GB825913A - Mechanism for opening a high voltage isolating device - Google Patents

Abstract

825,913. High-voltage switches; snap-action switches; switch cases; operating members for switches; arcing preventing in switches. S. & C. ELECTRIC CO. Jan. 7, 1957, No. 552/57. Class 38 (5). A mechanism for opening under load a high-voltage isolating device, e.g. a disconnecting switch or fuse 16, comprises a stick 37, a support member 30 rigidly mounted on the stick, an auxiliary circuit interrupter 27 flexibly mounted on the support member, contact means 28 on the interrupter for connection to a fixed contact 18 of the isolating device and contact means 29 on the support member 30 for connection to the moving contact 17 of the isolating device, the arrangement being such that on manipulation of the stick 37 the contacts 17, 18 are opened without arcing due to the shunt circuit through the interrupter 27 and the interrupter is then opened to break the load circuit. In the arrangement shown, a contact ring 28 on the interrupter 27 is engaged with a contact arm 24 on the fixed contact 18 and a stud 29 on the support 30 is engaged with a ring 19 extending from the moving contact 17, relative motion between the interrupter 27 and the support member 30 being permitted by a spring-biased universal joint 109. The stick is then pulled to disengage the contacts 17, 18 and to subsequently open the interrupter 27. The interrupter 27 comprises outer and inner relatively movable insulating tubes 47, 73, the inner tube carrying a sleeve contact 95 and a conducting arm 106 and the outer tube carrying a cap 49 with the contact ring 28. A rod 51 extending from the cap 49 carries a cam member 54 and is connected by a conductor 56 to a contact 58 mounted on the lower end of a metallic tube 65. A tension spring 57 is fixed to the member 54 and the contact 58 and initially the tube 65 is engaged by pivoted latch 66 mounted on the inner insulating tube 73 and the contacts 58, 95 are in engagement. The initial downward movement of the stick 37 which opens the contacts 17, 18 causes the inner tube 73 and tube 65 to move downwardly so stretching the spring 57 while the contacts 58, 95 remain engaged. Then the cam member 54 releases the latch 66, Fig. 8, so that the spring is able to pull up the contact 58 and tube 65 to open the contacts 58, 95 with a snap action. The arc drawn between these contacts is extinguished by gas evolved from a liner 80 secured within the tube 73 and from a member 60 secured to the contact 58. The contact 95 is slotted so as to form contact fingers and the bottom portion of the liner 80 has a tapered groove 100, Fig. 12, over each finger for arc location purposes. The arc-gases escape through the contact 95 and vents 91, 104. A lower cap 103 is of light-transmitting material to permit the operator to observe the formation of the arc and its extinction before removing the mechanism. Specification 825,914 is referred to.