GB811962A - Improvements in or relating to electric fusible devices - Google Patents

Abstract

811,962. Fusible cut-outs cable couplings. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. April 15, 1957 [April 26, 1956], No. 12247/57. Class 38 (1). [Also in Group XXXVII] A current-limiting fuse cornprises a cylindrical insulating casing 1 containing an insulating core 3 with a helically grooved surface and a cylindrical fusible foil 9 located between the core and casing and connected at one end to a terminal cap 2 and at the other end to an apertured vent plug 6. The core 3, or both the core and the casing, may be formed of gas-evolving, arc-quenching material. Fig. 2 shows a modification in which a further fuse element 13 which operates on low overload is connected in series with the foil 9 and located in a tube 14 forming an extension of the casing 1. This type of fuse may be used in a tapping connector as shown in Fig. 4. The terminal cap 2 is coupled to a line-clamp 20 and a tapping cable 23 connected to a conductor 19 secured to element 13. Ejection of the conductor 19 on rupture of element 13 gives an indication that the fuse has blown or alternatively a compression spring arranged to separate the element 13 may project an indicator below the bottom of the tube 14. The basic fuse shown in Fig. 1 may be used in cut-outs as shown in Figs. 5 and 7. In Fig. 5 the vent plug has an apertured extension 6a for attachment of the fuse to a terminal 27 and the terminal cap 2a is formed with a terminal 30 which is also used for the attachment of a porcelain housing 29. In Fig. 7 the upper terminal cap 47 is adapted for attachment to an insulating handle 45 by means of which the fuse may be inserted in or withdrawn from an insulator 49 in which are supported coaxial contacts 48, 51, the lower end of the fuse having in this case a cap contact 52 for engagement with contact 51. Other applications of the fuse shown in Fig. 2 are in outdoor types of cut-out (Figs. 6 and 8, not shown), wherein the lower end of the fuse is connected to a pivot through a toggle held set by the conductor 19. On rupture of element 13, the toggle collapses and allows either the door of the casing which carries the fuse in one application, or the fuse itself, to swing down, at the same time disconnecting the fuse from fixed contacts. A handle on the door or on the fuse permits manual operation if desired.