US2995638A - Cut-off switch - Google Patents

Cut-off switch Download PDF

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Publication number
US2995638A
US2995638A US742869A US74286958A US2995638A US 2995638 A US2995638 A US 2995638A US 742869 A US742869 A US 742869A US 74286958 A US74286958 A US 74286958A US 2995638 A US2995638 A US 2995638A
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US
United States
Prior art keywords
arc
contact
switch
cut
strips
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
US742869A
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English (en)
Inventor
Andre A H Souchet
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.)
Telemecanique SA
Original Assignee
La Telemecanique Electrique SA
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.)
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Publication date
Application filed by La Telemecanique Electrique SA filed Critical La Telemecanique Electrique SA
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Publication of US2995638A publication Critical patent/US2995638A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts
    • H01H9/44—Means for extinguishing or preventing arc between current-carrying parts using blow-out magnet
    • H01H9/446—Means for extinguishing or preventing arc between current-carrying parts using blow-out magnet using magnetisable elements associated with the contacts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H01H1/20—Bridging contacts

Definitions

  • the invention is especially, though not exclusively, applicable to cut-off switch arrangements wherein fiat switch contacts are carried in mutually opposed relationship at adjacent ends of two flat strip like conductors extending in generally reverse directions to each other away from said adjacent contact-bearing ends, and wherein the contact making and breaking displacements involve a displacement of one of said conductors towards and away from the other, normally to the plane of the contact elements.
  • a known are quenching expedient sometimes used in connection with such cut-off switches involves the provision of metal plate elements disposed symmetrically on opposite sides of said contacts in spaced relation therewith and extending in planes generally normal to the planes of said contacts.
  • the arc-quenching action of such a device relies on the fact that the magnetic field present around the arc cooperates with the magnetic characteristics of the plate to generate a magnetomotive force which tends to shift the arc towards one or the other plate, whereupon the arc is rapidly quenched, mainly due to the cooling eflfect of the plate.
  • the invention is based on the finding just stated and in accordance therewith achieves improved arc quenching action in a cut-off switch by providing a quenching member on only one side of the switch contacts. It will be understood that in such conditions no matter where the are happens to originate over the entire surfaces of the contact elements, it will be urged by the electromagnetic forces only in the direction of said one side, and will under no circumstances tend to dwell in the central area of the contact surfaces. Greatly improved arc quenching action is thus obtained.
  • the invention therefore provides a cut-off switch arrangement having a pair of opposed generally flat contact elements movable into and out of engagement with each other in a direction generally normal to the plane of said elements, and a metallic member adjacent to only one side of said contact elements and spaced therefrom, whereby a cut-off are occurring on disengagement of said elements will tend to shift laterally towards said member to be quenched thereby.
  • the member is in the form ice of an angularly bent plate having two portions at right angles to each other respectively extending alongside a longitudinal and transverse side edge of both contact elements.
  • the contact elements are supported on respective fiat striplike conductors at positions laterally displaced from the longitudinal midline of said conductors towards said metallic quenching member. It is found that the further dissymmetry thus introduced is accompanied by a correspondingly increased dissymmetry in the magnetomotive forces acting on the arc and that the quenching action is thus further accelerated.
  • the longitudinal side of each contact element remote from the metallic quenching member is preferably provided beveled.
  • the invention further includes within its scope the application of the above specified cut-off switch arrangement to circuit breaker switch devices of the type including a movable bridging conductor member displaceable into and out of contacting cooperation with a pair of spaced contacts.
  • circuit breaker switch devices of the type including a movable bridging conductor member displaceable into and out of contacting cooperation with a pair of spaced contacts.
  • Such devices are advantageous in that the cut-off arc is divided into two smaller arcs of weaker energy content.
  • FIG. 1 is a perspective view of a conventional cut-off switch arrangement
  • FIG. 2 is a plan view of one contact of the conventional arrangement shown in FIG. 1;
  • FIG. 3 is a plan view of an arrangement according to the invention in a simple construction form
  • FIG. 4 is a perspective view of a cut-off switch arrangement according to the invention in a more elaborate form thereof;
  • FIG. 5 is a section on line VV of FIG. 4.
  • FIG. 5a is a similar view relating to a modification
  • FIG. 6 is a perspective view illustrating the application of the invention to a bridge type circuit breaker.
  • FIG. 6a is a similar view of a modified construction.
  • a conventional cut-off switch arrangement of the general type to which this invention relates comprises a pair of parallel flat conductor bars or strips 1 and 2 extending in generally opposite directions and having secured to the adjacent ends of them in facing relationship, the respective rectangular contact lugs 1a and 2a.
  • the contact lugs are adapted to be pressed against each other for establishing the circuit and separated for breaking the circuit, by displacement of conductor 2 as indicated by the arrow 0.
  • the current at an instant of time, can be represented by the chain-line arrows indicated as passing from conductor 1 to conductor 2.
  • This current path includes three sections: section 3 extending through conductor '1, section 3a which is constituted by an arc discharging across the contacts, and a third section 3 along conductor 2.
  • the arc section 3a is freely movable under the influence of the fields generated by the sections 3 and 3
  • the field forces generated by these sections and acting on the are 3a are respectively indicated as F and F
  • the are itself generates a symmetric field surrounding it, and because of this symmetry this field'has no influence upon the path followed by the are.
  • the invention proposes, in efifect, to increase and develop this dissymmetry effect in order to force the arc to reach surrounding metal surfaces of the assembly to be thereby cooled, damped and quenched.
  • FIG. 3 there is arranged adjacent the contact lugs 1a and 2a an element of magnetic sheet material 5 bent at right angles so as to comprise two flanges both parallel to the direction of relative displacements of the contacts towards and away from each other, so as to enclose said contacts on two sides thereof, while the remaining two sides are free.
  • the magnetic field H which surrounds the arc present at the position A is rendered dissymmetrical due to the presence of the flanges of the magnetic element 5, so that only the field components such as H and H are effective.
  • the field components generate the magnetomotive forces F, and P which act to displace the arc towards the element 5. The are then becomes caught on the surface of the element and is quenched due to strong cooling effect.
  • the contacts 1a and 2a may be arranged dissymrmetrically at the ends of the respective conductors 1 and 2, i.e. displaced towards the element 5.
  • the distribution of the lines of current flow across the contacts is such as to provide an initial dissyrnmetry in the forces at the instant the are is generated, and thus accelerates the displacement of the arc ends towards the quenching element.
  • the dissymmetrical efi'ect described can further be emphasized by forming both rectangular contact lugs with bevel side portions 6 over at least that side edge of each contact remote from the element 5. In practice, it is suflicient if such a bevel is formed on the edge of the contact remote from element 5 and parallel to the direction of the conductors 1 and 2.
  • the angular metallic element will simultaneously serve to protect the wall of the casing and prevent damage of its by the arc.
  • FIG. 6 illustrates the application of the invention to a bridge contact arrangement in a circuit breaker or similar cut-off switch apparatus.
  • the bridging member 9 is operated through the insulated rod 10 so as to be displaced in the direction indicated by the arrow 0 to break the circuit, and displaced in the opposite direction to establish connection between the conductors 11 and 12.
  • the bridging member carries the contact lugs 9a and 9b at its respective ends, and the conductors '11 and 12 carry the cooperating contact lugs 11a and 12a.
  • Each cooperating pair of contact lugs 9a-11a, and 9b- 12a is surrounded on two sides by a related angular metallic element 13 or 14.
  • each said cooperating s contact pair is displaced laterally to one side of the related conductors towards the related metal element. That edge of each contact lug directed away from the parallel flange of the related element and parallel to the direction of the conductors is bevelled. Adjacent each bevel edge of each contact lug a free area such as 15 is defined on the related conductor, while the opposite edge of the contact lug extends flush with the adjacent edge of the conductor, or may even project beyond the conductor edge as indicated in FIG. 5a.
  • the angular metal elements 13 and 14 are arranged in mutually opposed relation, so that they may be rigidly secured to or form part of opposite casing walls of a common casing enclosing the switch device. Further, the opposed relationship between the elements 13 and 14 results in the bridging member 9 being symmetrical, so that it can be rotated about its vertical axis without impairing the operation of the switch. While this may have its advantages in facilitating the assembly of the device, it will be evident that such construction is not essential and that instead the arrangement shown in FIG. 6a may be used, wherein both angular elements 13 and 14 are disposed on the same side of the bridge member, and where consequently the free areas 15 of the conductors would also lie on the same side.
  • a cut-off switch comprising a pair of conductor strips extending endwisely in opposite directions, a pair of generally flat contact lugs on adjacent ends of said strips, with flat contact faces of said lugs in face-to-face relationship, said strips being relatively movable in a direction normal to said contact faces to move said faces into and out of interengagement, and arc-quenching means of metallic magnetic material spaced from said strips and lugs and disposed at only one of opposite sides of said conductor strips; the spacing of said means from any are formable between said lugs being such as to cause attraction of the arc to said means, free of counter-attraction from the other of the opposite sides of the conductor strips, said conductor strips being of flat material and disposed with adjacent ends thereof in overlapping relation, said arc-quenching means comprising a member of magnetic sheet metal of L-shape in section, the legs of the L extending in planes normal to the planes of said contact faces, one of said legs being at said only one of opposite sides of said conductor strips, and the
  • a cut-off switch comprising a pair of conductor strips extending endwisely in opposite directions, a pair of generally flat contact lugs on adjacent ends of said strips, with flat contact faces of said lugs in face-to-face relationship, said strips being relatively movable in a direction normal to said contact faces to move said faces into and out of interengagement, and arc-quenching means of metallic magnetic material spaced from said strips and lugs and disposed at only one of opposite sides of said conductor strips; the spacing of said means from any are formable between said lugs being such as to cause attraction of the are to said means, free of counter-attraction from the other of the opposite sides of the conductor strips, said contact lugs being generally rectangular and said arc-quenching means having two flat surfaces in rightangular interrelation, one of said flat surfaces being at said only one of opposite sides of said conductor strips and the other of said fiat surfaces extending transversely of said strips adjacent to said contact lugs and to the end of one of said strips.
  • a cut off switch comprising a pair of coplanar conductor strips extending endwisely in opposite directions, flat, rectangular, first contact elements carried by the nearest end portions of said strips, a conductive bridging member movable normally to the plane of said strips, second contact elements carried toward opposite ends of said bridging member and arranged to conductively engage said first contact elements upon such movement of the bridging member, and two separate L-shaped arc-quenching members of magnetic metal disposed separately in arc-attracting association with each pair of such conductively engageable contact elements, each of said arcquenching members having flanges, normal to the plane of said strips and a first of said flanges being adjacent to corresponding sides of said strips and bridging member and a second of said flanges being adjacent to an opposed end of said bridging member.
  • a cut-01f switch according to claim 3 said first flanges of the two arc-quenching members both being adjacent to corresponding sides of said strips.
  • a cut-off switch according to claim 3 said first 6 flanges of the two arc-quenching members being adjacent to the contact element toward opposite ends of the bridging member and to opposite longitudinal sides of said strips.

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  • Arc-Extinguishing Devices That Are Switches (AREA)
  • Breakers (AREA)
US742869A 1957-07-03 1958-06-18 Cut-off switch Expired - Lifetime US2995638A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1102869X 1957-07-03

Publications (1)

Publication Number Publication Date
US2995638A true US2995638A (en) 1961-08-08

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Application Number Title Priority Date Filing Date
US742869A Expired - Lifetime US2995638A (en) 1957-07-03 1958-06-18 Cut-off switch

Country Status (7)

Country Link
US (1) US2995638A (hu)
BE (1) BE568997A (hu)
CH (1) CH347563A (hu)
DE (1) DE1102869B (hu)
FR (1) FR1178143A (hu)
GB (1) GB853162A (hu)
LU (1) LU36206A1 (hu)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155790A (en) * 1960-09-09 1964-11-03 M T I Le Materiel Tech Ind Reversing relays having increased cut-off power
US3483343A (en) * 1966-11-07 1969-12-09 Gen Electric Electric circuit breaker with special arc extinguishing structure
US4320820A (en) * 1980-07-28 1982-03-23 Harvey Hubbell Incorporated Section insulator with improved arc control
US4491705A (en) * 1981-10-16 1985-01-01 Fuji Electric Co., Ltd. Electrical switch

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE621142A (hu) * 1961-08-11 1962-12-03
DE3023673A1 (de) * 1980-06-25 1982-01-14 Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt e.V., 5300 Bonn Verfahren zur loeschung des abreissbogens in schaltern und magnetfeldanordnung im kathodenbereich eines schalters zur durchfuehrung dieses verfahrens

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH68768A (de) * 1913-08-09 1915-04-16 Landis & Gyr Ag Elektrizitätsselbstverkäufer
US2343323A (en) * 1942-08-11 1944-03-07 Westinghouse Electric & Mfg Co Electric switch
US2356039A (en) * 1942-07-31 1944-08-15 Westinghouse Electric & Mfg Co Arc limiting device
US2411892A (en) * 1943-07-08 1946-12-03 Gerhard W Peters Circuit breaker with magnetic arc extinguishing means
US2524287A (en) * 1945-01-19 1950-10-03 Westinghouse Electric Corp Circuit interrupter
US2618716A (en) * 1948-06-10 1952-11-18 Wadsworth Electric Mfg Co Electric circuit breaker
US2704315A (en) * 1951-12-18 1955-03-15 Fed Electric Prod Co Magnetic blow-out for circuit-breakers
US2836685A (en) * 1955-05-26 1958-05-27 Square D Co Magnetic blowout switch

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH68768A (de) * 1913-08-09 1915-04-16 Landis & Gyr Ag Elektrizitätsselbstverkäufer
US2356039A (en) * 1942-07-31 1944-08-15 Westinghouse Electric & Mfg Co Arc limiting device
US2343323A (en) * 1942-08-11 1944-03-07 Westinghouse Electric & Mfg Co Electric switch
US2411892A (en) * 1943-07-08 1946-12-03 Gerhard W Peters Circuit breaker with magnetic arc extinguishing means
US2524287A (en) * 1945-01-19 1950-10-03 Westinghouse Electric Corp Circuit interrupter
US2618716A (en) * 1948-06-10 1952-11-18 Wadsworth Electric Mfg Co Electric circuit breaker
US2704315A (en) * 1951-12-18 1955-03-15 Fed Electric Prod Co Magnetic blow-out for circuit-breakers
US2836685A (en) * 1955-05-26 1958-05-27 Square D Co Magnetic blowout switch

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155790A (en) * 1960-09-09 1964-11-03 M T I Le Materiel Tech Ind Reversing relays having increased cut-off power
US3483343A (en) * 1966-11-07 1969-12-09 Gen Electric Electric circuit breaker with special arc extinguishing structure
US4320820A (en) * 1980-07-28 1982-03-23 Harvey Hubbell Incorporated Section insulator with improved arc control
US4491705A (en) * 1981-10-16 1985-01-01 Fuji Electric Co., Ltd. Electrical switch

Also Published As

Publication number Publication date
FR1178143A (fr) 1959-05-04
GB853162A (en) 1960-11-02
BE568997A (hu)
DE1102869B (de) 1961-03-23
CH347563A (fr) 1960-07-15
LU36206A1 (hu)

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