GB1260649A - Expulsion fuse - Google Patents

Abstract

1,260,649. Fusible cut-outs. S & C ELECTRIC CO. 19 May, 1970 [15 Sept., 1969], No. 24276/70. Heading H2G. An expulsion fuse comprises a cylindrical contact sleeve 65, (Fig. 6), an insulated fuse tube 25, (Fig. 4) with a mounting terminal 51, 52 and an exhaust terminal 63, the latter telescopically engaging the contact sleeve and being provided with sealing ring 69 (e.g. of "Teflon", Registered Trade Mark) of lower coefficient of friction to permit telescoping which prevent the escape of exhaust products and a fuse assembly comprising a fusible element 35 and.a strain wire 34 secured between a stud 32 in the exhaust terminal and an arcing rod 37. The arcing rod is electrically connected with terminal 51 via part of the tube wall 49 and fingers 44, the latter being retained in contact with the collar portion 43 by a garter spring 46. On the fuse being blown, the arc rod retreats up the tube 40 and 38 under the action of spring 54, passing through arcextinguishing material 39 (e.g. boron), any gases generated passing out via the exhaust terminal end-plate (61, Fig. 5, not shown) which is retained by the nuts 33. The end 52 is passed through an end cap 19, (Fig. 1) carrying contact blades 23 and secured in an insulator 18, attached by bracket 17 to a fuse panel 11, forming the front of a fuse drawer 10. Insulating barrier plates 15 are provided in the drawer and fixed exhaust control devices 26, mounted by bracket 27 on to insulator 28 are attached to a fixed switch gear panel (not shown), conductor rods extending through the insulator 28 making contact with the device 26 and the load conductor. The sleeve (65) is secured to the exhaust device (Fig. 2, not shown) such that when the drawer 10 is withdrawn, the exhaust terminal is withdrawn from the sleeve. Fingers (71) assisted by a garter spring (72) ensure electrical contact between an inserted fuse and the exhaust device. The exhaust control device 26 (Fig. 6) comprises an elongate metal housing 67 with condensing and cooling means 79; including wire mesh coils around studs 80. A conical copper alloy deflector 76 directs gases from a blown fuse which enter the device via sleeve 65 through the coils and out via the holed plates 82.