, not shown).