Abstract: A circuit protection device suitable for use with a photovoltaic power generation system. The circuit protection device includes an electronic control unit and a dual path fuse. The dual path fuse has a first current path defined by a main conductor and a second current path defined by a fuse element. In response to an overcurrent condition, the control unit activates the dual path fuse to open the first current path, thereby shunting current to the second current path. Residual follow-on current flows through the fuse element via the second current path until the fuse element melts. The control unit is programmable with multiple threshold current levels and associated time delays in order to provide different activation response times that are dependent upon the detected current level.

Abstract: A fuse that includes an insulating housing made from two housing pieces made of thermoplastic material, terminals extending through slots in the ends of the housing, and a fusible element having ends connected to both of the terminals. The housing includes a tubular portion and slotted end portions located at each of the two ends of the tubular portion. Each of the terminals has an internal portion inside the housing to which a fusible element is attached, an external portion outside of the housing, and a middle portion between the internal and external portions and located within one of the slots.

Abstract: An electrical fuse including a fuse casing having a tubular wall including multiple-filament reinforcing yarns that have been braided in the tubular shape of the wall and a synthetic resin bonding the yarns together and impregnating the yarns, a pair of terminals secured to the ends of the fuse casing, and a fusible element inside the casing and connected to the terminals.

Abstract: An electric fuse of the type which has a tubular fuse casing and a solid fuse end terminal telescopically received within the fuse casing is provided with an annular seal which is contained within an annular groove formed in the outer lateral wall of the end terminal. The seal is formed from a settable material which has been injected into the groove through a seal injection opening in the outer end of the end terminal which extends from the axial outer end and into fluid communication with an annular groove provided in the end terminal. A seal material bleed opening is provided in the end terminal which also extends from the axial outer end of the end terminal and into fluid communication with the annular groove. The bleed opening is positioned substantially diametrically opposed to the seal injection opening.

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: A fillerless electric fuse having a wire-like fusible element is provided with a body of thermoplastic material which cooperates with the fusible element to establish an impermeable barrier within the fuse between the fuse end terminals. The thermoplastic material is preferably a hot melt adhesive introduced into the casing in a fluid state.

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: An electric fuse is provided with a blown fuse indicator mounted on a lateral wall of the fuse. One of the end terminals of the fuse is provided with a first opening therein in a surface which faces the interior of the fuse casing. The same end terminal is provided with a second opening therein which is in a peripheral surface of the terminal and which lies in a plane which is substantially parallel to the longitudinal axis of the fuse casing. The end terminal is further provided with an internal passageway therein which communicates the first and second openings. The fuse casing is provided with an opening therein which is in axial alignment with the second opening in the end terminal.A spring loaded blown fuse indicator is mounted through the opening in the fuse casing and is fixedly and conductively engaged with at least a portion of the end terminal passageway.

Abstract: This invention relates to electric fuses meeting the requirements of Underwriter's RK1 classification. It includes a high-current interrupter in the form of a fusible element having serially arranged points of reduced cross-section and a low-current interrupter in the form of a plunger soldered to the high-current interrupter. The plunger is spring biased, and when the solder joint softens, the plunger separates under the action of the spring from the fusible element leaving a large gap between them. The separation of the plunger from the fusible element is allowed to be particularly large on account of the fact that the plunger may be allowed to move into a special fuse cap, known as a cap having a rejection feature as described, for instance, in U.S. Pat. No. 2,943,295 to V. N. Stewart; June 28 1960 for REJECTION TYPE FUSE CLIP and in many other patents.

Abstract: A fusible element for electric fuses based on M-effect, i.e. the severing of a high fusing point base metal by a low fusing point overlay metal by a process of metal interdiffusion. The M-effect, or Metcalf effect, as widely used in electric fuses, has a main limitation consisting in requiring too long periods of time for severing the base metal. The problem of severing the base metal by the overlay metal in shorter times is solved, according to this invention, by arranging the overlay metal on the front side and on the rear side of the base metal, in spaced relation to a point of reduced cross-section of the base metal.While the invention is applicable to all M-effect fuses, it is of particular importance in regard to Standard for Class L fuses of the Underwriters Laboratories Inc. which have fusible elements that are of copper, as distinguished from Class L fuses having fusible elements of silver, or Class L fuses having fusible elements in part of copper, and in part of silver.

Abstract: The current path of an electric indicating or striker pin fuse, and more particularly its fusible element, includes a point of maximum resistance where fusion of the latter must take place. That predetermined point is arranged in such a way that the pulverulent arc-quenching filler does not impair the proper operation of the indicating or striker pin device.

Abstract: The terminal elements of an electric fuse are made up of two separate parts of which the axially outer part is circular in cross-section and the axially inner part has a smaller area than the axially inner end surface of the axially outer part. The aforementioned two parts define ducts at the interfaces thereof. The ends of the fusible elements are inserted into these ducts. Solder joints conductively connect the ends of the fusible elements to the parts of which the terminals consist and affix the smaller of these parts to the larger of these parts.

Abstract: An electric fuse is closed by a pair of ferrules or caps which engage the lateral surfaces of the casing and have end surfaces provided with a relatively large, circular, concentric bore. The fuse further includes a pair of rods generally hexagonal in cross-section, each having an end portion circular in cross-section, substantially equal in diameter to the diameter of said bore in each of said pair of caps and inserted into said bore.

Abstract: The electric time-lag fuse involves a substantially T-shaped shorting strip shorting the insulating gap formed between a pair of metal overlays on an insulating strip, and a helical tension spring having a variable diameter affixed with one of the ends thereof to said T-shaped shorting strip, and resting with the other end thereof against the annular surface of a tubular member.

Abstract: A narrow strip of metal-clad material, as used in printed circuitry, is placed inside the casing of a fuse taking the place of the fusible conductor or element. The metal layer is, in part, removed from the strip by etching, or otherwise, leaving a central zone which is completely bare and two axially outer zones where the metal layer is substantially I-shaped. The axially inner ends of this I-shaped metal overlay are conductively interconnected by a spring-biased shorting strip which shorts said completely bare zone. The shorting strip is attached by soft solder to the axially inner ends of the I-shaped overlays and is spring-biased to a circuit interrupting position. The axially outer ends of the I-shaped overlays are connected by blind solder joints to terminal caps mounted on the ends of the casing of the fuse.

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: A blown fuse indicator is supported by a socket separate from the casing of the fuse whose blowing the indicator is supposed to indicate. The indicator includes an indicating pin of relatively large size under the bias of a relatively powerful helical spring. The pin is biased in a direction at right angles to the longitudinal axis of the fuse, or of its casing, respectively. Normally the pin is restrained by a latch projecting into a recess in the lateral wall of the pin. The latch is spring biased in the pinrestraining position thereof. When the bias of the latch is overcome by an external force, the pin moves to the indicating position thereof.

Abstract: A miniature fuse for small current ratings and small voltage ratings has a casing of porous cellulosic material, a pulverulent non-fulgurite-forming arc-quenching filler, a fusible element of low fusing point metal having ends bent upon the outer surface of the casing and squashed by the pressure of terminal caps press-fitted on the casing, and bodies of a cured synthetic resin imparting dimensional stability to the ends of the casing, firmly affixing the terminal caps to the casing, and resulting in the formation of a conductively stable mechanical connection between the fusible element and the terminal caps.

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.

Abstract: A d-c fuse having a clearing ability ranging from currents close to the minimum fusing current to major fault currents is provided with a wide ribbon fuse link having a matrix-like system of perforations. The fuse link is wrapped around gas-evolving rod means in such a fashion as to form a gap between the longitudinal edges thereof resulting in the formation of currents of arc-quenching gas evolving from said rod means and flowing transversely across said edges of said ribbon fuse link.