US2831947A - Circuit interrupters - Google Patents

Description

April 22, 1958 J. M. KozLovIc CIRCUIT INTERRUPTERS 3 SheecS-Sheet 1 Filed Jan. 3l, 195'? ATTORNEY 224 @Zia/w April 22, 1955 J. M. KozLovlc CIRCUIT INTERRUPTERS 3 Sheets-Sheet 2 'Filed Jan. 31, 1957 J. M. KoZLovlc CIRCUIT INTERRUPTERS pil 22, 1958 5 Sheets-Sheet 3 Filed Jan. 3l, 1957 Fig.`8.

5e 55 eo 55o United States Patent O CIRCUIT INTERRUPTERS yJohn M. Kozlovic, Greensburg, Pa., assgnor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 31, 1957, Serial No. 637,549 8 Claims. (Cl. 200--147) This invention relates to circuit interrupters in general, and more particularly to arc-extinguishing structures therefor. l

A general object of the present invention is to provide an improved circuit interrupter, which will have a more eiectivemagnetic structure than those heretofore known in the art, and which, as a result of such improved magnetic structure, will etect the extinction of the established v an improved circuit interrupter having one or more magnetizing windings in which at least one turn of each magnetizing winding extends substantially around the periphery of a pole plate portion of the circuit interrupter.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

Figure l is a side elevational view, partially in vertical section, of a magnetic air-breaktype of circuit interrupter embodying the principles of the present invention, and shown in the closed-circuit position;

Fig. 2 is a fragmentary, vertical sectional view taken along the line II-II of Fig. l looking in the direction of the arrows;

Fig. 3 is an enlarged side elevational view of one of the insulating plates used in the are chute of the circuit interrupter illustrated in Fig. l;

Figs. 4 and 5 collectively diagrammatically indicate the winding construction associated with the magnetizing coils of the circuit interrupter of Fig. 1;

Fig. 6is a somewhat diagrammatic, vertical sectional l View of a modied type of circuit interrupter, particularly one having an H-type magnet structure, embodying the principles of the present invention, and the contact structure being shown in the partially open-circuit position;

Fig. 7 is a fragmentary, side elevational view of the circuit interrupter illustrated in Fig. 6;

Fig. 8 is a plan sectional view taken substantially along the line VIII-VIII of Fig. 6; and

Figs. 9 and 10 collectively diagrammatically illustrate the turns of the magnetizing coils associated with the H-type magnet structure employed in the circuit interrupter of Figs. 6-8.

Referring to the drawings, and more particularly to Fig. 1 thereof, the reference numeral 1 generally designates a circuit interrupter having a U-shap'ed blowout magnet structure 2, which includes a pair of pole plate portions 3 and an interconnecting yoke portiony 4. A pair of electrically parallel magnetizing coils 5 encircle the yoke portion 4 to generate magnetic ilux between the n, pole plate portions 3 to elect upward movement of the lee established arc 6 which is drawn between a relatively stationary arcing contact 7 and a movable arcing contact 9.

The relatively stationary arcing contact 7 is a portion of a relatively stationary contact structure, generally designated by the reference numeral 10, and including a .stationary` main contact 11, a relatively stationary secondary contact 12 and the aforesaid mentioned relatively stationary arcing contact 7. The relatively stationary contact structure 10 is supported at the outer end of a conducting terminal stud 13, which extends centrally through a supporting insulator bushing 15, the latter being supported in any suitable manner.

The movable arcing contact 9 is disposed at the outer extremity of a rotatable contact arm 16, the latter being pivotally mounted about a lower terminal stud, not shown, analogous to the terminal stud 13, as well understood by those skilled in the art.

Carried with the rotatable contact arm 16 is a main bridging contact 17, the latter being biased by a pair of compression springs 19 away from the contact arm 16, and into engagement with a pair of relatively stationary main contacts 11 and 20. As previously mentioned, the relatively stationary contact 11 is electrically connected to the upper terminal stud 13, whereas the lower main stationary -contact 20 is rsupported by, and electrically connected to a lower terminal stud, not shown. The compression springs encircle a pair of guide studs 21, which have one end thereof threadedly secured to the/main bridging contact 17 and pass through suitable apertures provided in the rotatable contact arm 16. Nuts 22 are threaded upon the outer ends of the guide studs 21 to limit the outward movement of the main bridging contact 17 relative to the rotatable contact arm 16.

As well understood by those skilled in the art, during the opening operation the rotatable contact arm 16 is moved in a clockwise direction about its pivotal support, not shown, and first causes a separation between the main bridging contact 17 and the main contacts 11, 20. Subsequently, the relatively stationary secondary contact 12 separates from a movable secondary contact 24, and finally, the relative movable arcing contacts 7, 9 separate to establish the aforementioned are 6.

Because of the loop circuit, including the two terminal studs and the rotatable contact arm 16the established arc 6 tends to bow upwardly into the arc chute, generally designated by the reference numeral 25, and into contacting engagement with a pair of arc horns 26, 28. It will be apparent that upon contact of the arc 6 with the rear are horn 26, the two magnetizing coils 5 will be in parallel with the arc portion 6a, and will tend 'to etect the extinction thereof. The outer end of the arc portion 6b will transfer to the front arc horn 28, which is electrically connected by a flexible conductor 30 with the contact arm 16, and therefore in electrical contact with the lower terminal stud, not shown.

Generally, the arc chute may include a plurality of spaced ceramic plates 31, the conliguration of Vwhich is more apparent from a study of Fig. 3 of the drawings. As shown, each ceramic plate 31 may have a tapered slot 32 therein, which terminates at an upper closed end 33. A plurality of such insulating plates 31 are employed with the upper closed end 33 alternated about the center-line 35 of the plate structure, so that Lupon assemblage the several slots 32 provide a zigzag arc passage 36, as more clearly shown in Fig. 2 of the drawings. The plates 31 are spaced apart by strips of asbestos rope 37, which are cemented to the outer edges of the plates '31. Thus, the plates 31 and the asbestos rope sections 37 are cemented together to form a unitary cemented stack structure, which may be bodily inserted downwardly within 3 a rectangularly-shaped, arc-chute jacket, designated by the referencenumer'al 38.

As shown more clearly in Fig. 2, the pole plates 3 straddle the arc-chute jackets 38 and the interiorly dispos'edstack of plates 31, so thatupon 'extinctionof 'the arc" portion 6a and 'consequent `energization of the 'two electricallyparallel magnetizing coils 5, a transverse 'mag` netic field 4G may passibetween thepolepiates 3, in a manner illustrated'in lig` 4 of'the drawings.

lThe"transverse magnetic flux 40, passing transversely across 'the Varc chute '25 betweenthe pole plates 3 will effectupward movement of'thearcb causing it to move upwardly between the arc horns 26,28, as'indicated by the further arc position "41. The arc 41 will continue to be forced'upwardlyby 'the'transverse magnetic field 40 within' the zigzag arc passage'36, until' the arc 1lireaches the upper closed ends 33 of the'slots 32. Arc extinction will quickly take-place at this position due to theblast of unionized gaspassingupwardlybetween the passages -'42 between the plates 3l, as afforded by the-spacing means constitutedby the asbestos rope sections 37.

The structure thus far described for purposes of illustration, is generally as set out in United States Patent No. 2,442,l99,'issued May 25, 1948, to Robert C.'Dickinson and Russell E. VFrink and assigned to the assignee of the'instant-application. The invention is more particularly concerned withthe use of an extra turn associated with each magnetizing coil 5, which substantially encircles, or'extends about the periphery of each pole plate `3,` as more clearly illustrated in Figs. 4 and 5 of the drawings. As illustrated in these figures, it will be apparent thatthe magnetizing coil has an extra turn 43 which encircles, or extends around the pole plate 3, and which terminates at a stud 45 which is connected to the rear arc horn 26, in the manner indicated in Fig. 1 of the drawings. As shown in Fig. 4, the other ends 46 of the magnetizing 'coils '5 are connected together, and lead by way of a conductor 47 to the relatively stationary Contact structure 1).

lt will be obvious that the two magnetizing coils 5 are velectr-ically in parallel between the relatively stationary contact structure l@ and the inner arc horn'26. Each magnetizing coil'S not only has a plurality of turns about the yoke 4 of the magnet structure 2, but also has the turn `A43 about the periphery of the pole plate 3, which terminates atthe'inner arc'horn 26.

It has been discoveredthat the use of the present invention results in increasing the flux density and consequently'the interrupting rating of the magnetic type circuit interrupters without a corresponding increase in the size of the interrupter. Up to the present time, the practice has been'to build a U-shaped magnetic circuit with a blowout coil around the bight or yoke of the U. With such a construction, because of the very large air gap, and the necessity for keeping the magnetic circuit downto practical Ilimits, there is a considerable amount of leakage lflux, 'which results in saturation of the iron at relatively low'ux densities in the air gap. The present invention'is concerned with a means for reducing this leakage'flux and increasing the useful flux in the air gap, thus increasing the interrupting rating of the breaker.

To'accomplish this, it is proposed to add a blowout turn around the legsof the magnet. This turn will be in series With'the present blowout coil and the polarity such that the ilux generated by the turn will oppose the leakage ux from the magnet. This means that more useful flux can be generated before the magnet yoke becomes saturated. `In addition to the increase in flux across the air gap because of the action described above, there Will be a further increase in ux due to the additional turn itself.

Another advantage of the invention is that at low currents, where the magnetic circuit is not saturated, and no corrective action for leakage is necessary, the flux pair `ofcenter arc horns `58.

4 produced by the additional turn aids that produced by the main Yblowout coil, 'thus 'reducing the interruptingtime at low current also.

A further advantage of the invention is that the flux generated in the additional turn is in time phase of that generated by the main blowout coil, and will tend to correct for the twist of thevmagnetic field out toward the open end of the magnet. This twist in the magnetic field is caused by the eddy currents that circulate in the iron. Still another advantage is the correction for leakage is not dependent upon the leakage, but it is a positive means for increasing the blowout field.

in Fig. 4 thedirectionof the current ow is indicated by the arrows 49 associated with the extra turns 43. The current flowing through the extraturns 43 will cause the generation of additional flux as indicated by the ux lines The return path 51 of these additional flux lines will reduce any leakage flux tending to flow across the outerends k:S2 of the pole plates A3, since the generated return flux path 51 will be in'the opposite direction, or in opposition to the leakage ux, not shown, which would tend to pass across the ends'52 of the pole plates 3.

Thus, the additional flux, set up by the extra turns 43 tends tooppose vthe leakage ux, and thereby increases the densityjof the flux 40 across the air gap. It will be notedfthat the flux 50, set up by the extra turns 43, also crossesthe air gap as useful flux. f

The application of the invention is not confined to a circuit vinterrupter utilizing a U-shaped magnet structure, suchlas illustrated in Fig. l, but the invention has wider applicatiomand Figs.'6-l0 illustrate an application of the invention to a center-coil type of arc chute having van lH-type magnet structure. With particular reference to Figs. 6-8, which somewhat diagrammatically illustrate the manner ofoperation of a center-coil type of arc chute, it will be observed,'with reference to Fig. 8 particularly, that an H-type of magnet structure, 'generally designated by the reference numeral 53, is provided. The magnet structure 53 includes a pair of pole plates 55 magnetically connected by a centrally located yoke, or coreportion 56, about vwhich encircles a pair of electrically parallel magnetizing coils 57, more clearly yshown in Fig. 9, and electrically connected between a A pair of ystack structures 60 are disposed on opposite sides of the magnetizing coils 57, as illustrated in Fig. 6. Each stack-structure'O includes aplurality of plates 31, and their function is `similar to that heretofore described in connectionwith the circuit interrupter of Fig. l. AV pair of inner and outer arclhorns 61, 62 'are employed, the inner lare horn 61 being electrically connected to the stationary contact structure 10, and thefouter arc horn `62 being electrically connected by-a vconnector `63 to a rotatable contact arm 16, and hence to a lower terminal stud 64.

During the openingy operation, the movable arcing contact 9 separates from'the relatively stationary arcing corr-` tact 7 and-establishes an arc 65 having three serially related .portionsf65a, 65b and 65C. The arc portions 65a, 65e respectively extend between the center arc horn 58 and the stationary contact structure 10 and the center arc horn 58 and the movable arcing contact 9, with the intermediate arc-portion 65b extending between the `center arc horns 58, and interrupted by the several spaced insulating plates'66 disposed therebetween.

The extinction of the arc portion 65b will electrically connect the two electrically parallel magnetizing coils 57 across the center arc horns 58, each magnetizing coil 57 carrying substantially half the load current.

With particular reference to Fig. 9, it will be observed that each'magnetizing coil 57 has an extra turn 67 extending-completelyabout the periphery of the pole plate 55 with the other end connectedto the other center archorn 58. The direction of the current flow is-indicated by thearrows'68. Referencemay be had to Fig. l0 in this connection.

The functioning of the extra turns 67 associated with the two magnetizing coils 57 will be generally similar to that heretofore described in connection with the extra turns 43 associated with the magnetizing coils 5 of the interrupter of Figs. 1-5, and hence will not be repeated.

It will be apparent that upon extinction of the arc portion 65h, and consequent energization'of the two magnetizing coils 57, that ilux will be built up in the H-type magnet structure 53 and will pass transversely across the pole plates 55 through the stack structures 60, and effect extinction of the two serially related arc portions 65a, 65e, which extend between the center arc horns 58 and the outer arc horns 61, 62. The slots 32 provided in the plates 31 will effect extinction of the arc portions 65a, 65e in the manner as heretofore described.

From the foregoing description of the H-type of magnet structure associated with the modified type of circuit interrupter 69, illustrated in Figs. 6-8, it will be apparent n that the principles of the present invention have wide application and may be employed wherever a pair of poleplate portions are interconnected bya yoke portion and straddle an arc-chute structure. It will be noted that the H-type magnetic circuit 53 of Fig. k8 may be considered to have two pairs of pole plate portions 55a, each pair of pole plate portions 55a straddling .a stack structure 60. The extra turns 67 will then substantially encompass the periphery of each pole plate portion 55a in the same manner as the extra turns 43 extended about the pole plate portions 3 of the magnetic structure 2 of the interrupter illustrated in Fig. l. Thus, the invention has wide application, and may be employed to eliminate leakage llux passing across the outer ends of a pair of pole plate portions, whether the magnetic structure is of U configuration, or of H-shaped configuration.

Although there have been shown and described specific structures, it is to be clearlyr understood that the same were merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art `without departing from the spirit and scope of the invention.

I claim as my invention:

1. A circuit interrupter including means for establishing an arc, a magnetic blowout structure including. at least a pair of pole plate portions and an interconnecting yoke portion, a magnetizing coil for generating magnetic ux across said pole plate portions to eect movement of said arc including one or more turns about said yoke portion, and said magnetizing coil also including a magnetizing turn extending substantially around the periphery of at least one of said pole plate portions.

2. The combination in a circuit interrupter of a magnet structure having at least one U-shaped magnet portion, said U-shaped magnet portion including a pair of pole plates and an interconnecting yoke portion, means for establishing an arc, means including said magnet structure for moving at least a portion of `said arc up between said pole plates to effect the extinction thereof, a magnetizing coil for generating magnetic ux across the space between said pole plates including one or more turns about Isaid interconnecting yoke portion, and at least an additional turn of said magnetizing coil extending substantially around the periphery of one of said pole plates.

3. The combination in a circuit interrupter of a magnet structure having at least one U-shaped magnet portion, said U-shaped magnet portion including a pair of pole plates and an yinterconnecting yoke portion, means for establishing an arc, means including said magnet strueture for moving at least a portion of said are up between said pole plates to effect the extinction thereof, a magnetizing coil for generating magnetic tlux across the space' of said U-shaped magnet portion, a serially related mag-r netizing coil in series with said are and generating magnetic flux between the legs of said U-shaped magnet portion, said magnetizing coil including one yor more turns about the yoke of said U-shaped magnet portion, and said magnetizing coil also including a turn about the periph` ery of one of said legs with the end of said last-mentioned turn terminating at one of said arc horns.

5. An air-break magnetic circuit interrupter including a U-shaped blowout magnet having a pair of spaced pole plates and an interconnecting yoke, a pair of arc horns disposed between the pole plates, a relatively stationary contact, a magnetizing coil connected between said relatively stationary contact and one of said 'arc horns and including one or more turns around said yoke, said magnetizing coil also including a turn about the periphery of one of said pole plates, a movable contact cooperable with said relatively stationary contact to establish an arc, and said arc transferring between said pair of are horns and moving between the pole plates of said U- shaped blowout magnet to become extinguished.

6. An air-break magnetic circuit interrupter including a U-shaped blowout magnet having a pair of spaced pole plates and an interconnecting yoke, a pair of are horns disposed between the pole plates, a relatively stationary contact, a pair of magnetizing coils connected between said relatively stationary contact and one of said arc horns and each coil including one or more turns around said yoke, each said magnetizing coil also including a turn about the periphery of one of saidkpole plates, a movable contact cooperable with said relatively stationary contact to establish an arc, and said arc transferring between said pair of arc horns and moving between the pole plates of said U-shaped blowout magnet to become extinguished.

7. A circuit interrupter including an H-shaped blowout magnet having a pair ,of pole plates interconnected by a yoke, a pair of center arc horns, a magnetizing coil connected between said center arc horns and having one or more turns about said yoke, said magnetizing coil `also having a turn substantially about the periphery of one of said pole plates, means for establishing an arc,

and said arc moving into engagementr with said pair of center arc horns.

y8. A circuit interrupter including an H-shaped blowout magnet having a pair of pole plates interconnected by a yoke, a pair of center arc horns, a pair of magnetizing coils connected between said center arc horns and each' coil having one or more turns about said yoke, each said magnetizing coil also having a turn substantially about the periphery of one of said pole plates, means for establishing an arc, and said arc moving into engagement with said pair of center are horns.

No references cited.

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