US2908787A - Electric circuit interrupter - Google Patents

Electric circuit interrupter Download PDF

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Publication number
US2908787A
US2908787A US703567A US70356757A US2908787A US 2908787 A US2908787 A US 2908787A US 703567 A US703567 A US 703567A US 70356757 A US70356757 A US 70356757A US 2908787 A US2908787 A US 2908787A
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United States
Prior art keywords
arc
plates
chute
adjacent
sidewalls
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Expired - Lifetime
Application number
US703567A
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English (en)
Inventor
Thomas J Scully
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General Electric Co
Original Assignee
General Electric Co
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Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US703567A priority Critical patent/US2908787A/en
Priority to FR781771A priority patent/FR1217934A/fr
Application granted granted Critical
Publication of US2908787A publication Critical patent/US2908787A/en
Anticipated expiration legal-status Critical
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
    • H01H9/34—Stationary parts for restricting or subdividing the arc, e.g. barrier plate

Definitions

  • This invention relates to electric circuit interrupters, and more particularly it relates to an arc extinguishing device for an electric circuit interrupter of the type having cooperating separable contact members.
  • Electric circuit interrupters are used for the purpose of interrupting the flow of current in electric power circuits.
  • the current interruption process is begun by separating the cooperating contact members of an interrupter, whereby a gap of air or gaseous matter is opened in the circuit.
  • the gases in the gap between the separated contact members although normally having relatively great dielectric strength or insulating ability, may temporarily be rendered electrically conductive due to the phenomenon of ionization. If there is simultaneously a suflicient potential difference between the separated contact members and a sufficient degree of ionization of the gases in the gap, the ionized gases will form an electricarc which must be permanently extinguished in order to interrupt the circuit current.
  • each arclet will have its own anode and cathode voltage drop region where the voltage gradient is relatively high.
  • a thin cathode or anode sheath of relatively high dielectric strength is formed adjacent the opposing surfaces of each pair of metal plates, and at least a certain minimum potential difference between adjacent plates is required to sustain or establish the associated arclet. Accordingly, the cumulative effect of a plurality of spaced metal plates is to raise the are or reignition voltage of the circuit interrupter.
  • the stacks of spaced apart metal plates are typically arranged so that each pair of adjacent plates are separated by the same distance, and a stack of such uniformly spaced plates is disposed in a straight line across the exhaust end of the chute so that some of the plates are located more remotely than others from the point of arc initiation.
  • This arrangement does not adequately take into account the fact that the are products to be exhausted are not under uniform pressure in the arc chute, and as a result, some of the plates are unable efficiently to contribute to the arc extinction process.
  • the arc will not reach the plates located adjacent high pressure regions of the chute, if at all, until after other portions of the are have been driven into contact with and chopped into arclets by the plates located closer to the lower pressure regions where the volume of are products exhausted is relatively small.
  • an object of this invention to provide an arc extinguisher of economical construction having a stack of spaced-apart metal plates so arranged that all pairs of adjacent plates are substantially equally and simultaneously effective in extinguishing the are.
  • a further object of the invention is to provide an arc chute having a stack of spaced-apart metal plates so arranged that the total voltage drop across this stack is distributed substantially equally among all of the pairs of the adjacent plates even though some of the plates are more remotely located from the point of arc initiation than others.
  • I provide an electric arc chute having spaced-apart sidewalls defining an arcing area and an outlet for the arc products. Separable contact members are provided for initiating an are at a predetermined point within the chute, and suitable means are provided for propelling the arc toward the outlet.
  • I provide a plurality of metal plates stacked across the outlet in spaced-apart planes disposed generally perpendicular to the sidewalls and to the arc, and the spacings between adjacent planes are progressively varied so that there is less area available for venting the are products between the adjacent plates nearest to the arcing area where the least volume of arc products is generated than between adjacent plates located closer to arcing areas where larger volumes of are products are being generated.
  • Fig. 1 is a side elevation of an arc extinguisher or are chute constructed in accordance with a preferred form of my invention
  • Fig. 2 is an enlarged section taken along lines 2-2 of Fig. 1;
  • Fig. 3 is an enlarged section taken along lines 33 of Fig. 1;
  • Fig. 4 is an enlarged section taken along lines 4-4 of Fig. 2; and i Fig. 5 is a side elevation diagrammatically illustrating an improved result obtained by the illustrated embodiment of my invention.
  • a circuit interrupter of the type that may be used in direct current electric power circuits. It should be understood at the outset that my invention is not limited to direct current circuit interrupters, and it may be applied to alternating current interrupters as well. However, the specific circuit. interrupter that I have chosen to show and describe in order to best illustrate my invention is particularly well suited for use as an anode breaker in a power rectifier system. As such, the interrupter may be called upon to interrupt unidirectional arc-back current which rises at an extremely high rate, such as 8,000,000 amperes per second, to a very large peak magnitude.
  • the particular circuit interrupter illustrated in Fig. 1 is a simplified showing of an interrupter described in detail and claimed in Patent No. 2,329,003, issued to J. W. Seaman on September 7, 1943.
  • the interrupter includes an upper terminal stud assembly .12 on which is movably supported a plurality of relatively stationary main contacts 13, only one of which appears in Fig. 1, and a stationary arcing contact 14.
  • Cooperating with the relatively stationary main contact 13 is a movable main contact 15, and cooperating with the stationary arcing contact 14 is a movable arcing contact 16.
  • Both the movable main contact 15 and arcing contact 16 are electri cally connected to a lower terminal stud 17 of the circuit interrupter.
  • the circuit interrupter is shown as supported on a base 18 of suitable insulating material.
  • the arc extinguishing device or are chute 11 is adapted to be mounted on the circuit interrupter adjacent to and principally above the arcing contacts 14 and 16.
  • the arc chute comprises a pair of spaced-apart sidewalls 20 and 21 of suitable insulating material for enclosing the are drawn between the contact members 14 and 16 upon separation thereof.
  • the outline of the sidewalls 20 and 21 is that of a rectangle having a portion of generally trapezoidal form adjoining its lower edge.
  • the are chute thus has relatively small and large arc initiating and exhaust openings, re-
  • the spacing between the opposing sidewalls 20 and 21 is determined and the arcing area is defined by suitable transverse members mounted therebetween.
  • suitable transverse members mounted therebetween.
  • a pair of abutting members 22 and 23 of insulating material are mounted between the sidewalls along the lower inclined edges thereof.
  • Adjacent each vertical edge of the sidewall 20 and extending transversely to the corresponding edge of sidewall 21 is another insulating member 24.
  • the sidewalls 20 and 21 and the transverse members 2224 are fastened together by suitable means such as bolts or screws, and the rigidity of the whole structure is maintained by horizontal braces 25 and an interlocking vertical brace 26 on the outside of each of the sidewalls 20 and 21.
  • These braces are bolted together with the sidewalls 20 and'2l. and the transverse members 22-24 by suitable means such as bolts 27.
  • Another pair of horizontal braces 28 are mounted adjacent both sides of the outlet of the arc chute 11 at its upper end, and as can be seen in Fig. 2, the bolts 27 securing these braces and the sidewalls 20 and 21 are provided with suitable insulating bushings 29 extending between the sidewalls.
  • the abutting transverse members 22 and 23 are disposed to extend divergently outwardly from the arc initiating end of the chute toward the discharge or exhaust end thereof. These members are arranged to support on their inner sides a pair of divergent arc runners 30 and 31, respectively.
  • The'lower end of the arc runner 31 is bent around the lower end of its supporting member 23 for engagement by the movable arcing contact 16 upon circuit opening operation of the interrupter.
  • the arc runner 31 is electrically connected to the lower terminal stud 17 by a suitable flexible conductor, not shown.
  • the stationary arcing contact 14 is mounted on the lower end of the arc runner 30, and this arc runner may be electrically connected to the upper terminal stud 12 by a suitable flexible conductor, not shown.
  • a protective plate 32 of high arc-resistant insulating material is inserted between the sidewalls and the transverse abutting member 23.
  • Suitable blowout coils may be connected between the above-mentioned flexible conductors and the arc runners 30 and 31 respectively.
  • a plurality of spaced-apart insulating barriers 33 may be provided in the arc chute 11.
  • the barriers are disposed in parallel relationship with respect to the sidewalls and 21.
  • the original arc is divided or split into a plurality of relatively thin parallel arcs in the narrow slots or. chambers defined by adjacent barriers 33, and these parallel arcs are cooled more readily than the whole are could be cooled.
  • a plurality of generally rectangular plates are stacked across the outlet of the arc chute 11 in spaced-apart planes disposed generally perpendicular to the sidewalls 20 and 21 and to the arc.
  • the lower portion 34 of each of these transversely extending rectangular plates is made of metal, as is best seen in Fig. 4, and spans the sidewalls 20, 21 intermediate the exhaust opening or outlet of the chute and the arc drawing means 14, 16.
  • the upper portion 35 of each plate is made of insulating material.
  • the insulating plates 35 are provided, among other reasons, to cool the streams of arcing gases and to maintain these streams segregated until safely cooled, thereby minimizing the possibility of an are being established exterior to the arc chute 11.
  • the manner in which the stack of arc-chopping plates is constructed may now be considered in detail. As indicated in Fig. 1, the plates are divided into six serially related groups 36a, 36b, 37a, 37b, 38a and 38b. The use of six separate groups rather than one continuous stack of plates is a matter solely of manufacturing and assembling convenience. The various groups of plates may have approximately the same overall dimensions but do not necessarily include the same number of plates.
  • Each group of plates comprises a plurality of the metal and insulating plates 34, 35, a plurality of spacer strips 39, and four insulated rods or bolts 40.
  • the relatively narrow spacer strips 39 are interposed between plates at transversely opposite ends thereof, as can be seen in Figs. 2 and 3.
  • the plates and the spacer strips are clamped together in a horizontal direction by means of the bolts 40, one bolt being located at each end of the metal plates 34 and one bolt at each end of the insulating plates 35.
  • the centrally located groups of plates The six groups of plates assembled in the manner described above are disposed in series relationship across the outlet of the arc chute 11.
  • each group is clamped in a vertical direction against a horizontal ledge 41 formed on the inside surface of each sidewall 20 and 21 by means of a pair of clamping bars 42 suitably secured to the sidewalls.
  • an appropriate barrier 43 of insulating material may be disposed between each group of plates, and one such barrier may be disposed between each of the outer groups of plates 38a and 38b and the adjoining transverse member 24 of the arc chute 11.
  • the spacing between adjacent plates in groups 37a and 37b is twice as great as the spacing between adjacent plates in groups 36a and 36b, and the spacing between adjacent plates in the outer groups 38a and 38b is three times the spacing used in the central groups 36a and 36b.
  • This progressive change in spacing provides for a greater venting ratethat is, a greater rate of flow or volume per unit time of the are products being vented-'between adjacent plates in groups 38a than between adjacent plates in group 37a, and similarly a greater venting rate between adjacent plates in group 37a than in group 36a.
  • the effective venting area between adjacent plates has been varied so that the groups of plates locatedat the opposite ends of the stack provide lower fiuid resistance than the groups of plates located nearer to the center of the stack.
  • the groups of plates 38 and 38b located nearest to the outward ends of the arc runners 30 and 31 have the greatest interplate spacings and hence the least fluid resistance, and accordingly these groups can rapidly exhaust all of the arc products generated in the adjoining areas or regions of the arc chute.
  • venting areas that are relatively small and hence have relatively high fluid resistance, but the volume of are products generated in the area adjoining these groups is relatively less. In other words, the venting areas are least where the amount of are products. to be exhausted are least. a
  • relatively high-pressure pockets of are products that might otherwise be formed are rapidly relieved and exhausted, and; the stream of ionized gases comprising the arc, which stream is moving behind the arc products, will quickly reach the lower exposed edges of all of the metal plates 34 substantially simultaneously. This enables each pair of adjacent plates to be utilized efiiciently, and optimum interrupting ability is realized.
  • the initial voltage drop in the stack of plates will comprise an aggregate uniformly distributed across substantially all of the adjacent pairs of plates.
  • the broken line 45 in Fig. represents the pattern of incandescence are products discharged during an actual circuit interrupting operation by a circuit interrupter having an arc chute provided with the arcchopping metal plates in accordance with my invention.
  • an electric arc extinguisher having spaced-apart sidewalls defining an arcing area and an outlet for the arc products, means for initiating an arc at a predetermined point within the extinguisher and for subsequently propelling the arc toward the outlet, and a plurality of metal plates stacked across the outlet in spaced-apart planes disposed generally perpendicular to the sidewalls and the arc, the spacing between adjacent planes being varied so that the effective venting. area between the adjacent plates nearest to said predetermined point is smaller than .the effective venting area between adjacent plates more remotely located;
  • An arc extinguishing device having in combination: an arc chute provided with a pair of opposing sidewalls having transverse members mounted therebetween; a pair of arc runners mounted on the inner sides of said transverse members, respectively, and disposed to extend divergently outward from the arc initiating end of the chute toward the discharge end thereof; and a plurality of groups of transversely extending spaced-apart metal plates stacked in series relation across the discharge end of the chute, the plates in the groups located nearest to the outwardv ends of the arc runners, respectively, being disposed to provide between adjacent plates spacings that are relatively great with respect to the spacings between adjacent plates in the other groups.
  • An electric circuit interrupter comprising: means for drawing an arc and an arc chute for receiving the are at one end and exhausting the arc products at another end thereof, said chute comprising a plurality of spacedapart metal plates mounted to extend transversely of the arc intermediate the are drawing means and the, exhaust end of the chute, the plates located most remotely from the are drawing means being disposed to provide between adjacent plates an effective venting area substantially larger than the venting area between adjacent plates located closer to said are drawing means.
  • a circuit interrupter including contact structure separable to establish an arc, an arc chute comprising a pair of spaced sidewalls for enclosing the arc, means disposed in the arc chute for directing the arc between the sidewalls toward an exhaust end of the chute, and a plurality of spaced-apart metal plates spanning the sidewalls to chop the are into a family of serially related a-rclets, the plates located closer to the contact structure being spaced at shorter intervals from adjacent plates than the plates further removed from the contact structure are spaced from adjacent plates.
  • a circuit interrupter including contact structure separable to establish an arc, an arc chute comprising a pair of spaced sidewalls for enclosing the arc, means including a pair of arc runners disposed in the arc chute for directing the arc from the vicinity of the contact structure outwardly toward an exhaust end of the chute, and a plurality of spaced-apart metal plates stacked across the exhaust end of the chute to chop the arc into a family of serially related arclets, the plates located nearest to the outer ends of the arc runners, respectively, being dis posed to provide greater venting area between adjacent plates than the plates located further from said outer ends are disposed to provide.
  • An electric circuit interrupter comprising: an arc chute having a relatively small openingat one end thereof, a generally divergent body portion for enclosing anelectric arc, and a relatively large exhaust opening'at the opposite end thereof; means associated with the arc chute for directing the are through said body portion toward said exhaust opening; and a plurality of arc-chopping metal plates mounted in variable spaced-apart relation intermediate said openings, said plates being disposed so that those located relatively close to relatively high-pressure arcing regions enclosed by the body portion of the arc chute are separated from their adjacent plates by spacings that are greater than the spacings maintained between adjacent plates located closer to relatively lowpressure arcing regions in the chute.

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  • Arc-Extinguishing Devices That Are Switches (AREA)
US703567A 1957-12-18 1957-12-18 Electric circuit interrupter Expired - Lifetime US2908787A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US703567A US2908787A (en) 1957-12-18 1957-12-18 Electric circuit interrupter
FR781771A FR1217934A (fr) 1957-12-18 1958-12-16 Interrupteur de circuit électrique

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Application Number Priority Date Filing Date Title
US703567A US2908787A (en) 1957-12-18 1957-12-18 Electric circuit interrupter

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US2908787A true US2908787A (en) 1959-10-13

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031552A (en) * 1959-05-28 1962-04-24 Gen Electric Electric circuit interrupter
US3296402A (en) * 1964-12-23 1967-01-03 Allis Chalmers Mfg Co Arc chute for air circuit breaker
US3327080A (en) * 1964-12-23 1967-06-20 Allis Chalmers Mfg Co Arc chute for electric circuit breaker

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2047739A (en) * 1932-03-23 1936-07-14 Westinghouse Electric & Mfg Co Circuit interrupter
US2180147A (en) * 1936-07-21 1939-11-14 Gen Electric Electric circuit interrupter
US2460727A (en) * 1945-10-08 1949-02-01 Gen Electric Arc extinguishing device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2047739A (en) * 1932-03-23 1936-07-14 Westinghouse Electric & Mfg Co Circuit interrupter
US2180147A (en) * 1936-07-21 1939-11-14 Gen Electric Electric circuit interrupter
US2460727A (en) * 1945-10-08 1949-02-01 Gen Electric Arc extinguishing device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031552A (en) * 1959-05-28 1962-04-24 Gen Electric Electric circuit interrupter
US3296402A (en) * 1964-12-23 1967-01-03 Allis Chalmers Mfg Co Arc chute for air circuit breaker
US3327080A (en) * 1964-12-23 1967-06-20 Allis Chalmers Mfg Co Arc chute for electric circuit breaker

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Publication number Publication date
FR1217934A (fr) 1960-05-06

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