GB170556A - Improvements in electrical circuit-breakers - Google Patents

Abstract

170,556. Metropolitan - Vickers Electrical Co., Ltd., (Assignees of Aalborg, C.). Oct. 18, 1920, [Convention date]. High-potential switches; mechanical switches with contacts reinforced electromagnetically; contacts; sparking, preventing, and arc-rupturing devices.-High tension switches are provided with main brush contacts 8, 9 secured to conductors 3, 4 and adapted to be bridged by a movable contact bar 5 secured by bolts 6 to an operating rod 7. Shunt contacts are provided, the fixed contacts 10, 11 being secured to the terminals 12, 13 and the movable contacts 14, 15 are attached by bolts 16, 17 to brackets 18, 19 pivoted on pins 20, 21 within the bridging member 5. Springs 22, 23 are connected between the inner ends of the brackets 18, 19 and fixed pins 24, 25, and a flexible strip connection 26 joins the contacts 14, 15. The interaction between the magnetic field set up in the zone between the conductors 3, 4 and the currents carried by the switch tends to distort or spread apart the contact members, and consequently presses the brushes 8, 9 more firmly into engagement with the bar 5. A similar interaction tends to force the shunt contacts apart, but as the field also acts upon a greater area of the flexible shunt strip 26 resting on the inner ends of the brackets 18, 19, the resultant electromagnetic forces will assist the springs 22, 23 to keep the shunt contacts together until the main contacts have moved apart a distance sufficient to prevent sparking. Stops 27, 28 limit the movement of the brackets 18, 19.