US2599646A - Current-limiting fuse - Google Patents

Current-limiting fuse Download PDF

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Publication number
US2599646A
US2599646A US226755A US22675551A US2599646A US 2599646 A US2599646 A US 2599646A US 226755 A US226755 A US 226755A US 22675551 A US22675551 A US 22675551A US 2599646 A US2599646 A US 2599646A
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Prior art keywords
fuse
current
link
casing
chamber
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US226755A
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English (en)
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Frederick J Kozacka
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Chase Shawmut Co
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Chase Shawmut Co
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Priority to US226755A priority Critical patent/US2599646A/en
Priority to CH308109D priority patent/CH308109A/de
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
    • H01H85/041—Fuses, i.e. expendable parts of the protective device, e.g. cartridges characterised by the type
    • H01H85/044—General constructions or structure of low voltage fuses, i.e. below 1000 V, or of fuses where the applicable voltage is not specified

Definitions

  • This invention relates to fuses for the protection of electric circuits, and more particularly to current-limiting fuses, i. e., fuses which do not permit the current in the circuit into which they are placed to reach the available shortcircuit current of the circuit.
  • Another object of this invention is to provide a composite current-limiting fuse structure consisting of identical fuse units jointly capable of effectively controlling currents over a very wide range.
  • Still another object of this invention is to provide an extremely compact fuse which drastically limits arc energy on interrupting fault currents of load proportions and on interrupting fault currents of short-circuit current proportions.
  • a further object of the invention is to provide an extremely compact current-limiting fuse of the type comprising a link of silver and a ller of quartz sand capable of effectively interrupting both currents of short-circuit current proportions and small fault currents of inadmissible duration.
  • the grain size of arc quenching fuse filler and more particularly the size of the grains of a quartz sand ller in a fuse having a link of silver may have an influence upon the maximum current interrupting ability of a fuse.
  • the grain size of the 'are quenching filler also has an important effect, jointly with other factors, upon the operation of current-limiting fuses in the small overload range.
  • Protracted ow of that leakage current on account of the potential prevailing across the terminals of the fuse may cause the 12.1 losses in the fused quartz sand body to become so high as to cause a restrike and rekindling of the arc after initial operation of the fuse and consequent total loss of all of its interrupting ability.
  • FIG. 1 is a view, partly in longitudinal section, of a current-limiting fuse unit embodying my invention
  • Fig. 2 is a cross-section along 2-2 of Fig. 1;
  • Fig. 3 is a view, partly in longitudinal section, of a modification of the structure shown in Figs. 1 and 2;
  • Fig. 4 is a view, partly in longitudinal section, of a multi-element fuse designed for very high currents, embodying my invention.
  • Fig. 5 is a cross-section along 5 5 of Fig. 4.
  • a current-limiting fuse comprising a casing I of considerable mechanical strength capable of withstanding high internal pressures.
  • the material of which casing I is made should be of a heat resistant type.
  • Materials complying with the requirements of high mechanical strength and high heat resistance are glass-cloth-silicon-resm laminates and glasscloth-melamine-resin laminates and I prefer such laminates for making the casings of fuses according to ⁇ my invention.
  • To impart the required mechanical strength to casing I its wall thickness is preferably in the order of half the external radius thereof. This figure is based on a considerable safety factor.
  • Terminal caps 2a, 2b are provided at the ends of casing I and these caps are particularly designed to withstand the action of high internal pressures within casing I.
  • casing I is provided with a pair of circular recesses Ia, Ib, one on each end thereof, and caps 2a, 2b are rolled into these recesses.
  • the internal volume of casing I is in the order of but several thousandths of a cubic inch per kva. capacity. In prior lart National Electrical Code cartridge fuses the internal volume of the casing per kva.
  • the fuse link 3 is of the multiperforated ribbon type and is attached to caps 2a and 2b by means of solder joints 4a, and lb.
  • the extremely compact space of chamber Ic inside of casing I is filled with quartz sand larger than No. 80 but smaller than No. 18 U. S. Standard Sieve Number.
  • Quartz sand of this grain range has occasionally been used in prior art fuses but the general trend was toward finer grained quartz sand because ner sand such as sand of 100 to 150 U. S. Standard Sieve Number is conducive to increased interrupting ability.
  • ner sand such as sand of 100 to 150 U. S. Standard Sieve Number
  • the fuse shown in Figs. 1 and 2 is provided with a link designed to limit the maximum continuous current of the fuse to less than 36 amperes.
  • This limitation of the continuous maximum current of the fuse is achieved by the provision of a plurality of equidistant circular perforations or holes 3a arranged along the axis of link 3 and provision of a tin rivet 5 in one of these perforations or holes.
  • the resulting alloy has a lower melting point and a higher resistance than silver and permits formation of an initial break at overload currents in the order of 30% less than would be required to form an initial break in an all silver fuse link.
  • Alloy formation involves a predetermined time and this results in a time-lag characteristic of the fuse for the low overload current range.
  • the rivet 5 is ineffective as far as interruption of currents of short-circuit current proportions is concerned. Such currents are interrupted before they can reach the available short-circuit current which the circuit is capable of producing. Reduction of the fusing temperature of a link metal by alloy formation with another is frequently referred to as Meffect and 'I use this term since it has been accepted in the trade literature.
  • the following table refers to a series of tests which I carried out with fuses which had a casing the internal volume of which was in the order of several thousandths of a cubic inch per kva. capacity and which hada silver link surrounded by a quartz filler.
  • the link wasl designed to limit the maximum continuous current of the fuse to less than 36 amperes.
  • the only variable in these tests was the fineness of the grains of the quartz sand filler.
  • test results tabulated above were-.obtained from data accumulated from tests with single rfuses having a current rating of 30 amperes and composite fuses having current ratings of :60 and amperes at 1000 volts. The design of .these composite fuses is described below. The 'tests were conducted over a widecurrent range from currents slightly exceeding the rated current up to 80,000 amperes available short-circuit current: The line potential was 1048 D. C.
  • Successfully operating fuses may be filled with a quartz filler which is a mixture of particles of various U. S. Standard Sieve Numbers, provided that the grain sizes lie within the limits suggested by the above table. In other words, satisfactory operation may be expected from mixtures that will pass through an 18 mesh screen and be held on an 80 mesh screen.
  • the table below refers to a new line of current-limiting fuses having current ratings varying between 30 and 200 amperes at 1000 volts filled with the preferred 30/40 grain size quartz sand.
  • the 30/40 filler grain has a maximum diameter of .0232" and a minimum diameter of .0164".
  • the fuse rated at 60 amperes was made up of two fuse units of the kind shown in Figs. 1 and 2 arranged in parallel. Similarly the fuse rated at 100 amperes consisted of three and the fuse rated at 200 amperes of seven fuse units of the type shown in Figs. 1 and 2.
  • These composite structures for fuses exceeding the 30 ampere rating are a consequence of the requirement that the maximum continuous current of -a single currentlimiting fuse be less than 36 amperes if the fuse is to interrupt low currents satisfactorily without resorting to special relatively complicated W current interrupting means as, for instance, a pair of contacts spring-biased to the open position thereof and adapted to break small fault currents upon fusion of a eutectic alloy normally holding the contacts in the closed position.
  • the multiperforated ribbon-type fuse link applied in the structure of Figs. 1 and 2 has a large surface to volume ratio and other properties conducive to effective interruption of short-circuit currents. These properties are enhanced by ⁇ assigning the relatively small continuous current carrying duty of less than 36 amperes to the link making it possible to minimize the amount of link metal.
  • the rated current of such a small current carrying duty and high current interrupting capacity link :arranged in a fuse structure of the kind under consideration is less than 40 amperes. Low fault current interruption is aided by the limitation of the maximum continuous current to less than 36 amperes and the use of an Meffect causing means on the link.
  • the fuse In interrupting short-circuit currents the fuse operates entirely differently without the pressure oscillations typical for low current interruptions and without the accompanying flows of diluted metal vapors back and forth through the voids or interstices between the quartz granules.
  • This difference in the mode of operation is apparently the reason why the optimum interrupting ability of quartz sand of given grain size is different for high current and low current interruptions and why a judicious compromise as to the neness of the quartz grains must be sought if a currentlimiting fuse is required to interrupt Without restriking small protracted overload currents in addition to short-circuit currents.
  • Fig. 3 diifers from that of Figs. 1 and 2 in that the right end of the fuse housing contains a ller of chalk which surrounds the Meffect causing portion of the fuse link. At low current interruptions arcing is initiated within that chalk filler and this results in the formation of carbon dioxide according to the equation CaCOaCOz-l-CaO.
  • the quartz sand filler and the chalk ller are separated from each other by a washer 1, which is loosely fitted into the casing I.
  • the provision of a small amount of chalk limited to the point of arc initiation has a plurality of desirable effects including the formation of an effective scavenging gas flow away from the point accadde of .are initiation towards the 'highly vleffective quartz sand deionizen the addition of a highly ⁇ neat conductive gas :to the gasesand. nietalvapoi's in the ,fuse casing, and an increase .of the pressure level prevailing therein With an attending lincrease .of the dielectric Strength of the gas .and vapor -rnixture within the lcasing -i-n conformity with Paaschens law.
  • the Vlink ofthe fuse of Fig. k3 is provided with a neck Vor reduced cross-sectionportion Sli-Which limits the let-through current of the fuse-Without affecting its maximum continuous current and rated current.
  • the operation of this particular neck or reduced cross-section portion .3b is more fully described in mv copending patent application Ser-idalNo. 298,548,1iled January 30, 1951, for Current Limiting Fuses, assigned to the saine .aS- signee as the present patent application.
  • the circuit into which the -fuse is inserted has been diagrammatically indicated by leads 8a, 8b in Fig. 3. In actual practice leads 8a, 8b will be lconnected to the terminal caps 2a, 2b by means of a fuse holder (not shown in Fig. 3).
  • the composite high capacity fuse shown in Figs. 4 and 5 is made up of a plurality .of single units of the type shown in Figs. 1 .to 3 of which each unit comprises a separate casing I.
  • the left terminal caps 2a of the individual -fuse units are inserted into cylindrical recesses 9' formed in a heavy metal block 9a.
  • the right terminal caps 2b of the individual fuse units are inserted into cylindrical recesses yEl formed in the heavy metal block 9b.
  • the space between the individual fuse units is filled with a granular material I3, such as quartz sand, adapted to Acope ⁇ with the arc products formed in the individual fuse units in case that one of these units should burst under the action vof ,excess pressure.
  • the blade contacts lila, IGb form integral parts of metal blocks 9a, 9b and are intended ⁇ for inserting the composite fuse into a fuse holder and an electric circuit, respectively.
  • Ihe cylindrical shell I I made of insulating material encloses the individual fuse units, the granular material I3 and the ⁇ metal blocks 9a, Sb and issecured to the latter ⁇ by means of vtransverse studs I4.
  • Outer ⁇ ferrules I5a, i511 arerarranged kon opposite ⁇ ends of shell II and overlap the cylindrical side Walls thereof.
  • fuses according to this invention are ap- .pucab1em A. c. circuits as wen as in D. o. circuits.
  • the .behavior of a pulverulent quartz nller in a .currentf-limiting silver link fuse depends also to some extent upon the .crosssectional area and upon ⁇ the configuration of the .cross-sectional area of the fuse link.
  • the critical grain size range which I :have discovered was found to exist with regard to -fuses the links of which were designed to limit the maximum .continuous current of the fuseto less than 36 amperes andrnore particular- Vly with regard te vfuses having multiperforated ribbcn-typelfuse links designed for such low currents .and yprovided with a .Meffect causing metal-element.
  • the relatively high temperature of the link enables to rapidly forrna Wide .gap bv vaporizationof link rnetal immediately upon .occurrence .of the M-eiec.t. .thus minimizing the .time required on interruption of lovv currents to forni the gap length needed ⁇ vfor permanent circuit interruption and simultaneously minimizing. aro v,duration .and arc energy- ,If vthe ⁇ capacity oi a circuit to loe protected lov the composite fuse structure of Figs. Il and 5 is N kva. and the number of fuse units which go .into the composite ⁇ structure is then .each .fuse unit should nave .an approximate .capacity y kva.
  • each fuse unit should be in the order of several thousandths, or 1/400- 1/soo of a cubic inch per N kva.
  • capacity in terms of kva. refers to the product of rated current and rated voltage, i. e. to the power carrying and power transmitting capacity of a fuse.
  • a current-limiting fuse comprising a casing having an internal volume in the order of several thousandths of a cubic inch per kva. capacity, a pulverulent ller larger than No. 80 but smaller than No. 18 U. S. Standard Sieve Number in said casing, and a fuse link adapted to limit the maximum continuous current of said fuse to less than 36 amperes arranged in said casing in contact with said filler.
  • a current-limiting fuse comprising a casing having an internal volume in the order of several thousandths of a cubic inch per kva. capacity, a. pulverulent quartz i-lller larger than No. 80 but smaller than No. 18 U. S. Standard Sieve Number in said casing, and a fuse link adapted to limit the maximum continuous current to said fuse to less than 36 amperes arranged in said casing in contact with said filler.
  • a current-limiting fuse comprising a casing of a glass cloth base having relatively thick walls and defining a chamber having an internal volume in the order of several thousandths of a cubic inch per kva. capacity, a pulverulent quartz ller larger than No. 80 but smaller than No. 18 U. S. Standard Sieve Number within said chamber, a ribbon-type fuse link having a plurality of circular perforations arranged within said chamber in contact with said filler, a, metal adapted to form an alloy with the metal of which said link is made having a lower fusing point than the metal of which said link is made in contact with said link, said plurality of perforations of said link being sufficiently large to cause alloy formation between said metal and said link at continuous currents of less than 36 amperes.
  • a current-limiting fuse comprising a casing of fiber-glass-cloth-resin-laminate having a wall thickness in the order of half the radius thereof and defining a chamber having an internal volume in the order of several thousandths of a cubic inch per kva. capacity, a pulverulent quartz ller larger than No. 60 but smaller than No. 20 U. S. Standard Sieve Number within said chamber, and a multiperforated ribbon-type fuse link arranged within said chamber in contact with said ller, said link having Meifect causing means thereon adapted to limit the maximum continuous current of said fuse to less than 36 amperes.
  • a current-limiting fuse comprising a casing dening a chamber having an internal volume in the order of several thousandths of a cubic inch per kva. capacity, a 'pulverulent quartz ller larger than No. 60 but smaller than No. 20 U. S. Standard Sieve Number within said chamber, and a ribbon-type fuse link having a plurality of perforations along the center line thereof adapted to limit the maximum continuous current ofv said fuse to less than 32 amperes arranged within said chamber in contact with said ller.
  • a current-limiting fuse comprising a casing of considerable mechanical strength having a wall thickness in the order of half the radius thereof and defining a chamber having an internal volume in the order of several thousandths of a cubic inch per kva. capacity, a pulverulent quartz filler in said chamber consisting of a mixture of grain sizes that will pass through a No. 30 U. S. Standard Sieve Number screen and be held on a No. 40 U. S. Standard Sieve Number screen, and a fuse link in said chamber in contact with said filler adapted to limit the continuous current of said fuse to less than 32 amperes.
  • a current-limiting fuse comprising a casing adapted to withstand considerable internal pressures defining a chamber in the order of several thousandths of a cubic inch per kva. capacity, a granular quartz ller within said chamber consisting of a mixture of grain sizes that will pass through a No. 30 U. S. Standard Sieve Number screen and be held on a No. 40 U. S. Standard Sieve Number screen, a ribbon-type fuse link having a plurality of aligned perforations arranged within said chamber in contact with said ller, and an Meffect causing means on said link adapted to become operative at continuous currents of less than 32 amperes.
  • a current-limiting fuse comprising a casing adapted to withstand considerable internal pressures deiining a chamber in the order of QO to 1500 cubic inch per kva. capacity, a pulverulent quartz filler in said chamber consisting of a mixture of grain sizes that will pass through a No. 18 and be held on a No. 80 U. S. Standard Sieve Number screen, and a fuse link of silver within said chamber in contact with said ller adapted to limit the maximum continuous current of said fuse to less than 32 amperes.
  • a current-limiting fuse comprising a glass cloth base casing having a wall thickness in the order of half the radius thereof and defining a chamber having an internal volume in the order of 1/400 to %00 cubic inch per kva. capacity, a pulverulent quartz filler within said chamber including a mixture of grain sizes that will pass through a No. 30 and will be held on a No. 40 U. S.
  • a ribbontype fuse link having a plurality of serially related portions of reduced cross-section within said chamber in contact with said ller, a metal element on said link adapted to form an alloy with the metal of which said link is made having a lower fusing point than the metal of which said link is made, and a gas evolving pulverulent ller within said chamber surrounding said alloy forming metal element, said alloy forming metal element and said link being adapted to alloy and fuse at continuous currents of less than 35 amperes.
  • a current-limiting device for a circuit requiring a capacity of N kva. including a plurality of n basic units adapted to carry current in parallel and combined to form a composite selfsustained structure, each of said 11. units consisting of a current-limiting fuse comprising a casing having an internal volume in the order of several thousandths of a cubic inch per N/n. capacity, a pulverulent quartz ller larger than No.' 80 but smaller than No. 18 U. S. Standard Sieve Number in said casing, and a fuse link adapted to limit the maximum continuous current of said fuse to less than 36 amperes arranged ink said casing in contact with said ller.
  • a current-limiting device for a circuit requiring a capacity of N kva. including a plurality of n basic units adapted-to carry current in parallel and combined to form a composite selisustained structure, each of said 11; units consisting of a current-limiting fuse comprising a casing of a glass cloth base having relatively thick Walls and renng a chamber having an internal volume in the order of several thousandths of a cubic inch per N/n capacity, a pulverulent quartz ller larger than No. 80 but smaller than No. 18 U. S.
  • a aribbon-type fuse link having a plurality of' circular perforations arranged within said chamber in contact with said ller, and a metal adapted to form an alloy with the metal of which said link is made having a lower fusing point than the metal of which said link '1s made in contact with said link, said plurality of perforations of' said link being suiiiciently large to cause alloy formation between said metal and said link at continuous currentsl of ⁇ less than 36 amperes.
  • a current-limitingv device for a circuit requiring a capacityv of N kva. including a plurality of n basic units adapted to carry current in parallel and combined toA form a composite selfsustained structure, each of said 'n units consisting of a current-limiting fuse comprising a casing of ber-glass-cloth-melamine-resn-laminate having a wall thickness in the order of half the radius thereof and defining a chamber having. an internal volume in the order of several thousandths of a cubic inch per N/n capacity, a pulverulent quartz ller larger than No. 60 ⁇ but smaller than No. U. S'.
  • Ay current-limiting device for a circuit requiring a capacity of N kva. including a plurality of n basic units adapted to carry current in parallel and combined to form a composite selfsustained structure, each of said n units consisting of a current-limiting fuse comprising a casing dening a chamber having an internal Volume in the order of several thousandths of a cubic inch per N/n capacity, apulverulent quartz Y iiller vlarger than No. but smaller than No. 20 U.
  • Av current-limiting device for a circuit requiring a capacity of N kva. including a plurality ofrn basic units adapted to carry current in parallel and combined to form a composite selisustained structure, each of said n units consisting of a current-limiting fuse comprising a casing of considerable mechanicalstrength having a Wall thickness in the. order of half the radius thereofv and defining a chamber having an internal volume in the order of several thousandths of a cubic inch per N/w capacity, a pulverulent quartz filler insaid chamber consisting of a mixture of grain sizes that will pass through a No. 30 U. S. Standard Sieve Number screen and be held on a No. 40' U. S. Standard Sieve Number screen, and a fuse link in said chamber in contact with said filler adapted to limit the continuous current of said fuse to less than 32 amperes.
  • a current-limiting device for a circuit requiring a capacity of N kva. including a plurality of n basic units adapted to carry' current in parallel and combined to form a composite selfsustained structure, each of said n units consisting of a current-limiting fuse comprising a casing adapted to withstand considerable internal pressures dening a chamber in the order of several thousandths of a cubic inch per N/n capacity, a granular quartz filler within said chamber consisting of a mixture of grain sizes that will pass through a No. 30 U. S. Standard Sieve Number screen and be held on a No. 40 U. S.
  • a current-limiting device for a circuit requiring a capacity of N kva. including a plurality of n basic units adapted to carry current in parallel and combined to form a composite selfsustained structure, each of said n units consisting of a ⁇ current-limiting fuse comprising a casing adapted to withstand considerable internal pressures dening a chamber in the order of 1/400 to l/auo cubic inch per N/n capacity, a pulverulent quartz ller in said chamber consisting of a mixture of grain sizes that will pass through a No. 18 and be held on a No. 70 U. S. Standard Sieve Number screen, and a fuse link of silver within said chamber in contact with said filler adapted to limit the maximum continuous current of said fuse to less than 32 amperes.
  • Ak current-limiting device for a circuit requiringa capacity of N kva. including a plurality of 'n' basic'units adapted to carry current in parallel and combined to form a composite selfsustained'structure, each of said n units consisting of a ⁇ current-limiting fuse comprising a glass cloth base casing having a wall thickness in the order of half the radius thereof and delining a chamber having an internal volume in the order ofOO to 1/500 cubic inch per N/'n capacity, a pulverulent quartz filler Within said chamber including a mixture of grain sizes that will pass through a No. 30 and will be held on -a No. 40 U. S.
  • a ribbon-type fuse link having a plurality of serially related portions of reduced cross-section within said chamber in contact with said ller, a metal element on said link adapted to form an alloy with the metal of which said link is made having a lower fusing point than the metal ci. which said link is made, and a gas evolving pulverulent llerwithinA said chamber surrounding said alloy forming metal element, said alloy forming metal element and said link being adapted to alloy and fuse at continuous currents of less than 36 amperes.
  • a pulverulent quartz ller larger than No. 80 but smaller than No. 18 U. S. Standard Sieve Number
  • a fuse link adapted to limit the maximum continuous current of said fuse to less than 36 amperes arranged in said casing in contact with said filler.
  • a current-limiting device including a plurality of n basic units adapted to carry current in parallel and combined to form a composite self-sustained structure arranged in said circuit, each of said n units consisting of a current-limiting fuse having a casing dening a chamber the internal volume of which is in the order of 1/400 to 1/100 cubic inch per kva.
  • a pulverulent quartz ller in said chamber consisting of a mixture of grain sizes that will pass through a No. 18 and be held on a No. 80 U. S. Standard Sieve Number screen, a ribbon-type fuse link arranged in said chamber in contact with said iiller, and said link having an Meiect causing means thereon limiting the maximum continuous current of said fuse to less than 36 amperes.
  • a current-limiting device including a plurality of n basic units adapted to carry current in parallel and combined to form a composite self-sustained structure arranged in said circuit, each of said n units consisting of a current-limiting fuse having a casing dening a chamber the internal volume of which is in the order of several thousandths of a cubic inch per kva.
  • a pulverulent quartz ller within said chamber larger than No. 70 but smaller than No. 20 U. S. Standard Sieve Number
  • a ribbontype fuse link having a plurality of circular perfora-tions along the center line thereof arranged in said chamber in contact with said filler, and a metal element adapted to form an alloy with the metal of which said link is made having a lower fusing point than the metal of which said link is made arranged at some point of said link and adapted to cause alloy formation and fusing of said link at continuous currents of less than 36 amperes.
  • a current-limiting device including a plurality of n basic units adapted to carry current in parallel and combined to form a composite self-sustained structure in said circuit, each of said n units consisting of a currentlimiting fuse having a casing dening a chamber the internal volume of which is in the order of several thousandths of a cubic inch per kva.
  • a pulverulent quartz iiller within said chamber consisting of a mixture of grain sizes that will pass through a No. 20 and be held on a No. U. S. Standard Sieve Number screen
  • a ribbon type fuse link arranged within said chamber in contact with said ller and a metal element adapted to form an alloy with the metal of which said fuse link is made having a lower fusing point than the metal of which said fuse link is made in contact with said link, said link and said metal element being adapted to limit the maximum continuous current of said fuse to less than 36 amperes.

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US226755A 1951-05-17 1951-05-17 Current-limiting fuse Expired - Lifetime US2599646A (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800554A (en) * 1953-06-23 1957-07-23 E M P Electric Ltd Electric fuses
US3077525A (en) * 1954-09-20 1963-02-12 Westinghouse Electric Corp Circuit interrupter
US3134874A (en) * 1961-01-30 1964-05-26 Westinghouse Electric Corp Current limiting fuse
US3197592A (en) * 1963-01-30 1965-07-27 Chase Shawmut Co Time lag fuses with fuse links having link-severing overlays
US3213242A (en) * 1962-02-23 1965-10-19 Westinghouse Electric Corp Current limiting fuse
US3513424A (en) * 1969-03-24 1970-05-19 Chase Shawmut Co Electric cartridge fuse having high operating temperature when carrying load current
US3571776A (en) * 1969-11-24 1971-03-23 Chase Shawmut Co High voltage fuse having helically wound ribbon fuse link
US4192534A (en) * 1976-11-11 1980-03-11 S & C Electric Company High voltage fuse having attached tubular members
US4533896A (en) * 1983-11-28 1985-08-06 Northern Telecom Limited Fuse for thick film device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800554A (en) * 1953-06-23 1957-07-23 E M P Electric Ltd Electric fuses
US3077525A (en) * 1954-09-20 1963-02-12 Westinghouse Electric Corp Circuit interrupter
US3134874A (en) * 1961-01-30 1964-05-26 Westinghouse Electric Corp Current limiting fuse
US3213242A (en) * 1962-02-23 1965-10-19 Westinghouse Electric Corp Current limiting fuse
US3197592A (en) * 1963-01-30 1965-07-27 Chase Shawmut Co Time lag fuses with fuse links having link-severing overlays
US3513424A (en) * 1969-03-24 1970-05-19 Chase Shawmut Co Electric cartridge fuse having high operating temperature when carrying load current
US3571776A (en) * 1969-11-24 1971-03-23 Chase Shawmut Co High voltage fuse having helically wound ribbon fuse link
US4192534A (en) * 1976-11-11 1980-03-11 S & C Electric Company High voltage fuse having attached tubular members
US4533896A (en) * 1983-11-28 1985-08-06 Northern Telecom Limited Fuse for thick film device

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Publication number Publication date
CH308109A (de) 1955-06-30

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