Total range fault interrupter

Claim 2

Electrical fault interrupter apparatus for suppressing external arcing under fault conditions, as well as providing a double-fused, dual fault-current-range protected, high current handling, electrical coupling between a high voltage power line energized with an electrical potential of a first predetermined level and electrical power-accepting means to be energized from said line, said apparatus comprising: a cut-out fuse device including an elongate electrical insulator adapted to have a zone thereof intermediate its ends conventionally supported upon utility pole structure or the like, a pair of electrically conductive assemblies mounted upon said insulator respectively adjacent the opposite ends of the latter and both extending laterally from said insulator in the same general direction and in spaced relationship to each other, said assemblies at their respective zones of closest proximity to each other and to said zone of said insulator being physically separated by respective distances, which are sufficient to normally preclude arcing therebetween of an electrical potential of said first predetermined level or of level within a first range of levels next above said first predetermined level, but which are insufficient to preclude arcing therebetween of an electrical potential of level within a second range of levels above said first range of levels under certain fault and other conditions of weather, contamination and the like, an elongate cut-out fuse link constructed to be actuated for interrupting an electrical circuit path therethrough in response to electrical current flow therethrough of a first predetermined magnitude, and means for supporting said link in laterally spaced physical relationship to said insulator and in longitudinally extending physical relationship between said assemblies, and for electrically coupling said link in normally circuit-completing relationship between said assemblies; a current-limiting fuse component including a pair of spaced apart connection terminals, and a fuse element electrically coupled between said terminals and constructed to be actuated for interrupting an electrical circuit path therethrough in response to electrical current flow therethrough of a second predetermined magnitude greater than said first magnitude, said component having the property that, upon actuation of said fuse element to interrupt the normal circuit path therethrough in response to a fault-produced current flow therethrough at least equal to said second magnitude, a back-voltage potential, which is of level within said second range, is produced and presented at said terminals, and means for supporting said current-limiting fuse component in physical disposition adjacent but beyond the extremity of the cut-out fuse device having one of said assemblies and one end of said insulator thereat with the one of said terminals being nearest said one assembly and the other of said terminals being displaced from said one assembly further than said one terminal in a direction generally away from said other assembly, and for electrically coupling said one terminal with said one assembly to place said fuse element of said current-limiting fuse component and said fuse link of said cut-out fuse device in series-coupled electrical relationship, said other terminal and said other assembly presenting a pair of physically remote external connection points for the apparatus which are spaced apart a distance greater than any of the aforesaid respective distances, one of said points being adapted for electrical coupling with said line and the other of said points being adapted for electrical coupling with said power-accepting means.

Claim 3

Apparatus as set forth in claim 1, wherein: said cut-out fuse device further includes elongate cover means disposed around said fuse link and having an open end for blow-out of gases generated upon actuation of the device in a direction away from said current-limiting fuse component.

Claim 4

Apparatus as set forth in claim 1, wherein: the longitudinal axes of said insulator and said fuse link are disposed to be generally upright, said one assembly is disposed adjacent the upper extremity of said cut-out fuse device, and said component is disposed above said one assembly.

Claim 5

A total range fault interrupter comprising the combination of: low range current interrupting apparatus operative to interrupt fault currents of relatively low magnitude; and high range current limiting fuse structure connected in series with said low range apparatus for interrupting all fault currents of high magnitude, said structure comprising: an elongated, hollow insulative housing, closure means integrally attached to said housing in covering relationship to opposed ends thereof to present a closed body, each of said closure means having conductive connective structure on the external face thereof respectively adapted to permit said fuse to be interposed within an electrical circuit, at least one relatively thin, elongated fusible element within said housing, the distal ends of said element being adapted for electrical connection with said respective external connection structure of said closure means, means electrically connecting each of said external connection structures with the distal ends of said fusible element to thereby create a current path through said fuse, a series of spaced zones along the length of said element within the housing having decreased cross-sectional areas relative to the remainder of the element, the ratio of the maximum cross-sectional area to the minimum cross-sectional area thereof being sufficiently high to cause said high range fuse to limit fault currents only of said high magnitude by the severance of said element at said zones of decreased cross-sectional area, an elongated, insulative saddle member of synthetic resin material having a plurality of circumferentially-spaced fins, said fins being provided with spaced attachment means at predetermined points about the marginal edges thereof for the attachment of said fusible element, said fusible element being helically wrapped about said saddle member and attached thereto by said attachment means to form an internal fuse assembly, said saddle member and fusible elements cooperatively acting to position and support each other within said housing with the convolutions of said elements being maintained in an aligned, spaced relationship about said saddle, and pulverulent arc-suppressing material within said closed body in substantially surrounding relationship to the convolutions of said element, said material being characterized by the property of acting to quickly suppress the electrical arc formed upon the severing of said fusible element under the influence of a fault current; said apparatus and the structure being cooperable to effect interruption of low and high magnitude fault currents with substantial isoenergy dissipation within predetermined relative narrow limits under all fault interruptions thereby.

Claim 6

A total range fault interrupter comprising the combination of: low range current interrupting apparatus operative to interrupt fault currents of relatively low magnitude; and high range current limiting fuse structure connected in series with said low range apparatus for interrupting all fault currents of high magnitude, said structure comprising: an elongated, hollow insulative housing, closure means integrally attached to said housing in covering relationship to opposed ends thereof to present a closed body, each of said closure means having conductive connective structure on the external face thereof respectively adapted to permit said fuse to be interposed within an electrical circuit, at least one relatively thin, elongated fusible element within said housing, the distal ends of said element being adapted for electrical connection with said respective external connection structure of said closure means, means electrically connecting each of said external connection structures with the distal ends of said fusible element to thereby create a current path through said fuse, a series of spaced zones along the length of said element within the housing having decreased cross-sectional areas relative to the remainder of the element, the ratio of the maximum cross-sectional area to the minimum cross-sectional area thereof being sufficiently high to cause said high range fuse to limit fault currents only of said high magnitude by the severance of said element at said zones of decreased cross-sectional area, an elongated, insulative saddle member of synthetic resin material having a plurality of circumferentially-spaced fins, said fins being provided with spaced attachment means at predetermined points about the marginal edges thereof for the attachment of said fusible element, said fusible element being helically wrapped about said saddle member and attached thereto by said attachment means to form an internal fuse assembly, said saddle member and fusible elements cooperatively acting to position and support each other within said housing with the convolutions of said elements being maintained in an aligned, spaced relationship about said saddle, and pulverulent arc-suppressing material within said closed body in substantially surrounding relationship to the convolutions of said element, said material being characterized by the property of acting to quickly suppress the electrical arc formed upon the severing of said fusible element under the influence of a fault current; said apparatus and the structure being cooperable to effect interruption of low and high magnitude fault currents with substantial isoenergy dissipation within predetermined relative narrow limits under all fault interruptions thereby.

Claim 7

A total range fault interrupter as set forth in claim 4 wherein said closure means is provided with apertures therein receiving respective distal ends of said fusible element and said means for electrically connecting the distal ends of said elements with said respective connective structure comprises: mechanical connection means within said apertures adapted to seal sAid closed body and secure said distal ends of the fusible element therein; and means electrically connecting said mechanical connection means and said respective external connection structure, thereby providing a current path through said fuse.

Claim 8

A total range fault interrupter as set forth in claim 5 wherein said mechanical connection means comprises expandable rivets operatively positioned in said apertures to secure said fusible elements within said housing.

Claim 9

A total range fault interrupter comprising the combination of: low range current interrupting apparatus operative to interrupt fault currents of relatively low magnitude, said apparatus comprising an elongated, substantially rigid insulative support member, first conductive means attached to said support, an elongated, insulative hollow fuse link tube of lesser length than said support releasably coupled to said first conductive means and depending therefrom, the lower end of said fuse link tube being open, a fuse link carried within said tube conductively attached to said first means to provide a current path through said cutout, said link being operable to sever under the influence of a fault current of said low magnitude, second conductive means attached to said support below said first conductive means and spaced therefrom, said second means being adapted to be electrically connected to a conductor extending away from said cutout, said fuse link extending from the lower end of said tube and electrically connecting with said second means, thereby completing the current path through said cutout, and biasing means cooperable with said fuse link to urge said fuse link tube out of engagement with said first member when said fuse link severs to thereby interrupt the current path through said cutout; high range current limiting fuse structure connected in series with said low range apparatus for interrupting all fault currents of high magnitude, said structure comprising an elongated, hollow insulative housing, closure means attached to said housing in covering relationship to opposed ends thereof to present a closed body, each of said closure means having conductive connection structure on the external face thereof respectively adapted to permit said fuse to be interposed within an electrical circuit, at least one relatively thin, elongated fusible element within said housing, the distal ends of said element being adapted for electrical connection with said respective external connection structure of said closure means, means electrically connecting each of said external connection structures with the distal ends of said fusible element to thereby create a current path through said fuse, a series of spaced zones along the length of said element within the housing having decreased cross-sectional areas relative to the remainder of the element, the ratio of the maximum cross-sectional area to the minimum cross-sectional area thereof being sufficiently high to cause said high range fuse to limit fault currents only of said high magnitude by the severance of said element at said zones of decreased crosssectional area, an elongated, insulative saddle member of synthetic resin material having a plurality of circumferentially-spaced fins, said fins being provided with spaced attachment means at predetermined points about the marginal edges thereof for the attachment of said fusible element, said fusible element being helically wrapped about said saddle member and attached thereto by said attachment means to form an internal fuse assembly, said saddle member and fusible elements cooperatively acting to position and support each other within said housing with the convolutions of said elements being maintained in an aligned, spaced relationship about said saddle, and pulverulent arc-suppressing material within said closed body in substantially surrounding relationship to the convolutions of said element, said material being characterizEd by the property of acting to quickly suppress the electrical arc forming upon the severing of said fusible element under the influence of a fault current; said apparatus and the structure being cooperable to effect interruption of low and high magnitude fault currents with substantial isoenergy dissipation within predetermined relatively narrow limits under all fault interruptions thereby.

Claim 10

A total range fault interrupter comprising the combination of: low range current interrupting apparatus operative to interrupt fault currents of relatively low magnitude, said apparatus comprising an elongated, substantially rigid insulative support member, first conductive means attached to said support, an elongated, insulative hollow fuse link tube of lesser length than said support releasably coupled to said first conductive means and depending therefrom, the lower end of said fuse link tube being open, a fuse link carried within said tube conductively attached to said first means to provide a current path through said cutout, said link being operable to sever under the influence of a fault current of said low magnitude, second conductive means attached to said support below said first conductive means and spaced therefrom, said second means being adapted to be electrically connected to a conductor extending away from said cutout, said fuse link extending from the lower end of said tube and electrically connecting with said second means, thereby completing the current path through said cutout, and biasing means cooperable with said fuse link to urge said fuse link tube out of engagement with said first member when said fuse link severs to thereby interrupt the current path through said cutout; high range current limiting fuse structure connected in series with said low range apparatus for interrupting all fault currents of high magnitude, said structure comprising an elongated, hollow insulative housing, closure means attached to said housing in covering relationship to opposed ends thereof to present a closed body, each of said closure means having conductive connection structure on the external face thereof respectively adapted to permit said fuse to be interposed within an electrical circuit, at least one relatively thin, elongated fusible element within said housing, the distal ends of said element being adapted for electrical connection with said respective external connection structure of said closure means, means electrically connecting each of said external connection structures with the distal ends of said fusible element to thereby create a current path through said fuse, a series of spaced zones along the length of said element within the housing having decreased cross-sectional areas relative to the remainder of the element, the ratio of the maximum cross-sectional area to the minimum cross-sectional area thereof being sufficiently high to cause said high range fuse to limit fault currents only of said high magnitude by the severance of said element at said zones of decreased crosssectional area, an elongated, insulative saddle member of synthetic resin material having a plurality of circumferentially-spaced fins, said fins being provided with spaced attachment means at predetermined points about the marginal edges thereof for the attachment of said fusible element, said fusible element being helically wrapped about said saddle member and attached thereto by said attachment means to form an internal fuse assembly, said saddle member and fusible elements cooperatively acting to position and support each other within said housing with the convolutions of said elements being maintained in an aligned, spaced relationship about said saddle, and pulverulent arc-suppressing material within said closed body in substantially surrounding relationship to the convolutions of said element, said material being characterizEd by the property of acting to quickly suppress the electrical arc forming upon the severing of said fusible element under the influence of a fault current; said apparatus and the structure being cooperable to effect interruption of low and high magnitude fault currents with substantial isoenergy dissipation within predetermined relatively narrow limits under all fault interruptions thereby.

Claim 11

A compact current limiting fuse adapted to be interposed in an electrical circuit to protect the latter from the effects of fault currents comprising: an elongated, hollow insulative housing; closure means integrally attached to said housing in covering relationship to opposed ends thereof to present a closed body, each of said closure means having conductive connection structure on the external face thereof respectively adapted to permit said fuse to be interposed within an electrical circuit; at least one relatively thin, elongated fusible element within said housing, the distal ends of said element being adapted for electrical connection with said respective external connection structure of said closure means; means electrically connecting each of said external connection structures with the distal ends of said fusible element, thereby creating a current path through said fuse; a series of spaced zones along the length of said element within said housing having decreased cross-sectional areas relative to the remainder of the element, thereby producing increased electrical resistance at said zones, whereby, under the influence of a fault current of predetermined magnitude, said element severs at least a sufficient number of said zones to effect a limiting of said current; an elongated, saddle member of relatively thin, electrically insulative material having a plurality of circumferentially-spaced fins, said fins being provided with spaced attachment means at predetermined points about the marginal edges thereof for the attachment of said fusible element, said fusible element being helically wrapped about said saddle member and attached thereto by said attachment means to form an internal fuse assembly, said saddle member and fusible elements cooperatively acting to position and support each other within said housing with the convolutions of said elements being maintained in an aligned, spaced relationship about said saddle; and pulverulent arc-suppressing material within said closed body in substantially surrounding relationship to the convolutions of said element, said material being characterized by the property of acting to quickly suppress the electrical arc formed upon the severing of said fusible element under the influence of a fault current.

Claim 12

A compact current limiting fuse adapted to be interposed in an electrical circuit to protect the latter from the effects of fault currents comprising: an elongated, hollow insulative housing; closure means integrally attached to said housing in covering relationship to opposed ends thereof to present a closed body, each of said closure means having conductive connection structure on the external face thereof respectively adapted to permit said fuse to be interposed within an electrical circuit; at least one relatively thin, elongated fusible element within said housing, the distal ends of said element being adapted for electrical connection with said respective external connection structure of said closure means; means electrically connecting each of said external connection structures with the distal ends of said fusible element, thereby creating a current path through said fuse; a series of spaced zones along the length of said element within said housing having decreased cross-sectional areas relative to the remainder of the element, thereby producing increased electrical resistance at said zones, whereby, under the influence of a fault current of predetermined magnitude, said element severs at least a sufficient number of said zones to effect a limiting of said current; an elongated, saddle member of relatively thin, electrically insulative material having a plurality of circumferentially-spaced fins, said fins being provided with spaced attachment means at predetermined points about the marginal edges thereof for the attachment of said fusible element, said fusible element being helically wrapped about said saddle member and attached thereto by said attachment means to form an internal fuse assembly, said saddle member and fusible elements cooperatively acting to position and support each other within said housing with the convolutions of said elements being maintained in an aligned, spaced relationship about said saddle; and pulverulent arc-suppressing material within said closed body in substantially surrounding relationship to the convolutions of said element, said material being characterized by the property of acting to quickly suppress the electrical arc formed upon the severing of said fusible element under the influence of a fault current.

Claim 13

The current limiting fuse of claim 8 wherein said saddle member is fabricated of synthetic resin material.

Claim 14

The current limiting fuse of claim 8 wherein said housing is generally cylindrical in shape and composed of fiber reinforced, synthetic resin material.

Claim 15

The current limiting fuse of claim 8 wherein said closure means are composed of conductive material, and said conductive connective structure is integral therewith.

Claim 16

The current limiting fuse of claim 11 wherein said closure means is provided with apertures therein receiving respective distal ends of said fusible element and said means for electrically connecting the distal ends of said element with said respective external connective structure comprises: mechanical connection means within said apertures adapted to seal said closed body and secure said distal ends of the fusible element therein; and means electrically connecting said mechanical connection means and said respective external connection structure, thereby providing a current path through said fuse.

Claim 17

The current limiting fuse of claim 12 wherein said mechanical connection means comprises expandable rivets operatively positioned within said apertures to secure said fusible elements within said housing.

Claim 18

The current limiting fUse of claim 13 wherein the external heads of said rivets are covered with fusible solder material to insure a substantially airtight seal about said aperture.

Claim 19

The current limiting fuse of claim 8 wherein said fusible element is composed of elemental silver.

Claim 20

The current limiting fuse of claim 8 wherein said zones of reduced cross-sectional area are defined by spaced transverse slots formed in said fusible elements along the length thereof.

Claim 21

The current limiting fuse of claim 8 wherein said saddle member is composed of four circumferentially-spaced fins radially extending from a common longitudinal axis, the marginal edges of said fins being provided with a series of spaced cradle openings for the reception of said fusible element.

Claim 22

The current limiting fuse of claim 17 wherein said cradle openings comprise generally circular openings in communication with the marginal edges of said fins, the maximum width of said openings being substantially equal to the widths of said fusible elements with the widths of said openings at the extreme edges of said fins being smaller than the widths of said fusible elements.

Claim 23

The current limiting fuse of claim 8 wherein said attachment means are positioned about said fins in disposition to support the fusible element in a symmetrical helical pattern about said saddle, the longitudinal axes of said saddle and the helically wound element being substantially coincident.

Claim 24

The current limiting fuse of claim 8 wherein said pulverulent material is silica sand.

Claim 25

The current limiting fuse of claim 20 wherein said sand has an average mesh size within the range of 30 to 70.

Claim 26

The current limiting fuse of claim 8 wherein said internal fuse assembly includes a single helically wound fusible element.

Claim 27

The current limiting fuse of claim 8 wherein two fusible elements are helically wound about said saddle member to form said internal fuse assembly, said separate helices being of substantially equal pitch and about one-half pitch out of phase respectively, thereby spacing the helical windings of said fusible elements along the length of said saddle.