GB1357383A - Composite sectionalized protective indicating-type fuse - Google Patents

Abstract

1357383 Fusible cut-outs WESTINGHOUSE ELECTRIC CORP 9 Aug 1971 [26 Aug 1970] 37281/71 Heading H2G A composite fuse 6 comprising high-and lowcurrent interrupting sections 6A and 6B respectively has the low-current section threadedly connected to the high-current section so that upon low-current interruption the low-current section 68 only requires replacement. The high current section comprises at least one fusible (spring silver) element 12 housed in a glass epoxy casing 8 which is filled with white sand 10 and has a ferrule 14, 16 at each end. Ferrules 14, 16 are respectively provided with tabs 14a, 16a for connection to the element 12, and threaded studs 14b, 16b. The low-current section 6B comprises a fibre-lined insulating tube 20 in which are located a contact terminal 24 which is screwed onto the stud 16b, a terminal 15 secured to a fuse link cable 32, and a Nichrome (Reg. Trade Mark) strain link and a tin-lead alloy fusible link connected in parallel between the terminals 24, 15. When the link 30 fuses it causes link 28 to fuse and thereby the release of the cable 32 under the action of a spring strap 3 (Fig. 1) which then takes up a position 34 to indicate that the fuse has blown. Other suitable forms of low-current section include an ejection spring and a boric acid lining of the insulating tube (Figs. 4 and 4A, not shown) to assist in the ejection of the cable upon fusion. A number of alternate forms (Figs. 8, 9, 12, not shown) for the fusible elements of the high-current section are also described. A particular high-current section, Figs. 10 and 11 (not shown), comprises a plurality of fusible elements (12) (Fig. 12, not shown) consisting of wires provided with a number of sections (27) of reduced diameter, supported in slots (33) provided in a supporting rod (18).