Abstract: A pin indicating fuse construction incorporates a protective shield member that isolates an indicator assembly from a main-fuse link. By use of the inventive protective shield, arc-quenching filler may be excluded, resulting in a less-costly, more reliable fuse construction. The main fuse link is arranged within the fuse in such a manner so as to minimize potential interference with the actuator assembly during activation of the indicator assembly.

Abstract: Apparatus to illuminate a light source when a fuse has blown and method of use. Apparatus including a circuit having: a power supply source, a switch, a load, a fuse housing containing a fuse and a light housing containing a light source.

Abstract: An interlock assembly is provided for use in a manually operated multi-phase fusible switch having a fuse in series with a blade for each phase and a handle for simultaneously controlling the position of the blades. Each fuse is CONDUCTIVE when it allows current to flow therethrough and is BLOWN when it does not allow current to flow therethrough. The handle is coupled to a drive rod and is movable between an OPEN position and a CLOSED position wherein the blades conduct current therethrough when the handle is in the CLOSED position and do not conduct current therethrough when the handle is in the OPEN position. The interlock assembly includes an interlock mechanism for preventing the handle from being moved from the OPEN position to the CLOSED position when one or more of the fuses are BLOWN or missing, thereby preventing the blade for each phase from moving into the CLOSED position when one or more of the fuses are BLOWN or missing.

Abstract: A device for providing a visual indication of the status of a fuse, i.e., whether or not the fuse has blown. The device includes a substrate onto which the elements of the visual indication device are printed. A pair of conductive terminals is screen printed upon that substrate, preferably spaced apart from each other along that substrate. Between the terminals, at least two spaced apart resistance elements are positioned upon the substrate. These two resistance elements are in series with each other, and they are also in series with the pair of conductive terminals. The first of these at least two resistance elements is comprised of a combination of a substance which melts at an elevated temperature, and also of carbon. The second of these at least two resistance elements is comprised solely of carbon.

Abstract: Between a rocking lever controlled by a striking pin of a cartridge and a resiliently loaded actuation knob of an alarm micro-switch, there is interposed an arm mounted on a pivot which pivot is spaced from the movement axis of the knob with result that the knob is engaged by the arm virtually without any mutual lateral sliding therebetween.

Abstract: A blown fuse indicator, having an insulating element, a current-carrying element overlaying the insulating element, and a substantially transparent window. A chemical composition coats at least a portion of the insulating element. The improvement comprises a meltable link in generally parallel proximity to the insulating element. The meltable link, which can be made of solder, melts to open an indicating circuit of the blown fuse indicator upon predetermined thermal overload conditions.

Abstract: A fuse box is provided with LED's interconnected with all fuses carried by the fuse box for identifying a blown fuse. The LED's are interconnected with the fuses between the positive (current in) input and ground. When a fuse is blown, the fuse results in an open circuit and the flow of electricity is rerouted through the LED to illuminate the LED. Also provided is a liner which fits over an existing fuse box and includes receptacles for fuses with corresponding LEDs associated with each receptacle for indicating a blown fuse. Also provided are individual liners for individual fuses. The individual liner is sized and configured to accept a fuse therein on a first side, and to extend into a fuse box on a second side thereof. The individual liner includes a LED interconnected therewith for indicating a blown fuse. Also provided is a remote indicator having a plurality of indicators positioned away from a fuse box. Additionally provided is a remote fuse box.

Abstract: A spiral wound fuse includes an elongated housing, a supporting substrate formed of an electrically non-conducting, resiliently deformable, and flexible material, disposed in the housing, a fusible conductor wound around the supporting substrate and end caps mounted to the housing and connected to the conductor at the first and second ends of the supporting substrate. The fusible conductor may be impressed into the resiliently deformable substrate to form ridges of material between adjacent windings of the conductor. The ridges physically separate the windings and help to prevent arcing or bridging when the conductor melts to interrupt the circuit.

Abstract: The present invention is substantially an indicator cap which is removably attachable to a prior art plug-in type fuse, and the cap having an indicator light for signaling that a fuse has blown so as to notify a user of the blown condition of the fuse. Furthermore, we provide unique circuitry which in combination with the existing circuitry provides unusual results, and we also provide a method of use therefore.

Abstract: An interlock assembly is provided for a fusible switch which has a fuse in series with a switch and an operating mechanism for controlling the operation of the switch. The interlock assembly is mechanically coupled to the operating mechanism and includes an indicator member disposed adjacent to the fuse for indicating the status of the fuse and an actuator member mechanically coupled to the operating mechanism for actuating the operating mechanism to open the switch when the fuse is BLOWN. A toggle member is coupled to the indicator member and to the actuator member for mechanically communicating the status of the fuse to the actuator member from the indicator member wherein the toggle member is in one position when the fuse is CONDUCTIVE and the toggle member is in another position when the fuse is BLOWN.

Abstract: Limiters for protection against fault currents in electrical distribution networks the limiter having externally visible indicator for indicating that a limiter element has fused and which visible indicator may be reset and reused after a fused limiter is replaced.

Abstract: A contact spring clip for a cartridge fuse blown fuse light indicator wherein the spring clip is manually squeezable for the installation and removal of the clip on the barrel of a cartridge fuse. The spring clip is provided with a track for holding an electrical contact assembly connected to the ferrules of the cartridge and which can either be connected to a blown fuse light indicator positioned at a location remote from the fuse, or connected to a blown fuse light indicator mounted on the electrical contact assembly.

Abstract: A blown fuse indicator for a cartridge fuse wherein conductive brackets are mounted between electrical insulating end caps and the ends of a tube housing a lamp and associated resistors. Each conductive bracket includes a disc portion having a polygonal aperture for receiving a sleeve integral with the cap, the sleeve having a polygonal cross-sectional configuration corresponding to the disc aperture. The free ends of the lamp and resistor leads extend through the disc portion of the conductive bracket and are pressed and gripped between the cap and conductive bracket. The conductive bracket also includes a blade portion which may have a planar surface, a corrugated surface or a reversely bent portion to provide direct and positive contact with the end walls of the fuse ferrules, whether they be flat, concave or convex.

Abstract: A fuse is provided which has a fuse housing with a transparent portion thereof, and a fuse element extending through the housing which is coated with a preferably non-hazardous temperature-responsive material. The temperature conditions generated at the interface between the coating and the fuse element cause the coating to leave the fuse element and deposit upon this transparent portion of the housing. The temperature-responsive coating on the fuse element will be transferred to the housing walls even where modest current overloads flow which do not immediately open the fuse. Different circuit overload conditions, including short circuit events, produce different visual indications or colorations on the transparent housings inside surfaces, which serves to identify the nature and degree of the overload problem existing in the circuit. Coatings, also capable of fluorescing under specific irradiation conditions, may be used.

Abstract: The blown fuse indicator is mounted to one of the opposed ferrules of a fuse and ejects a streamer therefrom in response to a blown or open fuse condition. The streamer is a strip of vinyl which is secured at one end to a plunger held within a housing mounted on one of the ferrules, and at its other end to a container which is ejected from the housing by the plunger in response to a fuse opening whereby the streamer unfurls to indicate the fuse is blown and open.

Abstract: A fuse tube is provided for cutout and power fuse assemblies. The fuse tube has a body with a red retroreflective portion and a white retroreflective portion. When conducting the red portion lies above the white portion. When the fuse blows, the white portion lies above the red portion. By observing whether the fuse tube has red over white or white over red, the condition of the fuse is determined. If the orientation is red over white, the fuse is all right. If the orientation is white over red, the fuse is dead, and needs to be replaced.

Abstract: A spring loaded blown fuse indicator is provided that is adapted to be mounted directly on the side of an electric fuse in parallel with the fuse current path.The indicator provides an indicating pin that extends perpendicular to the longitudinal axis of the fuse. The indicator body comprises two identical molded halves which facilitate assembly and allow the indicator restraining wire to be readily encapsulated in an arc-quenching epoxy adhesive.

Abstract: An improved safety end-connector used for extension cord includes: a circuit protection fuse, a detachable fuse box for easy inspection and replacement, two lead-in wires clamped firmly by a tail clamp of a base, a plurality of pairs of socket openings each pair of socket openings protected by a shutter slide, and an indicator lamp furnished for indicating the receptacle during night time or in a dark place, or serving as a trouble indicator.

Abstract: An electric fuse link (10), which is preferably a cartridge fuse with a cylindrical ceramic body (11) with metal end caps (12), has means for indicating burning out of the fuse element. This consists of a conductive deposit (13) in parallel with the fuse element, but of higher resistance. This is preferably covered by a nonconductive deposit (14) of light color which prevents arcing and highlights burn-out of the conductive deposit when the element blows.

Abstract: A solid state switching circuit for energizing a lamp (L) is connected around a fuse (12) across an AC supply for detecting a voltage differential at the opposite sides of a blown fuse and applying that differential across the control (g) and switching (c) electrodes of the solid state switch (SCR) to render the same conductive. Current limiting resistors (RL1 and RL2) are placed in the ends of wire conductors which are to be connected at opposite sides of the fuse, thereby to limit current flowing in the conductors over the entire length of the conductor, minimizing electrical shock hazard upon damage to the conductor.

Abstract: A holder for an electric fuse is provided with apparatus which senses the flow of electric current along the current path of the fuse holder, and, which responsive to such sensing, electromagnetically induces an ascertainable signal. The signal may be detected and processed to provide an indication of whether current is flowing through the fuse holder.

Abstract: A holder for an electric fuse is provided with a Hall-effect sensor arrangement which is integrally mounted in the fuse holder in close proximity to the current path through the holder. The Hall-effect sensor provides an output voltage responsive to the magnetic field resulting from the flow of current along the current path. The output from the Hall sensor is then processed to provide an indication of whether current is flowing through the fuse holder.

Abstract: This is a method, and apparatus for practicing the method, by which electrical fuses or circuit breakers which have become inoperative by failure or overload can be instantly identified. The method and apparatus involves the use of light emitting diodes or the like connected in parallel with fuses in such a manner that when a fuse or circuit breaker fails in carrying an electrical load the flow of electrical current will be diverted to the light emitting device and cause it to visually signal the failure.

Abstract: An elongated fuse housing includes a fusible wire longitudinally extended and coaxially mounted within a housing having end terminals. A spring indicator unit is secured to one end and includes a relatively large diameter loosely wound section forming a helical compression spring in combination with an integral, coaxial and tightly wound elongated indicator coil which extends axially of the spring. The spring/indicator unit is located within the housing with the coil spring held compressed by the fusible wire. The one end terminal includes an opening aligned with the wire-wound indicator coil. Disruption of the fusible wire releases the coil spring which expands within the housing to rapidly separate the fuse wire and simultaneously move the elongated wire-wound indicator coil through the opening, thereby indicating operation of the fuse.

Abstract: An integrity indicator formed as an illuminable bead is combined with the pair of flat terminal blades of a miniature plug-in fuse and is positioned in a central window provided in the top wall of the insulator housing thereof. The housing defines a chamber having an open bottom and a central section with relatively narrow lateral sections in which upper portions of the blades are secured. A fuse-wire extends across the central section conductively interconnecting the blades. The illuminable bead has a pair of wire leads extending oppositely into the lateral sections of the chamber, each wire lead conductively contacting the upper portion of one of the blades and connecting the bead in parallel circuit with the fuse-wire. Clamping components formed on the interior of the top wall and on the upper portion of each terminal blade secure each wire lead in operative position.

Abstract: A brake and operation indicator for a movable contact of a switch, the movable contact being rapidly moved by ignition of a power cartridge to open the switch. A thin-walled sleeve is positioned conformally about a movable pin, a portion of which is lightly held in a bore of an end member of a housing for the switch. The sleeve is shorter than the distance between a head on the pin and the end member. The bore is normally closed by a thin membrane. When the contact is moved, it ultimately abuts the head, moving the pin through the membrane to a position beyond the end member where a portion of the pin is visible. Movement of the pin also collapses the sleeve between the head and the end member in accordion-like fashion to dissipate the kinetic energy of and stop the contact. The presence of the pin within the sleeve renders the collapse controlled, uniform, and efficient. The visible portion of the pin informs that the switch is open.

Abstract: A fuse comprises a flat carrier panel (2) which carries a fusible conductor (8) interconnecting two electrical contactors (7). A cover (11) is fitted onto the carrier panel (2) by means of integral legs (14) which snap around opposed edge portions (4') of the carrier panel to enclose the fusible conductor (8) within an insulating housing. The contactors (7) extend out of the housing to provide external connections for the fuse.

Abstract: An alarm indicator fuse (1) for large current and high temperature applications. The fuse assembly comprises apparatus (16, 121, 162) slidably engaging alarm indicator apparatus (14, 15) coupled between one conducting member (12) and a fuse element (13) electrically connected to another conducting member (11) to electrically couple the fuse element to the one conducting member and enable release of the alarm indicator apparatus upon opening of the fuse element. The electrically coupling and release enabling apparatus shortens the current path of the fuse between the electrical conducting members to increase the current capacity and improve the temperature characteristics of the fuse.

Abstract: A plug-in fuse assembly is disclosed which includes a fuse element made up of a pair of elongated current-carrying portions in spaced relationship and a fuse-forming link portion extending between the current-carrying portions. The fuse element is placed in an insulating casing with its terminal portions projecting therefrom. Means is provided for providing a fuse opening indication in response to heat generated from the fuse-forming link portion when it opens up.

Abstract: In a fuse cartridge the indicator button, normally retained within a head of the cartridge and adapted to protrude outwardly when the latter has "blown", is disposed axially to the said head and the contact blade corresponding to the latter has a notch formed in its inner transverse edge (the edge connected to the head) in order to define a space which may receive the indicator button. Moreover the lateral sides of the blade have laterally projecting ribs to limit the portion of said blade which may be inserted into the clamp of a cartridge support, thus preventing such a clamp from hindering the protruding movement of the indicator button.

Abstract: An improved high-voltage fuse, the blown or unblown condition of which can be readily ascertained, is disclosed. Known fuses include a fusible element and a movable component, such as an arcing rod, which is held in a normal first position as long as the fusible element is present and remains intact. When the element fuses and arc is struck, the arcing rod moves through an arc-extinguishing medium to extinguish the arc, coming to rest in a second position. The fusible element, arcing rod, and arc-extinguishing medium are contained within an opaque, insulative housing for the fuse. In the improved fuse, the housing is made of an insulative material which is translucent. The housing's translucency is such that it may be difficult if not impossible to observe the condition of the fuse--blown or unblown--from the fuse's exterior. Accordingly, a member, mounted for movement with the arcing rod, is provided.

Abstract: An electric fuse is of the type including indicating means for indicating if the main fusible element has melted. The indicating means includes a first and second auxiliary fusible element, each having a higher resistance than the main fusible element. When the fuse is fully assembled, and the main fusible element has melted, the path of current is through the first and second auxiliary fusible elements. The second auxiliary fusible element functions to restrain movement of an indicator button. When current flows through the auxiliary fusible elements, the second auxiliary fusible element is designed to melt first, thereby causing the indicator button to move. The operability of the first and second auxiliary fusible elements can be independently and non-destructively determined before and after assembly of the fuse. After fuse assembly, the fuse can be non-destructively disassembled so as to determine the operability of the first and second auxiliary elements.

Abstract: An electric fuse is disposed within a fluid tight submersible enclosure. The status of the fuse is indicated by an externally mounted neon lamp. The outside surface of the enclosure is coated with conductive paint for safety. Likewise, most of the inside surface of the enclosure is coated with conductive paint to reduce corona therein. A relatively thin annular band of semiconductive paint is disposed between terminals of the fuse apparatus on the inner surface of the enclosure. The enclosure is made primarily of insulating material. When the fuse blows, the voltage difference between the opposite ends of the fuse is capacitively coupled through the enclosure to the indicator. The indicator is sensitive to a change in voltage thereacross and periodically illuminates to indicate that the fuse within has blown.

Abstract: Semiconductive paint is applied to a narrow strip on the inside surface of an insulating enclosure for a submersible fuse. The enclosure is generally watertight. The semiconducting paint marginally overlaps two isolated regions of electrically conducting paint. The combination of the conducting paint and semiconducting paint covers the entire inner surface of the enclosure and acts cooperatively to prevent or reduce corona therein. At the place of overlap, rounded ridges are provided for shielding the relatively sharp interface corner of the conductive paint on the inside surface of the electrically insulating material to reduce the corona at that relatively critical point. A flowable rubber gasket is provided for insertion between two separable portions of the enclosure. The gasket not only provides watertight sealing for the enclosure when completely assembled but has a bead on the inside surface thereof which shields the corners of the two portions of the enclosure to reduce the corona effects thereat.

Abstract: A thermal limiter assembly for controlling an electrical circuit in response to the existence of a sensed condition beyond a predetermined time period. A housing body of the assembly includes a gas-filled cavity in which are disposed functional electrical elements in the form of a heater element and a thermally responsive switch or fuselike element. The heater element is arranged to raise the temperature of the thermally responsive element to a critical temperature at which it changes its state of conductivity and is thereby adapted to alter an external circuit connected to it. As disclosed, the heat transfer relationship between the heater element and the thermally responsive element is relatively independent of environmental temperature conditions so that the time period to actuate the thermally responsive element is not substantially affected by such temperature conditions.

Abstract: A fuse for elevated circuit voltages is provided with first fusible element means having a relatively low resistance and wound substantially helically around a mandrel formed of insulating plates. The fuse is provided with a spring-biased blown fuse responsive device for indicating whether or not the fuse has blown, or for tripping a switching device with relatively movable contacts, e.g. a disconnect. The blown fuse responsive device is under the control of a second fusible element means which has a relatively high resistance. Said second fusible element means includes a plurality of spaced sections forming therebetween a voltage-responsive break-down spark gap. The mandrel for supporting the first fusible element has a perforation immediately adjacent the end thereof at which the blown fuse responsive device is arranged. Two contiguous sections of the second fusible element are spaced from each other and form a voltage responsive break-down spark gap.

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.

Abstract: An on-line indicator connected to each fuse of an electrical circuit includes an LED which becomes illuminated if its protected fuse blows. Groups of these on-line indicators can be connected via an OR gate to a single master fuse status indicator which also includes an LED which becomes illuminated if any of the on-line indicators connected thereto has its LED illuminated. The circuitry can accommodate power supplies of different voltages of either polarity. Opto-isolators can be used to reduce stand-by current drain and to isolate the on-line indicators from each other.