US3612795A - Shielding arrangements for vacuum-type circuit interrupters of the two-contact type - Google Patents

Shielding arrangements for vacuum-type circuit interrupters of the two-contact type Download PDF

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Publication number
US3612795A
US3612795A US789981A US3612795DA US3612795A US 3612795 A US3612795 A US 3612795A US 789981 A US789981 A US 789981A US 3612795D A US3612795D A US 3612795DA US 3612795 A US3612795 A US 3612795A
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United States
Prior art keywords
shield
vapor
contacts
short
metallic
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
US789981A
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English (en)
Inventor
Werner S Emmerich
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
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Westinghouse Electric Corp
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Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
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    • 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
    • H01H33/662—Housings or protective screens
    • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
    • 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
    • H01H33/662—Housings or protective screens
    • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
    • H01H2033/66269—Details relating to the materials used for screens in vacuum switches
    • 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
    • H01H33/662—Housings or protective screens
    • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
    • H01H2033/66284—Details relating to the electrical field properties of screens in vacuum switches
    • 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
    • H01H33/662—Housings or protective screens
    • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
    • H01H2033/66292—Details relating to the use of multiple screens in vacuum switches

Definitions

  • a narrow special shield incorporated into the vacuum circuit-interrupter geometry of the two-contact type.
  • This shield is to be made of well-out gassed metal and sufficiently thick so as to have maximum effectiveness in catching metallic vapor emitted from the electrode region.
  • the material chosen should also be one for which the sticking probability is naturally good, that is, it welds easily with the electrode material.
  • the short shield may be backed up by other shields, either metallic, or nonmetallic, of arbitrary thickness, whose only function is to shield the insulator against residual metallic vapor from the arc.
  • Such shields could be mounted on the insulators, on the end plates, or on the electrode stems.
  • the auxiliary shield is of such thickness that it constitutes an auxiliary electrode, to which arcing may occur, and thus constitute a circuit interrupter which establishes two arcs in series.
  • Still further embodiments of the present invention involve a shielding arrangement in which the shield material is formed of an electrode-type material, so that erosion thereat may be maintained at a minimum.
  • Another object of the present invention is the provision of an improved vacuum-type circuit interrupter in which the shield is of minimum axial length.
  • Another object of the present invention is the provision of an improved shielding arrangement for a vacuum-type circuit interrupter in which the shield may constitute an auxiliary electrode in which two arcs are drawn thereat during a normal operation of the interrupter.
  • Still a further object of the present invention is the provision of an improved vacuum-type circuit interrupter in which the short shield is formed of a suitable electrode material to prevent arc erosion, and to constitute auxiliary electrode means.
  • FIG. 1 is a cross'sectional view of a vacuum-type circuit interrupter of the two-contact type embodying the invention in one form;
  • FIGS. 2-5 illustrate modifications of the short vapor shield of the present invention
  • FIGS. 69 illustrate variants of the shield construction of 1 FIGS. 1-5 except that the short vapor shield is of sufficient thickness so as to be capable of withstanding arcing;
  • FIG. 10 illustrates a modification of the invention in which the short shield is made of an electrode material
  • FIG. 11 illustrates a phenomenon which has been observed to occur during circuit interruption in prior art structures.
  • a highly evacuated envelope 10 comprising a tubular casing 11 of insulating material, such as a suitable glass, and a pair of metallic end caps 12 and 13 closing off the ends of the casing. Suitable seals 14 are provided between the end caps and the casing to render the envelope [0 vacuumtight.
  • the electrode 17 is a stationary electrode suitably united to the end cap 12, whereas the electrode 18 is a movable electrode suitably mounted for reciprocal movement, and projecting through an opening in the end cap 13.
  • a flexible metallic bellows 20, interposed between the end cap 13 and the movable electrode 18, provides a seal about the removable electrode, and allows for reciprocal movement thereof without impairing the vacuum inside the interrupter. As shown on the drawing, the bellows 20 is sealingly secured at its respective opposite ends to the electrode 18 and to the end cap 13.
  • Coupled to the end of the movable electrode 18, I provide suitable actuating means (not shown), which is capable of driving the electrode rapidly inwardly from its solid-line position of FIG. I to its dotted-line position to close the interrupter, and which is also capable of returning the electrode to the solid-line position to open the interrupter.
  • a short metallic shield 25 In order to prevent this metallic vapor from condensing on the internal insulating surfaces 11a of the casing 11, there is provided a short metallic shield 25.
  • This short metallic shield 25 is of a generally tubular configuration, and extends along the length of the casing 11 for only a short distance.
  • the shield 25 is electrically isolated from both of the electrodes 17 and 18 and, preferably, is also isolated from ground; or in other words, the shield is at a floating potential relative to the two electrodes l7, l8.
  • This electrical isolation between the shield 25 and the electrodes l7 and 18 is achieved by mounting the shield 25 on the insulating casing 11 adjacent the central region of the shield, as at 1112, and by spacing the short shield 25 radially inwardly from the tubular insulating casing 11 at all points on opposite sides of the centrally disposed mounting region.
  • the metallic vapor emanating from the electrode region 9 is a vacuum-type circuit interrupter deposits on the vapor shield in a relatively narrow band extending not much beyond the open space between the electrodes. If, for instance, the electrode spacing 9 is one-half inch, a shield length of lkinches, extending one-half inch on either side, would catch most of the emitted metallic vapor. Not only that, but any vapor particles striking a shield beyond that distance are not likely to be scattered into a space, where they could be detrimental to the interrupting capability of the circuit breaker.
  • This shield 25 is preferably made from well-outgassed metal, and sufficiently thick so as to have maximum effectiveness in catching metallic vapor emitted from the electrode region 9.
  • the material chosen should also be one for which the sticking probability is naturally good, that is, it welds easily with the electrode material l7, 18.
  • Such preferable materials are metals and alloys having a vapor pressure lower than magnesium but are not as refractory as tungsten. Nickel, copper, silver and stainless steel are examples of suitable materials which may be used.
  • the short shield 25 may be backed up by other shields, either metallic or nonmetallic of arbitrary thickness, whose only function is to shield the insulator 11 against residual metallic vapors from the arc.
  • Such shields may be mounted on the insulator 11, on the end plates 12, 13, or on the electrode stems 17a, 18a, as shown in FIGS. 2-5 of the drawings.
  • an outer backup shield 30 is provided together with end metallic shields 31, 32 connected, respectively, to the electrode stems 17a, 18a.
  • FIG. 3 illustrates a modified construction in which the relatively short central shield 25a has inwardly extending end portions 25b, 25c to assist in confining the metallic vapor emitted from the arcing region 9.
  • end metallic shields 31, 32 are provided fixedly attached to the electrode stems 17a, 18a.
  • FIG. 4 illustrates a construction in which the relatively short central vapor shield 25 has cooperating therewith end metallic shields 40, 41, which are attached, respectively, to the electrode stems 17a, 18a and curve inwardly.
  • FIG. 5 shows a modified arrangement in which the short shield 25a has inwardly extending end portions 25b, 25c, and the end shields 33, 34 project inwardly from the end plates 12, 13 of the interrupter.
  • FIGS. 6-10 illustrate modifications of FIGS. 1-5 with the exception that the short shields 25 are of considerable thickness, as is evident from an inspection of the figures.
  • the short shields can tolerate the heavy-current arcing, which, in fact, may exist.
  • end metallic shields 33a, 34a are again fixedly attached to the end metallic plates 12, 13.
  • the inner adjacent ends of the end shields have an enlarged peripheral portion, such as provided by a spinning operation, for example, to enlarge the radius of curvature to thereby reduce the electrical field gradient.
  • the end shields 31, 32 may be additionally used, as shown.
  • FIG. 10 illustrates an electrode geometry capable of supporting a double-gap arc without damage.
  • the central auxiliary electrode 50 is made of an electrode-type material, so that arcing may occur without damage to the shield.
  • the central auxiliary electrode 50 is made of the same type of contact material, and capable of withstanding erosion, as the separable main contacts 17, 18 of the circuit-interrupting device.
  • a copper-silver alloy may be employed, or the electrode material set forth in U.S. Pat. application filed May 29, 1967, Ser. No. 64l,88l now abandoned by Alfred Alexander Robinson may be used.
  • This is a material comprising a matrix of chromium, cobalt, nickel or iron infiltrated with a second metal, such as copper, copper alloy, silver or a silver alloy, or an alloy of copper and zirconium, tantalum or titanium, as set forth in the aforesaid application, Ser. No. 641,881.
  • a vacuum-type circuit interrupter of the two-contact type comprising, in combination:
  • the vapor-condensing shield being spaced radially inwardly of the inner wall of the outer tubular casing and close to the separate contacts;
  • the vapor-condensing shield being at a floating electrical potential and not electrically connected to either of the separable contacts;
  • said short shield having its ends curved inwardly toward the contacts to confine the metallic vapor emitted from the arcing region.
  • a vacuum-type circuit interrupter comprising, in combination:
  • the vapor-condensing shield being spaced radially inwardly of the inner wall of the outer tubular casing;
  • the vapor-condensing shield being at a floating electrical potential and not electrically connected to either of the separable contacts

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  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
US789981A 1969-01-09 1969-01-09 Shielding arrangements for vacuum-type circuit interrupters of the two-contact type Expired - Lifetime US3612795A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US78998169A 1969-01-09 1969-01-09

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US3612795A true US3612795A (en) 1971-10-12

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US789981A Expired - Lifetime US3612795A (en) 1969-01-09 1969-01-09 Shielding arrangements for vacuum-type circuit interrupters of the two-contact type

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US (1) US3612795A (de)
CH (1) CH504090A (de)
DE (1) DE1963625A1 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006331A (en) * 1975-08-27 1977-02-01 General Electric Company Vacuum interrupter for high voltage applications
US4039792A (en) * 1975-12-19 1977-08-02 General Electric Company Compact high-current vacuum circuit interrupter comprising a metal housing that is electrically connected to one contact of the interrupter
DE2815059A1 (de) * 1977-06-17 1978-12-21 Elektro App Werke Veb Schaltstueckanordnung fuer niederspannungs-vakuumschuetze
US4386249A (en) * 1980-11-25 1983-05-31 Westinghouse Electric Corp. Vacuum circuit interrupter with auxiliary contact for plural arc path device with arc rotating means associated with the primary and auxiliary contacts
US4540861A (en) * 1983-05-18 1985-09-10 Mitsubishi Denki Kabushiki Kaisha Contact material for vacuum circuit interrupter
US4746777A (en) * 1986-07-11 1988-05-24 Siemens Aktiengesellschaft Vacuum switching tube
US5438174A (en) * 1993-11-22 1995-08-01 Eaton Corporation Vacuum interrupter with a radial magnetic field

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU213123A1 (ru) * Вакуумный выключатель
GB379342A (en) * 1930-05-28 1932-08-29 Gen Electric Improvements in and relating to electric switches of the vacuum type
US2900476A (en) * 1956-04-17 1959-08-18 Era Patents Ltd Electrical switching apparatus
FR1230339A (fr) * 1959-07-18 1960-09-15 Cie Constr Gros Mat Electromec Coupe-circuit
US3185800A (en) * 1963-02-18 1965-05-25 Gen Electric Vacuum type circuit interrupter with improved vapor-condensing shielding
US3189715A (en) * 1962-05-21 1965-06-15 Jennings Radio Mfg Corp Internal shield and seal structure for vacuum sealed switch envelope
US3372258A (en) * 1965-05-28 1968-03-05 Gen Electric Electric circuit interrupter of the vacuum type with arc-voltage control means for promoting arc transfer
US3470341A (en) * 1965-09-30 1969-09-30 English Electric Co Ltd Vacuum switch with liquid filled bellows operation

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU213123A1 (ru) * Вакуумный выключатель
GB379342A (en) * 1930-05-28 1932-08-29 Gen Electric Improvements in and relating to electric switches of the vacuum type
US2900476A (en) * 1956-04-17 1959-08-18 Era Patents Ltd Electrical switching apparatus
FR1230339A (fr) * 1959-07-18 1960-09-15 Cie Constr Gros Mat Electromec Coupe-circuit
US3189715A (en) * 1962-05-21 1965-06-15 Jennings Radio Mfg Corp Internal shield and seal structure for vacuum sealed switch envelope
US3185800A (en) * 1963-02-18 1965-05-25 Gen Electric Vacuum type circuit interrupter with improved vapor-condensing shielding
US3372258A (en) * 1965-05-28 1968-03-05 Gen Electric Electric circuit interrupter of the vacuum type with arc-voltage control means for promoting arc transfer
US3470341A (en) * 1965-09-30 1969-09-30 English Electric Co Ltd Vacuum switch with liquid filled bellows operation

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006331A (en) * 1975-08-27 1977-02-01 General Electric Company Vacuum interrupter for high voltage applications
US4039792A (en) * 1975-12-19 1977-08-02 General Electric Company Compact high-current vacuum circuit interrupter comprising a metal housing that is electrically connected to one contact of the interrupter
DE2815059A1 (de) * 1977-06-17 1978-12-21 Elektro App Werke Veb Schaltstueckanordnung fuer niederspannungs-vakuumschuetze
US4386249A (en) * 1980-11-25 1983-05-31 Westinghouse Electric Corp. Vacuum circuit interrupter with auxiliary contact for plural arc path device with arc rotating means associated with the primary and auxiliary contacts
US4540861A (en) * 1983-05-18 1985-09-10 Mitsubishi Denki Kabushiki Kaisha Contact material for vacuum circuit interrupter
US4746777A (en) * 1986-07-11 1988-05-24 Siemens Aktiengesellschaft Vacuum switching tube
US5438174A (en) * 1993-11-22 1995-08-01 Eaton Corporation Vacuum interrupter with a radial magnetic field

Also Published As

Publication number Publication date
CH504090A (de) 1971-02-28
DE1963625A1 (de) 1970-07-30

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