GB705463A - Improvements in or relating to arc-chutes for electric contact breaking apparatus - Google Patents

Abstract

705,463. Arc-rupturing in switches. ELECTRICAL APPARATUS CO., Ltd. 'March 14, 1952, No. 6615/52. Class 38(5) An arc chute has blow-out coils so arranged that magnetic forces expand the are into a predetermined path and reverse magnetic forces prevent it from expanding beyond that path. The arc chute has three groups of fins or plates 18, 21 and 22, adjacent plates having oppositely-inclined edges so as to make the arc assume a folded or zig-zag shape as it rises in the chute. Plates 16, 17, between the groups, have their lower edges at right-angles to the sidewalls of the chute, so that the arc has to pass below these lower edges. The magnetc blow-out coils 3, 4 are each associated with a pole face 5, 6, core pieces 9, 10, and a yoke 7, 8, the coils being so wound and connected as to establish a magnetic field 26 between the pole faces 5, 6 to drive the arc upwardly in the chute and a magnetic field 25 acting in the opposite direction to prevent the arc being blown out of the chute. Thus when the contacts 1, 2 are opened, the arc is driven by the field 26 up into the groups of plates 18, 21, 22 and when the upper portions of the arc come approximately into alignment with the upper parts of the coils 3, 4, further upward movement of the arc is prevented by the field 25. The yoke plates 7, 8 may be extended in the region of the moving contact 2 to prevent the arc escaping out of the bottom of the arc chute.