Abstract: An arc quenching, current limiting fuse utilizing a fuse link having a plurally of bends which cause the fuse link to come in contact or come in close proximity to the inside wall of the fuse body. When a short circuit and electrical arc occurs, the fuse link material burns toward the fuse wall creating an interaction with the fuse wall and an increase in pressure which extinguishes the arc.

Abstract: The disclosed electrical fuse has a fuse link in a filling of sand and a binder that imparts high thermal conductivity to the filler. The binder is a shiny coating on the grains of sand extending from grain to grain. It is an amorphous coating. The exemplary binder is boric oxide, B.sub.2 O.sub.3.

Abstract: A protective fuse assembly for a current limiting fuse of the type, including a dielectric housing enclosing the fuse, an end cap secured to the lower end of the fuse by a pyrotechnic charge assembly, the end cap supporting the housing on the fuse, an end cap mounted on the upper end of the fuse for centering the housing on the fuse, and an electrically conductive wire connecting the charge to the fuse whereby the charge is detonated when the fuse senses a fault current to release the lower end cap from the fuse so that the housing drops to the bottom of the fuse.

Abstract: A spiral wound sand fuse has a non-reactive fiber core permitting use of the fuse to interrupt high fault currents in high voltage circuits.

Abstract: The high speed fuse employs stamped end bell and terminals rather than forged or machined parts. A slot for the terminal is punched through the end bell. The terminal is inserted into the slot in the end bell and staked in position. This insures a strong tight fit without requiring welding or soldering. One end of each terminal has coined ridges to facilitate automatic welding of the fuse link to the terminals. Round balls are used to seal the fill holes for the arc quenching material. Metal pins secure the end bells within the fuse housing but are not electrically connected to the terminals because of the insulative end bells.

Abstract: A high speed fuse 8 having terminals 14 staked to non-electrically conductive end bells 12 with fusible element 30 connected to ridges 44 on terminal 14 by projection welding, and round balls 18 plugging sand holes 20.

Abstract: A high power current-limiting fuse comprises a cylindrical envelope which closely surrounds a metallic fusible element in the form of a wire or ribbon. The cylindrical envelope is made of high density rigid ceramic such as Alumina of formula Al.sub.2 O.sub.3, and Beryllium oxide of formula BeO. The two ends of the envelope are metallized to form two terminals respectively connected to the ends of the fusible element, whereby the current-limiting fuse is connectable to an electric circuit to be protected through the two so formed terminals. A sheath of fiberglass or ceramic can be mounted around the cylindrical envelope so as to increase the mechanical rigidity of the current-limiting fuse.

Abstract: The disclosed fuse has a tube of insulation, terminals at the ends of the tube, a link connecting the terminals, and a granular filler. At least one end cap is made of sheet metal which has one or more integrally extending tabs and a respective hole for each tab, each tab and its hole having the same size and shape. Granular fill is introduced via said hole(s) while the tab(s) are raised to provide wide openings. The end cap is sealed by driving the tab(s) into the hole(s). After the fuse contains granular filler but before driving the tab(s) into the hole(s), the fuse may be impregnated with a fluid, first adjusting the tab(s) to be narrowly open to retain the granular filler while admitting the impregnant.

Abstract: A fuse comprising a body (20) encapsulating a fuse element (22), said body (20) including a baseplate (16) formed from a material having good thermal conductivity; a pair of elongate terminals (12) being connected at one end to the baseplate (16) through the intermediary of a layer of electrically insulating, heat conducting material (26) so as to extend away therefrom and project from said body (20); the fuse element (22) being provided between the terminals (12) within the body and being surrounded by an arc quenching material (24).

Abstract: A fuse for an alternating current power circuit. The fuse comprises an input terminal (4), a first contact (5) electrically connected to the input terminal, an output terminal (9) and a second contact (8) electrically connected to the output terminal. A fusible element (11) electrically connects the first and second contacts and completes a normal electrical path between the input and output terminals. An arcing contact (6) is positioned in relation to the first contact (5) so as to form a potential arc path between the first contact and the arcing contact, along which path an arc will become established after the fusible element breaks in response to fault current. The arcing contact (6) is electrically connected to a third terminal (41) and is electrically isolated from the output terminal (9).

Abstract: A fuse for an alternating current power circuit in the medium voltage (3.3 kV to 38 kV) range. The fuse comprises a sealed chamber and a first electrode (41) is mounted within the chamber, the first electrode having a substantially circular periphery (42) and being electrically connected to a first terminal (3) to which a first conductor may be connected. A second electrode (35) is arranged with a conductive surface internally of the chamber, the conductive surface being spaced from the first electrode. A coil (10) is connected in an electrical path between the second electrode (35) and a second terminal (18) to which a second conductor may be connected. An additional electrical contact (44) is mounted within the chamber and in direct electrical connection with the second terminal, and a fusible element (43) directly electrically connects the first electrode (41) and the additional electrical contact (44). An electronegative halogenated medium fills free space within the chamber.

Abstract: A fuse assembly includes a housing having a base, side and end walls and a removable cover. Studs extend through the base and a current limiting fuse is connected between the studs. The cover, which has an edge gasket, is held against the side and end walls by fasteners which extend through the cover and threadedly engage the studs, the fasteners having enlarged heads to press against the outer surface of the cover and hold it firmly in place, forming a sealed interior chamber for the fuse. A locking filament inhibits unscrewing the fasteners.

Abstract: A vacuum fuse (10) including a pair of arcing electrodes in the form of parallel, confronting, spaced apart disks (13, 14) supported on the inner ends of aligned contact rods (11, 12). The confronting surfaces of the electrodes define an arc gap (18) and are provided with a plurality of arcuate slots (54). A fusible element (19) projects from bores (23, 24) which are recessed relative to the confronting disk surfaces to bridge the arc gap and it and the arcing electrodes (13, 14) are electrically connected to the contact rods (11, 12). The fusible element (19) is flattened at the mid-point of the arc gap and a hole (22) is drilled in the flattened section. The outer housing (1) of the fuse (10) includes a metallic housing member (7) and ceramic end plates (4, 6). Use of a metallic housing (7) eliminates the need for a separate, axial, metallic shield to prevent deposition of vaporized metallic particles during current interruption.

Abstract: The high current interrupting fuse of the invention includes an envelope free of sand or similar arc quenching material. The envelope preferably has terminal end caps enclosing the ends of the envelope between which caps a fuse element extends. The envelope has an arc-quenching gas-releasing material at least at the inner surface of the envelope. Arc barrier plugs made of an ablative material surround each end of the fuse element which for ease of assembly freely pass through bores of plugs. The fuse element also preferably passes through metal plates externally of the plugs and adjacent to the end caps.

Abstract: A fuse for an alternating current power circuit in the medium voltage (3.3 kV to 38 kV) range. The fuse comprises a sealed chamber and a first electrode (41) is mounted within the chamber, the first electrode having a substantially circular periphery (42) and being electrically connected to a first terminal (3) to which a first conductor may be connected. A second electrode (35) is arranged with a conductive surface internally of the chamber, the conductive surface being spaced from the first electrode. A coil (10) is connected in an electrical path between the second electrode (35) and a second terminal (18) to which a second conductor may be connected. An additional electrical contact (44) is mounted within the chamber and in direct electrical connection with the second terminal, and a fusible element (43) directly electrically connects the first electrode (41) and the additional electrical contact (44). An electronegative halogenated medium fills free space within the chamber.

Abstract: A current limiting fuse has an electrical subassembly which includes fusible elements that are helically wound about a plurality of support plates which, in turn, are secured on each end to a terminal bracket. A leg member electrically and mechanically interconnects the terminal bracket to an end cap assembly fixed to a fuse housing and is flexible for allowing variation in distance between the end cap assembly and the internal subassembly such as would occur when the fuse is exposed to thermal excursions. The flexible leg has a portion which extends in generally transverse relation to the longitudinal axis of the subassembly, and the leg portion is swingable in an arc as the associated end cap assembly shifts relative to the position of the terminal bracket.

Abstract: A fuse (12) comprising a tube of insulating material having an inner (16) and an outer wall surface (18) and forming a fuse housing (14). The fuse includes a pair of conductive fuse terminals (24, 26) secured at opposite axial ends (20, 22) of the tube. A fuse element (23) is axially disposed within and extends between the ends of the fuse housing, and its ends are electrically and physically directly connected with the adjacent fuse terminal. A plug of initially solid, arc-quenching material (32) at preferably only at one end of the fuse housing occupies only a limited axial extent thereat and evaporates under fuse blowing conditions to fill the housing with an arc-quenching vapor.

Abstract: A fuse cartridge for example of the cylindrical type comprising an insulating cylindrical body ending in two conducting end pieces and a fuse element connected electrically to the end pieces, further comprising two pistons housed in the body which are movable in translation in opposite directions to each other and collect the gases released by the electric arc at the time of its appearance, so that the pressure of the gases exerts on each piston a force which causes it to move towards a position in which the arc is totally sheared.

Abstract: An electric fuse for high voltage circuit comprises an insulative tubular casing closed at both ends with metal caps and has an insulative cylindrical member within said tubular casing disposed eccentrically and is offset relative to the major axis of said tubular casing so as to define an annular space therewith which is non-uniform in width. The annular space has a wider portion on one side of said tubular member and a narrower portion on the other side thereof. A fusible element is stretched in said narrower portion of said annular space and is secured at both ends to said metal caps.

Abstract: An end cap assembly for a fluid resistant electrical device includes a solderable insulating tube end cap and an insert having a solderable cylindrical body portion positioned within a tubular opening of the end cap. The body portion of the insert has a circumscribing groove containing a quantity of solder. During assembly, the walls of the end cap defining the tubular opening are magneformed inwardly to tightly engage the body portion and thus provide limited frictional resistance to movement of the insert relative to the end cap. Next, the end cap and insert are heated until the solder melts. The end cap assembly provides a strong, torque resistant connection between the insert and the end cap while also maintaining a highly effective seal to preclude fluid leakage when the device is immersed.

Abstract: A current limiting fuse with less-inverse time-current characteristics characterized by a tubular housing having electrical terminals at each end, a fusible structure in the housing and interconnected between the terminals, the fusible structure comprising first fusible portions of silver alloy and second fusible portions of tin alloy intermediate the first fusible portions, and an arc-extinguishing filler around the second fusible portion.

Abstract: A self-recovery type current limiting element for suppressing overcurrent conditions and capable of recovering so as to be operated under normal current conditions including two identical element cylinders coupled therebetween by a coupler. A series of annular insulating members are provided within the element cylinders and include through holes for current limiting material providing a current limiting path extending longitudinally of each cylinder from an entrance opening at one end connected to the coupler to a buffer at the other end. The through holes in certain members nearer the coupler have a cross-sectional area smaller than the other annular members in the respective cylinders, providing a constricted region of the path. The current limiting material vaporizes when heated by current overload so as to increase resistance to suppress the current passing through.

Abstract: A high voltage fuse having a fuse assembly embedded in a granular dielectric material within a cylindrical dielectric housing, the fuse assembly including a number of fuse support surfaces, a support ring at each end of the plates to hold the plates in on equally spaced radial rotation, a conductive plate secured to each of said rings and including a threaded boss, a fuse element helically wound around said support surfaces and being electrically connected to said support plates, an electrically conductive end cap having a threaded stud and being mounted at one end of said housing, whereby the boss on one end of said fuse assembly is connected to said stud.

Abstract: There is provided by this invention a current limiting fuse having a fuse element wound about support means consisting of a non-stoichiometric oxide core that produces an electro-negative gas when heated by the melting fuse element. The generation of the electro-negative gas results in more rapid and efficient arc extinction.

Abstract: An explosively-assisted fuse is passively triggered (without electronics) by means of an auxiliary fuse in series with the main conductor. The auxiliary fuse provides a detonating voltage across a gap formed therein on melting in response to a fault current. The auxiliary fuse is configured to facilitate sizing for a variety of current loads with a standard fuse configuration.

Abstract: The invention relates to an assembly for a current limiting high voltage fuse, comprising a preferably tubular support body (1), consisting of quartz glass, and fusible conductors (2) attached over their entire length to the support body, which conductors (2) are of a width of minimum 0.5 mm and maximum 1 mm and of a thickness of maximum 50 .mu.m.These fusible conductors are applied in parallel paths, the distance between the paths being at least twice as large as the width of the fusible conductors. Also the fusible conductors are provided with narrow sections (4) separated in longitudinal direction of the fusible conductor over regular distances, and interconnected at both ends by an electrically conducting sleeve (3) applied to the support body (1).

Abstract: There is provided a current limiting fuse having a uniform and supported element with arc voltage controlling and shaping capabilities that can withstand high mechanical and electrical stress.

Abstract: There is provided by this invention a current limiting fuse having a zinc oxide core electrically connected in parallel with an array of wire fuse elements capable of shaping and controlling the arc voltage developed during current interruptions.

Abstract: There is provided a current limiting fuse having an electrically parallel connected non-linear resistor element for limiting and shaping the arc voltage developed during current interruption.

Abstract: A current-limiting fuse comprises a hollow insulating housing; metallic end cap assemblies at opposite ends of the housing; a multi-ribbed dielectric spider assembly having metallic terminator plates connected at opposite ends disposed within the housing with each terminator plate electrically and mechanically connected to an associated end cap assembly; a plurality of fusible elements helically wound on the spider assembly with their ends electrically and mechanically secured to the terminate plate; a visual indicator pin mounted on one end of the spider assembly and movable by a biasing spring from a retracted position wherein it is secured by a fusible wire to a tripped (fuse-blown) position wherein it projects through aligned holes in an associated terminator plate and end cap assembly; and granular dielectric material filling the housing.

Abstract: A high-speed switch usable at high voltage includes a pair of contacts movable apart along a fixed line. When the contacts are normally interconnected, at least one of them contributes to the definition of an enclosed chamber. Pressurization of the chamber by the ignition of a power cartridge therein rapidly drives the contacts apart, forming a first gap between them. The first gap is electrically insulated and is shielded from the ignition products of the cartridge. Any arc forming in the first gap is constricted and subjected to arc-extinguishing gas. When the contacts are interconnected, a first one of them is electrically connected to a terminal. After the contacts move apart, a second gap forms between the first contact and the terminal. The second gap is electrically insulated and is shielded from the ignition products of the cartridge. A fuse may be connected in shunt with the contacts and the insulated gaps.

Abstract: This high voltage fuse comprises a pair of spaced terminals and a fusible conductive element connected between the terminals. At spaced locations along the length of the fusible element, there are bodies of a material that exothermically reacts when heated to a predetermined temperature. Connected between the terminals independently of the fusible element is a triggering circuit. The bodies of exothermic material are connected in good heat-transfer relationship with the triggering circuit and the fusible element so that the heating effect of current through the triggering circuit upon disruption of the fusible element causes the material of said bodies to exothermically react and thus cause further disruption of the fusible element at additional locations respectively located adjacent said bodies.

Abstract: A current limiting fuse has a main fusible element and an auxiliary fusible element each helically wound over an insulative support member. Each end of the auxiliary element is connected to conductive metal clips or electrodes in which blocks of metal oxide varistor material are fixedly secured and placed in contact with the main fusible element. Subsequent to the initial burn back of the main fusible element, the metal oxide varistors precisely initiate electrical arcs between the terminal clips at the ends of the auxiliary fusible element and the main element at points adjacent to these terminal clips. The presence of these arcs quickly sever the main element or elements at these points thereby producing additional burnback areas in the main fusible element or elements.

Abstract: The present invention concerns the use of polyester materials in arc quenching applications, particularly in the cutout fuse tube industry. In one embodiment of the present invention a fuse tube is disclosed as comprising a laminate two-layered structure including as its inner layer, (or liner), a polyester filament winding supported in a cured cyclo-aliphatic epoxy resin matrix. The outer layer includes wound glass filaments supported within a cured epoxy resin matrix.

Abstract: The present invention concerns improvements in the use of polyester materials in arc quenching applications, particularly in the cutout fuse tube industry. In one embodiment of the present invention a fuse tube is disclosed as comprising a laminate two-layered structure including as its inner layer, (or liner), a heat-treated polyester filament winding supported in a cured cyclo-aliphatic epoxy resin matrix. The outer layer includes wound glass filaments supported within a cured epoxy resin matrix. The heat treatment of the polyester filament substantially improves the mechanical and electrical character of the fuse tube.

Abstract: A high speed high voltage electrical switch opens a current path in which the switch is included. The switch includes first and second normally electrically interconnected contacts which normally carry current in the current path. The contacts are relatively movable along a fixed line of direction. When the contacts move apart, the electrical interconnection therebetween is broken to open the first current path. A piston carried by the second contact defines an enclosed chamber in conjunction with the first contact when the contacts are interconnected. A power cartridge or the like selectively pressurizes the chamber to rapidly drive the contacts apart. The piston enhances the action of the power cartridge by ensuring that pressure increases caused thereby are effected to drive the contacts apart. The piston may be configured to ensure positive sealing engagement with the walls of a cylinder through which the piston and the second contact move following the ignition of the power cartridge.

Abstract: A fuse cartridge specifically designed to resist axial compressive forces is disclosed. The tubular body of the cartridge is reinforced by an insulating spacer between the heads of the cartridge which is capable of resisting such compressive forces. The spacer is normally located on the axis of the cartridge but may itself be tubular and surround the fusible elements if desired. The cartridge is particularly designed for mounting radially on a rotatable support with its outer end secured thereto and a fixing lug may be provided for this purpose. To compensate for the mass of the lug, a lateral cutaway is formed in the head from which it extends.

Abstract: This concerns a fuse of the type having a central mandrel or fuse spider around which is wound one or more fuse elements. At least one longitudinal strut of the mandrel is disposed to be freely rotated about its axis within limits during a fusing operation. Ideally, spaced struts are disposed to rotate in opposite directions about their axes. The aforementioned fuse element is fixedly secured to the struts so that the opposite rotational movement will strain each fuse element after a fusing operation has begun, thus mechanically breaking those fuse elements in several places to enhance the low current clearing capability of the fuse. An appropriate device for causing the rotation is provided. The device may be driven by an electrically actuated, highly controlled explosive charge which moves a plunger which in turn actuates interlinked levers, thus causing the desired rotation. The foregoing fuse is especially helpful in current limiting operations for high voltage, low current situations.

Abstract: An electric fuse has rod supports for the helically wound fusible element which are of a laminate of glass cloth and a synthetic resin. This is a material which is slightly gas evolving. The rods have inserts of a material which is highly gas evolving, and they provide a substantial spacing between the path of the fusible element--and the arc path--and the surface of the rod supports for it. The limited gas evolving capacity of the rods combined with the large gas evolving capacity of the inserts and combined with the spacing between the arc path and the surface of the rods allows proper operation of the fuse in the absence of any ceramic insulators or ceramic supports for the fusible element.

Abstract: An electric fuse having a support for the helically wound fusible element or elements. The support includes a plurality of rod-like supports each made of one uniform material. Some of the plurality of rod-like supports consist solely of a non-gas-evolving material, while at least one of the plurality of rod-like supports consists solely of a gas-evolving material.

Abstract: An oil immersible current limiting full range fuse including a tubular housing, end caps hermetically sealed to each end of the housing and supporting a full range fuse assembly within said housing, the housing being filled with a granular arc extinguishing filler, the hermetic seal provided between the housing and the end caps is formed by a resilient gasket mounted at each end of the housing and epoxy adhesive provided in the end caps, the adhesive being displaced by the gasket on insertion into the space between the end cap and the outer wall of the housing.A method for testing the hermetic seals for leaks which includes the steps of injecting sulfur hexafluoride into the housing, sealing the housing, confining the fuse in a closed space for a predetermined period of time and testing the atmosphere of the confined space to determine the presence of sulfur hexafluoride.

Abstract: In fuses embodying this invention each of the terminal elements has a port for the passage of fluid through the casing of the fuse during normal operation thereof, i.e. while the fuse is carrying current. A tubular fusible element conductively interconnects said port in each of said terminal elements. The fuse further includes a toroidal body of quartz sand filling the space between said casing and said tubular fusible element. The fusible element has perforations covered by annular structures of electric insulating material precluding said quartz sand from penetrating into said tubular fusible element during the normal operation of said fuse. The fuse is further provided with a pair of check valves which open during normal operation of said fuse and then allow the flow of fluid through said tubular fusible element and close on occurrence of a build-up of a predetermined amount of pressure inside of said tubular fusible element and then inhibit said flow of fluid.

Abstract: A high-voltage fuse having a casing closed at each end thereof by a pair of composite plug terminals. Each of these composite plug terminals is made up of a pair of semi-cylindrical complementary parts. The fuse includes a pair of helically wound fusible element means whose longitudinal axes are parallel to each other and spaced from each other. One of said pair of fusible element means and one pair of semi-cylindrical terminal parts are arranged to one side of a plane of symmetry extending in a direction longitudinally of the casing of the fuse. The other of said pair of fusible element means and another pair of semi-cylindrical terminal parts are arranged to the other side of the aforementioned plane of symmetry.

Abstract: A high-voltage fuse having a pair of axially spaced paper labels at the relatively cool ends thereof remote from the plateau-like high temperature zone formed by the fuse when carrying current.