GB562744A - Improvements in or relating to fluid-blast electric circuit breakers - Google Patents

Abstract

562,744. Fluid blast switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. March 31, 1943, No. 5177. Convention date, March 31,1942. [Class 38 (v)] A liquid or gas-blast switch wherein the blast is directed through a passage or vent leading from an arcing-chamber, has means for moving the are away from the vent or passage during relatively high instantaneous values of current, whereby the arc, which cannot well be extinguished at such values, does not impede the flow of blast-medium, but is allowed to return to the vent neighbourhood at relatively low current values and be acted upon by the blast so as to be quenched at current minima. In Fig. 1, series-connected movable contacts 8, 9 are separable from fixed contacts 6, 5 adjacent vents 3, 2 in a casing 1, the current direction being shown at 33. The repulsion between the parts 37, 38, respectively, of the bridge member 7 and the arcs 35, 36 causes the latter at high current values to assume the positions 39, 40 laterally of the vents, whereby the pressure exhausts through the latter unimpeded by the arcs. At low current values, the arcs return to the normal positions and are readily extinguished by the blast. The latter is assisted by a piston member 21 operating member 7 through crank 15 and rod 11. In Fig. 3, main contacts 49, 53 and arcing contacts 51, 55 are mounted on opposite ends of bridge members 45, 47 which are free to pivot slightly on the operating rod 43 and are urged upwards against stops 79, 81 by springs 71, 73 bearing on washers 75, 77 fast on rod 43. The main current paths from contacts 57, 61 to bridges 45, 47 open first and divert the current to the arcing contacts by way of conductors 101, 103, the circuit in both cases being completed by flexible conductors 69, 70. Conductors 101, 103 make half-circles about the vents 83, 85 so as to divert the arcs 107, 109 laterally of the latter. The rod 43 carries a pin 91 which, in closing, engages a spring piston 87 which augments the blast due to low currents and with high currents scavenges the arc-chamber after arcextinction. Magnetic material may be employed adjacent the are, for example, embedded in the casing, Fig. 9 (not shown), or, Fig. 11, in the form of a partial cylinder 157 on the exterior so as to direct the single arc 149 between contacts 151, 153 to position 158 in which an insulating barrier 159 prevents further movement. Alternatively, a series coil may be arranged outside and coaxia,l with the vent, Fig. 15 (not shown). A U-shaped bridge 165, Fig. 13, co-operates with fixed contacts 167, 169, of which the latter is connected to terminal 179 by a conductor 171. which is divided to form parallel paths about the outlet of the single vent 185, the are 183 being thereby moved to position 184, notwithstanding the opposing force due to arc 181 at contact 167. In another form utilizing a U-shaped bridge, the mutual repulsion causes the two arcs to move away from one another laterally of the associated vents; Fig. 7 (not shown).