GB605623A - Improvements in fluid-blast electric circuit breakers - Google Patents

Abstract

605,623. Fluid-blast switches. GRUNEWALD, F., and FERGUSON PAILIN, Ltd. Jan. 1, 1946, No. 57. [Class 38 (v)] In a fluid-blast circuit-breaker, parallelconnected main and auxiliary contacts are separated in turn, contact pressure between the latter being increased as the fluid pressure increases. A main movable cylindrical contact 13 engaging contact fingers 14 is urged downwards against a spring 26 as air admitted to an annular space 35 passes through apertures 28. The pressure on a nozzle contact 15 of an auxiliary piston contact 16 is increased by the air entering the space 29, until this contact 16 is suddenly moved downwards against a spring 23 as an internal projection 33 of the contact 13 strikes an abutment 36 attached to the piston 16. The nozzle 15 and fingers 14 are conductively connected to a member 17 and a terminal plate 18, the latter having a circular series of apertures, through which contact surfaces of the spring-urged fingers 14 project only slightly, so that the airflow is not greatly disturbed. The contacts 13, 16 are insulated from one another by a sleeve 34 and the abutment 36, but are both connected electrically to a lower terminal block through flexible connections 31, 27 and a metal cylinder 24 and base 12. The blast air emerging from the nozzle 15 may impinge on a probe for including resistance in circuit therewith. The moving auxiliary contact may be of nozzle, not piston, formation; communicating with the interior of a supporting tube.