GB388175A - Improvements in or relating to electric circuit breakers having arc-rupturing devices - Google Patents

Abstract

388,175. Arc-rupturing in switches. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.- (Assignees of Johnson, F. B.; P.O. Box 91, Murrysville, Pennsylvania, U.S.A.) Jan. 8, 1932, No. 601. Convention date, Jan. 24, 1931. [Class 38 (v).] A " deion " circuit-breaker comprises a series of groups 43 of spaced conducting and insulating plates separated by blow-out coil sections 45 by means of which the arc drawn on opening the breaker is caused to split up and rotate until extinguished. The conducting plates 59 of copper in each group have extensions 63 provided with a slot 65 having a curved tip 67, the tips being all inclined in the same direction in one group. Slots 75 are provided to reduce eddy currents, these being oppositely directed in adjacent plates throughout the group. Surrounding each plate 59 and arranged to move the arc along the slot therein is a co-planar plate 61 of magnetic material having projections 76 for engagement by projections on the plate 59 to prevent the latter from buckling. The composite plates formed by plates 59, 61 are separated-from one another by insulating members 77, 79 of fish paper, which are shaped to provide an annular space 83 round which the arc rotates and into which the slots.67 lead tangentially. An opening 99 leads to a space 101 in which the arc gases are deionized by the large surfaces of the plates 59, 61. Each coil section 45 contains a coil 105 so connected between the endplates 109 as to cause the arc to rotate in opposite directions in adjacent sections 43, Fig. 1, the slots 67 being oppositely directed in adjacent sections to allow of this. Below each plate 109 is a spaced plate 111, Fig. 5, with a slot 115 and below the coils 105 are similarly-shaped metal plates 121 separated by fish-paper plates 125, the slots in which are slightly longer and less tapered than the slots 115. Endplates 131 at the ends of the complete stack are also slotted and connected in circuit by being soldered to the end of coil 105 on one side and on the other by contact with further plates 47, 49, the latter being connected with surfaces 31, 33 of fixed arc-horns 25, 27. The current path from the leads 39, 41 and through the horns is shown by the arrows at 35, 37, which current sets up a magnetic field to move the arc from the horns into the stack. The arc horns are, as shown in Fig. 2, formed of a series of spaced plates of magnetic material, arc gases being allowed to escape through the spaces in advance of the arc. The movement of the arc into the stack is assisted by the shape of the horns and by an arrangement of magnetic plates 137, separated by insulating plates 139 of similar shape, these being located below the plates 61 as extensions thereof and extending downwards, some to the arc horns and some to the arcing contacts, Fig. 1. Fibre plates 147 with heatresisting inserts 149 protect the plates 137 from the action of the arc. A pair of insulating sheets 153 with embedded tinfoil 155 constitutes a static shield.