US1896763A

US1896763A - Arc extinguishing structure

Info

Publication number: US1896763A
Application number: US591798A
Authority: US
Inventors: Walter M Austin
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1932-02-09
Filing date: 1932-02-09
Publication date: 1933-02-07
Anticipated expiration: 1950-02-07

Description

Feb. 7, 1933. w. M. AUSTIN ARC EXTINGUISHING STRUCTURE Filed Feb. 9, 1932 2 Sheets-Sheet l 0 lNvENToR VVG/fer /VZ AUS /f? Feb. 7, 1933. A W4 M, AUSTIN 1,896,763

ARC EXTINGUISHING STRUCTURE Filed Feb. 9, 1932 2 Sheets-Sheet 2 WITNESSES'. l() INVENTOR @m1 7% f@ www M. Auw/n (l BY Patented Feb. 7, 1933 UNITED .STATES PATENT OFFICE WALTER M. AUSTIN, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA ARC EXTINGUISHING STRUCTURE .Application led February 9, 1932. Serial No. 591,798.

My invention relates generally to circuit breakers and more particularly to devices for extinguishing large-current arcs in air or g The arc-extinguisher of my invention is of the spaced-plate type, in which an arc is drawn and moved into a converging slot that leads to a deionizing chamber having a. plurality of spaced conducting or deionizing plates which sub-divide the arc into a plurality of short arcs. The short arcs, under the influence of the fluX of a radial ield, rotate at a very high velocity between the conducting plates until they 'become extinct.

My invention is a further improvement of circuit. breakers of the type disclosed in Patent No. 1,784,760, issued to Joseph Slepian. December 9, 1930, and certain subject matter described herein is claimed in the applications for Letters Patent, Serial No. 510.981. filed January 24, 1931, by Frederick I3. Johnson. and Serial No. 511,010, tiled January 24. 1931, by Robert C. Dickinson, all of which are assigned to the assignee of the present invention.

An object of my invention is the provision of an arc extinguishing device that shall be simple and reliable in operation and be readily and economically manufactured and installed. i'

Another object of my invention is to provide a deionizing structure having a stack ot plates open at both the top and the bottomso that a direct vent is provided for Ventilating the short arcs.

A further object of my invention is to provide a direct vent for each of the short arcs and` at the same time, prevent the arcs from passing through the vents.

It is also an object of my invention to prevent the building-up of gas pressure in advance of the arc as it moves into the spaces between the deionizing plates` so that a relatively weak blow-in field, without the provision of heavy multi-turn blow-in coils, is sutiicient to move the arc in the said spaces.

Another object of my invention is to provide a Ventilating passage having a width snbstantiallyv the same as the width of the deionizing plates, so thatA the heat generated ,by the arcs may be directly ventilated to the atmosphere.

Another object of my invention is to provide a plurality of deionizing plates, each of which being surrounded by a complementary magnetic plate of approximately the same thickness and substantially in the same plane therewith.

Other objects of the invention will hereinafter become apparent.

For a fuller understanding of the nature and objects of my invention, reference may be had to the following detailed description taken in connection with the accompanying drawings, showing the preferred embodiment of my invention, in which:

Figure 1 is a view in elevation of my deionizing structure;

Fig. 2 is a vertical cross-sectional view of my deionizing structure taken along the line II-II of Fig. 3, and illustrating the contact members of a switch associated therewith;

Fig. 3 is a vertical view, in section, of my deionizing structure taken along the line III-III of Fig. 2;

Fig. 4 is a vertical cross-sectional view of my deionizing structure, taken along the line 'IV-IV of Fig. 2; and

Fig. 5 is an exploded perspective view of my deionizing structure. In View of the lack of sufiicient length to show the exploded structure, the various parts are shown in two horizontal lines. The parts shown in the lower horizontal line are to be considered as disposed to the left of the parts shown in the top horizontal line, so that, when the members are assembled they will constitute the complete lassemblage of my deionizing structure. However. in this view, I have omitted a number of the centrally disposed parts, since they are merely a duplication of the centrally disposed parts shown.

Inasmuch as the construct-ion of operating mechanisms of circuit breakers is well known in the art, together with the fact that it constitutes no part of my invention, I have illustrated only the contact members thereof in association with my deionizing structure` As illustrated, my deionizing structure is' mounted directly above the contacts of th Y a plurality A into a unitary device.

circuit breaker so that the arc may be immediately moved into the deionizing chamber and there extinguished. A y s As shown in Fig. 2, the

reference characters

14 and 16 represent, respectively, the movable and the stationary main contacts of a circuit breaker connected to interrupt the large current power lines 10 and 11. Associated with, and electrically connected to, the

movable contact 14 is an arcing contact member 15 rest-ing against the stationary arcing contact member 52 of my deionizing structure, and which opens later than

main contacts

14 and 16. This construction is in accordance with the general features of a circuit breaker that is utilized in interrupting high-voltage, large-current circuits, the circuit being finally interrupted at the

arcing contacts

15 and 52 to prevent burning of the

main contacts

14 and 16. The operating lever and the toggle arrangements, which are generally utilized for operating the main contacts of a circuit breaker, are not shown in the accompanying drawings, as they constitute no part of my present invention.

Referring more .particularly to the drawings, my invention comprises generally a plurality of conducting or deionizing

plates

27 and 30, each of which is surrounded by a complementary magnetic plate 36 disposed in substantially the same plane therewith, of insulating

members

33, 34, and 35 which separate the conducting and vtheir complementary magnetic plates in order to provide direct Ventilating passages for the'short arcs, and two

convolute coils

54 and 70 disposed respectively on each side of the plates. A bolt 23 extending through the central portion of the plates, in conjunction with the two

iron end plates

21 and 22, is utilized for holding the deionizing structure Preferably, the conducting or'deionizing

plates

27 and 30 are constructed of copper and the magnetic plates of iron.

As shown best in Fig. 5, the assemblagel of al copper 'conducting

plate

27 or 30 withinan iron plate 36 constitutes a unitary or composite member of my deionizing arc-extinguisher, and will hereinafter be referred to as a composite plate. y

The lower part of the'copper conducting plates 30 have a V-shaped portion 37 removed, which, when the plates are stacked, constitutes the apex portion of the converging slot that directs the arc into the spaces between the said conducting plates, while the copper conducting plates 27 that are disposed at each end of the stack of plates 30 have no portion of their lower part removed. Therefore, when the conducting

plates

27 and 30 are assembled and spaced in a unitary deionizing structure, the lower part of the copper conducting plates 27 constitutes sides of the apex of the entrance slot formed by the il-shaped slots 37 of the conducting plates 30.

Although ducting plates 3() I have shown live of the conin the present embodiment of -my invention, it is to be understood that I 'do not intend to confine myself to this number because the number depends upon the voltage andthe current of the power circuit to be interrupted. Generally, the number of plates can be determined by dividing the voltage of the power circuit by 150, which represents the r. In. s. cathode voltage drop between the respect-ive conducting plates at the instant of zero current.

The central lower part ofthe iron magnetic plates 36 are cut away to form the lower or base portion of the converging slot, which meets the apex portion of the said slot formed by the copper conducting plates 30. In other words, a continuous, converging entrance slot is formed by the portions removed from the iron and copper plates. In this manner, the arc incident to the interruption of a large current circuit is moved into and concentrated at the apex of the slot just before the arc is sub-divided into a plurality of short arcs. As shown best in Fig. 3, the apex of the converging slot extends well into the copper plates so that the radial field flux produced by the

coils

54 and 70 aids in transferring the arc between the copper plates. The

edges of the converging slot formed by the from the intense heat of the arc, and are also electrically insulated therefrom, by adjacently disposed

barriers

83 and 84 which are constructed of an insulating and refractory material. The barriers are secured in position by having their lower edges lit within grooves formed by the sides of the arc terminal member 50 and the iron plates 36 (see Figs. 3 and 4), together with having the

projections

86 and 87 that are formed integral therewith extend through the openings 88 and 89 provided in the end plate 22. The converging slot formed by the copper conducting plates and their complementary iron plates is so shaped that, when the

insulating barriers

83 and 84 are positioned along the sides thereof, the barriers and that portion of the slot provided in the copper conducting plates constitutes one continuous, converging slot for directing the arc between the conducting sulatingk member 33 is substantially co-eX-l tensive with the iron plates, but its central opening is somewhat smaller than the central opening of the `iron plates so that it overlaps the copper conducting plates to prevent the short arcs from passing through the narrow space where thecopper and the iron'plates (See Fig. '3.) The broken line 90, in 4ig. 3, represents the boundary of the copper plates whereas the line 95 represents the edge of the central opening of the insulating member 33. The central opening of the insulating member 33 is substantially round, except for that part where the arc enters tangentially thereto, so that the short arc, under the action of the'lux of the

convolute coils

54 and 70, may trace recurrent paths between the copper plates until they become extinct The insulating members 34 and' 35 are disposed along opposite sides of the iron plates ,when the three insulatingv members .33, 34, and 35 are assembled between the composite copper and iron plates they form a passage 80 between the adjacent plates for directly ventila'ting each of the short arcs, the ventilating passage having a lateralwidthequal to the vdistance between the kinsulating

members

34 and 35.

Since the insulating member 33 completely coversthe iron plates, on one side of the ventilating passage 80, the short arcs are preventedfrom leaving the copper plates, while the hot gases are permitted to ventv directly to atmosphere through the vents 80.

.Disposed on opposite sides of the stack of the composite copper and iron plates are

coils

54 and 70, which set up a radial field flux for causing the short arcsto trace rapidly recurrentpaths between the copper conducting plates, Thefouter end of the coil 54 (see Fig. 5) is connectedto the upper. end of the arc terminal member which constitutes a support forlthe Contact member 52 on which one end `of the arc plays as it is moved through the converging slot into/the spaces between the copper conductingg plates. Disposed immediately above the areing contact 52, and attached to'the 'are terminal 50,2is an arc rcsisting contact 53, preferably made of a silver-.tungsten mixture for preventing the arc vfrom injuring and burning the are terminal 50. l

TheI inner end 57y of thevconvolute coil 54 it may be connected to the adjacently disposed copper conducting plates 27. The inner end 57 and the outer end of the co-il 54 may be connected, respectively, to the ad* jacently disposed copper conducting plate 27 and to the upper end of the arc terminal 50 by any well known manner, such as by silver solder. After the inner end of the coil 54 is soldered or connected to the adjacently disposedA copper plate 27, a split insulating washer 55 is disposed therebetween for the purpose of preventing shortcircuiting of the turns of convolute coil 54. As shown in Fig. 5, that part of the central opening of the washer 54 where the inner end of the coil 54 is connected to the adjacently disposed copper plate 27 is cut away so as to fit around the inner end of the said coil. The outer dimension of the'split insulating washer 55 is such that it tits snugly within the central o-pening of one of the sets of insulating

plates

33, 34, and 35 that is disposed substantially in the same plane therewith. In other words, the

plates

33, 34, and 35, when assembled, surround, and lie in edgeto-edge relation, with the split washer 55. Also, for preventing short circuiting of the turns of the coil 54, a strip of insulating material 58 is wound between each turn thereof.

` (See Figs. 2 and 5.) and partly surround the copper plates so that The other convolute coil 70 is substantially the same as the coil 54, except that it is mounted on the opposite side of the stack of plates (see Figs. 2, 4 and 5) The inner end 72 of the coil 70 is bent to the right so that it may be` connected by silver soldering to the, adjacently disposed copper plate 27. A split washer 74, somewhat similar to the split washer 55, is'disposed between the coil 70 and the adjacently disposed copper plate 27 in order to prevent short circuiting of' the turns of the said coil. Likewise, that portion of the central opening of the split washer 7,4 where the inner end of the coil issoldered to the adjacently disposed copper plate 27 is cut away soas to fit around the inner end of said coil. Also, the outer dimension of the split washer 74 is such that it fits snugly within the central opening of one of the sets of insulating:

plates

33, 34 and`35 that is disposed substantially in edge-to-edge relation therewith. A strip of insulating material 7l is wound between adjacent turns of the coil 70 in order to prevent the short circuiting of its respective turns (see Fig.

)The outer end of the coil 70 is connected to side plate 22 by means of screws 8l and the threaded openings 73 provided in the outer end of the said coil (see Figs. l and 4). The

coils

54 and 70, when assembled, are insulated, respectively, from the

side plates

21 and 22 by means of

the'insulating members

76 and 78. f

G5 is bent tothe left (see Figs. 2 and 5), so that For the purpose of holding the stack of composite co-pper and iron plates, and the insulating members in their proper relation, a

pluralityof insulating pins

46, 47, 48, and 49 are provided. The insulating pins, when the structure is assembled, extend through the openings shown in the iron plates and in the insulating members.

The bolt 23 that extends through the central opening o-f the copper plates, is surrounded by an insulating tube or member 24 which insulates the bolt 23 from the side plates 2l and 22 and the copper conducting plates. A relatively large, thick insulating washer 25' is and the side plate 22 for distributing the force that holds the plates together and for insuring vfurther insulating protection.

In describing the operation of the deionizing structure, let it be assumed that the arcing

contacts

15 and 53 have` just opened, drawing an arc in the converging slot and that, during this part of the cycle, the current is flowing from the power line 10 to the power line 11. Under this condition, the

25 flux produced by the arc itself interlinks the iron plates and, in consequence, draws the arc inwardly through the converging slot, because the said lines of flux assume the path of the least magnetic reluctance. Since the insulating

members

33, 34, and 35 provide a direct vent through the stacks of plates, no appreciable gas pressure is established in advance of the arc, and the relatively weak field produced by the arc itself is suficient to draw the arc through the converging slot.

plates is great enough to cause thermalionization of the 'gas adjacent to the cold copper conducting plates.

However, simultaneously with the arc entering the apex of the converging slot provided by the copper plates, a radial field is' set-up by the are current flowing through the convolute coils 54 and 7 0 which causes the short arcs to move concentrically between the copper plates until they become extinct. As shown in Figs. l, 2 and 4, the arc current upon leaving the stationary contact member 52 flows through the arc terminal 50, the outeryturn of the convolute coil 54 to the inner turn thereof, the copper conducting plates, in the form of a plurality of short arcs, the inner turn of the convolute coil to the outer turn thereof, thence across the end line l1.

disposed between the nut 26.

plate 22 to the terminal lug 82, as indicated by the arrows in Fig. l, and then out to power I have indicated generally in Fig. 2, the paths of radial eld flux established by the

coils

54 and 70 by the broken lines having arrows thereon indicating their direction of flow. As will be observed, the direction ofthe flux, as it passes between the copper plates, is perpendicular to the current of the short arcs. This relation between the radial field iux and the short arcs produces a tangential force that causes the short arcs to r0- tate concentrically at a very high velocity between the conducting plates untilV they become extinct, which usually occurs when the arc current passes through the first zero point, unless there are suiicient ions present to reignite the are.

The rapid rotation of the short arc prevents any one spot of the copper conducting plates from being heated suiiiciently to cause melting thereof. Because of the direct vents 8O provided by my invention for each of the short arcs, the hot gases and the heat generated thereby are ventilated directly to the atmosphere. This ventilating action maintains the conducting plates aty a relatively low temperatureso that a large current circuit maybe successfully interrupted at frequent and continued-intervals.`

At this point, I wish to again point out that the width lof the Ventilating passages 80 is substantially the same width as the copper conducting plates. Thus the heat generated by the short arcs is vvented out to atmosphere without encountering any substantial resistance. "If for ,anyreason the short arcs attempt to pass through the Ventilating passages 80, they will immediately be prevented from doing so, because one side of said passage is completely covered by the insulating 'member 33'.

Therefore, I have disclosed a deionizing arc-extinguishing structure that provides a direct vent for each Iof the short arcs and, at the same time, prevents the said arcs from passing through the said vents.

' .Since certain changes in my invention may be made without departing from the spirit and scope thereof, it is intended that all matters contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense; x

Iclaim as my invention: I

1. In an arc-extinguishing structure. a plurality of non-magnetic conducting plates, aj magnetic,y .plate substantially co-planar with, and surrounding, each ofthe said nonmagnetic conducting plates, and insulating means for spacing the said plates, said insulating means being such as to confine the arc on said vconducting plate and to provide a passage for ventilating'the said plates.

2. In an arc-extinguishing structure, a

plurality of deionizing members, a magnetic plate substantially co-planar with, and surrounding, each of the said deionizing members, and 'means for spacing the said members, said spacing means including a sheet of insulating material which is substantially coextensive with the magnetic plates andv which so overlaps the deionizing members that it causes the are to contact only the deionizing members.

3. In an arc-extinguishing structure, a plurality of deionizing members having means associated therewith for impelling the arc to Contact the deio-nizing members, and means for spacing the deionizing members, said spacing means including a sheet of insulating material which covers the outer annular portion of each of the deionizing members, except for that portion where the arc initially contacts the deionizing plates, and including means for spacing said insulating sheets from one of the adjacent deionizing members.

4. In an arc-extinguishing structure, a plurality of members disposed substantially perpendicular to the are for sub-dividing the arc into a plurality of short arcs, means for spacing the members, and means disposed between the spaced members for providing a substantially annular confined space for the short arcs to move, said means having a thickness less than the width of the space between the members in ord'er to provide a passage for ventilating the arc.

5. In a circuit breaker, a plurality of spaced members disposed substantially perpendicular to the arc for sub-dividing the arc into a plurality of short arcs, and insulating means for spacing the said members and for providing a substantially annular confined space for the short arcs to move, said insulating means having portions removed to pro-- vide a passage for admitting the arc to contact initially the spacedmembers and for emitting the hot gases from the spaced members, one side of that part of the passage through which the hot gases pass being pro vided with a portion of said insulating means in order to prevent the arc from leaving the said annular space.

6. In a circuit breaker, a plurality of spaced members disposed substantially perpendicular to the arc for subdividing the arc into a plurality of short arcs, and means for spacing the said members in such manner as to provide a passage having an exit portion allowing the escape of gas for ventilating the said members, the exit portion of said passage having one side thereof covered with an insulating material in order to prevent the are from passing through the entire length of the passage.

7. In an arc-extinguishing structure, a plurality nof conducting members disposed substantially perpendicular to the arc for sub-dividing the arc into a plurality of short arcs, a magnetic member substantially coplanar with, and surrounding each of the said conducting members, the said conducting and magnetic members being so shaped as to provide a converging slot for directing the arc to, and concentrating it at, the apex of the slot where it is sub-divided into a plurality of short arcs and transferred between the said conducting members, means for maintaining the short arcs in continuous motion until they become extinct,V and means for spacing the said conducting and magnetic members in such manner as toy provide a pas- A sage having an exit portion allowing the escape of gas for Ventilating the said members, the exit portion of the said passage having one side thereof covered with an insulating material in order to prevent the arc from passing through the entire length of the passage.

8. In an arc-extinguishing device, a plurality of conducting members for sub-dividing the arc into a plurality` of short arcs, and insulating members for spacing the said conducting members, said insulating members being so formed as to provide a passage having an eXitportion allowing the escape of gas for Ventilating the said members, the exit portion of the said passage being provided with insulating means in order to prevent the arc from passing through the entire length of the passage.

9. In an arc-extinguishing device, a plurality of conducting members for sub-dividing the arc into a plurality of short arcs, means for spacing the said'members, the conducting and the spacing members being so formed as to provide a passage between the spaced conducting members extending from one edge thereof to another edge thereof, and means Vier so insulating the passage at one edge of said conducting members that the arc is prevented from passing through the entire length of the passage.

l0. In an arc-extinguishing device, a plurality of conducting members for sub-dividing the arc intoa plurality of short arcs, said conducting members having aradial slot to prevent the induction of eddy currents, a magnetic member substantially co-planar with, and surrounding each of the said coumagnetic members, the spacing means being so formed as to provide aV passage open at opposite ends for Ventilating the said oon' tween and so overlapping the outward annular portion of the conducting member that it prevents the short arcs from leaving the said conducting members as they are maintained in continuous motion, means associ-v ated with said sheet for spacing said conducting and magnetic members, said spacing means being so formed that it provides a passage forventilating the conducting and magnetic members, and means for maintaining ,the arc in continuous motion until the short arcs become extinct.

12. In an arc-extinguishing structure, a

plurality of conducting plates for sub-divid# ing the arc into a plurality vor short arcs, means for so spacing the said plates, as to provide a passage for Ventilating each short arc and means covering the portion of the conducting plates at said Ventilating passage to yprevent the short arcs from leaving the conducting plates.

13. In' an arc-extinguishing structure, a

plurality of conducting plates for sub-dividingthe arc into a plurality of short arcs, means for so spacing the said plates as to provide a passage for Ventilating the short arcs, said passage having a lateral width s ub stantially the same as the lwidth of the conA ducting plates.

14. ln an' arc-extinguishing structure, a

i plurality of spaced deionizing members disposed substantially perpendicular' to the arc for sub-dividing the arc into a plurality' of short arcs, a plurality of magnetic plates associated with the deionizing members, means for spacing the deionizing members and the magnetic plates, the said magnetic plates being so shaped that when they are assembled they provide a converging entrance slot or'directing the arc in between' thedionizing members, and insulating barriers ydisposed along the sides of the converging slot for preventing the arc from contacting the 6 magnetic plates.

15. An arc-extinguishing. structure comn prising, in combination, a plurality of spaced de ionizing members disposed t substantially perpendicular to the arc for sub-dividing the 35 arc into a plurality of short arcs, means for negates spacing the deionizing members, means including the converging edges of a plurality of plates for directing the arc in between the deionizing members, and a barrier positioned along the edges of said plates for preventing the arc from contacting therewith.

16. In an arc extinguishing structure, a plurality of members of conducting material positionedsubstantially perpendicular to the arc path for sub-dividing the arc into a plurality of short arcs, means positioned between said members comprising .sheets of insulating material, each of which has a centrally disposed opening through which the arc may play between said members of conducting material and only one slot connecting said opening with one edge of said sheet,

and means at the edge portions of said sheets` Vof insulating material for providing ventilating passages through said arc extinguisher.

17. In an arc .extinguishing structure, a plurality of members of conducting material positioned substantially perpendicular to the arc path for subdividing the arc into a plurality of short arcs, and means positioned between said members comprising sheets of insulating material, each of said sheets of insulating material having a body portion of less thickness than at least one of the edge portions, the diering thickness of said portions providing ventilating passages between said members.

In testimony whereof, l have hereunto subscribed my name this 5th day of February,

WALTER M. AUSTlN.