US3602671A - Oil circuit interrupter having improved stack insulating washer structure - Google Patents

Oil circuit interrupter having improved stack insulating washer structure Download PDF

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Publication number
US3602671A
US3602671A US880667A US3602671DA US3602671A US 3602671 A US3602671 A US 3602671A US 880667 A US880667 A US 880667A US 3602671D A US3602671D A US 3602671DA US 3602671 A US3602671 A US 3602671A
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United States
Prior art keywords
disks
contact
shell
bayonet
oil
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Expired - Lifetime
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US880667A
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English (en)
Inventor
Herbert M Pflanz
Joseph M Ramrath
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Allis Chalmers Corp
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Allis Chalmers 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
    • H01H33/70—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid
    • H01H33/72—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid having stationary parts for directing the flow of arc-extinguishing fluid, e.g. arc-extinguishing chamber
    • H01H33/75—Liquid-break switches, e.g. oil-break

Definitions

  • Benson ABSTRACT An arc interrupting device for use in an oil-type v circuit interrupter comprises a hollow tubular insulated exterbetween it and the stationary contact is constricted in the narrow annular space and is thereby more readily cooled and extinguished.
  • the bayonet contact and the space which accommodates it both have a C-shaped cross-sectional configuration.
  • PATENTED AUB31 1971 3.602671- sum 1 [1F PATENTED A0831 IS nowadays SHEET 2 OF 2 El m paw. #9
  • This invention relates generally to oil-type electric circuit interrupters and, particularly, to are interrupting devices employed therein.
  • a typical oil-type circuit interrupter comprises an oil filled tank in which one or more arc interrupting devices are disposed and submerged in oil. Each device, for example,.
  • bayonet is relatively large, i.e., on the order of 2 inches in diameter in order to carry heavy continuous currents.
  • large diameter bayonets generally reduce the interrupting performance of the interrupting device. This is because the are time constant is a measure of the thermal recovery of an arc plasma column and is proportional to the arc radius squared.
  • an arc interrupting device for submersion in oil which comprises a hollow tubular external structure made of insulating material and preferably having annular oil pockets on the interior surface of the wall and oil flow nozzles through its wall.
  • a stationary contact assembly is associated with one end of the structure.
  • An internal structure made of insulating material and preferably having annular oil pockets on its exterior surface is concentrically disposed inside the external structure and cooperates therewith to define a narrow annular space.
  • a relatively large diameter hollow movable bayonet contact for cooperation with the stationary contact is adapted to be inserted in and withdrawn from the space, surrounding the internal structure in the process.
  • the space and bayonet contact have substantially C-shaped cross sections, rather than annular cross sections.
  • Another object is to provide devices of the aforesaid character which employ movable bayonet contacts and have improved means for constricting the are formed as the bayonet contact is withdrawn from the device.
  • Another object is to provide devices of the aforesaid character wherein the arc is constricted substantially along its entire length.
  • Another object is to provide devices of the aforesaid character wherein the constricted arc is exposed to an increased number of oil turbulence pockets along its entire length.
  • an arc interrupting device 8 in accordance with the invention is adapted to be disposed inside the tank of a high voltage-high current oil circuit breaker and is completely submerged in oil.
  • the device is mounted on an electrically conductive contact member or casting 10 which is understood to be connectable to one side of the line in an electric circuit which a circuit interrupter controls.
  • Casting 10 is understood to be circular in shape and is provided with'screw threads 12 on its outer periphery by means of which an external interrupter structure 14 of the interrupting device is supported on the casting.
  • Casting 10 is further provided with a central opening 16 by means of which an internal interrupter structure 18 is supported on the cast- External structure 14 comprises a hollow cylindrical outer shell 20 which is made of insulating material and has a plurality of nozzle openings 21 through the wall thereof to accommodate oil flow.
  • Shell 20 is provided with cylindrical, internally threaded inserts or collars 22 and 24 at its top and bottom ends, respectively.
  • Top insert 22 engages the threads l2 on casting 10.
  • Bottom insert 24 is adapted to engage a closure member or plate 26 which is circular in shape and is provided with screw threads 30 on its outer periphery and with a central opening 32.
  • Assembly 34 comprises an electrically conductive circular retainer 36 having a central opening 38 therein.
  • Retainer 36 carries a plurality of electrically conductive contact fingers40 which are radially arranged around opening 38 and biased inwardly by springs 42.
  • a plurality of retaining rings 44, 46 and 48 made of insulating material maintain the contact fingers 40 and the springs 42 in proper position.
  • Stationary contact assembly 34 is held in position by entrapment of its retainer 36 between contact casting 1 0 and a shoulder 50 formed in shell 20 of external structure 14.
  • An electrically conductive path exists between each contact finger 40, retainer 36 and contact casting 10.
  • each washer 54 has the same outside diameter but the diameterof a cen-, tral opening 56 in each washer 52 is smaller than that of a cen-' tral opening 58 ineach washer 54. Consequently, disposition of one or more washers 54 between each pair of washers 52 provides a series of annular oil pockets 60 along the interior of external structure 14.
  • the washers 54 adjacent the oil nozzles 21 are provided with openings 62 which accommodate oil flOW. i
  • Internal interrupter structure 18 comprises an elongated solid cylindrical insulating support member or rod 64 having a tapered head 65 which engages opening 16 in contact casting 10.
  • the lower end of rod 64 is provided with screw threads 66 on. which a nut 68 made of insulatingmaterial is disposed.
  • a plurality of washers 70 and 72 made of insulating material are stacked on rod 64 and held in place by entrapment between nut 68 and a cylindrical sleeve 74 made of insulating material and located at the top of the'rod.
  • the washers 70 and 72 have central openings 76 which are of the same diameter but the outside diameter of each washer 70 is greater than that of each washer 72.
  • bayonet contact 82 is electrically connectable to the other side of a line in a circuit which the circuit interrupter controls. Clearance between the inside and outside surfaces of bayonet contact 82 and the washers 70 and 52 is preferably at a minimum consistent with good engineering practice. In practice, for example, bayonet contact 82 hasan outside diameter on the order of 3% inches and has a crosssectional area suitable for carrying high continuous current and higher momentary currents. A large bayonet diameter provides a proportionately large circumference and permits many contact fingers such as 40 to be in engagement therewith and this reduces overall contact resistance.
  • An arc interrupting device operates as follows. Assume first that bayonet contact 82 is in contact closed position as shown in the drawing wherein its tip is in electrical contact with the contact fingers 40 of stationary contact 34. Further assume that there is current flow through the contacts. To open the contacts, bayonet contact 82 is moved downwardly by suitable means (not shown) and an arc is drawn between the tip of contact 82 and the contact fingers 40. As downward travel of contact 82 continues, the arc terminals transfer from the contact fingers 40 to the lower inner edge of retainer 36 of stationary contact 34 and the arc is completely confined or contained in the annular space vacated by bayonet contact 82 between external structure 14 and internal structure 18.
  • the are being so constricted has a smaller diameter along its entire length than would otherwise be the case and is effectively cooled by vaporized and dissociated gases formed from the oil until interruption occurs. If the arc being interrupted is an alternating current arc, more rapid cooling of the arc occurs by the time the current zero point is reached and faster dielectric recovery along the arc path is obtained. Oil flow and circulation through the nozzles 21, through the annular space vacated by bayonet contact 82, and in the plurality of oil pockets 60 and 78 enhances the cooling effect and the arc is eventually extinguished.
  • FIG. 3 shows an embodiment of the invention wherein an interrupting device 108 comprises external and internal structures 114 and 118, respectively, which are integrally formed and therefore provide a space 180 which has a substantially C- shaped cross section and accommodates a bayonet contact 182 which has a substantially C-shapedcross section.
  • Device 108 comprises a cylindrical shell in which a stack of insulating disks, each having an exterior section 152 and an integrally formed interior'section and an'opening 172. The openings 172 align to provide the space which accommodates bayonet contact 182. By providing a stack of disks which have openings 172 of different sizes, oil pockets such as 160 and 178 are provided.
  • Device 108 is similar to device 8 as regards construction, components and operation except that no separate supporting means such as rod 64 in device 8 are required. r
  • An arc interrupting device for use in an oil-type circuit interrupter and adapted for electrical and mechanical connection to an electrically conductive contact member, said device comprising:
  • a hollow insulating shell having one end adapted for mechanical connection to said member
  • said shell having at least one nozzle opening in the wall thereof
  • stationary contact means mounted in said shell near said one end thereof and adapted for electrical connection to said member
  • a plurality of stacked insulating disks in said shell providing an external insulating structure and an internal insulating structure between which a space is defined for accommodating passage of a hollow bayonet-type contact,
  • the disks located adjacent said nozzle opening being provided with openings which communicate between said nozzle opening'and said space,
  • said plurality of stacked insulating disks comprises a first set of stacked disks which provides said external insulating structure and a second set of stacked disks which provides said internal insulating structure, wherein said hollow bayonet-type contact is cylindrical in cross section, and wherein said means for supporting said plurality of disks comprises a closure member engaging said shell for holding said first set of disks in place and further comprises an insulated support member mechanically connected to said contact member and on which said second set of disks are mounted,
  • said insulated support member having a threaded end on which a nonconductive nut is mounted.
  • a device comprising disks which have a substantially C-shaped opening therein, wherein said openings align to provide said space for said contact and said oil turbulence pockets, wherein said hollow bayonet-type contact is C- shaped in cross section, and wherein said means for supporting said plurality of disks comprises a closure member engaging said shell.
  • a device wherein said closure member is externally threaded and engages a threaded insert in said shell.
  • a device wherein said closure member is externally threaded and engages a threaded insert in said shell.

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  • Circuit Breakers (AREA)
US880667A 1969-11-28 1969-11-28 Oil circuit interrupter having improved stack insulating washer structure Expired - Lifetime US3602671A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US88066769A 1969-11-28 1969-11-28

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US3602671A true US3602671A (en) 1971-08-31

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US880667A Expired - Lifetime US3602671A (en) 1969-11-28 1969-11-28 Oil circuit interrupter having improved stack insulating washer structure

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US (1) US3602671A (enrdf_load_stackoverflow)
JP (1) JPS5040787B1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050271809A1 (en) * 2004-06-04 2005-12-08 Boris Kobrin Controlled deposition of silicon-containing coatings adhered by an oxide layer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63174671U (enrdf_load_stackoverflow) * 1987-03-16 1988-11-14
JPH01146862U (enrdf_load_stackoverflow) * 1988-03-31 1989-10-11

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050271809A1 (en) * 2004-06-04 2005-12-08 Boris Kobrin Controlled deposition of silicon-containing coatings adhered by an oxide layer

Also Published As

Publication number Publication date
JPS5040787B1 (enrdf_load_stackoverflow) 1975-12-26

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