GB361924A - Improvements in or relating to electric circuit-breakers - Google Patents

Abstract

361,924. Heavy current switches. REYROLLE & CO., Ltd., A., Hebburn-on- Tyne, COATES, F., Cranlea, Whitburn Road, Cleadon, Durham, and ALLAN, A., Cragside, Ashleigh Grove, Tynemouth. Aug. 27, 1930, Nos. 25560/30 and 16277/31. [Class 38 (v).] Arc-rupturing devices.-In a circuit-breaker having arcing contacts, the latter, during the later part of the closing movement and earlier part of the opening movement of the breaker, form part of a circuit having auxiliary conductors disposed so that the resultant electromagnetic force on the moving parts is reduced to a value small enough to ensure that the breaker can always be moved with certainty by its operating mechanism even under short-circuit conditions. The arcs are moreover blown out in a radial direction by horizontal electromagnetic forces. In the form shown diagrammatically in Fig. 4, the main fixed contacts B, B<1> are bridged by a member C in the closed position and support a pair of fixed arcing contacts D, D<1>, which with further fixed arcing contacts E, E<1> interconnected by fixed conductors F<4>, F<5> form four brakes in series. Auxiliary conductors H2, J<2>, H<3>, J<3> are carried by an extension of the operating rod C<1> and carry movable arcing contacts H, H<1>, J, J<1>, the auxiliary conductors being in circuit when the arcing contacts, during closure, are in engagement but before the main contacts engage. With the current direction as shown, interaction between the currents in F<4>, F<5> and J<2>, J<3> tends to force the moving parts upwards against the action of forces exerted between conductors B<4>, B5 and H2, H3. By suitably locating the various conductors, the vertical forces can be arranged to neutralize one another. This arrangement can be modified by making the conductors F<4> F<5> movable also. In another diagrammatic form, Fig. 8, the movable arcing contacts R, R<1>, S, S' are caused by rods T, T<1> secured to the main movable contact L, and the fixed arcing contacts P, P<1>, Q, Q<1> are carried by vertical posts N, N<1>, O, O<1> which are connected together and to the posts M, M<1> carrying the fixed main contacts K, K<1> by means of conductors O<4>, M<2>, M<3>. In this form, the upward force on the rods T, T<1> due to the posts N, O and N', O<1> are balanced by the downward force exerted on those rods by conductors P<4>, Q<4> and P<5>, Q<5> and by the vertical parts of the current path including the arcing contacts.