GB544152A - Improvements in or relating to electric circuit interrupters having arc extinguishing devices - Google Patents

Abstract

544,152. Gas-blast switches; actuation of switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Jan. 9, 1941, No. 334. Convention date, Jan. 23, 1940. [Class 38 (v)] A gas-blast switch comprises a movable contact 33 separable from a fixed contact 17 in an arc-chute 13 and subjected to a cross blast through a hollow supporting insulator 11 from container 7. Contact 33 is pivoted at 35 and operated by a link 53 and lever 49 from a fluid motor 43, the lever 49 having an extension 59 which opens the blast valve 63 during the closing and opening switch movements. The chute, Fig. 2, comprises side plates 21 and end plates 23, 25, and leads into a passage 69 comprising walls 27, 29 and members 67, Fig. 3 arranged so that the passage rapidly widens from the point about halfway across the contacts. Space plates 73 of gas-forming .material extend into the neighbourhood of the arc and have notches 75 into which the arc is blown and so kept away from the walls of member 67. The lower ends of the plates 73 fit in grooves in the latter and are tapered so as to provide parallel-sided passages 77 at those ends. Insulator 11 contains a nozzle 65 which directs the blast, at the velocity of sound, so as to prevent it spreading when it leaves the nozzle during the interruption of low currents, at the tip of the plate 73 which is nearest the fixed contact 17. The arc is thus forced against the edges of and between, the plates 73, excessive penetration into the chute being prevented by metal plates 79. The gas produced by the arc on plates 73 may be excessive at heavy currents but the pressure at the nozzle 65 is relieved by the space between the arc in the upper parts of the notches 75 and the diverging wall of members 67, so allowing removal of the ionized arc gases from behind the arc. The degree of divergence and separation between the plates 73 varies through the chute, as does also the number of metal cooling grids 81 which are made concave towards the arc so as to keep the gases away from the plates 73.