EP0175349A2 - Interrupteur à vide - Google Patents

Interrupteur à vide Download PDF

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Publication number
EP0175349A2
EP0175349A2 EP85111755A EP85111755A EP0175349A2 EP 0175349 A2 EP0175349 A2 EP 0175349A2 EP 85111755 A EP85111755 A EP 85111755A EP 85111755 A EP85111755 A EP 85111755A EP 0175349 A2 EP0175349 A2 EP 0175349A2
Authority
EP
European Patent Office
Prior art keywords
electrode
circuit breaker
melting point
vacuum circuit
electrodes
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.)
Withdrawn
Application number
EP85111755A
Other languages
German (de)
English (en)
Other versions
EP0175349A3 (fr
Inventor
Yukio Kurosawa
Kiyoji Iwashita
Morihisa Matumoto
Ryuji Watanabe
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP0175349A2 publication Critical patent/EP0175349A2/fr
Publication of EP0175349A3 publication Critical patent/EP0175349A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
    • H01H33/66—Vacuum switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/0203—Contacts characterised by the material thereof specially adapted for vacuum switches

Definitions

  • the present invention relates to a vacuum circuit breaker having improved electrodes.
  • a vacuum circuit breaker has an insulated cylinder both ends of which are closed by end plates so as to form a vacuum vessel in which are disposed a pair of electrodes opposing each other.
  • the electrodes are supported by respective conductor bars which are extended in the axial direction of the vessel so as to project outside the vessel.
  • a bellows is secured at its one end to one of the conductor bars which is axially movable and at its other end to the inner surface of the adjacent end plate so that the conductor bar can move without breaking vacuum in the vessel.
  • Each electrode is provided with a contact surface layer'for contact with the other electrode.
  • the contact surface layer is made of a material which contains a metal having a low-melting point.
  • the use of such a material is advantageous in that, since the materials containing low-melting point metals are mechanically brittle, the actuator can separate the electrodes with small power even in the event of fusion and welding of two electrodes to each other as a result of melting thereof by Joule heat produced by, for example, an abnormally large electric current caused by an accident.
  • Electrodes materials which contain Bi, Pb, Te, Se, etc. as the low-melting point metal.
  • Metals such as Cu, Ag, Co and Cr are used as the main component of these electrode materials.
  • the low-melting point metals such as Bi, Pb, etc. mentioned above, however, cannot form any solid solution with these main components and tend to precipitate in the grain boudaries.
  • the present inventors have found that, when the vessel is heated in a vacuum furnace during vacuum brazing conducted for brazing the electrode to the associated conductor bar or for evacuating the vessel, small projections are formed in the electrode surface, thereby deteriorating the withstand voltage property of the electrode. This is attributable to a fact that, when the electrode is heated in vacuum, the low-melting point metal such as Bi or Pb existing in the grain boundaries of Cu grains constituting the main electrode material is molten and forms projections which project towards the opposing electrode. When such an electrode is used, the electric field is concentrated locally to such projections, thereby lowering the withstand voltage property of the electrode.
  • the intermetallic compound formed by main component such as Cu and low-melting point metal such as Se or Te exhibits such a specific phenomenon that the main component such as Cu is freed when the compound is heated to a temperature between about 250°C and 500°C. The freed main component projects in the form of whisker, thereby lowering the withstand voltage property.
  • the conventional vacuum circuit breakers have sufferd from a problem in that the withstand voltage property of the electrode itself is not fully utilized.
  • an object of the invention is to provide a vacuum circuit breaker which incorporates electrodes having higher withstand voltage property over the conventional vacuum circuit breakers.
  • a dense film of high-melting point metal which is not reactive with the low-melting point metal, is formed on the electrode surface so as to prevent any exudation of the low-melting point metal towards the electrode surface and any whisker of the main component of the electrode material from being formed.
  • a vacuum circuit breaker according to the present invention is generally designated at a reference numeral 1.
  • the vacuum circuit breaker 1 has a vacuum vessel 2 which is composed of an insulating cylinder 3 and both end plates 4A and 4B.
  • a pair of conductor bars 5 and 6 are disposed in the vacuum vessel so as to oppose each other. The other ends of the conductor bars are extended to the outside of the vacuum vessel.
  • a bellows 7 is secured at its one end to one 6 of the conductor bars and at its other end to the inner surface of the end plate 4.
  • the conductor bar 6 is adapted to be moved by an actuator (not shown) towards and away from the other conductor bar 5 as indicated by arrows.
  • Electrodes 8 and 9 are attached by vacuum brazing to the inner opposing ends of the conductor bars 5 and 6.
  • the electrode 9 carried by the conductor bar 6 is adapted to be brought into and out of contact with the other electrode 8.
  • Arc is generated between two electrodes when the electrode 9 is just going to contact the other electrode 8 or be separated from the same.
  • an intermediate shield 11 is disposed between the insulating cylinder 3 and the electrodes 8,9.
  • the intermediate shield 11 is secured to the inner surface of the insulating cylinder through brackets 12. Since both electrodes 8,9 have an identical construction, only one of the electrodes represented by a numeral 10 will be described with reference to Fig. 2.
  • the electrode 10 may be made of a material containing a main component such as Cu or Ag with addition of a low-melting point metal such as Bi, Pb or the like.
  • a film 13 is formed on the surface of the electrode 10 made of the material mentioned above. The film 13 is formed by evaporating Cr onto the electrode surface.
  • the film 13, however, may be made from other materials such as metals belonging to iron group e.g., Co, Ni, Fe, etc., as well as refractory metals such as Ta, Mo, W, etc. All what is required for the film material is that the melting point of such film material is equal to or higher than that of the main component of the electrode material.
  • the electrodes 9,10 incorporated in the vacuum circuit breaker of the invention is covered with the film 13 of, for example, Cr which is not reactive with Co, Ag and Se even at an elevated temperature of, for example, 1000°C at which the vacuum brazing is conducted in the course of fabrication of the vacuum circuit breaker, so that the undesirable projection of whisker of, for example, Ag in the Co-Ag-Se alloy is prevented by the dense film of Cr on the electrode surface. This in turn avoids any tendency of local concentration of the electric field, thereby ensuring improved withstand voltage property of the electrode.
  • the wetting of the electrode surfaces by the melting of the low-melting point metal which is necessary for attaining an easy contact and separation of two electrodes, is impaired by the presence of the film 13 on the electrode surfaces.
  • the film 13, however, is easily broken by a tensile force which is generated when both electrodes are separated from each other, i.e., when the circuit is opened, so that the electrode surfaces are sufficiently wetted to ensure an easy separation of two electrodes.
  • the film in the described embodiment is formed by evaporation, this is not exclusive and the film may be formed by another method such as plating.
  • the vacuum circuit breaker of the invention features a film of a high-melting point metal formed on the surface of each electrode made of a material containing a low-melting point metal.
  • the film effectively prevents exudation of the low-melting point metal and formation of whisker of main component of the electrode material during heating of the electrode under a vacuum in the course of fabrication of the vacuum circuit breaker. It is thus possible to obtain a vacuum circuit breaker capable of withstanding high voltages.

Landscapes

  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
  • Physical Vapour Deposition (AREA)
EP85111755A 1984-09-19 1985-09-17 Interrupteur à vide Withdrawn EP0175349A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59194733A JPS6174222A (ja) 1984-09-19 1984-09-19 真空遮断器
JP194733/84 1984-09-19

Publications (2)

Publication Number Publication Date
EP0175349A2 true EP0175349A2 (fr) 1986-03-26
EP0175349A3 EP0175349A3 (fr) 1988-04-06

Family

ID=16329326

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85111755A Withdrawn EP0175349A3 (fr) 1984-09-19 1985-09-17 Interrupteur à vide

Country Status (3)

Country Link
EP (1) EP0175349A3 (fr)
JP (1) JPS6174222A (fr)
KR (1) KR860002845A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0234246A1 (fr) * 1986-01-30 1987-09-02 Siemens Aktiengesellschaft Pièces de contact interrupteur pour appareils interrupteurs sous vide et procédé pour leur fabrication
EP0343663A2 (fr) * 1988-05-27 1989-11-29 Kabushiki Kaisha Toshiba Contacts d'un interrupteur à vide et méthode de fabrication
DE3842919A1 (de) * 1988-12-21 1990-07-05 Calor Emag Elektrizitaets Ag Schaltstueck fuer einen vakuumschalter und verfahren zur herstellung eines solchen schaltstuecks oder eines entsprechend beschaffenen bauteils

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6246096B2 (ja) * 2014-08-08 2017-12-13 一般財団法人電力中央研究所 ガス絶縁開閉装置の状態診断方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1347932A (fr) * 1962-12-04 1964-01-04 Heraeus Gmbh W C Métal composite
FR1437162A (fr) * 1964-11-19 1966-04-29 Perfectionnements aux interrupteurs électriques sous vide
EP0042152A1 (fr) * 1980-06-18 1981-12-23 Hitachi, Ltd. Interrupteur à vide
US4420346A (en) * 1980-11-28 1983-12-13 Belkin German S Method of preparing contacts and electrodes of electric vacuum apparatuses

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1347932A (fr) * 1962-12-04 1964-01-04 Heraeus Gmbh W C Métal composite
FR1437162A (fr) * 1964-11-19 1966-04-29 Perfectionnements aux interrupteurs électriques sous vide
EP0042152A1 (fr) * 1980-06-18 1981-12-23 Hitachi, Ltd. Interrupteur à vide
US4420346A (en) * 1980-11-28 1983-12-13 Belkin German S Method of preparing contacts and electrodes of electric vacuum apparatuses

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0234246A1 (fr) * 1986-01-30 1987-09-02 Siemens Aktiengesellschaft Pièces de contact interrupteur pour appareils interrupteurs sous vide et procédé pour leur fabrication
US4749830A (en) * 1986-01-30 1988-06-07 Siemens Aktiengesellschaft Contact pieces for vacuum switchgear, and method for the manufacture thereof
EP0343663A2 (fr) * 1988-05-27 1989-11-29 Kabushiki Kaisha Toshiba Contacts d'un interrupteur à vide et méthode de fabrication
EP0343663A3 (en) * 1988-05-27 1990-07-18 Kabushiki Kaisha Toshiba Vacuum interrupter contacts and process for producing the same
US5109145A (en) * 1988-05-27 1992-04-28 Kabushiki Kaisha Toshiba Vacuum interrupter contacts and process for producing the same
DE3842919A1 (de) * 1988-12-21 1990-07-05 Calor Emag Elektrizitaets Ag Schaltstueck fuer einen vakuumschalter und verfahren zur herstellung eines solchen schaltstuecks oder eines entsprechend beschaffenen bauteils

Also Published As

Publication number Publication date
EP0175349A3 (fr) 1988-04-06
KR860002845A (ko) 1986-04-30
JPS6174222A (ja) 1986-04-16

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Inventor name: IWASHITA, KIYOJI