US2442477A

US2442477A - Circuit interrupter

Info

Publication number: US2442477A
Application number: US562798A
Authority: US
Inventors: James M Wallace; Herbert L Rawlins; James M Cumming; Wayne S Aspey
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1941-06-24
Filing date: 1944-11-10
Publication date: 1948-06-01
Anticipated expiration: 1965-06-01

Description

June l, 1948. J. M. WALLACE Er A1. 2,442,477

CIRCUIT INTERRUPTER Original Filed June 24, 1941 2z Q a! 26 ATTORNEY Patented June 1, 1948 clacurr m'rERRUr'rEn James M. Wallace, Braddock, Herbert L. Rawlins, Pittsburgh, and James M. Cumming and Wayne S. Aspey, Turtle Creek, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Original application June 24, 1941, Serial No.

399,452. Divided and this application November 10, 1944, Serial No. 562,798

12 Claims. 1

This invention relates to electric circuit interrupters in general, and more particularly to automatic reclosing circuit breakers.

This invention is a division of the subject matter of our copending application on Circuit, interrupters, Serial No. 399,452, filed June 24, 1941 and assigned to the same assignee of this inven'- tion.

`Automatic reclosing circuit breakers of the type with which this invention is primarily concerned, generally include separable contacts which are biased closed, and are adapted to be separated in a closed arc chamber by electro-responsive means having lost motion therewith, to permit overtravel of the contacts dependent upon the pressure developed by the arc. may be provided for automatically retaining the breaker contacts separated in response to a predetermined number of closely successive circuit interrupting operations, after which the contacts must be manually reclosed.

One object of this invention is to provide, in a circuit breaker of the type described which employs a liquid arc extinguishing medium and a means utilizing said liquid for controlling the rate of Contact movement, novel means controlling the supply of fresh liquid to the arcing zone to replenish liquid in the' arcing zone between successive circuit interrupting operations.

Another object of this invention is to provide, in a. circuit breaker having separable contacts adapted to strike an arc in aclosed, liquid-filled, arc extinguishing chamber, novel means for replenishing the liquid between successive circuit interrupting operations. i

Another object of this invention is to provide, in an automatic reclosing circuit breaker, novel means for delaying closing movement of the breaker contacts.

More specifically, it is an object of this invention to provide, in an automatic reclosing circuit breaker, novel means for maintaining the-contacts separated following a circuit interrupting operation, in combination with" time delay means for finally releasing said contacts to close the circuit.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of a preferred embodiment thereof, when taken in connection with the attached drawing, in which:

Figure 1 is a substantially central vertical section through a circuit breaker embodying this invention with certain parts thereof shown in elevation;

In addition, meansl Fig. 2 is a partial elevational view of the operating mechanism shown in Fig. 1;

Fig. 3 is a transverse sectional view of the breaker shown in Fig, l taken substantially on the line III-III thereof with certain parts omitted.

Fig. 4 is a fragmentary sectional view of the A lockout integrating mechanism employed in the breaker shown in Fig. 1;

Fig. 5 is a view like Fig. 4 but showing the parts of the mechanism in a different position from that shown in Fig. 4; and

Fig. 6 is also a partial sectional view illustrating the mechanism of Figs. 4 and 5 in a still different position of the parts thereof.

The circuit breaker constituting this invention is shown by way of example as being mounted in a tubular insulating casing 2 which may be of any desired insulating material, preferably porcelain or the like. The casing 2 is provided with a closed bottom and an open top, with the top being closed by a cover assembly 4, and the bottom of the casing having associated therewith a terminal assembly B. Intermediate the ends of the casing 2 there is provided a cylindrical `surface 8, and a supporting bracket I2 is adapted to be clamped around this cylindrical surface with resilient material I0 interposed between the clamp I2 and the outer casing wall to prevent damage thereto.

The terminal assembly 6 at the bottom of the casing includes a terminal bolt I4 of conducting material adapted to extend through a substantially central aperture in the bottom casing wall, and the bolt is provided with an enlarged head I8 interiorly of the casing, with packing material 20 interposed between the head I8 and the bottom wall of the casing. A nut 22 and washel 24 cooperate with bolt I4 to retain the same in position, and a conductor 28 may be secured to the bolt, for example, as by a second nut 26. Bolt I4 is preferably provided with a substantially central bore 30 for the purpose of draining casing 2, the lower end thereof being adapted to be closed by a screw-threaded closure plug 32.A

The upper end of casing 2 is ribbed, and a supporting flanged ring 34 is adapted to be secured to this ribbed portion of the casing, for example, as by cast metal, or the like, 36. Supporting ring 34 is adapted to have cover assembly 4 secured thereto in any desired manner, not shown.

The casing and terminal structure B described above are substantially identica1 with those more particularly described and claimed in the copending application of J. M. Wallace and H. L.

'sulating i spacer sleeves 64.

. A 3 Rawlins, Serial No. 374,688, tiled January 16, 1941, and in their Patent No. 2,318,421, issued May 4, 1943, both oi which are assigned to the same assignee as this application.

Cover assembly 4 comprises an integral casting having a ange'lj .formed integrally with the lower end thereof and adapted to seat on the upper end wallof casing 2 and extend over the interior of the casing. Flange Il is also provided with integral outwardly extending ears (not shown) adapted to be bolted to ears formed on supporting ring 64. The cover assembly casting is provided with a hollow portion including the top wall 40, side walls 42, Il and

end walls

44 and 45, with 'the bottomoi the hollow portion being open and located over the open top of casing 2. At one upper corner oi the hollow portion oi cover assembly 4, an inclined wall -is provided with a threaded aperture for cooperation with, a threaded ller plug 46, by means ot which casing 2 may be filled with an arc extinguishing fluid. Top wall 40 of the hollow portion oi the cover assembly is extended beyond the hollow portion and slightly inclined downwardly as at 48 to form the top wall of a sleet hood portion having side walls 52 and 63. The top wall 4I of the hood portion terminates in an angularly downwardly extending lip 50, for a purpose to be hereinafter described. e

As appears from Figs. 1 and 3 of the drawing, flange 38 of the cover assembly l has portions which extend over the open top of casing 2, and these portions are adapted to insulatingly support the circuit breaker contacts and operating mechanism, for example, as by the tubular in- The spacer sleeves 54 have the opposite ends thereof threaded for cooperation with screws 56 and 56, to secure the spacers to ange 38 and the. upper leg |06 of a U-shaped supporting frame 60, respectively. '.l'he other leg |08 of U-shaped frame l0 is secured to one end of a generally rectangular frame 6I. and the other end of this frame is preferably kformed integral with the top cap 66 of an interrupter chamber 68.

The interrupter chamber 68 includes an insulating tube of liber or the like, having one end threaded into top cap 66, and having the other end threadedly received in a bottom terminal cap .14. Top cap 66 is provided with a substantially central aperture 69 for closely slidably receiving a contact piston rod 12, and the cap is also provided with' spaced outlet apertures 13 adapted to be controlled by a sliding valve plate |02, normally biased by a coil compression spring |04 into engagement with the adjacent end oi.' insulating tube 10. 'I he lower end cap 14 of the interrupter chamber is provided with inlet passages 16, and with a substantially centrally located threaded aperture for receiving the threaded end of an adjustable ilxed contact 18 which is secured in position, for example, as by a loci: nut 80. The outer end of end cap 14 yis reduced in size to form a shoulder 62 4on which is seated one end of a coil compression spring 84, with the other end of this spring bearing against the head I8 of terminal bolt Il. Spring Il should be of some good resilient conducting material. such, for example. as a copper alloy or the like.

The lower end of contact piston rod 12 is provided with a socket for receiving the upper end or contact rod 86, secured in the socket, for ex ample, as by a rivet 08. The lower end ot contact rod 86 is enlarged to form a contact head a central aperture 6| so that the piston may be slidably mounted on contact rod Il for movement between contact head l0 and the lower end of contact piston rod 12. The lower end of contact piston rod 12 is counterbored to receive a coll compression spring 03 which normally operates to bias liquid directing piston 92 towards contact head 90, As shown, piston 62 is provided centrally with a hollow portion to which access is obtained by means oi' a plurality oi top apertures 04, and a single lower aperture 05 concentric with contact head 00 so as to form an annular liquid passage therewith. Liquid director piston I2 may have a. peripheral slot for the reception of a piston ring 96 to kprevent leakage of liquid between the piston and inner wall of tube 10. A stop ring 08 is secured in position between the lower end oi insulating tube 10 and lower end cap 14 and, as shown, projects inwardly so as to form a stop for liquid director piston 02, so that when the contacts are closed, the piston is maintained in a position intermediate the limits of its movement on contact rod 86. The inlet apertures 'I6 in cap 14 are adapted to be controlled by a check valve plate |00 freely mounted between the end wall of end cap 14 and stop ring 98. The interrupter chamber described above is substantially identical with that described and claimed in the above-mentioned copending application of J. M. Wallace and H. L. Rawlins, Serial No. 374,686, except that in the interrupter chamber herein described, valve plate |02 is spring biased in one direction, rather than being frictionally associated with' contact piston rod 12 as in the said copending application.

The operation of the interrupter chamber herein disclosed and illustrated is subtantially the same as that in the above-identified copending application and comprises, briefly, utilization of iluid pressures generated by an arc drawn, to obtain contact separation. This is accomplished by the instant structure, because it will be observed that as soon as contact piston rod 12 isv moved upwardly and contact head 90 moves out of engagement with ixed contact 10 to strike an arc, the action of such an arc on the arc extinguishing liquid within the chamber, such, for example, as oil or the like, will decompose the same to generate a gas which will build up a pressure within chamber 68. As soon as this pressure builds up, it will obviously force check valve plate |00 and valve plate |02 outwardly relative to insulating tube 10 to close both the inlet and outlet apertures 16 and 13, respectively. Outward movement of valve plate |02 readily I occurs because the upper side of this plate is vented by aperture |03. Accordingly, such pressures within the chamber will act on contact piston rod 12 in a piston-like manner to force the same to move outwardly of the chamber, and thereby increase the contact separation. In the upward movement of contact rod '86, liquid director piston 92 remains stationary until contact head engages the upper wall of the director to thereby draw the arc out to an optimum length before moving the director to cause a iiow ot liquid through

apertures

94 and 96 and into the arc to extinguish the same. Contact piston rod 12 and contact rod 86 will be moved outwardly by the pressure developed within arc chamber 68 until the combined action of attenuation of the arc and dow of liquid therethrough cause extinction. As soon as the arc is extinguished. the contact piston rod 12 is adapted to be moved downwardly towards iixed contact 16 in a manner to be hereinafter further described. and since pressure is no longer being generated within the chamber, spring |04 will be free to move valve plate |02 downwardly to open outlet passages 18 and permit exhaust of gasesv and used liquid out of the upper end of the arc chamber. This up-flow of gas and used liquid from the chamber will be taken care of by an ini'iow of fresh liquid through inlet apertures 18, which will cause check valve plate to be unseated due to the pressure at the bottom of the casing because of the head'of liquid therein, and yespecially because of the difference in pressure due to the diilerence in the head of liquid between inlet apertures 18 and outlet apertures 18. Consequently, it can be seen that the fluid pressure developed by the arc is utilized in this interrupter to-obtain contact separation, and that during a closing operation of the breaker contacts, the used arc extinguishing uid within the chamber is replaced by fresh fluid from casing 2.

As previously stated, the substantially U- shaped supporting frame member 80 is secured to the upper end of rectangular supporting frame 84, and the frame member 60 is for thepurpose of supporting a solenoid coil ||2. The upper and lower legs |06 and |08 of supporting member 80 are connected by spaced integral legs ||0vposi tioned at one side thereof, so that the solenoid coil ||2 may be assembled with support 60 by merely slipping the entire coil between legs |08 and |08 through the open side of support 60. The legs |05 and |08 of the U-shaped frame 60 are provided with aligned apertures adapted to coincide with the central bore' provided in solenoid coil H2, and a securing sleeve I4, of insulating material, is adapted to be inserted through the aperture in leg |08 of the U-.shaped support 80 into engagement with a shouldered plug IIS seated against a shoulder provided about the aperture through leg |06 of U-shaped supporting frame 80. Securing sleeve ||4 is maintained against movement downwardly from the supporting frame 80, as viewed in Fig. 1, by the connection of rectangular frame 64 thereto, inasmuch as the end plate ||8 of this frame is provided with a shouldered aperture, with the adiacent end of securing sleeve ||4 seated on the shoulder of this aperture to prevent movement thereof with respect to U-shaped frame 60. Frame 80 is of magnetic material to form a stationary frame for coil ||2 as well as a support therefor. Rectangular frame 84 is secured to the lower leg |08 of U-shaped frame 60. for example, as by screws 62, or the like. It will be noted that solenoid coil ||2 is provided with a. plurality of taps ||8 which are connected to different sections of the coil, and located away from the connecting legs ||0 of the U-shaped support 60, at the open side thereof so as to be readily accessible for the purpose of changing the coil connections when desired. Rectangular supporting frame 84 is provided with the side plates integral with top plate |,|8 at one end thereof, and with top cap 88 for the interrupter chamber at the other end thereof.

The upper end of contact piston rod 12 is peripherally grooved as at |22 to f-orm a notch and a latch projection |24 at the upper end thereof, for cooperation with a latch lever |28. The latch lever is adapted to 'be pivotally mounted on top end cap 88 of the interrupter chamber,

|28, respectively, for biasing the latch lever in a clockwise direction about its pivot, as viewed in Fig. 1. 'I'he latch lever is provided with a plurality oi' latch lugs |82 and |84 for cooperation with the latch projection |24 on the upper end of contact piston rod 12, and with the core of solenoid coil |i2. A contact operating rod |88 is rigidly secured to contact piston rod 12 and extends from the upper end thereof through a sleeve |81 extending through the central opening 0f solenoid coil ||2 and securing sleeve ||4. The lower end of sleeve |81 is enlarged as shown at |88 to receive the upper end o'f a coil compression spring |44. with the lower end thereof bearing against the bottom wall of a tubular solenoid core member |48. The tubular solenoid core |40, which is of magnetic material, has the bottom wall thereof apertured to be slidably mounted on contact operating rod |88. and has adjacent the upper end thereof a peripheral inwardly extending rib 42 of a size to closely engage the outer surface of enlarged portion |88 of sleeve |81. Adjacent the lower end of solenoid core |40 are radially directed vent apertures |48, for a purpose to be hereinafter described.

In the operation of the mechanism thus far described, it will be apparent that upon the occurrence of predetermined circuit conditions, solenoid coil |2 will become sufficiently energized to attract core |40 and cause it to move upwardly on operating rod |88 and compress spring |44 between the core and sleeve |81. Furthermore, because of the close fit between core |40, securing sleeve 4 and enlarged portion i'38 of sleeve |81, and since these parts are all immersed in the arc extinguishing fluid, it will be obvious that upward movement of core |40 will be relatively slow because of the necessity of displacing the fluid within securing sleeve- |4 through the relatively small clearance between the core and sleeve. However, after suillcient movement of the core upwardly so that rib |42 clears the upper end of enlarged sleeve portion |88, there will then be a relatively large annular passage through core 40 and outlet apertures |48 for liquid entrapped in securing sleeve ||4, so that further movement of core |40 upwardly will take place at a relatively rapid rate. During this rapid movement of the core, the bottom wall thereof will engage the lower end of enlarged sleeve portion |38 to cau-se movement of the sleeve upwardly with the core, and engagement of the upper end of the sleeve with shoulder |41 formed on contact operating rod |88, will thus quickly separate contact head from fixed contact 18. This movement of contact head 80 by solenoid core |40 away from fixed contact 18 need be but a small amount, because as soon as the contacts are separated suiflciently to draw an arc, the pressure generated by such an arc operates to increase the contact separation ysufficiently to extinguish the arc. Obviously because of the sliding connection of solenoid core |40 with respect tocontact oper ating rod |88, the contact operating rod and contact head 80 are permitted to have a considerable overtravel independent of solenoid core 40 'in response to pressures built up within the interrupter chamber 68. As soon as the arc is extnguished and the pressure drops within interrupter chamber 88, contact operating rod |36 is permitted to move downwardly to reclose the contacts. However, its downward motion is halted by engagement of latch projection |24 at the top of contact piston'rod 12 with upper latch lug |82. In the meantime, solenoid core |40 returns very slowly under the biasing forces of gravity and spring |44, to the position shown in A }'Fig.,1. because of the dashpot action thereof in securing Ysleeve ||4, so that considerable time "'jmuste'lapse until the solenoid core |40 moves down into engagement with the upper end of vlatch lever |25. vand therebycauses counterclockwise rotation of the latch lever to disengage its upper lug |32 from contact piston rod projection core |40..

The reason why a plurality'of lugs |32, |34 are provided on the latch lever to successively halt downward movement of contact head 90 towards ilxed contact 15 is that it is necessary tomaintain the contacts separated, during the 4time delay period before reclosure,'a lsuicient distance apart so that the dielectric therebetween will be `capable of safely withstanding circuit voltage. Because of contamination and .deterioration ofthe dielectric on the interruption of high current arcs, this4 distance is quite large. n the other hand, it is desired to make thev time delay between a circuit interrupting operation and a reclosure of the circuit as long as possible with the available time delay means including the dashpot comprising solenoid core |40 and securing sleeve ||4. Lug |32 on the latchlever, therefore, is positioned to engage the moving contact to hold it separated from fixed contact 18 a distance corresponding to the safe gap therebetween according to the dielectric being used. If lug |34 were not also provided on the latch lever, then the time delay between a circuit interrupting operation and a reclosure of the breaker contacts would'be too short, and accordingly. to lengthen this period, the second llug |34 is provided for momentarily delaying reclosure of the breaker contacts after release of the moving contact from lug |32, to thereby obtain a longer time delay in reclosing without undue danger of ilashover, inasmuch as the period of time which lug |34 operates to maintain the breaker contacts separated is so short that ionization of the path between the breaker contacts does not have time to be completed prior to reclosure of the contacts. Also on interruption of low currents, the pressure maybe insumcient to move contact projection |24 as high as latch lug |32 and since the dielectric will not be unduly impaired by low current interruptions, engagement with latch lug |34 will provide a safe gap between the contacts while using full time delay on reclosure.

The upper end of contact operating rod |38 is pivotally secured as by pivot pin |50 to one end of a pair of insulating links |45, with the other ends of the links being connected to an angled crank lever |52, for example, as by the pivot pin |53. Crank lever |52 is pivotally mounted at its other end on a shaft |54 extending across the hollow portion of the top cover casting, and its outer ends are mounted in 'apertures provided in the side walls 42 and 43 of the cover relative endwise movement of shaft |54.

hollow portion, with the outer ends of these apertures being closed by screw plugs |55 to prevent Angled crank lever |52 is rotatably mounted on shaft |54, 'and a generally U-shaped yoke |58 has the leg portions thereof also rotatably mounted on shaft |54, with one leg of yoke |58 pivotally connected to one end of toggle link |50, and the other ends of this toggle link being plvotally connected to a toggle lever |86, which is, in turn, secured on the squared end of ashaft |55 rotatably mounted in an angled portion of end wall 46 of the cover assembly in a bearing sleeve |12, by a. bolt |10, which also acts to secure an operating handle |14 to the other squared end of shaft |65. Operating handle |14 is provided at the outer end thereof with a hook eye aperture |18 for the reception of a hook stick or other operating member.` Actuating handle |14 is limited in its movement in a counterciockwise direction by a stop screw |15 winch. may be secured in an adjusted position, for example, as by a lock nut |80.

rA pair of concentric coil springs |52 and |54 are provided about shaft |54 within the hollow portion of the cover assembly 4, with one end of the outer large diameter coil spring |84 engaging flange 35 of the cover assembly, and the other end |58 thereof engaging the connecting portion l |89 of yoke |55, to thereby bias the yoke for movement about shaft |54 in a counterclockwise direction. This movement of the yoke is normally prevented by virtue of the toggle formed by links |60 and |66 being below their dead-center position when actuating handle |14 is in engagement with stop screw |15. One end of the smaller diameter inner coil spring- |82 is extended to engage the angled portion of crank lever |52. and the other end of this spring also engages the connecting portion |59 of yoke |55, so that when the yoke is locked by toggle levers |60 and |66 against movement in a counterclockwise direction, biasing spring |82 will operate to bias crank lever |52 downwardly or in a clockwise direction relative to shaft |64, to thereby bias contact actuating rod |36 and contact head 90 downwardly, and cause engagement of the contact head with fixed contact 18.

The circuit through the interrupter herein disclosed extends from a terminal bracket |04 secured to the top cover assembly, for example. as by a. screw v|98 with the bracket having a terminai socket |96 for the reception of a line conductor, through the cover casting, by way of a conductor 200 to one tap I9 of solenoid coil H2, through the coil, conductor 202 to contact piston rod 12, contact rod 86, contact head 90, fixed contact 18, end cap 14, compression spring 04, terminal bolt |4. to another line conductor 20. Thus, it can be seen that the solenoid coil ||2 is connected in series in the circuit including ythe breaker contacts, and as shown, the whole coil is connected in series, inasmuch as the end taps of the coil are used,- and, therefore, the connection is for Ithe lowest rating of the Ibreaker which can be obtained with the coil employed. inasmuch as the maximum iiux generating capacity of the coil is employed to thereby obtain sumcient force to separate the contacts on relatively low currents. To obtain higher current ratings, it would be merely necessary to connect

conductor

202 or 200 to other taps III of the coil to utilize smaller portions of the coil winding. It will be noted that the entire circuit breaker mechanism including the breaker oontacts and interrupting chamber are supported as a unit with the casing cover assembly 4, so that they may be removed with the cover from the casing when desired by merely unfastening the securing means of the cover to support 04 on the casing. Another feature of the particular supporting means for the circuit breaker mechanism illustrated is the specific support of the solenoid coil permitting ready replacement thereof by another similar coil, or by a coil having a different number of turns to thereby change the available ratings of the breaker. In order to remove coll |I2, it is merely necessary to remove screws 02 holding U-shaped frame 60 and rectangular frame 64 together. This permits securing sleeve i I to drop downwardly out of U-shaped frame 00, and then by removing one pivot pin, for example, the pivot pin |50, the

entire contact operating rod and sleeve |01 can be slipped out of U-shaped frame 00 through apertures in legs |06 and |00 of the infame, whereupon coil I2 may be slipped laterally out of the open side of U-shaped frame 00. To insert a new coil, it is simply necessary to slide it in the open side of U-shaped frame 60 until the bore therethrough is aligned with the apertures in legs |00 and |00 of the frame, whereupon contact actuating rod |00 and securing sleeve ||4 may be inserted through the apertures and through the bore in the coil. and rectangular frame 04 secured to the lower leg |00 of the U- shaped supporting frame to thereby firmly secure the solenoid coil in operative position. Consequently, in order to remove the coil, it is only necessary to remove two screws 62 and one pivot pin |50.

The operation oi' contact`biasing spring |02 mounted on shaft |54 in cover assembly 4 is believed to be obvious from the foregoing. In other words, when the circuit is interrupted by energization of solenoid coil ||2 sumciently to raise core |40 and separate the contacts against the bias of spring |02, this spring will be eiective as soon as the circuit is interrupted to move the contact operating rod and contact head 00 downwardly towards xed contact 10, until projection |24 on contact piston rod 'I2 is engaged by latch lug |32, whereupon reclosure of the contacts will be delayed until the latch is released by solenoid core |40 in the manner previously described.

In the event an overload occurs on the circuit which is not self-clearing but continues after a predetermined number of successive interrupting operations, there is provided means for tripping the toggle which normally prevents rotation of yoke |50, so that spring |04 becomes effective to rotate the yoke in a counterclockwise direction to the dotted line position shown in Fig. 1, and, consequently, raise crank lever |52, by engagement of the cross bar |00 of the yoke with a projection |9| on the lever, together with contact actuating rod |06 and contact head 90 to a position wherein the contact head is mainin the bottom wall thereof controlled by a ballcheck valve 2 I0 to permit ilow of liquid into tube 204, butpreventing outilow of liquid. A piston member 206 is slidably mounted within cylindrical tube 204, and the upper end thereof fis reduced in width, as shown at 226, to more closely nt guide rod 220. Contact actuating rod |36 is adapted to extend through the slot 224 so that the bottom portion of the pawl seats on flange 202 formed on the upper end of sleeve |31 slidable on the contact actuating rod. Guide rod 220 is formed with an intermediate shoulder on which a washer 220 is adapted to be seated, with a coi-l compression spring 200 engaging between washer 220 and the lower leg of U-shaped pawl 222 to normally maintain the pawl in the position shown in Fig. 4.

In the operation of the circuit breaker, it will be observed that each time solenoid core |40 is drawn upwardly to open the circuit and engage the lower end of enlarged portion |30 of sleeve |01 to move the same upwardly, that it will cause a tilting of pawl 222 against the bias of spring 200, into engagement with notch 2|4 of piston 200 so that continued upward movement will move the entire piston upwardly and thereby unseat ball-check valve 2|0 and cause a predetermined amount of liquid to be drawn in the lower end of sleeve 204. As soon as the circuit is interrupted, and the contact actuating rod and associated parts are moved downwardly by biasing spring |02 in the manner previously described, compression spring 200 on guide rod 220 is operative to withdraw the upper leg of pawl 222 from the notch 2|4 in piston 206, so that the piston remains at the position to which it has been moved, while the contacts are reclosed. Now if the fault on the circuit has been removed, piston 206 will gradually sink to the position shown in Fig. 4 by displacement of the liquid below the piston through the relatively small clearance between the piston and cylindrical sleeve '204, so that eventually it will attain its original position shown in Figs. 1 and .4. However, in the event the fault in the circuit has not cleared upon the first reclosure of the breaker contacts, they will again be opened by solenoid I2, and this tune pawl 222 will engage notch 2|6 in piston 206, as shown in Fig. 5, inasmuch as the piston will not have had time to sink to its original position and the piston will be moved upwardly to the position shown in Fig. 6 of the drawing. As soon as the arc is extinguished, the contacts will again be reclosed by biasing spring |82, and if the fault has cleared, piston 206 will again slowly sink to its original position as before. However, ii' the fault has not cleared before piston 206 has an opportunity to sink much below the position shown in Fig. 6, the contacts will again be opened,

and this time pawl 222 will be pivoted into engagement with the lower notch 2|8 in piston 206 and cause the same to be moved upwardly a further amount and into engagement with the knee of the toggle formed by levers |60 and |66 to move the knee of the toggle overcenter, thereby releasing spring |64 and permitting the same to rotate yoke and move the toggle levers and contact operating rod to the dotted-line position shown in Fig. 1 of the drawing, wherein the breaker contacts are maintained by spring |84 in y an open circuit position.

breaker contacts are now maintained in an open` circuit position. When piston 206 has tripped the toggle, it will be observed that since contact operating rod |36 is maintained inan upper position, pawl 222 will be maintained in engagement with notch 2|8 on piston 206 to maintain the piston in its uppermost position. Accordingly, when it is desired to manually reclose the breaker contacts .by movement of operating lever |14 in a counterclockwise direction to reset the toggle levers to the position shown in full lines in Fig. l, it will be observed in the first place, that in the event it is thus attempted to close the circuit while an overload is present, that the breaker is trip-free in that it is free to open against the i bias of contact biasing spring |82 irrespective of the position of actuating lever |14. In the second place, it will bev noted that since piston 206 has had but a little time to move downwardly from its outermost position with respect to cylindrical sleeve 204, that in the event the breaker is reclosed manually upon an overload in the circuit, that on the consequent circuit interruption and movement of the contact operating rod and associated parts upwardly, pawl 222 will be caused to engage the lower notch 2 |8,o1' piston 206 to therepfmove the toggle overcenter and again permit spring |34 to maintain the contacts in an open position.

Thus, it can be seen that the circuit breaker herein disclosed is capable of automatically opening the circuit with an inverse time current characteristic due to the dashpot action of core |40 in securing sleeve ||4, and yet the contacts are separated with a relatively fast action due to the venting of the dashpot formed by core |40 and sleeve |44 adjacent the end of its stroke. This feature is the invention of J. M. Wallace and is more particularly disclosed and claimed in his copending application Serial No. 399,453, filed June 24, 1941, now Patent'No. 2,333,604, issued November 2, 1943, to the same assignee of this invention. Following a circuit interrupting operation, the breaker contacts are automatically reclosed with a time also due to the dashpot action of core |40 and sleeve I I4, while maintaining substantially to adjacent the end of the timed period a safe gap between the breaker contacts. Also,

in `response to a predetermined number of closely successive circuit interrupting' operations, novel means'arer provid'edi'for maintaining'the .breaker contacts 'in an 'openl position,- which includes la biasing' 'means 1normallyheld inactive by "a toggle which 'isinoved over'centrlby a piston actuated a predeterminedqamount upon each. interrupting operation ="Ihe' arc chamber: herein -disclosed is provided with arl outlet valve. which is positive in i operation, and the electroresponsive solenoid contact'opening means is supported-in a manner to'liender the same readily replaceable, and 'is provided with a plurality oftaps s'o that the -rating of the breaker may be `readily changed. The specific arrangement oi' the contact closing spring and the spring for maintaining the contacts separated is especially important with respect to space considerations and eiiiciency of operation.

An operation counter 234 is adapted to be mounted on the end wall 45 of the hollow portion of cover assembly 4 and to be located beneath the hood portion thereof so as to be readily visible from the exterior of the breaker while protected from the elements by the hood. This operation counter may be of any well known type provided with an actuating crank lever 236, mounted on an operating shaft extending through the angled portion of wall 45 like shaft Hi8,v and with crank 236 pivotally connected to an operating link 238I which, in turn, is connected to pawl 222, so as to actuate the counter on each circuit interrupting operation of the breaker. The connecting link 238 is provided with an insulating portion,240 to insulate the counter from pawl 222.

There is preferably provided within the hollow portion of cover assembly 4, in a socket 242 provided therefor on top Wall 40, a lightning arrester assembly, which may `be of any well known type including electrodes 256 spaced by an insulating plate 250 to form a gap in series with a porous block 260. in the circuit between top wall 40 of the cover and terminal 244 of the assembly. A tubular insulating sleeve 262 is positioned between the assembly and the side wall of socket 242, and insulating disk 210 supports terminal 244 and is secured to the cover assembly 4 by screws 266, with a sealing gasket 264 therebetween to maintain the arrester assembly in socket 242. A shunt 263 connects terminal 244 and a contact plate 21| and this plate is maintained in contact with block 260 by a spring 212. Thearrester terminal 244 is connected by conductor 246 to the top leg |06 of U-shaped frame 60 to thereby form a circuit by-passing solenoid coil ||2. This obviously will-prevent the solenoid coil from opening the breaker contacts in response to surges inasmuch as the coil will co-operate with the shunt circuit through the arrester assembly to by-pass such surge currents around the coil and limit the voltage across the coil insulation, and' such surges will be ineii'ective to cause a circuit interrupting operation of the breaker. The arrester assembly herein disclosed utilizes a single series porous block and gap of the type shown in the plural series block and gap arrester shown in the patent to L. R. Ludwig. et al., No. 2,135,085, issued November 1, 1938. It will be understood that plural series porous block and gap assemblies may be used with this circuit breaker, if desired.

Also positioned beneath the hood portion of the cover assembly is a tubular sight gauge glass 250, held in position against an integral lug 248 on end wall 45 of the cover assembly, by an apertured threaded plug 249, and an indicating rod 252 is slidably mounted through the apertur'ed plug and tubular sight glass, and is provided with a float 254 secured tothe lower end thereof within casing 2 so that the level of liquid within casing 2 may be readily determined from theexterior thereof by inspection of the sight glass beneath the hood portion of the cover assembly. i

Thus, there is provided in a single unit anautomatic reclosing circuit breaker characterized the coil insulation and prevent operation of the breaker in response to the occurrence of surges in the circuit. Moreover, the cover assembly for the breaker casing 2 is arranged with a sleet hood portion at one`side thereof to conceal an operating handle which is projected into view upon lock-lopen operation of the breaker contacts to direction. whereby to control closing movement 'of said contacts.

4. In a circuitinterrupter, a closed arc chamber. separable contacts in said chamber at least indicate this condition, and also houses liquid modifications may be made in this particular embodixnent without departing from the broad spirit and scope of the invention. Therefore, it is desired that the invention be interpreted as broadly as possible and that it be limited only by the prior art and by what is expressly set forth in the following claims.

We claim as our invention:

1. In a circuit breaker, separable contacts. electroresponsive means for separating said contacts, means biasing said contacts closed, means responsive to circuit interrupting operation of said breaker for releasably latching said contacts separated an amount at least suiiicient to provide a safe gap between the contacts which will not break down under impressed circuit voltage, time delay means adapted to be set in operation in response to a circuit interrupting operation for releasing said latch means a predetermined time thereafter, another latch means adapted to automatically maintain said contacts separated a lesser distance than said first latching means to prevent too quick reclosure thereof upon release of said iirst latching means, and said time delay means also being effective to release said lastmentioned latch means a predetermined time after release of said iirst latching means to permit said biasing means to finally close said contacts.-

2. In a circuit breaker, separable contacts.

- electroresponsive means for separating said contacts, means biasing said contacts closed. latch means for preventing quick reclosure of said contacts by said biasing means. said latch means including a` plurality of spaced latch portions adapted to maintain said contacts diiierent distances apart, respectively, and time delay means effective in response to a circuit interrupting operation to release said latch portions successively at predetermined times after a circuit interrupting operation, respectively, and at least the iirst of said latch portions released by said time delay means adapted to ,maintain a safe gap .between said contacts.

Y 3. In a circuit breaker, separable contacts, electroresponsive means for separating said contacts. means biasing said contacts closed, latch means for preventing quick reclosure of said contacts by said biasing means, said latch means including a latch lever having a plurality of spaced latch portions adapted to maintain said contacts diiierent distances apart, respectively, said latch portions adapted to be successively effective to maintain said contacts separated said different distances and to be successively released upon movement of said lever in one direction. time delay means effective in response to a circuit interrupting operation to slowly move said latch lever in said one one of which is slidably mounted through a wall of said chamber in a piston-like manner, electroresponsive means having a lost motion connection with said one contact to move said one contact outwardly of said chamber and away from the other of said contacts and to permit overtravel of said one contact under the iniiuence of pressure generated in said chamber by the arc struck when said contacts separate. means biasing said one contact for movement in a direction tol en- Sage 4the other of said contacts, latch means for automatically latching said electroresponsive means upon opening movementv thereof to prevent reclosing movement of said one contact, said latch means effective to latch said electroresponsive means at a plurality of positions at which said one contact is held at different ldistleinces spaced away from said other contact. respective# ly, at least the position of said one contact at which it is maintained the greatest ditsance from the other of said contacts providing a safe gap between said contacts, and time delay means operative in response to a circuit interrupting operation to actuate said latch means at predetermined times thereatter in a manner to successively release said one contactto permit the same to move to said dinerent positions and i'inally into engagement with said other contact, successively.

5. In a circuit breaker, separable contacts, electroresponsive means for separating said contacts,

means biasing said contacts closed. latch means for preventing quick reclosure of said contacts by s'aid biasing means, said latch means eii'ective to latch said contacts in a plurality of open positions at dierent distances apart, respectively, at least the open position of said contacts at which they are latchcd the greatest distance apart providing 'a safe gap between said contacts, and time delay means operative in response to a circuit interrupting operation to actuate said latch means at predetermined times thereafter in a manner to successively release said contacts to permit the same to move under the influence of said biasing means to said different positions and finally into engagement.

6. In a circuit interrupter, a closed arc chamber, separable contacts in said chamber at least one of which is slidably mounted through a wall of said chamber in a piston-like manner, electroresponsive means having a lost motion connection with said one contact to move said one contact voutwardly of said chamber and away from the other of said contacts and to permit over-travel of said one contact under the influence of pressure generated in said chamber by the arc struck when said contacts separate, said arc chamber adapted to be immersed in a body of insulating fluid, lower inlet and upper outlet openings for said chamber, check valves controlling said openings, respectively, and responsive to pressure in said chamber for closing said openings, at least said outlet valve being biased to open said outlet contacts. latch means for said one contact for automatically latching said one contact upon opening movement. thereof to prevent reclosini movement, said latch means effective to latch said one contact in a plurality of open positions at diil'erent distances from said other contact, re'

spectively, at least the position of said one contact at which it is maintained the greatest distance from the other of said contacts providing a safe gap between said contacts, and iluid time delay means also immersed in said duid and utilizing the same so as to be operative in response to a circuit interrupting operation to actuate said s latch means at predetermined times thereafter in a manner to successively release said one con-- tact to permit' the same to move to said different positions and iinaliy into engagement with said other contact, successively, and insure flushing of said chamber after each circuit interrupting operation prior to reclosure of contacts.

7. In a circuit interrupter, a closed arc chamber, separable contacts in said chamber, electroresponsive means having lost motion relative to said contacts and adapted to separate said con,- tacts at least an amount suicient to strike an arc. means responsive to pressure generated in said chamber'by an arc to further separate. said contacts, said lost motion permitting overtravel of said contacts under the inuence of pressure generated in said chamber by the arc struck when said contacts separate, said chamber adapted to be immersed in a body of insulating fluid, lower inlet and upper outlet openings for said chamber, check valves controlling said openings, re.

spectively, and responsive to pressure in said chamber for closing said openings,'and at least the outlet valve being biased to open said outlet passage to insure opening thereof upon extinguishment of the arc in said chamber and consequent lowering of pressure, to provide for flushing saidchamber by flow of said liquid through said chamber after each circuit interrupting operation and insure flushing of said chamber after each circuit interrupting operation prior to reclosure of said contacts.

8. In a circuit interrupter, a closed arc chamber, separable contacts in said chamber, electroresponsive means having lost motion relative to said contacts and adapted to separate said contacts at least an amount suiiicient to strike an arc, means responsive to pressure generated in said chamber by an arc to further separate said contacts, said lost motion permitting overtravel of saidl contacts under the influence of pressure generated in said chamber by the arc struck when said contacts separate, said chamber adapted to be immersed in a body of insulating fluid, lower inlet and upper` outlet openings for said chamber, check valves controlling said openings respectively, and responsive to pressure in said chamber for closing said openings and at least the outlet valve being biased to open said outlet passage to insure opening thereof upon extinguishment ,of the arc in said chamber and consequent lowering of pressure to provide for flushing said chamber by ilow of said liquid through said chamber after each circuit interrupting operation to insure ushing of said chamber after each circuit interrupting operation prior to reclosure of sai-d contacts, and said inlet valve being freely mounted for limited movement so as to b e responsive to pressures developed in said chamber to close said inlet, and responsive to the pressure due to the head of liquid outside said chamber to open said inlet.

9. In a circuit interrupter, a closed arc cham'- ber, separable contacts in said chamber at least one. of which isv slidably mounted through a wall of said chamber in a piston-like manner, electroresponsive means having a lost motion connection with said vone contact to move said one contact outwardly of said chamber and away from the other of said contacts and to permit overtravel of said one contact under the iniluence of pressure generated in said chamber by the arc struck when said contacts separate, said arc chamber adapted to be immersed in a body of insulating fluid. lower inlet and upper outlet openings for said chamber, check valves controlling said openings, respectively, and responsive to pressure in said chamber for closing said openings, at least said outlet valve being biased to open said outlet passage to insure opening thereof upon extinguishment of the arc in said chamber and consequent lowering of pressure to provide for flushing said chamber by flow of said liquid through said chamber after each circuit interrupting operation, means biasing said one contact for movement in a direction to engage the other of said contacts, and fluid time delay means also immersed in said iluid and utilizing the same so as to be operative in response to a circuit interrupting operation to delay closing movement of said one contact a time sufficient to permit the carrying out of said ilushing opera- 10. In a circuit interrupter, 'a closed arc chamber, separable contacts in said chamber, electroresponsive means for separating said contacts at least sufllciently to draw an arc, means responsive to pressure generated in said chamber by the arc to further separate said contacts, said arc chamber adapted to be immersed in a body of insulating iluid, lower inlet and upper outlet openings for said chamber, check valves controlling said openings, respectively, and responsive to pressure in said chamber for closing said openings. at least said outlet valve being biased to open said outlet passage to insure opening thereof upon extinguishment of the arc in said chamber and consequent iowering of pressure to provide for flushing said chamber by flow of said liquid through said chamber after each circuit interrupting operation, means biasing said contacts for movement in a direction to engage the other of said contacts,

and fluid time delay means also immersed in said iluid and utilizing the same so as to be operative in response to a circuit interrupting operation to delay closing movement of said contacts a time sumcient to permit the carrying out of said ilushing operation.

1l. In a circuit breaker, separable contacts. electroresponsive means for separating said contacts, means biasing said contacts closed, latch means for preventing quick reclosure of said contacts by said biasing means, said latch means effective to latch said contacts in a plurality of open positions at different distances apart, respectively, said latch means being ineil'ective to latch said contacts at least for a predetermined short distance apart, atleast-the openposition of said contacts at which they are latched the greatest distance apart providing a safe gap between said contacts, and time delay means op-` erative in response to a circuit interrupting operation to actuate said'latch means at predetermined times thereafterin a manner to succes- .s sively release said contacts to permit the same to move under the influence of said biasing means to said different positions and'nally rapidly into.

engagement with said other contact. successively.

12. In a circuit interrupter, a closed arc chamber, separable contacts in said chamber, electrobeing biased closed, latch means for preventing 5 quick reclosure' of said contacts by said biasing means. said latch means effective to latch said electroresponsive means at a plurality of positions wherein said contacts are diiierent distances apart. respectively, at least the open position ot said contacts at which theyare iatched the greatest distanceA apart providing a safe gap between said contacts, yand time delay means operative in response to a circuit interrupting operation to actuate said latch means at predetermined times l5 1s iiuenoe of said biasing means to said diirersnt positions and ilnally into engagement with other contact, successively.

JAMES M. WAILACE. HERBERT IL RAWLINB. JAMES M. CUMMING, WAYNE S. ABPEY.

ammonta crrsn The following references are of record in the ille of this patent:

UNITED STATES PATENTS