EP0016467A1 - Elektrische Schmelzsicherungen mit Schmelzleitern, die aus verschiedenen Metallen zusammengesetzt sind - Google Patents

Elektrische Schmelzsicherungen mit Schmelzleitern, die aus verschiedenen Metallen zusammengesetzt sind Download PDF

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Publication number
EP0016467A1
EP0016467A1 EP80101485A EP80101485A EP0016467A1 EP 0016467 A1 EP0016467 A1 EP 0016467A1 EP 80101485 A EP80101485 A EP 80101485A EP 80101485 A EP80101485 A EP 80101485A EP 0016467 A1 EP0016467 A1 EP 0016467A1
Authority
EP
European Patent Office
Prior art keywords
fuse
metals
metal
electric fuse
portions
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.)
Ceased
Application number
EP80101485A
Other languages
English (en)
French (fr)
Inventor
Vojislav Narancic
Milenko Braunovic
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.)
Kearney-National (Canada) Ltd
KEARNEY NATIONAL CANADA Ltd
Original Assignee
Kearney-National (Canada) Ltd
KEARNEY NATIONAL CANADA Ltd
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 Kearney-National (Canada) Ltd, KEARNEY NATIONAL CANADA Ltd filed Critical Kearney-National (Canada) Ltd
Publication of EP0016467A1 publication Critical patent/EP0016467A1/de
Ceased 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
    • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
    • H01H85/05—Component parts thereof
    • H01H85/055—Fusible members
    • H01H85/06—Fusible members characterised by the fusible material

Definitions

  • Fuse elements for such fuses commonly consist of one or more strips or ribbons of metal mounted in a suitable casing, and the design of such a fuse element requires the careful choice of different parameters among which are the metal from which the element is made, the dimensions of the strip or ribbon, whether or not the strip is notched or provided with eutectic spots (Metcalf effect) along its length; whether or not the element is wound on a ceramic or deionizing gas producing core; whether or not the element consists of two different metals connected in series; and the choice of the material surrounding the element.
  • the ribbon may be of silver and provided along its length with up to about 100 notches, or holes, each of which is the potential site for melting and the initial formation of an arc; the element is completely buried in quartz sand which acts to absorb the energy generated by the arcs, and also to receive the melted element material.
  • silver has a desirable high conductivity and resistance to oxidation, but has a high melting point (960°C), and a high heat of evaporation and -is costly.
  • Metcalf or M-effect a eutectic alloy is formed, the melting temperature being lower at the spot (approximately 230°C) to make the fuse applicable for low current operation, but such spots exhibit with time a non- reversible change under the effect of non-melting current flows that can lead to damage of the fuse.
  • Cadmium is a low melting point metal (321°C) with a very low temperature of evaporation (750°C). It has an excellent arc extinguishing characteristic and therefore it is widely used in electrical contacts. Moreover, it has very high burnback rate and is very convenient for interruption of low currents. Cadmium has low conductivity and current carrying capacity while the resultant cadmium oxide is a very good insulator.
  • Zinc is a low melting point metal (419°C) that is resistant to oxidation, has a high burnback rate and has a non-linear coefficient of resistivity, which is useful, but has a conductivity 3-4 times lower than that of silver.
  • other metals and alloys thereof show some disadvantages when all of the necessary characteristics are evaluated.
  • Aluminum has a high current capacity and low melting point (658°C) and the oxide produced is non-conductive, which are all desirable, but the oxide film prevents disbursement of the melted metal into the surrounding sand and the melting characteristic for low currents applied for long times becomes inconsistent.
  • an electric fuse for use in circuits of at least 1000 volts comprising:
  • the said different metals being of different electrothermal properties such that each portion which is of one of the said metals will melt before the portion or portions of the otheJ metal to increase the current density through the unmelted portic or portions.
  • the said one of said two metals may be of lower melting point.
  • the said one metal may be a low melting point metal selected from the group consisting of tin, lead, zinc and cadmium
  • the said other metal may be a high melting point metal selected from the group consisting of silver, copper, nickel, magnesium and aluminum.
  • a fuse element for use in an electric fuse of the invention consists of at least two separate metals, each of which is tesent in the form of at least one so-called separate fuse element portion, and preferably the different fuse element portions are metallurgically bonded to one another at their adjoing surfaces where they contact one another to form in effect a composite metal body.
  • the fuse element preform illustrated therein consists of two thin flat portions 10 and 12, each of which'has the form of a thin flat strip or ribbon having two parallel wider faces and two parallel narrower faces or edges.
  • the two strips are placed face to face and metallurgically bonded to one another by, for example, coextrusion, cold rolling or by hot rolling at below the melting temperature of the lower melting material.
  • the portion of lower melting temperature metal is formed by casting against the body portion of the higher melting temperature metal, the resulting composite body then being extruded, cold or hot rolled, etc.
  • one portion consists of a plurality of uniformly- spaced metal wires or rods 10 which are enclosed in the second body porticn 12 by casting the latter metal around them. The resultant rod or wire can then be rolled or extruded as required.
  • a single body portion 10 is enclosed by the other metal portion 12.
  • the metallurgical bonding of the two body portions at their abutting surfaces is further increased by hot rolling the cast body.
  • Each of the preforms illustrated is processed, for example, to give it the specific dimensions necessary for fuse elements; notching and mounting the element between a pair of fuse terminals; and embedding the element in a suitable surrounding medium, such as quartz sand, in a suitable container.
  • a suitable surrounding medium such as quartz sand
  • an electric fuse consisting of a tubular housing 16 of an insulating material, provided with end caps 18 and 20 of a suitable conducting material at each end thereof.
  • Outer caps 22 and 24 are secured about the end caps 18 and 20 respectively by a press fit and are secured to the tubular housing 16 by cement layers 26 and 28 respectively.
  • An end terminal sleeve 30 and an end terminal cap 32 are fastened respectively to the inner surfaces of end caps 18 and 20, and the housing is filled with a granular filler consisting of silica sand 34.
  • helical fusible elements 36 through 44 Disposed within the housing of the fuse and embedded within and supported by the sand filler are a plurality (5 in this embodiment) of coaxial helical fusible elements 36 through 44, each of which has its two ends connected respectively to the terminal 30 and 32. As is apparent from Figure 3 the helical fusible elements are each provided along its length with a large number of spaced notches 46.
  • the metals to be employed in a fuse element of the invention preferably are selected from the group consisting of silver, copper, tin, lead, nickel, magnesium, zinc, aluminum and cadmium.
  • a preferred embodiment employs only zinc and aluminum either in the form of a sandwich (Fig. 2) or of a wire of aluminum, which has the higher melting point of the two, enclosed by the zinc which is cast around it, while another preferred embodiment employs only cadmium and silver either in the form of a sandwich (Fig.2), or of a wire of silver enclosed by the lower melting point cadmium which is rolled around it (Fig. 4).
  • the temperature/time characteristics of the composites of the invention are characterized by two different stages.
  • the initial stage is a normal exponential increase of temperature with time as the fuse is subjected to its normal load current.
  • the initial stage is a normal exponential increase of temperature with time as the fuse is subjected to its normal load current.
  • the temperature When an overload is present the temperature of course increases, and upon reaching the melting temperature of the lower melting component, there will be a rapid increase of temperature with time, due to a reduction in the cross sectional area of the element caused by successive melting of the lower temperature component and consequent increase in the current density through the remaining component.
  • the metals employed in a composite fuse element of the invention are specified as being different as to their electrothermal properties, by which are meant any one or more of their characteristics; resistivity, thermal conductivity, melting point, boiling point, heat of fusion, and heat of evaporation. It will be understood that different metals may have such similar electrothermal properties as not to be suitable for application of the invention.
  • the different portions of the element have as intimate an interface as possible, in order to obtain the best possible electrical and thermal conductivity between the metals without having the undesirable interaction of two metals during the premelting time.
  • each metal present in the composite should be present in an amount not less than 3% by volume of the entire element body, since otherwise there will not be sufficient present to significantly affect the properties of the composite. It will be apparent that each metal must be present in the form of a separate body or plurality of bodies that will extend through the intended melt and arc zone of the fuse element in the direction of flow of the current therethrough.
  • one of them will be of high conductivity and high melting point (e.g. silver and aluminum in the preferred combinations), while the other is of low melting point(e.g. cadmium and zinc respectively), so that element melting is initiated at any and all locations along the element which reach the melting temperature of the low melting point constituent, starting, of course, at the notches 46.
  • high conductivity and high melting point e.g. silver and aluminum in the preferred combinations
  • low melting point e.g. cadmium and zinc respectively
  • the preferred metals may be arranged in a high melting point group consisting of silve (960°C), copper (1083°C), nickel (1350°C), magnesium (651°C) and aluminum (658°C), and a low melting point group consisting of tin (232°C), lead (327°C), zinc (419°C), and cadmium (321°C), although the grouping in this manner does not preclude that a fuse element of the invention may be made using two metals from the same group.
  • the selection of the metals is based not only.-on their melting temperature, but also on the need to avoid any structural changes prior to the melting of the low melting component of the composite.
  • the vaporisation temperature of the lower melting point metal is below the melting temperature of the other metal, since it will then be completely-vaporised before melting of the other metal begins.
  • Another preferred property of any combination is that the metals exhibit a peritectic effect.
  • barrier layer between the adjoining contacting surfaces, the barrier layer being as thin as possible to provide the desired thermal exchange between the fuse element portions.
  • a suitable barrier layer can consist for example, of a thin film of a preformed alloy of the two materials, which may additionally be pre-aged so that there are no substantial changes in characteristic with time.
  • Other forms of barrier are a third metal, an oxide coating of one of the metals and an adhesive, preferably an organic adhesive so as not to react with the metals.
  • the cadmium preferably is present in the amount of from 97 to 53% by volume with the balance silver.
  • the percentages by volume of cadmium to silver were 80 to 90 percent of cadmium with the balance silver.
  • the melting characteristic of the resulting fuse element corresponds to that of cadmium with a melting temperature of about 320°C., the characteristic being fully reversible up to the melting point.
  • the cadmium/silver combination also has the advantages that the vaporisation temperature of cadmium is below the melting point of silver, and in addition the metals exhibit a p eritectic- reaction with one another. Moreover, the cadmium oxide that results from the initial melting is a good insulator and therefore does not affect the fuse characteristic and establishes good dielectric strengths so as to assist the arc extinguishing process.
  • the zinc preferably is present in the amount of from 97 to 53% by volume with the balance aluminum.
  • the percentages by volume of zinc to aluminum were 80 to 90.
  • the melting characteristic of the resulting element corresponds to that of an eutectic zinc/aluminum alloy with a melting temperature of about 380°C. It was found that the composite showed a non-linear increase in resistance with temperatures beginning at about 200°C, up to the melting point of 380°C, and that this increased resistance characteristic was fully reversibl up to the melting point.
  • a fuse element of the form illustrated by Figure 2 is preferred, in which a high melting temperature strip is sandwiched between two low melting temperature strips. It is also found that there is a preferred ratio of width to thickness of each strip, and with the cadmium/silver combination this should be about 10:1, and may of course vary between say 8:1 and 12:1.
  • An 8O amp fuse as described above will typically employ 12 helical elements connected in parallel each measuring about 2.5mm by 0.25mm.
  • the silica sand filler 34 preferably is in the form of approximately spherical grains of random size within a given range. These grains preferably are composed of at least 99% silica and approximately 98% of the grains are retained on sieve mesh size 100 while approximately 2% of the grains are retained on sieve mesh size 30. Approximately 30% of the grains are retained on sieve mesh size 40 while approximately 75% are retained on sieve mesh size 50.
  • the pellets are identified as 109 G.S.S.
  • the fusible elements 36-44 melt practically simultaneously at all of their reduced sections 46 to form a chain of arcs. These arcs quickly lengthen and burn back from their roots.
  • the energy of the arc in the form of heat is absorbed by the filler material in the granular form 34.
  • the exchange of energy between the arcs and the filler material is influenced by the surface area of filler grains which is exposed to the arcs.
  • the invention is concerned with high voltage currents of 1,000 volts and above, it is herein categorized as a high voltage fuse.
  • a fuse constructed according to this invention is well suited for use in protecting circuits and their connected apparat such as transformers, capacitors, switchgear and the like.
  • a fuse is provided which is capable of effective fast acting current limiting action for currents of high magnitud and which also operates reliably for low currents which are but slightly in excess of the normal rated current of the fuse due in part to the fact that the fusible elements may be raised by relatively low fault currents to temperature levels approaching melting without establishing an excessively high overall fuse temperature.
  • the preferred illustrated fuse is of coreless design which is to be preferred.
  • cores are objectionable because contact with the fusible element reduces the area over which energy exchange between the arcs and the filler material can take place. Since the interrupting process requires that most of the arc energy be transferred to latent heat of fusion of the filler material any reduction of the area of contact with the filler material is undesirable.
  • the areas of contact between the elements and core can produce high temperatures in the core.
  • the ceramic materials commonly used exhibit marked reduction in their insulating properties at such elevated temperatures. This reduction in insulating property of the core results in a non-uniform voltage distribution across the fuse in the period following arcing.

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  • Fuses (AREA)
EP80101485A 1979-03-21 1980-03-21 Elektrische Schmelzsicherungen mit Schmelzleitern, die aus verschiedenen Metallen zusammengesetzt sind Ceased EP0016467A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2238179A 1979-03-21 1979-03-21
US22381 1979-03-21

Publications (1)

Publication Number Publication Date
EP0016467A1 true EP0016467A1 (de) 1980-10-01

Family

ID=21809303

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80101485A Ceased EP0016467A1 (de) 1979-03-21 1980-03-21 Elektrische Schmelzsicherungen mit Schmelzleitern, die aus verschiedenen Metallen zusammengesetzt sind

Country Status (7)

Country Link
EP (1) EP0016467A1 (de)
JP (1) JPS55159537A (de)
AU (1) AU533549B2 (de)
BR (1) BR8001683A (de)
CA (1) CA1128100A (de)
MX (1) MX147542A (de)
ZA (1) ZA801645B (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2217531A (en) * 1988-03-23 1989-10-25 Yazaki Corp Electric fuse
US5099218A (en) * 1990-12-07 1992-03-24 Avx Corporation Binary fuse device
WO2001086684A1 (de) * 2000-05-08 2001-11-15 Abb Research Ltd Schmelzleiter und verfahren zu seiner herstellung sowie sicherungsleiter und sicherung
US6774761B2 (en) * 2002-03-06 2004-08-10 Uchihashi Estec Co., Ltd. Alloy type thermal fuse and fuse element thereof
WO2007034130A1 (en) * 2005-09-23 2007-03-29 Yazaki Europe Limited A fuse
DE102006009236A1 (de) * 2006-02-28 2007-09-06 Infineon Technologies Ag Vorrichtung und Verfahren zur temperaturunterbrechenden Absicherung eines elektrischen Bauelements
CN102543612A (zh) * 2012-01-13 2012-07-04 东莞市贝特电子科技有限公司 一种熔丝、制造熔丝的装置及熔丝的制造方法
CN104347312A (zh) * 2013-07-29 2015-02-11 泰科电子日本合同会社 保护元件
CN104871283A (zh) * 2012-12-28 2015-08-26 泰科电子日本合同会社 保护元件
US11145480B2 (en) * 2017-02-28 2021-10-12 Dexerials Corporation Fuse device

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6267445U (de) * 1985-10-17 1987-04-27
US10978267B2 (en) * 2016-06-20 2021-04-13 Eaton Intelligent Power Limited High voltage power fuse including fatigue resistant fuse element and methods of making the same

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR445270A (fr) * 1911-06-26 1912-11-07 Vernon Hope Coupe-circuit fusible pour controler les courants électriques
DE624633C (de) * 1933-06-11 1936-01-27 Siemens Schuckertwerke Akt Ges Verfahren zur Herstellung von geschlossenen, kurzschlusssicheren und ueberstromtraegen Schmelzsicherungen
DE664793C (de) * 1936-03-04 1938-09-12 Schiele Industriewerke Inhaber Schmelzleiter fuer elektrische Sicherungen
DE717681C (de) * 1938-04-06 1942-02-19 Wickmann Werke Ag UEberstromtraege Glaspatronenschmelzsicherung
US3268691A (en) * 1963-07-22 1966-08-23 Mc Graw Edison Co Protectors for electric circuits
DE1563785A1 (de) * 1966-12-15 1970-04-16 Siemens Ag Schmelzleiter fuer traege Schmelzeinsaetze
US3810062A (en) * 1972-05-04 1974-05-07 Chase Shawmut Co High-voltage fuse having full range clearing ability
US3869689A (en) * 1972-12-26 1975-03-04 Mikizo Kasamatu Time-delay fuse element
DE2551627A1 (de) * 1975-11-18 1977-06-02 Borchart Hans F Dipl Ing Schmelzleiter fuer traege elektrische schmelzsicherungen

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR445270A (fr) * 1911-06-26 1912-11-07 Vernon Hope Coupe-circuit fusible pour controler les courants électriques
DE624633C (de) * 1933-06-11 1936-01-27 Siemens Schuckertwerke Akt Ges Verfahren zur Herstellung von geschlossenen, kurzschlusssicheren und ueberstromtraegen Schmelzsicherungen
DE664793C (de) * 1936-03-04 1938-09-12 Schiele Industriewerke Inhaber Schmelzleiter fuer elektrische Sicherungen
DE717681C (de) * 1938-04-06 1942-02-19 Wickmann Werke Ag UEberstromtraege Glaspatronenschmelzsicherung
US3268691A (en) * 1963-07-22 1966-08-23 Mc Graw Edison Co Protectors for electric circuits
DE1563785A1 (de) * 1966-12-15 1970-04-16 Siemens Ag Schmelzleiter fuer traege Schmelzeinsaetze
US3810062A (en) * 1972-05-04 1974-05-07 Chase Shawmut Co High-voltage fuse having full range clearing ability
US3869689A (en) * 1972-12-26 1975-03-04 Mikizo Kasamatu Time-delay fuse element
DE2551627A1 (de) * 1975-11-18 1977-06-02 Borchart Hans F Dipl Ing Schmelzleiter fuer traege elektrische schmelzsicherungen

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2217531A (en) * 1988-03-23 1989-10-25 Yazaki Corp Electric fuse
GB2217531B (en) * 1988-03-23 1992-09-30 Yazaki Corp Fuse and manufacturing method therefor
US5099218A (en) * 1990-12-07 1992-03-24 Avx Corporation Binary fuse device
WO1992010846A1 (en) * 1990-12-07 1992-06-25 Avx Corporation Binary fuse device
US6791448B2 (en) 2000-05-08 2004-09-14 Abb Research Ltd Fusible element, method for production thereof, safety circuit and fuse
WO2001086684A1 (de) * 2000-05-08 2001-11-15 Abb Research Ltd Schmelzleiter und verfahren zu seiner herstellung sowie sicherungsleiter und sicherung
AU2001246284B2 (en) * 2000-05-08 2004-11-11 Abb Research Ltd Fusible element, method for production thereof, safety circuit and fuse
US6774761B2 (en) * 2002-03-06 2004-08-10 Uchihashi Estec Co., Ltd. Alloy type thermal fuse and fuse element thereof
WO2007034130A1 (en) * 2005-09-23 2007-03-29 Yazaki Europe Limited A fuse
DE102006009236A1 (de) * 2006-02-28 2007-09-06 Infineon Technologies Ag Vorrichtung und Verfahren zur temperaturunterbrechenden Absicherung eines elektrischen Bauelements
CN102543612A (zh) * 2012-01-13 2012-07-04 东莞市贝特电子科技有限公司 一种熔丝、制造熔丝的装置及熔丝的制造方法
CN104871283A (zh) * 2012-12-28 2015-08-26 泰科电子日本合同会社 保护元件
CN104347312A (zh) * 2013-07-29 2015-02-11 泰科电子日本合同会社 保护元件
US11145480B2 (en) * 2017-02-28 2021-10-12 Dexerials Corporation Fuse device

Also Published As

Publication number Publication date
AU533549B2 (en) 1983-12-01
AU5671480A (en) 1980-09-25
CA1128100A (en) 1982-07-20
BR8001683A (pt) 1980-11-18
ZA801645B (en) 1981-09-30
MX147542A (es) 1982-12-13
JPS55159537A (en) 1980-12-11

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Inventor name: NARANCIC, VOJISLAV

Inventor name: BRAUNOVIC, MILENKO