Abstract: A high voltage fuse with an element operating at relatively high temperatures and having such element comprised of a metallic material which is highly susceptible to oxidation at such temperatures is disclosed. The fuse element has predetermined dimensions so as to have a predetermined time-current characteristic. The high voltage fuse has a sealed environment for housing the fuse element. The fuse element has a thickness dimension sufficiently great so that any oxide layer that may accumulate on the fuse element over a service period of 15 years does not significantly affect the predetermined time-current characteristic of the fuse element during the period.

Abstract: For interrupting all values of electric current in a high voltage circuit which cause operation of a fuse within one hour, a plurality of parallel connected helically configured fusible elements formed of cadmium are embedded within quartz sand in granular form disposed within a housing structure which includes a tubular member of insulating material to the ends of which terminal caps are secured and connected to the ends of the fusible elements respectively so that currents of a high order of magnitude are interrupted in a fraction of a half cycle in a current limiting fashion and so that currents of a low order of magnitude and which are slightly in excess of normal rated load current of the fuse cause the temperature of the fusible elements to rise to the melting point within a longer predetermined period of time and then to establish a gap sufficient to withstand the recovery voltage.

Abstract: A protective fuse comprising a fusible element disposed within an enclosure formed by a gas generating fiber tube connected at one end to a conductor rod and at the other end to an arc intercepting member. The arc intercepting member is connected to an elongated tubular resistor element which in turn is connected at its opposite end to a cap comprising a conductor connected to the fusible element. Upon parting of the fusible element an arc established by the fault current comes into contact with the arc intercepting member so that a circuit is established through the resistor element thereby momentarily reducing the fault current to a level which can be extinguished by the deionizing gases generated within the interior of the fuse. The conductor rod is formed of a magnetic material which is capable of generating a substantial magnetic flux which functions to bias the arc against the interior wall of the fiber tube to enhance the generation of deionizing gases.

Abstract: A three-terminal thermal switch having a common connector arm biased against a terminal of fusible material. When the terminal is softened or melted by current, the connector arm is released and moves into contact against a second terminal. Positioned in the base of a long-life dual-filament incandescent light bulb, the switch causes one filament to be energized until it burns out, and then connects the other filament to be energized.

Abstract: A fuse element is a ribbon of aluminum or aluminum alloy having a terminal at each end of the ribbon. Each terminal is made of copper sheet material having a portion that is tin plated. The tin plated portion is folded over the end of the ribbon to contact both sides and is welded to the ribbon to form a connection capable of carrying short circuit currents and able to withstand repeated temperature changes. Preferably the weld consists of three side-by-side spot welds extending on either side of the ribbon to the respective tin plated terminal portion.

Abstract: For interrupting all values of electric current in a high voltage circuit which cause operation of a fuse within one hour, a plurality of parallel connected helically configured fusible elements formed preferably of cadmium are embedded within quartz sand in granular form disposed within a housing structure which includes a tubular member of insulating material to the ends of which terminal caps are secured and connected to the ends of the fusible elements respectively so that currents of a high order of magnitude are interrupted in a fraction of a half cycle in a current limiting fashion and so that currents of a low order of magnitude and which are slightly in excess of normal rated load current of the fuse cause the temperature of the fusible elements to rise to approximately the melting point so that the fusible elements melt in random sequence following which arcs are established progressively by commutation action along a substantial portion of the length of each fusible element by direct arc contact, b

Abstract: A fusible element for electric fuses including a core or layer of copper, an outer layer of silver plating, and an M-effect overlay on the silver layer of a low fusing point metal, e.g. tin, capable of severing the current path through the plating of silver and the core of copper by a metal diffusion process.The M-effect overlay is arranged in spaced relation in regard to the point of the fusible element where the highest temperature prevails to maximize the temperature difference, or temperature gradient, between the M-effect overlay and the hottest point of the fusible element when the latter is carrying current.

Abstract: A fusible element having an ability to withstand a large number of on-off cycles is provided. The element comprises a ribbon of copper without any M-effect causing means. The element is bent in a zig-zag shape to establish a plurality of contiguous planar sections enclosing obtuse angles with each other and forming straight edges of the loci of intersection of the planes defined by the planar sections. The straight edges are non-perforated to maximize their flexure strength. Each of the planar sections is provided with at least one point of reduced cross-section remote from the straight edges. The ribbon of copper is electro-plated with sulfamate of nickel forming a dull, ductile layer of nickel.

Abstract: A fusible element of a current-limiting fuse has a plurality of hole groups with at least two holes in each group. Separation between adjacent holes within the group is substantially less than separation between adjacent groups. Accordingly, while fault currents driven by voltages at two different levels are effectively extinguished, the back voltage developed by the fuse during interruption of a fault current driven by the lower voltage is prevented from exceeding a selected value.

Abstract: A current limiting fuse includes a fusible strip having semi-circular apertures formed therein, centrally disposed between the longitudinal edges of the strip. The diametric edges of the apertures lie transverse to the longitudinal edges of the fusible strip. The curved edges of the apertures are disposed in opposing relationship. Electrical weak spots which are less conductive than the remaining areas of the strip are defined between the semi-circular apertures and the longitudinal edges of the fusible strip. Semi-circular cut-outs may be included along the longitudinal edges of the fusible strip adjacent the centrally disposed semi-circular apertures to define the electrical weak spots between the cut-outs and centrally disposed apertures.

Abstract: An electric fuse according to this invention incorporates metal end caps and an elongate fuse element having regions of reduced cross-sectional area and extending in electrical series between the metal end caps, wherein the fuse incorporates within each end a respective gasket of an absorbent material impregnated with an arc-inhibiting substance. Materials which have been found to be particularly effective for the gaskets are asbestos and absorbent types of paper, including strawboard and cardboard, impregnated with an arc-inhibiting compound constituted, suitably, by sodium silicate.

Abstract: A laminated electric safety fuse which is built up laminated design consisting of various conductive materials which are embedded on an electrically insulating supporting member. The supporting member comprises one or more layers of electrically insulating material, a predominant part of which is a material having good thermal conductivity.In this design a narrowing effect is obtained which is up to 10 times larger than in known fuses, without sacrificing the current-carrying capacity of the non-narrowed parts of the fuse element.The various layers from which the safety fuse is built up can consist of materials with different electric conductivity, providing a new variable for obtaining an increased narrowing effect. The individual layers can be built up as films, e.g. by evaporative deposition.

Abstract: Electric fuses according to this invention aim to increase the ratio between current-carrying capacity and i.sup.2 .multidot.t values. This means, in other words, to increase the current-limiting action for any given current rating.The fusible element of such fuses comprises an axially inner substantially planar portion of silver having at least one short-circuit neck adapted to initiate circuit interruption when said neck reaches approximately the fusing temperature of silver. The fusible element of such fuses further comprises a pair of non-planar axially outer portions of copper each having a larger width and a larger surface than said axially inner portion. The axially inner portion and the axially outer portions are conductively interconnected.

Abstract: An electric fuse, in particular an electric time-lag fuse, comprising a tubular casing, a pair of terminal elements, a granular arc-quenching filler, and a pair of parallel fusible elements inside the casing interconnecting the pair of terminal elements. Each of the pair of fusible elements has a plurality of juxtaposed points of reduced cross-section. Juxtaposed points of reduced cross-section support an M-effect causing overlay thereon. Each of the M-effect causing overlays extends from a pair of juxtaposed points of reduced cross-section in opposite directions longitudinally of said pair of fusible elements. A substantially E-shaped member of a solid gas-evolving material having three arms is associated with said pair of fusible elements. One of said three arms is interposed between said pair of fusible elements at the region thereof where the juxtaposed points of reduced cross-section are located.

Abstract: A high voltage fuse comprised of a fuse element wrapped about a core, enclosed in a housing member, and surrounded by a granular quartz material is disclosed. The core has a plurality of cutouts along its outer surfaces having preselected dimensions relative to the width of a fuse element of such values as to assure that at least one cutout is interposed between adjacent turns of the fuse element. The interposed cutouts increase the creepage between the adjacent turns of the fuse element. The preselected dimensions of the cutouts relative to fuse-element width provide a single core that is capable of accommodating numerous types and different numbers of fuse elements. The core is also provided with a gas evolving material attached to the cutouts and separated from the fuse element by a predetermined amount to provide controlled release of arc-quenching gas, when arcing inside the fuse occurs.

Abstract: A composite fusible element for electric fuses comprising a pair of spaced drawn wires substantially circular in cross-section, at least one pair of spaced plates of sheet metal in contact with said pair of wires, and electrical bonds conductively connecting each of said pair of wires and one of said pair of plates. The pair of wires is preferably of silver, and the pair of plates is preferably of copper. A fuse according to the invention includes a fusible element as described above.

Abstract: A current-limiting fuse including a fusible element that comprises a relatively long portion of sheet copper and one or two end portions of sheet silver. The portions of sheet silver are each shorter than the portion of sheet copper. The portion of sheet copper is perforated, establishing points of reduced cross-section. The portion or portions of sheet silver are likewise perforated. The points of reduced cross-section established by the perforation, or perforations, in the portion or portions of sheet silver have a considerably smaller cross-section than the points of reduced cross-section in the portion of sheet copper.

Abstract: A current limiting fuse has a helically coiled fuse element of ribbon-like material extending within a tubular casing between metallic end caps. The ribbon-like material is edge on to the axis of the helix for permitting a greater length of fuse element than if the ribbon-like material had its flat side towards the axis. In a preferred form, the ribbon-like material has ripples or indentations across it with the ripples having a greater displacement at the edge of the ribbon-like fuse element nearer the axis.

Abstract: A laminated electric safety fuse which is built up laminated design consisting of various conductive materials which are embedded on an electrically insulating supporting member. The supporting member comprises one or more layers of electrically insulating material, a predominant part of which is a material having good thermal conductivity.In this design a narrowing effect is obtained which is up to 10 times larger than in known fuses, without sacrificing the current-carrying capacity of the non-narrowed parts of the fuse element.The various layers from which the safety fuse is built up can consist of materials with different electric conductivity, providing a new variable for obtaining an increased narrowing effect. The individual layers can be built up as films, e.g. by evaporative deposition.

Abstract: A fusible element for electric fuses capable of combining time-lag in the range of overload currents with current-limiting action for currents in the range of short-circuit currents. The fusible element comprises a relatively wide perforated center section and axially outer heat dam sections. The center section has points of reduced cross-section imparting to it a predetermined fusing i.sup.2 .multidot.t. The center section of the fusible element is folded in a direction longitudinally thereof to effect mutual heating of the portion, or portions, thereof to different sides of the fold, or folds. This allows to increase the mass of the center section and results in an increase of time-lag. Relatively narrow heat-dam-strip sections extend from the ends of said center section. The fusing i.sup.2 .multidot.

Abstract: An electric fuse for elevated circuit voltages, such as, e.g. 5 to 15 KV. It includes a tubular casing or electric insulating material, terminal elements and a pulverulent arc-quenching filler. It further includes a plurality of equidistantly spaced fusible elements electrically connected in parallel, wound substantially helically in planes defining a prism and forming part of a current path conductively interconnecting the pair of terminal elements.The point of novelty consists in that the fusible elements are formed by a unitary metal stamping. That stamping also includes aligned metal bridges conductively interconnecting all the fusible elements. The preferred number of planes or sides of the aforementioned prism is four and the preferred number of bridges is n-1 for each quarter turn of the fusible elements, wherein n is the number of fusible elements connected in parallel. The bridges are arranged in spaced relation from the edges of the prism.

Abstract: An electrical fuse is taught having a ribbon-like fuse element therein. The fuse element has a generally uniform width along its length, but the depth of the fuse element is tapered in some regions. Holes or openings of various shapes are disposed along the length of the fuse through the depth thereof. The holes may be circular, triangular, or rectangular in shape and may be through a central portion of the fuse element or may comprise notches at the edges of the fuse element or both. The depth of the fuse element may increase with longitudinal distance from a relatively thin central portion of the fuse element to relatively thick end portion thereof, or vice versa. During low current clearing, the relatively thin portion will melt first and then burns back along the tapered portions until the fault current is extinguished.

Abstract: A fuse-element for electric fuses is shaped as a metal strip with one or more zones of diminished cross-section.The temperature rise conditions of the fuse-element and of its zones of diminished cross-section can be established and evaluated in combination and--based on these data--a fuse-element can be designed the temperature distribution characteristics of which include different local peak values and the spots where such peak values develop can be set in a manner that the whole fuse-element consists of two parts as far as the temperature distribution is concerned, i.e. a first part where this distribution is in accordance with a steady state distribution (the highest current value still failing to cause any melting), and a second part where the temperature rise distribution determines the character of the melting process, this being the so-called transient distribution characteristic.

Abstract: A pair of parallel fusible elements is sub-divided, or separated by points of reduced cross-section into two parallel strings of fusible element sections. The pair of fusible elements is supported by a support of electric insulating material including a portion arranged between the pair of fusible elements and extending in a direction longitudinally thereof. The support further includes transverse arms arranged to both sides of the portion of the support that extends in the direction of the pair of fusible elements. These transverse arms are planar and support said planar fusible element sections and consequently the pair of fusible elements. The arms sandwich the planar fusible element sections which are arranged between the arms. If fusible elements of the above kind are connected in parallel into an electric circuit, the fusible elements will fuse sequentially at low currents at one or more points thereof. This process is often referred-to as "triggering".

Abstract: A ribbon-type fusible element is subdivided by equidistant points of equally reduced cross-section into a plurality of serially connected fusible element sections. These include first angularly bent fusible element sections comprising two half-sections, second fusible element sections being planar and arranged in spaced relation from the first fusible element sections, a planar support for the second fusible element sections; and third fusible element sections which are angularly bent and conductively interconnect the first and the second fusible element sections. The above planar support includes a portion that extends in a direction longitudinally of the fusible element and transverse arms that are in registry with the second fusible element sections. Fastener means project through said transverse arms and said second fusible element sections. As a result, the sections of the fusible element situated between contiguous fasteners are fixedly supported.

Abstract: A wide-range current limiting fuse assembly particularly adapted to protect capacitors. The device comprises a current limiting portion having a corrugated fusible ribbon for high fault current protection, and a low current portion having a fusible link surrounded end to end by a conductive metal sleeve connected to one terminal of the fusible link. The current limiting portion may, alternatively, be provided with a circularly cross sectioned fusible wire connected in series with the fusible ribbon.

Abstract: A fuse having a composite fusible element comprising a plurality of separate, parallel, equidistantly spaced wires. A plurality of bridges of electric insulating material is arranged substantially transversely to the aforementioned wire-like fusible elements at spaced fixed points thereof integrating said plurality of fusible elements into a ribbon-like unitary structure and maintaining said wire-like fusible elements equidistantly spaced at said plurality of points thereof. Said plurality of wire-like fusible elements are wound helically around a prismatic surface in such a way that said plurality of bridges are located between the edges of said surface.

Abstract: A novel fuse arrangement for electrical and electronic circuits is provided having shorter arcing time and arc-extinguishing time as compared to the prior art fuses. The fuse arrangement described herein comprises a pair of electrodes having contact terminals for connection to the circuit and a support member preferably disposed triangularly relative to the electrodes. In one embodiment, a fusible wire elment is stretched between the electrodes and has its mid portion supported by the support member. The support member is made from a material of large heat capacity and high thermal conductivity to provide a heat dissipating surface for the heat generated in the fusible wire element.

Abstract: A fusible element for a current limiting fuse includes two silver ribbons, each provided with a plurality of holes spaced apart along the length thereof which define fusible points of reduced cross sectional area, one of these ribbons including a conventional "M" spot consisting of a body of low melting temperature alloy such as tin-lead solder, in intimate contact with the silver ribbon. One end of each of the silver ribbons is joined to a respective end of a centrally disposed tin wire element by a copper interconnecting member. This tin wire central portion of the fusible element has a melt I.sup.2 t which is equal to or greater than that of the silver ribbons in series with it.

Abstract: An improvement in a high voltage, full-range, current limiting fuse of the type which includes a perforated ribbon main fusible element wound about a gas evolving spider within a sand filled enclosure, and having a portion in intimate contact with a body of low melting temperature alloy, and an auxiliary fusible element whose ends are closely spaced from the main element on opposite sides of the alloy body.The portions of the main element in contact with the alloy body, and adjacent the ends of the auxiliary element are relatively long portions having a uniform cross sectional area less than half the cross sectional area of an unperforated remaining portion of the main element, to thereby reduce the time required for the fuse to clear the low magnitude fault current.

Abstract: A current limiting fuse is characterized by a self-standing tubular fuse element having a high surface area-to-volume ratio to augment cooling and thus increase the steady-state current rating of the fuse and also having a plurality of axially spaced, generally diamond-shaped perforations each of which extends circumferentially somewhat less than 360.degree., with axially successive perforations displaced 180.degree. apart in a circumferential direction, thereby forming a plurality of axially spaced, ring-shaped portions providing parallel arcuate current paths and with axially extending interconnections between successive pairs of ring-shaped portions disposed on diametrically opposed sides of said tubular element to thereby further increase the length of current path through said fuse element and develop a high arc voltage.

Abstract: The fusible element of a single-element, dual-function, electric fuse is disposed within a passage within a housing of inorganic ceramic material which has a high thermal conductivity; and the major portion of that fusible element is displaced radially from the axis of that passage to be in intimate heat-transferring relation with one side of that passage. Two of the "weak spots" of that fusible element are in close heat-transferring relation with the terminals of that electric fuse; and a portion of that fusible element which is intermediate those two weak spots is in intimate heat-transferring relation with the opposite side of that passage. The resulting transference of heat from that fusible element to that passage enables those two weak spots to continuously carry the rated current of that fusible element even though those two weak spots have very small cross sections, and hence are able to provide desirable current-interrupting action.

Abstract: A current limiting fuse of the general purpose type utilizes a mandrel which has a plurality of longitudinally oriented and radially spaced ceramic rods around which is wound a fuse element. Gas evolving clamps are disposed along the mandrel to hold the fuse element against the rods of the mandrel. This arrangement tends to maintain the spacing of any given portion of the wound fuse element relative to the other portions thereof. In addition, the gas evolving material evolves arc quenching gas in localized regions between the clamps and the rods during a fusing operation. The pressure of the gas as it is expelled from the localized regions tends to prevent the formation of fulgurites in the regions after the fusing operation has been completed. A fulgurite if formed would enhance the opportunity for a restrike of the arc which is undesirable.

Abstract: In fuses for a sufficiently elevated circuit voltage the single breaks formed near the center of the fusible element at the occurrence of small overload currents does not produce a sufficiently high arc voltage to bring the current down to zero. In such instances it is necessary to produce series multibreaks to achieve interruption of the overloaded circuit.The present invention describes new means to produce series multibreaks. In fuses according to this invention the fusible element is subdivided into a plurality of spaced elements in parallel to reduce the concentration of metal vapors. Each of the element forms a break near the center thereof. This occurs at different times t.sub.1, t.sub.2, t.sub.3, etc. even though the elements are identical. Each break-formation is accompanied by a concomitant increase of current in the remaining fusible elements, and each break-formation is accompanied by a concomitant voltage spike or voltage surge -- L(di/dt).

Abstract: A high voltage fuse of the current limiting type including a housing of insulating material, a cylindrical support formed by an inorganic asbestos thread or string threaded on end plates which are mounted in a spaced relation on a support rod, the thread forming a cylindrical support for a fusible element which is spirally wrapped about the cylindrical support. An arc quenching material is used to fill the housing and completely surround said fusible element.

Abstract: An electric fuse is disclosed whose metallic fuse element is in a glassy state. The disclosed fuse is fast-acting and is particularly suited to protect delicate electronic apparatus against current overload.

Abstract: A high voltage current limiting fuse is taught which has a plurality of radially oriented, notched, pleated fuse ribbons. The fuse ribbons feed through radial slots in spacers at either end of the fuse barrel. A double fold in the fuse ribbon in the region of the slot in each case provides a locking terminal for abutting the fuse ribbon against the spacer. In addition, the double fold arrangement allows the fuse ribbon to be routed conveniently radially over the edge of the spacer and along the side of the fuse barrel, between the fuse barrel and the inside of a ferrule. This secures the end of the fuse element and provides electrical continuity between the fuse element and the ferrule.

Abstract: An insulating support for fusible elements in ribbon form having points of drastically reduced cross-sectional area which reduces the dimensional stability of the fusible elements to such an extent that they are not capable of supporting themselves. The support consists of a strip of electric insulating material arranged in spaced relation from, and parallel to, the fusible element. The strip has a plurality of arms projecting transversely from the former. Each of said plurality of arms supports the fusible element at a region situated between points of drastically reduced cross-sectional area thereof.

Abstract: The fusible element of an electric fuse has a first electrical path, a second electrical path in parallel relation with the first electrical path, a weak spot in the first electrical path which can respond to a potentially-hurtful overcurrent to fuse and thereby form a first arc in the first electrical path, and a weak spot in the second electrical path longitudinally displaced from the weak spot in the first electrical path which can respond to that overcurrent to fuse and thereby form a first arc in the second electrical path. The weak spots form primary arcs as they fuse; and one important function of those primary arcs is to establish the point at which the rate of rise of the overcurrent starts to diminish, while another important function of those primary arcs is to burn the adjacent portions of the respective electrical conducting paths.

Abstract: Electric fuses having supports for their fusible element or elements which supports are formed of bundles of glass fibers in form of cords, rovings, or the like glass fiber structures made up of fibers which extend but in longitudinal direction, i.e. do not include fibers which extend in transverse direction. The fibers are under considerable stress in longitudinal direction, so as to form a supporting structure of considerable dimensional stability. The terminal elements of the fuse are preferably in the form of terminal plugs and provided with means to control the stress to which the glass fibers are subjected. The latter may be impregnated with chemical compounds that evolve protective and arc-quenching gases under the heat of electric arcs.

Abstract: An arrangement of electrode for positive temperature coefficient semiconductor (PTCS) for use in heating and drying devices and the like, which PTCS is provided with a pair of electrode plates, each having a fork-like configuration with a plurality of branches or fingers in the form of strips extending forward from its base. The strips of both electrodes are disposed alternately on one of the opposing planes of the PTCS body. Each electrode has an extended portion serving as terminal which is bonded on the other plane of the PTCS body in such a manner that the terminal is not confronted, through the PTCS body, with any strips of opposite electrode.

Abstract: An electric fuse has helically wound fusible element means which are supported by a mandrel made up of insulating plates. The latter engage grooves provided in terminal plugs of the fuse. The mandrel-forming plates are locked in position inside said grooves by cooperating abutment means. These abutment means are formed by recesses in the mandrel-forming plates, and by projections formed by displaced portions of the metal of which the plug terminals of the fuse are made, which portions enter into said recesses in said mandrel-forming plates and preclude relative movement of the latter and the plug terminals.

Abstract: An electric fuse has an undulated fusible element provided with a plurality of aligned, spaced perforations. A straight rod preferably of a gas-evolving material extends through said plurality of perforations. The rod increases significantly the dimensional stability of the fusible element structure and contributes at the same time significantly to arc-extinction, if made of a gas-evolving material.

Abstract: A fuse strip used in protecting electrical circuits comprises an elongated strip-shaped body on which a plurality of polygonally-shaped apertures are spaced in the transverse direction. A current-carrying neck portion of uniform width is formed by respective longitudinal parallel sides of each adjacent pair of apertures, and a transverse band of uniform width is formed by two rows of apertures which are spaced in the longitudinal direction, each row of apertures having transverse sides which respectively lie on a common line extending in the transverse direction.

Abstract: A fuse for elevated circuit voltages having a fusible element that is substantially in the shape of a helix and is, in essence, supported only by the pulverulent arc-quenching filler of the fuse, i.e. which is supported without resort to a mandrel of electric insulating material around which the fusible element is wound. The casing of the fuse is sealed to preclude the escape of hot arc products by circular disks of asbestos fibers and by ferrules mounted on the ends of the casing. Plug terminals performing that sealing function are dispensed with. The steps involved in assembling the fuse are described in detail.

Abstract: A current limiting device includes a duct containing a current-limiting material therein which serves to interconnect two spaced terminals but which is evaporable when subjected to an over-current flowing through the material between the terminals. The wall forming this duct includes a region made from a highly-temperature-resistant material which has a relatively small cross-section that connects with another region of the duct having a larger cross-section, and the wall part forming the region of smaller cross-section is surrounded by a resistor member connected electrically in parallel with the current-limiting material disposed therein and which has a resistance value such that the current-limiting material is relieved of current following onset of an over-current condition.

Abstract: The fuse is of the general purpose type having a casing closed at the ends by terminal caps; a core inside the casing; a main fusible element wound about the core and connected between the caps; a pair of arcing clips mounted in spaced relation on the core adjacent the main fusible element; and, an auxiliary element also wound about the core and connecting together the arcing clips. The improvement comprises that segments of the main element passing over the arcing clips are provided with additional reduced cross-sectional necks for improving the melting response of the element upon arcing between the element and the clips.

Abstract: A fusible resistor has a substrate on which two terminal paths are formed. A resistor in the form of an area of resistive material deposited onto the substrate extends between the terminal paths. The expected line of fracture of the substrate, upon a current flowing through the resistor such that the rate wattage is exceeded, crosses at least one of the terminal paths. Desirably at least one line or zone of weakness is formed in the substrate.

Abstract: A circuit interrupter has a pair of contacts, a self-restoring type current limiting element and a first electromagnetic trip device serially interconnected. The current limiting element is connected across a parallel connected resistor and a second electromagnetic trip device. Both trip devices have a common magnetic circuit including a single stationary core and a single movable iron piece. The first trip device responds to a shortcircuiting current flowing through it to open the contacts but the second trip device is operative to open the contacts only after the current limiting element has performed the operation of limiting a shortcircuiting current.

Abstract: Electric fuses having a helically wound fusible element are provided with simple, cost-effective sheet metal means performing the dual function of supporting insulating plates which, in turn, support the helically wound fusible element, and of establishing conductive connections between the ends of the helically wound fusible element and a pair of ferrules by which the casing of the fuse is closed.