GB660047A - Improvements in or relating to electric circuit interrupters, having arc extinguishing arrangements - Google Patents

Abstract

660,047. Arc-rupturing in switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Jan. 31, 1949. [Feb. 11, 1948] No. 2594/49. Class 38 (v). [Also in Group XXXVI] In order to grade the voltage distribution between the arc-horns 30, 44, of a circuitbreaker similar to that of Specification 630,838, the arc-chute has a layer or layers of conducting or semi-conducting material provided in or on the wall of the chute. A layer 56 of high resistance paint (see Group XXXVI) is applied on the inside surface of the arc chute, the opposite ends of the layer being connected to the arc horns through the arc horn fixing screws 58. The backs of end liners 57 also have a layer 57a of the paint in contact with the heads of screws 58, and connected to layer 56 by springs 60. The resistance between the arc horns is preferably within the range of 100 megohms to 10,000 megohms. A further layer 51 is coated on the outside of the chute, this layer being connected to the blow-out magnet poles 38, 39 so as to short out the air void between the chute and the poles, and thereby increase the resistance to corona. The layer 51 is covered with a protective coat of varnish. The Specification as open to inspection under Sect. 91 comprises also a modification, in which layers of tin foil are included in the housing of the chute, as it is formed, the outside paint layer 51 and an internal layer at each end being provided. Alternatively, the internal and external layers may be of tin foil also. In a further modification the coil and yoke assembly is coated by dipping or spraying. In this case the chute is only coated at the end nearest the horn 44. This subject-matter does not appear in the Specification as accepted.