GB528896A - Improvements in or relating to electric circuit interrupters having arc extinguishing arrangements - Google Patents

Abstract

528,896. Gas-blast switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. May 16, 1939, No. 14651. Convention date, May 25, 1938. [Class 38 (v)] A switch comprises an arc passage of insulating material, relatively-movable contacts for establishing an arc within the passage, a tubular movable contact normally substantially filling the passage, and a plunger formed at least partially of insulating material substantially closing one end of the passage but movable thereinto for restricting the cross-section thereof, whereby the products of decomposition produced by the arc are expelled from the passage through the arc path and tubular contact. In Fig. 1, a pair of similar arc-extinguishing structures are mounted on the insulating plate 10 on a gasreceiving housing 54 having an escape-valve 58, and are connected in series by a bridge-member 30 operated by member 32. Each structure comprises an insulating tube 14 on which is screwed a collar 16 carrying a conducting ring 18 and conducting cap 20, the inside diameter of which equals that of the tube 14. The tubular movable contact 28 substantially fills the tube 14 and co-operates with a sectioned fixed contact 24, between which and an arcing-ring 40 is connected a radial-field producing coil 38 protected by insulation 42 from the arc. Supported on the tube 28 is a plunger 44, the outside diameter of which is such that when moved into tube 14 it forms therewith a narrow arc-passage, for example, 1/32 to 1/8 inches wide, the width being larger when the tube or plunger is of arc-extinguishing gasevolving material. An arc is struck between contacts 24, 28 and subsequently transferred to ring 40, coil 38 is energized, the field of which may be intensified by a magnetic core in the plunger 44. When refractory materials are employed for the tube and plunger, the arc is extinguished at zero of the cycle by deionization in the narrow arcing passage. When gas evolving material is used for those members, the blast escapes through the annular passage 52 and out of the tube 28. The plunger may be provided with circumferentially-arranged channels in which gas emitted at the current-maxima is stored so as to be given up at the current-zero, Fig. 6 (not shown). Grooves or pockets may also be provided along the arc-passage itself by replacing member 14 by a structure of spaced plates 64 clamped between end-plates 68, 70, the latter supporting contact 24 &c. Fig. 4. The spaces 72 between the plates 64 form large storage chambers and provide a larger cooling surface, the cooling being further facilitated by annular metal plates arranged between spacers 74. Alternatively, the plates may be thinner and closer together, Fig. 5 (not shown). Specification as open to inspection under Sect. 91 included also a form using a fixed filling member, Fig. 8 (Cancelled) (not shown). This subject-matter does not appear in the Specification as accepted.