US2769066A - Circuit interrupters - Google Patents

Description

Oct. 30, 1956 A. R; CELLERINI CIRCUIT INTERRUPTERS Filed Feb. 2, 1953 2 Sheets-Sheet l Oct. 30; 1956 I A. R. CELLERINI 2,769,066

CIRCUIT INTERRUPTERS Filed Feb. 2, 1953 2 sheets-sheet 2 `w|TNEs z lNvENToR /ff M Albert R. Cellerin.

United States Patent() CIRCUIT IN TERRUPTRS Albert R. Cellerini, Beaver, Pa., assiguor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 2, 1953, Serial No. 334,551

14 Claims. (Cl. 200-147) This invention relates to circuit interrupters in general, and, more particularly, to arc-extinguishing structures therefor.

The main object of my invention is to provide a more effective circuit interrupter than has heretofore been manufactured; and also in addition to such eectiveness, I intend to provide such an improved circuit interrupter of reduced dimensions.

A more specific object of my invention is to change the disposition of the metallic plate structure over that heretofore used in connection with circuit interrupters. In other words, heretofore it has been the custom to dispose the spaced metallic plates substantially parallel to the length of the circuit-breaker base. In my improved construction I dispose the spaced metallic plates substantially perpendicularly to the longitudinal axis of the base. There occurs the advantage that the terminal structure of the breaker does not interfere with ready and facilitated venting of the arc gases through the extinguisher.

Another object is to provide an improved arc-extingisher for a circuit interrupter of the spaced-plate type.

Still a further object is to provide an improved arcextinguisher in which the arc is constantly kept in motion by preventing it from settling at the geometrical centers of the plates, thereby causing a hot spot to occur thereat.

Still a further object is to provide an improved spacedplate type of arc-extinguisher in conjunction with a narlatch @11d 30 Which COOPYHCS With row slot type of arc-extinguisher and improving the plate structure so that the consequent heating thereof during arc interruption will be minimized.

A further object of my invention is to provide an improved spaced-metallic-plate type of arc-extinguisher in which an improved pair of arc-guide non-gas-evolving wa-ll members are utilized.

A further object of my invention is to provide an improved circuit interrupter in which the active length of the spaced metallic plates may be increased, yetA the length of the interrupter is reduced. This is of particular advantage since one form of circuit interrupter utilizing my invention may be used in the walls of houses in which the studding width is standard. Thus there is no advantage to reducing the height of the interrupter, but there is a distinct advantage in reducing the length thereof. This is obvious since the overall vertical mounting space is thus reduced.

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

Figure l is a vertical sectional view taken through a circuit interrupter embodying my invention and shown in the closed-circuit position;

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

Fig. 3 is a side elevational view of one of the shield plates utilized in the construction depicted in Fi-g. l;

Fig. 4 is a side elevational view of one of the metallic plates utilized in my improved arc-extinguisher;

to the outer end thereof and of the handle 18 to the ofi ICC Fig. 5 is a vertical sectional view taken through a modied type of circuit interrupter embodying my invention, the contact structure being shown in the closed-circuit position;

Fig. 6 is a section-al View taken along the line VI-VI of Fig. 5 looking in the direction of the arrows;

Fig. 7 is a top plan view of one of the insulating shield plates utilized in the arc-extinguisher of Figs. 5 and 6; and

Fig. 8 is a plan View of one of the magnetic plates utilized in the arc-extinguisher of Figs. 5 and 6.

Referring to the drawings, and more particularly to Fig. 1 thereof, the circuit interrupter 1 comprises generally a base 2 and a cover 3 of molded insulating material, end terminals 4, 5, a stationary contact 6, a movable contact 7, and operating mechanism, generally designated by the reference character 8. A current-responsive trip device 9 is also included, as is also an arc-extinguisher 10, the latter being provided to interrupt the arc drawn upon separation of the contacts 6 and 7.

The movable contact 7 is secured to a resilient contact arm 13, which, in turn, is secured by suitable means to a channel-shaped frame 14, pivotally supported by means of a pivot pin 15 on a U-shaped main frame 16.

The operating mechanism 8 comprises a U-shaped operating lever 17 having an operating handle 18 secured projecting through an opening 19 in the cover 3. The mechanism 8 also includes a cradle 21, a toggle comprising a pair of toggle links 22, 23 and a pair of overcenter springs 24 (only one of which is shown). The operating lever 17 is pivotally mounted on pivot pins 25 supported in the sides of the frame 16, and the cradle 21 is pivoted on a pin 26 also supported in the frame 16. One end of the toggle link is pivotally connected to the cradle 21 by a pin 27, and the toggle link 23 is pivotally connected to the f-ree end of the channelshaped member 14 by means of a pin 28. The toggle links 22, 23 are pivotally connected together by a knee pivot pin 29. The overcenter springs 24 are tensioned between the knee pin 29 of the toggle 22-23 and the outer end of the operating lever 1'7. The cradle 21 is provided with a a bimetallic strip 31 adapted to releasably restrain the cradle 21 in the position shown. The operating member 17 is provided with an extension 32 which is adapted to cooperate with the cradle 21 in order to relatch the cradle 21 by manual movement position after the breaker has been tripped open.

Under fault current conditions the bimetallic strip 31 will bend toward the left, as viewed in Fig. 1, to release the cradle 21. The cradle 21 will then be rotated in a clockwise direction by the overcenter springs 24. During this rotation the line of action of the springs 24 changes to cause collapse of the toggle 22, 23 and opening of the contacts 6, 7.

Before the contacts may be closed, it is necessary to relatch the cradle 21 with the latch member 31. This is effected by moving the operating handle 18 in a counterclockwise direction, during which movement the eX- tension 32 of the operating lever 17 engages and rotates the cradle 21 in the same direction to re-engage bimetallic strip or latch 31. The contacts 6, 7 can now be closed by moving the handle 18 and the operating lever 17 to the extreme right-hand position. This movement changes the line of action of the overcenter springs 24 so as to straighten the toggle 22, 23 and thus effect closing of the contacts 6, 7.

The breaker may be opened manually by moving the handle 18 toward the left. During this movement the line of action of the overcenter springs 24 is moved to the left of the pivot pin 27, causing the springs to exert a force on the knee of the toggle 22-23 in a direction to cause collapse of the toggle, which results in movement of the movable contact 7 to the open position. The contacts 6, 7 are closed in the previously described manner.

My invention'is particularly concerned with the arcextinguisher 1t), which is utilized to interrupt the arc drawn between the contacts 6, '7 during the opening operation of the interrupter. The extinguisher lrcomprises a plurality of spaced non-magnetic metallic plates 33, the conguration of which is more clearly shown in Fig. 4 of the drawings.

With reference to this `ligure it will be observed that each non-magnetic plate 33 has aslot 34 formed therein and a pair'of leg portions 35. A pair of shield Vplates 37, preferably formed of liber or other gaslevolving material are disposed on opposite sides of the 'plates 33. In certain instances it may, however, be desirable to form the shield plates 37 -of a suitable non-gas-evolving insulating material, such as asbestos.

Associated with the stationary'contact 6 is an arichorn or arc-'runner 44, with which the end metallicplate 33A makes contact, as shown in Fig. 1. Essentially therefore the end plate 33A forms an extension or right angle bend `of the arc-'runner 44, so that when the movable contact has moved to the open position, as indicated by the `dotted-lines 45, the established arc 46 will rapidly move successively through the positions 47, 4S to the position 49, in which it cis substantially parallel to the longitudinal V`axis of the base 2. The arc 49 moves into the apex 41 of each plate 33 and hence onto the plates 33 where the arc 49 is subdivided into a plurality Vof serially-related arc-portions, designated bythe reference character v51 in Fig. 1. i

To assist in the upward travel of the arc 46, I preferably provide a blowout coil 53, which is serially connected in the circuit as shown in Fig. l. The blowout coil 53 has one end 54 connected with the terminal '5 and has the other end 55 connected with the stationary contact 6, as 'shown in Fig. l. Consequently, in the closed-circuit position of the interrupter, as indicated in Fig. l, the electrical circuit passes from the left-hand terminal 4 through the strip 56, through the bimetallic strip `31 and through the exible connector 57 to the movable contact 7. The circuit extends from the stationary contact 6 throughthe connection 55 and through the blowout coil 53, by way 'of the connection 54, to Tthe right-hand terminal of the interrupter. It will, therefore, be understood that the blowout coil 53, being in series circuit at all times, will constantly be energized and will Yset `up va magnetic tluX through the core 58, spaced by an insulating tube 59 from the blowout coil 53, and through a pair of magnetic pole plates 60 disposed on opposite sides of the extinguisher 10. v

Supporting the spaced metallic plates 33 in a fixed spaced relation are a pair of slotted insulating support plates 61, more clearly shown in Figs. 2 and 3 of the drawings. With Vreference vto Fig. 3 it will be notedv that each insulating support plate 61 has a plurality of slots 62, into which tit the plates 33, the olfset or shoulder portions 63 of the plates 33 coming to rest at the bottoms of the slots '62 of the plates 61. Thus'I have constructed an arc-chute employing slotted metallic plates 33, and have 'included the added feature of connnilg the arc 47-49 into as narrow a slot 64 as desire It is a well-known fact that either'of the above means is employed singly in circuit breakers. Both of these means of extinguishing an arc, however, have not been successfully combined heretofore. This is due to the fact that a narrow slot 64 has generally been thought to require that the metallic plate also be narrow to tit into l the slot. The result has been that not enough metal is present to dissipate vthe heat generated by the arc, and, therefore, in the 'past the'plates have been destroyflt In my improved arc-extinguisher 10, means are provided by which 'the arc can be confined into a narrow slot while at the same time a wide metal plate 33 may be used.

The slotted supporting plate 61 is preferably formed of an insulating material such as asbestos board or porcelain and having the slots 62 as shown. When two of these plates are placed side by side the adjacent slots 62 form a means by which the metal plates 33 may be inserted at the back so that a 'stack of plates 33 is 'formed to subdivide the Yestablished arc. The plates 33 .are supported in the substantially parallel slots '62, as shown in Fig. 1 -of the drawings. As indicated in Fig. 4, the plates 33 'have the usual slots 34 and function in the customary manner of Vsubdividing the initially established arc. The subdividing function of the plates 33 is not impaired at all by the above method of supporting them.

The breaker contacts 6, 7 are located between the lower ends of the two Aceramic plates 61 so that vthe initially established arc 46 will be drawn into the slot 64 between the two ceramic plates V61. The arc, a ulater position Aof which is indicated by the reference numeral 49, can, therefore, be confined and deionized in a slot 64 having "the width of the distance between the support plates 61.

It will be observed that each plate 33 has an area greater than the area of the slot 64 and, although the arc 49 'cornes in direct contact with 'the plates 33 only at 'the area 6'4, yet the heat therefrom will be dispersed immediately over the total plate area including not only that between plates V61, but also the areas 65, 66 outside of the support plates 61. The arrangement, therefore,

will squeeze 'the arc '49 within area 64, but still will permit the'use of a wide plate 33 for good heat dissipation.

It will be observed that the magnetic flux passing between l'the 'pole "plates 60, as indicated bythe arrows V63 in Fig. 2, will assistin upward movement of the arc 49.'

An insulating lplate 69 protects the blowout coil l53 from thearc '46, `and the shield plates 37 protect the pole plates from the arcs Y51 near the top of the extinguisher10.

From the foregoing description it will be apparent that I have changedthe location or disposition of the spaced metallic plates 'inthe circuit breaker, with respect lto the constructionwhich/has previously been used in this type of breaker.` As well known by those skilled in the art, previously'the metallic plates were disposed substantially horizontally, or parallel to the longitudinal Yaxis of the base 2. VIn'the construction disclosed herein the plates not only may be longer than these heretofore used Vbecause Yof A their 'particular location, but also lthe terminal structu'reS does 'not impair venting as was the case in the prior art interrupters of thistype. Moreover, the circuit interrupter `as `a whole is Vshorter in a lengthwise direction since no space needbe provided for the plates 33 between the terminal structure 5 and the contacts 6, 7 as was the case heretofore.

In addition, when the breaker is constructed as above, 'the vent 72 in the cover 3, which may be provided wtih a'suitable cooling screen 73, is disposed Moreover, an exgases between the rnet'al plates 33. This expansion space 74 is, of course, readily vented by the immediately adjacently disposed screened vent 72. I

The above construction rapidly moves the arc 46 away from both contacts 6, 7 immediately after opening of said contacts and keeps the arc moving and stretching in a manner which lis not possible with conventional breakers of -vthis type,

arc gases is -at a point sufliciently far away from the con-v The'iinal location of the Aarcs 51 and the tets 6, 7 to prevent contamination of the Contact area by these gases. Since the plates 33 may be longer than in conventional nterrupters of this type, the plates will correspondingly have more area with the result that cooling action is increased, and also the arcs 51 can be kept in motion longer than is possible in a shorter conventional circuit interrupter. In addition, the V-shaped slot can be made longer and shallower so that the splitting up of the arc 49 is facilitated. Especially important is the fact that with this arc chute 16 it is open at the top leading into the expansion chamber 74, so that the arc motion will be positive and unobstructed.

' The general manner of operation will be obvious from the foregoing description. Briefly, in recapitulation, the separation of the contacts 6, 7 will cause the initially established arc 46 to expand upwardly and outwardly to the successive positions 47 and 48, the lower terminal thereof, running rapidly outwardly along the arc runner 44, shielded from the blowout coil 53 by the insulating plate 69. The arc nally assumes a configuration substantially parallel to the longitudinal axis of the base 2, Wherein it is substantially horizontal assuming the interrupter to be maintained in the position shown in Fig. 1.

The magnetic eld between the pole plates 60, as indicated by the arrows 68 in Fig. 2, moves the arc between the closely-spaced insulating supports 61 and through the apices of the plates 33 and thereonto. Not only are the terminals ends of the arc portions 51 cooled by the plate structure itself, but also the intervening arc portions 51 are cooled by the immediately adjacently disposed insulating support plates 61, because of the restricted space 64 therebetween. The arcs continue to move upwardly until they are cooled and extinguished.

Preferably the non-magnetic plates 33 are formed of a nickel-chromium alloy, as set out and claimed in my co-pending application led February 16, 1950, Serial No. 144,461, now Patent No. 2,687,462, issued August 24, 1954, and assigned to the assignee of the instant applica- Ition. The support plates 61 and the side shield plates 37 may either be formed of a non-gas-evolving insulating :material such as asbestos, or of a suitable gas-evolving ma-terial, such as fiber or boric acid depending upon the current and voltage interrupting requirements, as well `known by those skilled in the art.

In the embodiment of my invention disclosed in Figs. .'5-8 the operating mechanism 8 and the trip device 9 are .the same as heretofore disclosed in connection with the interrupter of Figs. 1-4, and, consequently, they will not be further discussed. In this embodiment of my invention, the blowout coil 58 heretofore described in connection with Fig. l is omitted, and the metallic plates 7S are formed of a suitable magnetic material, such as iron or the like. The modified type of arc-extinguisher 76 may be used with ceramic supports 77, the configuration of which is more apparent from an inspection of Figs. 6 and 7. These supports 77 serve two purposes. One purpose is to support the plates 75 and the other purpose is to serve as arc shields. Referring to Fig. 7 it will be noted that the ceramic support plates 77 are provided with full grooves or slots 79 on one side and short grooves 80 on the other. This results in the provision of a plurality of pairs of spacing members 90 (Fig. 7) integrally formed with the supports 77. Thus a spacing member 90 of one support 77 cooperates with a spacing member 90 of the other support 77 to constitute a pair of spacing members. The plates 75 are provided with legs 81, the inner sides 82 of which tit into the outer slots 79 of the cooperating support plates 77, as more clearly shown in Fig. 6 of the drawings. It will be noted that the central portion 83 of the plates 75 extend downwardly to form an apex 41. The plates 75 are slipped into the grooves 79, 80 from the back, and following assembly bolts 84 are provided to hold the plates 75 and the two support plates 77 together, as shown more clearly in Fig. 6.

. This type of construction may also be used for interrupting large amperage currents since it will be noted that a considerable portion of the legs 81 of the plate 75 is external to the support plates 77 and hence is available for transmission and dissipation of heat to the ambient space during arc interruption. The design permits very elective cooling and exhaustion of the hot gases to the outer end of the extinguisher 76. At the same time the arc 49 can be drawn between non-gas-forming cool ceramic walls. The walls of the spaced supports 77 are tapered to form a tapered entrance portion or entering arc passage S5 with a small throat for apices 41 in thev metal plates 75.

This groove 85 forces the arc 49 to reduce in crosssection as the magnetic field forces it back into the throat 41, thereby increasing the arc resistance and the rate of arc cooling. This squeezing of the arc 49 makes its path outside the plates 75 unstable; therefore, the arc 49 readily splits up and enters the plates 75 as the arc portions 51. This action takes place in conventional spaced slotted metallic plate structures where no shields 77 are used, but the trouble has been that the arc 49 may resist being squeezed into the throat 41 and may hang on to the legs of such slotted plates of prior art arc chutes.

The magnetic field is set up as indicated by the arrows 86 of Fig. 8 and acts on the arc 49 as in ordinary are chutes. However, with my improved construction involving the wide plates 75, the plates will not heat up as much as in prior art arc chutes because the wide plate area can absorb the heat without overheating too much.

Referring to Fig. 8, it will be observed that there are provided locks or tabs 36 to secure the outer sides of the plates 75 to a pair of insulating side plates 87. Also each metallic plate 75 is provided with an aperture 39, which align in the assembled state, as viewed in Figs. 5 and 6, to support a gas-evolving rod 40, which passes substantially through the geometric centers of the plates 75. In addition, disposed between aperture 39 and the apex 41 of each plate 75 is a smaller aperture 42, the function of which will be more apparent hereinafter.

When an arc moves to the apices 41 of the plates 75 and enters the solid parts of the plates 75, it will move back to the geometric center of the solid section of the plates 75 and then settle there because the magnetic forces acting on the arc are at equilibrium at that point. Unless the arc 51 goes out very quickly, therefore, the plates will be burned at that point.

It is an additional purpose of my invention, in the construction shown in Figs. 5 and 6, to provide a means of keeping the arcs 51 in motion until they are extinguished by the plates 75 so that no hot spots occur in the plates 75.

As previously mentioned in connection with Fig. 8, each metallic plate 75 has two holes 39, 42 provided in them in line with the normal travel of the arcs 51. The small hole 42 is left open, but the large hole has a fiber rod 40 extending through the plates 75 so that it forms a solid iber column in the direct path of the arc. As the arc 51 moves upwardly away from the apex 41 of the plate 75 it tirst meets the small hole 42 in its direct path. This hole 42 then deflects the arc 51 to the left or right, as viewed in Fig. 6, so that the arc 51 strikes the fiber rod 40 sideways as indicated by the arrow 71. The heat from the arc 51 will now generate a small amount of iber gas from the rod 40 and this gas will shoot out through the arc body 51 and therefore cause the arc to move slantwise away from the fiber column 40. When the arc has moved out of the vicinity of the liber, no more gas will be generated and therefore the arc 51 will come to rest. At this point, the arc 51 is not at the geometric centers of the plates any more; therefore, the inherent magnetic forces will come into play and force the arc 51 towards the liber column 4i) again. This action can repeat indefinitely until the arc is extinguished.

. It can be seen, therefore, that in this way the arc 51 can be kept constantly in motion all the time of its duration, thereby preventing overheating of the plates 75 in spots with its resultant deleterious eiects. on. are extinctionand dat'rage to` the plates..

The manner of are extinction is generally similar to that heretofore described in connection with Figs. l` and 2. The arc 49 is moved rapidly upwardly by the distorted magnetic iield thereabout as caused by the presence of the several spaced magnetic plates 7S. It moves quickly upwardly or outwardly between the inner walls of the non-gas-evolving support plates 77 until it reaches the apices 4l, where it enters the plates 75 as subdivided arcs 51. The arcs 51 are deilected by the holes 42 into angular contact with the gas-evolving liber rod 4d, the latter being disposed substantially at the geometric centers of the plates '75; The arcs 51 will constantly move or vibrate between the rod 4@ and the immediately adjacent-ly disposed areas of the plates 75 by two con iicting forces. One force, of course, will be the forcey exerted by the gas evolved atth'e rod 40 by the heat of the arcs 51; The other opposing force will be the inherent magnetic tendency for the arcs 51 to become stabilized at the geometric centers of the plates 75. The net result is rapid movement of the arcs 51 to decrease any localized heating of the plates 75 to rapidly bring about arc extinction.

While this process is going on there occurs a rapid flow of gas outwardly between the plates 75 into the expansion space 74. Arc extinction soon results.

From the foregoing description of two different ernbodirnents of my invention, it will be apparent that I have shortened the length of the breakers l, 89 by placing the plates 33, 75 substantially perpendicularly to the base 2. and by swinging the initially established arc 46 around from an initial position substantially perpendicular to the base 2 to an ultimate position where it is substantially parallel to the base 2. The plates 33, 75 may be longer than in conventional structures even though the interrupter l, 89 is shorter, considered as a whole. Rapid gas ow occurs through the spaced plate structure and into the expansion space '74, where it is rapidly vented out of the breaker through the vent 72 and at a location away from the terminal structure 5.

Although I have shown and described speciiic structures, it is to be clearly 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:

l..l A circuit interrupter including a base, contact means for establishing an ,arc initially substantially perpendicularly to the base, means for subsequently swinging the arc around in a plane substantially perpendicular to the base so that the arc is substantially parallel to the base, a plurality of spaced metallic plates disposed substantially .perpendicularly to said base, and means including saidspaced metallicl plates for extinguishing the arc.V

2. A circuit breaker including an insulating base, a stationary contact mounted on said base, a movable contact separable away from the stationary contact to establish an :arc initially substantially perpendicularly to the base, means including an arc runner for subsequently swinging the arc around in a plane substantially perpendicular to the base to a position that is substantially parallel to the base, a plurality of spaced metallic plates disposed substantially perpendicularly to the base, and the arc moving onto the metallic plates to be subdivided thereby to effect the extinction thereof.

3. A circuit interrupter including enclosing means, a base and a cover defining said enclosing means, the cover having a vent opening, contact means disposed interiorly of the enclosing means and separable to establish an arc initially substantially perpendicularly to the base, means for swinging said arc -around in a plane substantially perpendicular to said base so that it is substantially parallel to the base, and a plurality of spaced metallic plates disposed substantially perpendicularly to the base for extin'guishing the arc;

4. circuit interrupter including means for establishing an arc, means including a plurality of spaced magneticl conducting plates to extinguish said arc, the arc being subdividedbly the conducting plates into a plurality of serially related a'rc portions, each of a plurality of said plates having. a relatively small opening therethrough adjacent the geometric center of the plate, and gas-evolving means extending through a plurality of such openings to assist in extinction of the arc.

5. A circuit interrupter including means for establishing -an arc, means including a plurality of spaced magnetic plates to extinguish said arc, each of a plurality of said plates having'. an opening therethrough adjacent the geometric. center of the plate, and a gas-evolving rod extending through a plurality lof such openings to assist in extinction' of. the arc'.

6. A circuit interrupter including. separable contact means for establishing an arc, a pluralityV of spaced, slotted, magnetic conducting plates for subdvidingl the established arc, each such plate having an arc receiving edge, a pair of cooperating, insulating, tapered, arcguiding shield support members, said shield support members having slots therein for supporting said magnetic plates in spaced relation, the pair of tapered shield support members forming a tapered entrance portion for progressively constricting the arc and forcing it to enter through the slots of the plates and onto the plates to be subdivided thereby, and the leg portions of the slotted plates being disposed exteriorly of the shield support members for cooling to the ambient space.

7. A circuit interrupter including separable contact means for establishing an arc, a plurality of spaced, slotted, magnetic conducting plates for subdividing the established arc,l each such plate having an edge for split.- ting up the arc, a pair of cooperating, insulating, tapered, arc-guiding shield support members, said shield support members having slots therein for supporting said magnetic plates in spaced relation, the pair of tapered shield support members forming a tapered entrance portion for progressively constricting the arc and forcing it to enter onto the plates, the shield support members extending an appreciable distance in substantially parallel spaced relation in the direction ofarc movement beyond said plate edges, and the leg portions of the slotted plates being disposed exteriorly of the shield support members for cooling to the ambient space.

8. A circuit interrupter including means for establishing an arc, spaced conducting magnetic plates for extinguishing the arc and between which the Iarc may be subdivided, a plurality of pairs of insulating spacing members for spacing the plates apart, the pairs of spacing members defining arcing spaces confining the movement of the arc onto the plates, and at least some of the magnetic plates having heat-dissipating portions outside of the arcing spaces and exteriorly -of the spacing members to take advantage of the cooling eiiect of the ambient space.

9. A circuit interrupter including means for establishing an arc, spaced U-shaped conducting magnetic plates for extinguishing the arc and between which the arc may be subdivided, a plurality of pairs of insulating spacing members for spacing the plates apart, the pairs of spacing members defining arcing spaces confining the movement of the arc onto the plates, and at least some of the magnetic plates having heat-dissipating portions outside of the arcing spaces and exteriorly of the spacing members to take advantage of the cooling eiiect of the ambient space.

l0. A circuit interrupter including means for establishing an arc, spaced U-shaped magnetic conducting plates for extinguishing the arc, a pair of spaced supports deiining a tapered entrance portion for the arc Iand having associated therewith a plurality of pairs of insulating spacing members for spacing the plates apart, the pairs of spacing members defining -arcing spaces confining the movement of the arc onto the plates, and at least some of the magnetic plates having heat-dissipating portions outside of the arcing spaces and exteriorly of the supports to take advantage of the cooling effect of the ambient space.

11. A circuit interrupter including a housing having a base portion, the housing having an opening opposite the base portion, an operating mechanism, a handle for actuating the operating mechanism projec 'ng through said opening in the housing, a relatively stationary contact mounted on the base portion and having an arc horn which initially extends substantially parallel to the base portion and then makes substantially a right angle bend toward the side of the housing through which the handle projects, a movable Contact cooperable with the relatively stationary contact to establish an arc, and one terminal `of the arc moving out along the arc horn to a position so that the larc is substantially parallel to the base portion.

12. A circuit interrupter including a housing having a base, the housing having an opening, an operating mechanism, a handle for actuating the operating mechanism projecting through said opening in the housing, a relatively stationary contact mounted on the base and having an arc horn which initially extends substantially parallel to the base portion and then makes substantially a right angle bend toward the side of the housing through which the handle projects, a movable contact cooperable with the relatively stationary contact to establish an arc, a plurality of spaced plates disposed substantially perpendicularly to the base for extinguishing the arc, and one terminal of the arc moving out along the -arc horn to a position so that the arc is substantially parallel to the base.

13. The combination in a circuit interrupter of a base, a cover for the base having an opening, an operating mechanism, a handle for actuating the operating mechanism projecting through the opening, contact means including a relatively stationary contact and a movable contact for establishing an arc, the relatively stationary contact having an arc runner which initi-ally extends substantially parallel to the base portion and then makes a right angle bend toward the cover, the contact means establishing yan arc, one terminal of which runs along the arc runner to a position so that the arc is substantially parallel to the base, and means for extinguishing arc.

14. The combination in a circuit interrupter of a base, Ia cover for the base having an opening, an operating mechanism, a handle for actuating the operating mechanism projecting through the opening, contact means inc nding a relatively stationary contact and a movable contact for establishing an arc, the relatively stationary contact having an arc runner which initially extends substantially parallel to the base portion and then makes a right angle bend toward the cover, the contact means establishing an arc, one terminal of which runs along the arc runner to a position so that the arc is substantially parallel to the base, and means for extinguishing the arc including a plurality of spaced plates disposed substantially perpendicularly to the base.

References Cited in the ile of this patent UNITED STATES PATENTS 1,868,442 Corbett July 19, 1932 2,065,357 Von Hoorn Dec. 22, 1936 2,116,791 Jackson May 10, 1938 2,174,232 Baker Sept. 26, 1939 2,240,623 Lindstrom May 6, 1941 2,564,178 Strobel Aug. 14, 1951 2,575,730 Sandin et al. Nov. 20, 1951 2,633,518 Miller Mar. 31, 1953

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