US3715698A - Current limiting fuse - Google Patents

Current limiting fuse Download PDF

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Publication number
US3715698A
US3715698A US00115197A US3715698DA US3715698A US 3715698 A US3715698 A US 3715698A US 00115197 A US00115197 A US 00115197A US 3715698D A US3715698D A US 3715698DA US 3715698 A US3715698 A US 3715698A
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US
United States
Prior art keywords
fuse
fuse element
heat
dielectric
dielectric member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00115197A
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English (en)
Inventor
D Blewitt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Application granted granted Critical
Publication of US3715698A publication Critical patent/US3715698A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H01H85/05—Component parts thereof
    • H01H85/055—Fusible members
    • 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
    • H01H85/47—Means for cooling

Definitions

  • ABSTRACT A current limiting fuse element comprising a fuse link or portions of reduced cross section of such a relatively small area or size that they would normally be unable to support themselves alone.
  • the fuse element is intimately bonded or attached to a relatively larger rigid dielectric mass by methods, such as printing, vacuum deposition or etching, so that the larger dielectric mass provides the structural support for the relatively thin current limiting regions or portions and also assists in removing heat from the fuse element during both normal operation and also during fusing of the fuse element.
  • the fuse element and'its dielectric support may be used independently or may be used as the fuse element in a cartridge-type fuse where the entire fuse element is disposed in a casing and em- .bedded in a pulverulent, arc quenching material, such as sand, which may be provided to assist in arc extinction upon fusing of the fuse element and to absorb the heat during fusing.
  • a pulverulent, arc quenching material such as sand
  • the relatively rigid, dielectric mass may be adapted to accommodate or receive a'heat transferring means through which fluid may flow. Heat generated during normal operation of the fuse or during a fusion operation may be removed by the moving fluid.
  • Current limiting fuses or fuse sections are often constructed by cutting or forming grooves, notches or other portions of reduced cross-section of various geometric shapes into fusible material which may initially be in the form of a ribbon or wire.
  • the notches are arranged to create small cross-sectional regions in the fusible ribbon or wire.
  • the fuse element or link conducts current through the small cross-sectional regions as the relatively larger adjacent regions or the regions where no grooves or notches have been cut serve to complete a continuous path for electrical current flow, and also to provide relatively larger surface areas for removal of heat which is generated or results in the smaller cross-sectional regions or portions.
  • the notched sections or portions of relatively smaller cross-sectional areas melt to first form a plurality of relatively larger, spaced portions of electrical conducting material with a plurality of electrical arcs established between them.
  • a predetermined number of arcs may be established during the initial melting of the fuse element. Since each arc represents a regionof high resistance to current flow in the fuse element, the maximum current which flows is limited by providing a number of arcs.
  • plastic strip in the latter patent is intended to be an insulating material so that the response of the fusible material is not affected by the presence of the strip material. It should also be noted that in the latter patent, that the flexible strip material may be subject to breaking, tearing, ripping or distortion.
  • a fuse structure includes a relatively large dielectric or electrically insulating, rigid mass or a member which is formed from a suitable material and used as both a supporting means and as a heat removing means for an associated fuse element having a plurality of relatively smaller or reduced cross-sectional areas which melt and arc over in the presence of large values of overload current.
  • the associated fuse element is secured to the relatively large dielectric mass or member by any one of a number of processes intimately bonding the fuseelement to the rigid dielectric member, such as vacuum deposition, printing or a combination photographicetching process with the fuse element sufficiently adhering to the dielectric mass to provide structural strength to the fuse element or link and to aid in the removal of heat from the fuse element.
  • the fuse element and its dielectric support will be assembled in a cartridge-type explosion proof fuse whereas in another embodiment of the invention, the combination of fuse element and dielectric support may be mounted in a fuse holder.
  • the dielectric support as disclosed is relatively rigid compared with flexible plastic tape, the likelihood of the supporting material breaking, cracking, stretching or distorting under mechanical or thermal stress is greatly reduced, while the ability of the dielectric support to remove heat from the associated fuse element is increased.
  • a complete internal fuse section may be created in a simple one-step process whereby fuse material is bonded to the adjacent dielectric material and the combination is then placed internal to the cartridge fuse.
  • the' relatively rigid dielectric support may be hollow or drilled in such a manner as to provide a passageway for cooling fluid to flow rapidly through it, thus increasing the heat removing capabilities of the entire fuse assembly such as would result when arcs are established during operation of a fuse structure.
  • FIG. 1 is an orthogonal view of a fuse section embodying the invention.
  • FIG. 2 is an orthogonal view of a mounted fuse section similar to the one shown in FIG. 1 including a heat exchanging duct.
  • FIG. 3 is a view, in elevation, partially cut away, showing one embodiment of the invention as used in a cartridge or enclosed type fuse.
  • the fuse assembly shown therein comprises a uniquely shaped fuse element 14 intimately bonded or secured to a relatively rigid dielectric mass or support member 12.
  • Dielectric member 12 may be formed from any electrically insulating material such as thermosetting resins of the phenolic, epoxy or polyester types with suitable fillers or ceramic type material such as alumina or beryllia provided it is relatively rigid and capable of supporting the associated fuse element or means 14 which is mounted thereon.
  • Fuse element 14 may be formed from an electrically conducting fusible material, such as silver.
  • fuse element 14 has a plurality of axially spaced, generally V- shaped notches, such as indicated at 18U and 18L, which may be oppositely disposed to form restricted portions such as indicated at 16A and 168, although any of the well-known restriction geometries or shapes as well as those not heretofore feasible may be used if desired.
  • Restricted portions 16A and 16B are shaped to provide a plurality of portions having relatively smaller cross-sectional areas.
  • electrical current flows through the relatively larger sections 20 of the fuse element 14 as well as the notched or reduced sections 16A and 168.
  • the area of notches 16A and 163 as shown in this example are designed to conduct a predetermined amount of high density electrical current without deteriorating.
  • Some of the suitable methods for intimately bonding fusible element 14 to dielectric support 12 are vacuum deposition of the fusible material, printing of the fusible material, pressing the fuse material 14 into the body of the dielectric mass or support 12 or a photographic masking and etching process such as that employed in preparing printed circuit boards.
  • the cross-sectional areas of the fusible material in the regions of notches or thin sections 16A and 168 must also be very small.
  • fuse element 14 would probably crack, break, bend, twist or shatter in the regions of notches 16A and 16B so that each relatively larger conducting section 20 would be spaced or separated from the adjacent conducting sections 20 even though no overload current had flowed to cause such a break.
  • the dielectric member 12 may be a rigid, relatively thin dielectric board or a much larger dielectric member with relative dimensions which differ from those indicated by the shape of the dielectric member 12 shown in FIG. 1.
  • FIG. 2 another embodiment of the invention is illustrated in a fuse assembly including a heat conducting duct or pipe 32 having a right end 36 and a left end 38 which is disposed generally parallel to the fuse element 140 and'to fit into opening or hole 30 i of dielectric mass or support 120 so that a cooling fluid such as indicated at 34 may flow through pipe 32 and 1 further aid in removal of heat generated in fuse element 140 during either normal operation or during an overcurrent condition when the fusible material in regions ⁇ 160A and 1608 heats up more rapidly than the fusible material in the adjacent sections 200.
  • a cooling fluid such as indicated at 34
  • Fuse assembly 100 may be mounted in a supporting structure 39 having an electrically insulating base 40 withtwo electrically conducting fuse holders or clips 42L and 42R disposed thereon. Current may flow in a circuit 1 which extends from wire or lead 48R, fuse holder 42R to fuse element 140, at region 46 through fuse element 140 to region 44 and then through fuse holder 42L to lead or wire 48L. 1
  • FIG. 3 another embodiment of the invention is illustrated in which a fuse assembly is mounted or disposed within a cartridge fuse 60.
  • Fuse assembly 10 is secured at one end 68 to a generally cylindrical conducting means 66 and at the other end to a similar conducting means (not shown).
  • Conducting means66 forms a closure means at one end of a cylinder 62 which is made of electrically insulating material. Cylinder or casing 62 is closed at the other end by the previously mentioned similar means.
  • Fuse caps or terminals 64A and 64B are mounted at the insulating cylinder 62 to form contacts, adapted to fit an associated fuse holder.
  • an electrical circuit through which current may flow extends from end cap 64A, through conducting section or member 66 into fuse element 14, through the other conducting member (not shown) and to the other end cap 648.
  • a finely divided, pulverulent. or granular material 70 such as silica or quartz sand, may be disposed to substantially fill the space between the fuse assembly 10 and the cylinder.
  • the material 70 acts as an absorber of thermal energy of arc currents when fuse element 14 is caused to melt or rupture due to overload current and it is also the absorber of heat generated during both steady state or normal operation and during an interrupting operation.
  • fuse assembly of the invention is illustrated in two embodiments, one of which is a cartridge fuse embodiment, other embodiments of fuse sections are possible. It should be noted that heat removing section 32 of the fuse assembly 100 shown in FlG. 2, need not be of the particular form and shape indicated therein. It should also be understood that a plurality of fuse sections 20 may be connected in parallel circuit configuration.
  • a current limiting fuse with a plurality of current limiting sections may be used to limit or to protect against predetermined values of overload current, in applications where anunsupported fuse element made of the same fusible material would not be feasible because it would lack structuralintegrity.
  • the adjacent dielectric material not only provides the structural strength required to It is to be understood that fuse element 14 may contain any number of reduced sections such as sections l6A'and 168, as determined by the voltage to be interrupted as well as other electrical characteristics. It is also to be understood that fuse element l4.with regions 16A and 1681 need not be formed only with generally rather than from disposed along the edges as illustrated i in FIG. 1.
  • a fuse element may be provided with one fuse portion including smaller cross-sectional areas formedby two notches such as shown in FIG. 1, and another fuse element support the associated fuse element but aids in removing heat during both normal operation and during an interrupting or fusing operation from the fuse element.
  • the relatively rigid, adjacent dielectric member may be drilled or otherwise formed to carry a cooling or heat removing fluid away from the fuse element to further enhance the heat removing characteristics of the fuse assembly.
  • the dielectric member 12 is structurally strong and requires no further support or reinforcement in at least certain applications. Intimate deposition or bonding of fuse elements provide a means whereby a fuse element with a very small cross-sectional area or portion may conduct relatively high current density during normal or other than overload conditions without melting the adjacent sections of the fuse element and may more easily remove heat.
  • An electric fuse structure comprising a substantially rigid dielectric heat conducting supporting member formed primarily from a thermosetting resinous material, a ribbon of fusible material having at least one notch to form a relatively smaller cross-sectional region intimately bonded along substantially its entire length to said dielectric member, said ribbon of fusible material being incapable of structurally supporting itself independently of the support of said dielectric member, said dielectric member including a separate integrally disposed tubular heat removing duct extending therethrough adapted toaccommodate the flow of heat absorbing fluid therein, a heat path existing from said fusible ribbon through said dielectric member into said tubular duct to the moving heat absorbing fluid.
  • An electric fuse member comprising a substantially rigid heat conducting dielectric supporting member formed primarily from a thermosetting resinousmaterial and including a generally tubular heat conducting duct therethrough adapted to carry a heat conducting fluid therethrough, a ribbon shaped fusible element intimately bonded along its entire length upon said supporting member by printing the fusible element thereon, said fusible element having at least one relatively smaller cross-sectional region which is incapable of structurally supporting itself independently of the support of said dielectric member, said intimate bond- 7 ing by printing facilitating the removal of heat generated in said fuse element during the operation of said fuse, said fusible element being generally parallel to said tubular duct.

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  • Fuses (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
US00115197A 1971-02-16 1971-02-16 Current limiting fuse Expired - Lifetime US3715698A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11519771A 1971-02-16 1971-02-16

Publications (1)

Publication Number Publication Date
US3715698A true US3715698A (en) 1973-02-06

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ID=22359836

Family Applications (1)

Application Number Title Priority Date Filing Date
US00115197A Expired - Lifetime US3715698A (en) 1971-02-16 1971-02-16 Current limiting fuse

Country Status (3)

Country Link
US (1) US3715698A (enrdf_load_stackoverflow)
JP (2) JPS4719356A (enrdf_load_stackoverflow)
DE (1) DE2207041A1 (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3793603A (en) * 1972-07-17 1974-02-19 Ferraz & Cie Lucien Fuse cartridges
US4309069A (en) * 1979-02-21 1982-01-05 Ahroni Joseph M Fused plug assembly with fuse unit having spare fuse elements
US4309068A (en) * 1979-12-05 1982-01-05 Ahroni Joseph M Fused plug assembly with spare fuse elements
DK156791B (da) * 1977-05-28 1989-10-02 Mc Graw Edison Co Elektrisk smeltesikring
US20030142453A1 (en) * 2002-01-10 2003-07-31 Robert Parker Low resistance polymer matrix fuse apparatus and method
US6801433B2 (en) * 2001-04-19 2004-10-05 General Electric Company Method and apparatus for cooling electrical fuses
US6840308B2 (en) 2002-05-31 2005-01-11 General Electric Co. Heat sink assembly
US20120211480A1 (en) * 2011-02-23 2012-08-23 Yazaki Corporation Resin molded product
US20150357144A1 (en) * 2014-06-04 2015-12-10 Hamilton Sundstrand Corporation Fuse assembly
WO2023151958A1 (de) * 2022-02-08 2023-08-17 Man Truck & Bus Se Kühlvorrichtung zur fluidkühlung einer passiven fehlerstromschutzeinrichtung
US12224146B2 (en) * 2020-03-30 2025-02-11 Huawei Technologies Co., Ltd. Embedded substrate, circuit board assembly, and electronic device

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0737069B2 (ja) * 1987-06-22 1995-04-26 株式会社フジクラ 架橋型熱収縮管の連続製造装置
US7385475B2 (en) * 2002-01-10 2008-06-10 Cooper Technologies Company Low resistance polymer matrix fuse apparatus and method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS42261Y1 (enrdf_load_stackoverflow) * 1964-03-11 1967-01-10
JPS4322201Y1 (enrdf_load_stackoverflow) * 1967-05-02 1968-09-18

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3793603A (en) * 1972-07-17 1974-02-19 Ferraz & Cie Lucien Fuse cartridges
DK156791B (da) * 1977-05-28 1989-10-02 Mc Graw Edison Co Elektrisk smeltesikring
US4309069A (en) * 1979-02-21 1982-01-05 Ahroni Joseph M Fused plug assembly with fuse unit having spare fuse elements
US4309068A (en) * 1979-12-05 1982-01-05 Ahroni Joseph M Fused plug assembly with spare fuse elements
US6801433B2 (en) * 2001-04-19 2004-10-05 General Electric Company Method and apparatus for cooling electrical fuses
US7570148B2 (en) * 2002-01-10 2009-08-04 Cooper Technologies Company Low resistance polymer matrix fuse apparatus and method
US20030142453A1 (en) * 2002-01-10 2003-07-31 Robert Parker Low resistance polymer matrix fuse apparatus and method
US6840308B2 (en) 2002-05-31 2005-01-11 General Electric Co. Heat sink assembly
US20120211480A1 (en) * 2011-02-23 2012-08-23 Yazaki Corporation Resin molded product
US9224567B2 (en) * 2011-02-23 2015-12-29 Yazaki Corporation Resin molded product
US20150357144A1 (en) * 2014-06-04 2015-12-10 Hamilton Sundstrand Corporation Fuse assembly
US12224146B2 (en) * 2020-03-30 2025-02-11 Huawei Technologies Co., Ltd. Embedded substrate, circuit board assembly, and electronic device
WO2023151958A1 (de) * 2022-02-08 2023-08-17 Man Truck & Bus Se Kühlvorrichtung zur fluidkühlung einer passiven fehlerstromschutzeinrichtung

Also Published As

Publication number Publication date
JPS4719356A (enrdf_load_stackoverflow) 1972-09-21
JPS5492341U (enrdf_load_stackoverflow) 1979-06-29
DE2207041A1 (de) 1972-08-31

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