US2686854A - Circuit interrupter - Google Patents

Description

1954 J. M. WALLACE ETAL' 2,685,854

CIRCUIT INTERRUPTER Filed Feb. 13, 1948 WITNESSES: j INVE/TOR$ ames A4. 14/0 ace nd g 40dr'ew M A a wards U 7. w

Patented Aug. 17, 1954 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER James M. Wallace, East McKeesport, and Andrew W. Edwards, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 13, 1948, Serial No. 8,044

9 Claims. 1

This invention relates to electric circuit interrupters generally, and more particularly, as to one aspect of the invention, to such interrupters as employ a liquid dashpot for delaying certain operations; and in regard to another aspect of the invention, to such interrupters as are of the automatic reclosing type.

Some difficulty has been encountered in circuit interrupters of the oil-immersed type which employ an oil dashpct to delay one or more operations of the interrupter, with gas accumulating in the dashpct and thus rendering the interrupter erratic in operation.

One object of this invention, therefore, is to operation of the counting means which causes a final locking open of the breaker contacts, resulting in extremely rapid and prolonged pumping of the breaker contacts.

Another object of this invention, therefore, is to provide in an automatic reclosing circuit breaker of the type described, novel means for momentarily delaying initial reclosing movement at least on a fast reclosing operation.

Another object of this invention is to provide in a circuit breaker of the type described having relatively fast and slow operations with novel means cushioning certain of the high speed operations.

provide novel means for preventing th access These and other objects of this invention will of gases to a liquid dashpot controlling operae me m e p aren up n n ideration of the tion of a circuit interrupter, particularly where fo lowing detailed description o a preferred the dashpot e th same liquid emplqyed f bodiinent thereof, when taken in connection with extinguishing the arc during circuit interruption. he a h r win in whi h the single fi r A o e specific bject of thi in ti i t illustrates a substantially central vertical section provide novel means for supplying arc extinguishing liquid to a dashpot employed for delaying operations of a liquid-immersed circuit interrupter, with such liquid supplying means for the dashpot supplying liquid from a zone which is separate from the arcing zone.

Automatic reclosing circuit breakers are now often made so as to have a first rapid circuit opening operation with later time delayed circuit opening operations in any sequence of closely successive operations, such as occurs on a continuing overload. Such breakers may also have a first rapid reclosing operation with later reclosing operations being delayed. In such circuit breakers it is not only necessary to have efiicient fast-acting arc extinguishing means, but where a fast reclosing operation is desired difiiculty has been encountered in flushing the arcing space rapidly enough to restore dielectric strength by the time the breaker contacts reclose.

Accordingly, another object of this invention is to provide in an automatic reclosing type of circuit breaker, novel arc extinguishing means having provision for rapid flushing of the arcing space as well as rapid and efiicient extinguishing of the arc.

Automatic reclosing circuit breakers of the type referred to above wherein different circuit opening times are obtainable usually embody a fast acting solenoid which is allowed to operate freely to obtain a fast opening operation, and fast reclosing has been due to a light permanent bias on the moving parts. Under certain conditions this reclosing operation has been too fast to permit proper flushing of the arc space or proper view of a circuit breaker embodying this invention.

The invention is illustrated on the drawing as being embodied in one form of automatic reclosing circuit breaker, with the particular breaker herein illustrated being more particularly described and claimed in the copending applications of J. M. Wallace et al., Serial No. 719,524, filed December 31, 1946, on Circuit Interrupters; H. L. Rawlins et al., Serial No. 719,572, filed December 31, 1946, on Circuit Interrupters and issued December 16, 1952, as Patent No. 2,622,167; and J. M. Wallace et al., Serial No. 718,942, filed December 28, 1946, on Circuit Interrupters and issued November 20, 1951, as Patent No. 2,575,738, all of which are assigned to the same assignee as this invention. This circuit breaker is mounted in a metal tank 2 having a closed bottom wall and an open top and adapted to be filled with a liquid up to the level L, preferably an arc extinguishing liquid such as oil or the like. Preferably, the tank is lined at least over the bottom wall and up to a point adjacent the open top of the container with a liner 3 of insulating material such as fiber, or the like. The upper end of tank 2 is provided with an outwardly extending flang 4 on which the flange 8 of a cover casting 6 is adapted to be seated, preferably, with a gasket Iii interposed therebetween. Flange 8 of cover casting 6 may be provided with an integral lip 12, and the cover may be secured to the tank in any desired manner, such for example, as by bolts (not shown) extending through openings in cover flange 8 and secured to suitably formed brackets on the tank.

The breaker contacts, arc extinguishing structure and the contact actuating mechanism are all adapted to be supported in tank 2 from cover casting 6 by means of a plurality of integral supporting lugs I8 (only one of which is shown) depending from the top wall of the cover casting and adapted to engage spacer sleeves 18 of insulating material suitably secured to supporting lugs l8 and to a supporting casting 28. A supporting plate 22 may be supported from casting 20, so that a solenoid coil 24 may be mounted between casting and supporting plate 22, with the central opening in the coil aligned with openings provided in casting 28 and plate 22. Supporting casting 28 and supporting plate 22, together with the bolts (not shown) securing them together, are of a magnetic material, such as iron or the like, to complete a magnetic circuit of low reluctance outside of solenoid coil 24, which terminates at opposite ends of the central opening through the coil in which the working air gap of the coil is located.

Spaced stationary contacts 28 of the breaker are supported within an insulating tube 28 at the lower end thereof, and on opposite sides of the tube, respectively. Tube 28 which may be of any desired insulating material, such as fiber or the like, is supported at its upper end from plate 22 by supporting brackets 38 which are welded or otherwise secured to plate 22, and have screws for securing tube 28 thereto, with the upper end of tube 28 being closely adjacent to, but spaced from plate 22. Stationary contacts 26 are each mounted on its own supporting bracket 32, with each bracket having a U-shaped portion for receiving the lower edge of the tube 28 and being secured thereto as by a bolt 84. Tube 28 has opposed vent openings 35 in opposite sides, located directly above stationary contacts 25, respectively, for a purpose to be described.

When movable bridging contact 88 is moved upwardly to interrupt the circuit, two arcs, which are in series, will be drawn to stationary contacts 28, respectively. These two arcs create considerable pressure inside tube 28. Because of the close spacing of the upper end of tube 28 in regard to supporting plate 22 on the order of inch, there will be relatively little flow of oil out the top of the tube, so that there will be a substantial quantity of fluid forced out the two vent openings 35 in a direction transversely of the arcs drawn across these vent openings so as to provide a flow of fresh oil through these arcs to extinguish them at a current zero. As soon as the arcs are extinguished, there will be a quantity of gas present within tube 28; and in instances where the contacts are reclosed without time delay, this gas must be rapidly removed from tube 28 in order to restore the dielectric strength within the tube and provide oil for subsequent interruption. While the close spacing of the upper end of tube 28 and supporting plate 22 restricts the out flow of liquid from the tube, it furnishes relatively free venting for gas, which vent is open at all times. Moreover, the space within tube 28 is immediately filled with fresh oil which may flow unobstructedly into the lower end of tube 28 due to the head of liquid in tank 2. Accordingly, in addition to providing a simplified structure which provides a transverse flow of fresh arc extinguishing liquid to quickly deionize the arcs when the circuit breaker opens, the structure described above provides extremely fast flushing of the arc chamber, which is of especial importance in this type of circuit breaker which may have one or the pivot supporting recesses 58 for toggle more circuit opening and closing operations which are not delayed but occur substantially instantaneously.

The upper end of contact actuating rod 44 has connecting links 48 pivoted thereon as by a pivot pin 48, with the upper ends of these connecting links mounted on a common pivot pin 58 for a pair of toggle levers 52 and 54. Toggle levers 52 and 54 are both formed of sheet material, with' lever 54 being bent to substantially channel form with outwardly extending flanges 58 adapted to be received at the free ends thereof in recesses 58 provided in the spaced downwardly depending fingers of an angled supporting bracket 88 which, in turn, is secured as by a screw 64 to a lug 62 integral with the cover casting. A coil tension spring 58 has one end hooked into an opening provided in toggle lever 52, and has the opposite end thereof hooked over an integral spring support on the cover casting. Toggle lever 52 has an integral hook portion 55 passing'through an opening in lever 54 to limit separation of the levers.

It will be observed that in the closed circuit position of the breaker illustrated on the drawing, the line of action of toggle spring 88 is below lever 54, and accordingly, the toggle spring acts to bias bridging contact 38 into engagement with stationary contacts 28 of the breaker, under a predetermined pressure. However, as soon as contact operating rod 44 moves upwardly to separate the bridging contact from the fixed contacts of the breaker, toggle lever 54 will pivot about recesses 58 and the line of action of toggle spring 68 will thus be caused to approach that pivot point so that in response to a very small contact separation the line of action of toggle spring 68 will pass through pivot recesses 58 which is the oncenter position of the resilient toggle arrangement comprising toggle levers 52 and 54 and toggle spring 88. As a practical matter, the opening movement of the contacts necessary to move toggle levers 52 and 54 to the on-center position mentioned above may be made very small, in one actual device being on the order of one-quarter of an inch. When toggle levers 52 and 54 reach their on-center position referred to above, further relative movement of the two toggle levers in the same direction is prevented because the upper edge of toggle lever 52 engages the base of the central channel formation of toggle lever 54. Moreover, since the point at which toggle spring 88 is hooked into lever 52 then substantially coincides with recesses 58 in which toggle lever 54 pivots during contact opening movement, it will be apparent that the remainder and major part of contact opening movement will occur substantially uninfiuenced by toggle spring 68.

Substantially the reverse of the above operation occurs when contact operating rod 44 moves downwardly to close the circuit from the full open contact position, because during the first and major part of contact closing movement, levers 52 and 54 will be in engagement so that such movement will be uninfiuenced by toggle spring 68. However, as soon as pivot 50 passes below a line drawn from the remote end of toggle spring 68 through pivot recesses 58 for link 54, toggle spring 88 will then be effective to move the toggle levers toward the full line position shown in Fig. l, and the force exerted by togglespring 68 thus tending to close the contacts will continue to increase as toggle levers 52 and 54 move fur-' ther away from their on-center positions.

Solenoidcoil 24 previously mentioned, .is adapted to be energized under certain conditions for automatically opening the circuit breaker contacts. The central opening through coil 24 preferably is provided with a cylindrical sleeve 14 in which a solenoid core 15 is adapted tobe slidably mounted in a piston-like manner. A flat washer 18, which may be of insulating material, is secured to contact rod 44 immediately above bridging contact 36, as by a split securing ring 80 mounted in 'a groove formed on rod 44, and core 16 has an enlarged piston flange H at the lower end thereof having a flat annular end surface adapted to seat on washer 18 at the normal position of the parts illustrated'on the drawing. It will be observed that solenoid coil 24 is spaced from supporting plate 22 by the apertured flange 84 of a sleeve 19 which is received in the lower end of dashpot cylinder sleeve 14. Depending from flange 84 of sleeve 19 is cylindrical skirt 85 which extends through the opening in supporting plate 22 about core 16 and into tube 28. The purposes and operation of these structures will be hereinafter described.

A contact actuating sleeve 82 is telescoped over contact actuating rod 44 and its lower end is received in core 16 preferably being threadably mounted therein. A coil compression spring 86 is provided within actuating sleeve 82 on contact collar secured to actuated rod 44 by a pin 80 extending transversely through actuating rod '44.

The circuit through the circuit breaker thus far described may now be traced from the points where it enters tank 2 through one of a pair of 96 of the bushing seated in an opening provided in the top .wall of cover casting 6. The circuit proceeds by conductor 98 directly to one fixed contact 26 of the breaker. When the contacts are in engagement, the circuit then proceeds through bridging contact 35 to the other fixed contact 26, and then by way of a conductor H to one terminal of solenoid coil 24. The other terminal of coil 24 is adapted to be connected by a conductor I02 to the conducting means in the other terminal bushing 90. It will be apparent that solenoid coil 24 is connected in series in the circuit through the circuit breaker so as to be energized at all times an amount dependent upon the value of the load current flowing in the circuit.

For anygiven rating of circuit breaker, solenoid coil 24 is designed to become sufliciently energized when the load current in the circuit exceeds its rating as to attract core and move it upwardly within sleeve 14. Assuming the upper end of sleeve 14 to be closed so fluid cannot escape, core- 16 will move upwardly, retarded by the necessity for displacing the liquid in sleeve 14 above the core through the relatively small clearance between the core and sleeves 14 and 82. Accordingly, opening movement of the core will be slowed up by the aforesaid dashpot action an amount determined by the current value of the overload, and, therefore, an inverse time-current characteristic on opening is obtained. As core 16 commences its upward travel, bridging contact 36 being held engaged by toggle spring 68 does not move, so that spring 86 is compressed until the upward force of the spring 86 is sufficient to overcome the force exerted by toggle spring 68, at which time contact actuating rod 44 will start to as actuating rod 44 moves upwardly, the force exerted by toggle spring 68 begins to decrease and in a very short distance has substantially no value at all, so thatv the remaining major part of the circuit opening movement of bridging contact 36 occurs extremely rapidly due to expansion of spring 86. Flange 89 is provided on rod 44 to obtain separation in the event there is any sticking or When the breaker contacts have attained their.

full open circuit position, the parts associated therewith are biased to return by gravity. This closing bias is relatively light and will be opposed action of core 16. Accordingly, the return movement will be relatively slow until moves below the line of action of toggle spring 60 when toggle levers 52 and 54 are in engagement, whereupon bridging contact 36 will be rapidly moved to efiect a snap-action closing of the breaker contacts by toggle spring 68. It will be observed that during circuit closing movement of dashpot core 10, the dashpot action is due to the necessity of supplying liquid to the upper end of the dashpot through the relatively small clearanc between core 16 and sleeves 14 and 82. As previously explained, gases are generated during a circuit interrupting operation in tube 28, and are vented from the upper end of the tube. In order that such gases do not find their way up through skirt on sleeve 19 into the dashpot space, especially during the first part of a circuit closing operation when there may be a transient pressure condition within container 2 due to the preceding circuit interrupting operation, the vents in flange 84 of sleeve 19 are provided so that the intake at the lower end of dashpot sleeve 14 is located above supporting plate 22 and consequently at a point where any gases present within tube 28 cannot enter the dashpot space.

In order to provide for maintaining the breaker contacts separated and to also provide for manual operation, spring means are provided for holding the breaker contacts open in response to the occurrence of a predetermined number of closely succeeding circuit interrupting operations, which means can be manually actuated. This means comprises a toggle lever I04 having a slot I06 at one end thereof for receiving a pin I08 mounted between spaced supporting arms IIO integral with cover casting 5. The other end of toggle lever I04 is pivoted, as by a pivot pin II2, to the adjacent end of a second toggle lever H4, and this, in turn, is mounted on a pivot pin IIB intermediate its ends on cover casting 6. A slot I20 is provided through the cover casting 6 for receiving the other end of toggle lever II4 which acts as a manual operating handle at the exterior of the circuit breaker casing, being provided with a hook eye I22 in its outer end. A coil compression spring I24 is mounted on toggle lever I04 and reacts between washers mounted on the toggle lever, one of which engages supporting pin I08, and the other of which engages a shoulder located adjacent pivot H2. Normally, toggle levers I04"and .I I4 are held with pivot II2 below the center-line connecting pins I08 and II6,..with the outer end of lever II4 positioned in and beneath an integral hood I26 on cover casting 6, in engagement with an adjustable'stop screw I28 mounted in the hood. I

In the position of toggle levers I04 and H4 illustrated, they have no efiect on operation of .the circuit breaker as previously described, being. normally inactive in this respect. However, the common pivot pin I I2 of toggle levers I04and I I4 is extended at one side toward toggle levers 52 and'54 and in the normal position of the parts extends beneath the adjacent flange 56 of toggle lever 54. Accordingly, if it is desired to manually open the circuit breaker contacts, a hook stick or similar operating member may be inserted in hook eye I22 of toggle lever I I4 and pulled downwardly to rotate the toggle lever in a counterclockwise direction about its supporting pivot I I6 to move toggle levers I04 and H4 overcenter in an upward direction, and in doing this, the common pivot pin II2 engages the adjacent flange 56 of toggle lever 54 and moves it upwardly in a counterclockwise direction, thus carrying contact actuating rod 44 with it to separate bridging contact 36 from stationary contacts 26. The contacts will be held open by spring I24 which maintains toggle levers I04 and H4 in their upper overcenter position. With the breaker contacts maintained at their open circuit position following the manual circuit opening operationdescribed above, it will be apparent that the outer end, of toggle lever II4 projects below hood I26 of cover casting 6 so as to provide a readily visible indication that the breaker contacts are maintained at an opencircuit position. It will further be apparent that the breaker contacts may then be closed only by manual operation of toggle lever II4 in the opposite direction, that is, by exerting an upward forceon the outer end of the toggle lever to rotate it in a clockwise direction to move it and toggle lever I04 back overcenter to the full line position illustrated on the drawing. This manual operation of toggle lever II4 does not directly close the breaker contacts but merely permits closure of the contacts in the manner previously described, that is, initial closing movement of the contacts beingdue to the bias of gravity, until bridging contact 36 is contacts 26 when toggle spring 68 is moved below its on-center position and suddenly becomes efiective to finally move the contacts into engagement rapidly.

An integrating mechanism for automatically moving toggle levers I04 and H4 upwardly over center and thus preventing reclosure of the circuit breaker only in response to a predetermined number of closely successive circuit interrupting operations, and at the same time for automatically controlling the circuit opening and closing times in a predetermined manner in any sequence of a plurality of closely successive circuit opening operations, is provided comprising a cylindrical tube I30 secured in casting 20, and this tube has a plug I32 threaded into the lower end thereof with the plug having a small central opening controlled by a ball-check valve I34, which permits flow of fluid into the lower end of tube I30 but prevents outflow. An integrating piston I36 is mounted in cylindrical tube I30 and normally rests on the upper end of plug I32. The upper end of piston I36 is provided with a reduced extension I38 at the upper endthereof,

having a plurality of spaced circular flanges I40 closely adjacent stationary r forming rackteeth thereon, and ha'vingian elongated extension I42 on thereof which is positioned below an extension I43 on toggle lever I04. A pawllever I44.is pivotally mounted at one end as at I46, this end of pawl lever I44 being split with legs located at each side of tube I30 and with pivot I46 supported on spaced supporting flanges I4I integral with casting 20. Pawl lever I44 has a connecting webintermediate its ends, and at thereof the sides-of the lever are extended outwardly and laterally as at I48, to normally be in engagement with a washer I50 mounted on sleeve 83 in engagement with an exterior shoulder on this tube. Pawl lever I44 is normally biased into engagement with washer I50 by a coil tension spring I52 hooked over theremote edge of the web of the pawl lever at one end andanchored to an ear integral with casting 20 at-its other end.. Pawl lever I44 is provided with a pawl member I54 pivoted thereon as at I56, and biased by a spring I58 in a counterclockwise direction to a position wherein a portion of pawl member I54 engages the connecting web of pawl lever I44.

In order to control the opening and closing times of the circuit breaker contacts to provide for different opening and closing times on predetermined circuit opening and closing operations in any sequence of closely successive operations, as on continuing overloads, the dashpot formed by sleeve 14 and solenoid core 16 has a vent I14 at the upper end thereof which is annular in form being provided in casting 20 about actuating sleeve 82. Annular vent I14 communicates with a laterally extending passage I16 also formed in casting 20, so that fluid may escape from the upper end of sleeve 14 through annular vent I14 and passage I16, and then through a pair of opposed openings I18 in tube I30 from whence it may escape through a discharge opening I80, also formed in casting 20. The openings I13 in integrator tube I30 are aligned with passage I16 and discharge opening I86.

.With the parts of the circuit breaker at their normal positions illustrated. in Fig. 1, it will be apparent that when the circuit breaker operates to open the circuit, the upper end of dashpot sleeve 14being open through annular vent I14, passage I16, openings I18 and discharge opening I80, solenoid core 16 will be moved upwardly very rapidly since the liquid in dashpot sleeve I4 above the core may be freely vented through the vent passages mentioned above, and consequently the initial circuit opening operation of the breaker will occur substantially instantaneously, During such an initial fast circuit opening operation, it will be apparent that contact rod 44 and the parts which move with this rod will be moving at a high speed and will have considerable momentum. At the end of circuit opening movement of the contact rod 44 and its associated parts, washer 18 on the rod approaches the flat surface at the lower end of core 16 formed on enlarged piston flange BI, and a braking action is obtained due to the necessity of forcing all liquid from-between these flat surfaces. y

As solenoid core 16 moves upwardly on such a first circuit opening operation, washer I50 will be carried upwardly with actuating sleeve 82 and thus carry the free end of pawl lever I44 upwardly with it to move pawl member I54 into engagement with, the upper one of, flanges I40 on into:

the extreme outer end.

the other end grating piston I36, and carry the piston upwardly a predetermined distance throughout opening Integrating piston off by piston I36. When the breaker recloses following such a first fast circuit interrupting operation, such reclosure will also occur extremecircuit breaker contacts will both occur substantially instantaneously with no time delay interposed due to the dashpot action of core 16 in dashpot sleeve 14. During reclosing of the breaker the first time, integrating piston I36 is left at the position to which it was advanced, since pawl member I54 is free to disengage the circular flanges I40, and if the breaker remains closed, integrator piston I36 will slowly reset to the position shown in Fig. 1, this resetting movement being relatively slow due to the necessity of displacing liquid drawn into the lower end of cylinder I30 by advancement of piston I36 during the opening operation, past the relatively small clearance between cylinder I36 and piston I36. This means, of course, that if an overload appears on the circuit at a later time, the breaker contacts will then be substantially instantaneously opened and closed in the manner described above.

Inasmuch as the initial circuit opening and following circuit closin operations are not restrained in any manner by the dashpot comprising core 16 and sleeves 14 and 82, these operations may occur so rapidly on relatively high overloads that the counting mechanism either does not operate or operates improperly. In order to overcome this, momentary time delay is imposed due to piston flange 8I of core 16 entering the cylindrical skirt 85 on sleeve 19, to provide a very short dashpot delaying action. This has been found sufficient to'provide for proper operation of the various parts of the breaker and, at the same time, does not materially add to the reclosing time on low overloads.

If the breaker immediately reopens after a first opening and reclosing operation, pawl member I54 this time'will engage the next lower circular flange I46 on the integrator piston I 36, so that the integrator piston acts as a valve to close oil the vent passage I14 from the upper end of dashpot cylinder 14. Inasmuch as the integrator piston I36 does not close the vent passage until bridging contact 36 is substantially at the end of its circuit opening movement, this second closely successive with substantially lnder 14 and core 16. However, on the succeeding reclosing operation, integrator piston I36 having closed the vent at the top of dashpot cylinder' 14, this reclosing operation will be delayed throughout in the manner previously described by the dashpot action of core 16 in cylinder 14. This second reclosing operation will result in leaving piston I36 at the further advanced position described above, from which it eventually will reset in the manner previously described it the breaker remains closed, so that an overload appearing on the circuit at a later time will eration of this series of closely succeeding circuit opening operations, where it blocks the vent passage from the upper end of dashpot sleeve 14.

The circuit closing operation of the breaker following the third openin will be delayed in the manner previously described, inasmuch as such third opening operation results in further advance of integrator piston I36 where it still blocks the vent passageway from the upper end of dashpot sleeve 14. The breaker may then continue to open and reclose if the overload continues, with each opening and closing bein delayed by the dashpot action of core 15 in dashpot sleeve 14 until finally pawl member I54 advances integrator piston I36 an amount sufficient to cause the upper extension I42 thereof toggle lever I04, and

be automatically moved u maintain the breaker contacts separated only in response to a predetermined number of closely successive circuit opening and closing operations, usually four such operations; however, in the event a lesser number of closely successive opening and closing operations occurs, the integrating mechanism will reset and the breaker contacts I I4 in the manner previously described.

In the preferred sequence of operations leading to the breaker contacts being maintained in current characteristic due to the dashpot action 14. Moreover, the

closing operation, with but a momentary delay, with the remaining circuit closing operations being delayed throughout by the dashpot action of core 16 in dashpot sleeve 14.

If desired, a protective gap device I66 of the expulsion type may be provided to prevent operation of the breaker on voltage surges, with the on an extension I68 of at the underside of solenoid coil 24, being secured thereto as by nuts I16 threaded on the tube of the protector device. of the protective device may be connected with conductor H and one side of solenoid coil 24, with the other terminal of the protective device (not shown) connected with the other terminal of coil 2d and conductor I82. This arrester and its particular manner of mounting and connection with this type of apparatus is more particularly disclosed and claimed in the copending application of H. L. Rawlins and J. M. Wallace, Serial No. 694,074 on Overvoltage Protective Devices, filed August 30, 1946, issued April 24, 1951, as Patent No. 2,550,124, and assigned to the same assignee of this invention. As stated above, the purpose of providing a protective device I68 connected in the manner described herein and in the aforesaid cop-ending application is to provide a by-pass for solenoid coil 24 on voltage surges such, for example, as those due to lightning strokes, which are not overloads on the circuit, and consequently, it is not desired that the breaker open on such surges.

It is believed apparent that this invention provides, especially for an automatic reclosing circuit breaker, a simplified type of arc extinguishing structure which provides a highly desirable cross flow of arc extinguishing fluid through the arc, and at the same time provides for extremely rapid gas venting and flushing of the arc space to rapidly restore the dielectric strength thereof on fast opening and reclosing operations of the breaker. This invention also contemplates the provision of an auxiliary time delay device providing for a momentary delay especially for such of the circuit breaker operations as are instantaneous in character. Moreover, the main dashpot for imposing time delay on operations of the breaker is arranged in a manner that contamination from gases produced during circuit interruption is prevented by the expedient of providing the dashpot intake at a zone protected from such gases. Another feature of this invention comprises the provision of a simple form of brake for stopping the high speed circuit opening operations of the breaker.

. Having described a preferred embodiment of theinvention in accordance with the patent statutes, it is desired that this invention be not limited to this particular structure inasmuch as it will be apparent, particularly to persons skilled in the art that many modifications and changes may be made in this particular structure without departing from the broad spirit and scope of the invention. i

We claim as our invention:

1. An automatic reclosing circuit breaker, comprising, a liquid container, separable contacts mounted in said container below the liquid level thereof, at least one of said contacts being movable in a predetermined generally vertical path into and out of engagement with the other contact, overload-responsive means for moving said movable contact to open the circuit, said movable contact being biased to engage the other of said contacts to automatically reclose the circuit following a circuit interrupting operation, tubular means of insulating material open at both ends and supported in a vertical position with said tubular means located entirely below the liquid level in said container to receive said movable contact during its movement to aid in extinguishing the are, a vent opening through said tubular means at one side at a point intermediate said contacts when at their open circuit position and remote from the open ends of said tubular means, the other of said contacts being supported at a position below said vent opening, whereby during a circuit opening operation said movable contact moves from a position below said vent opening upwardly past the vent opening and the gas bubble formed by the action of the are on the liquid rises from a posi- 'tion below the vent opening upwardly past said vent opening to cause movement of the liquid out through said vent opening, and means restricting but not closing the opening at the upper end of said tubular means of insulating material so as to substantially impede the flow of liquid therefrom but permitting substantially free venting of gases therefrom at all times.

2. An automatic reclosing circuit breaker, comprising, a liquid container, separable contacts mounted in said container below the liquid level thereof, at least one of said contacts being movable in a predetermined generally vertical path into and out of engagement with the other contact, overload-responsive means for moving said movable contact to open the circuit, said movable contact being biased to engage the other of said contacts to automatically reclose the circuit following a circuit interrupting operation, tubular means of insulating material open at both ends and supported in a vertical position with said tubular means located entirely below the liquid level in said container to receive said movable contact during its movement to aid in extinguishing the arc, a vent opening through said tubular means at one side at a point intermediate said contacts when at their open circuit position and remote from the open ends of said tubular means, the other of said contacts being supported at a position below said vent opening, whereby during a circuit opening-operationsaid movable contact moves from a position below said vent opening upwardly past the vent opening and the gas bubble formed by the action of the are on the liquid rises from a position below the vent opening upwardly past said vent opening to cause movement of the liquid out through said vent opening, and a flat plate extending across the upper end of said tubular means of insulating material but slightly spaced therefrom to provide freely open vent means at a plurality of points about the upper end of said tubular means.

3. An automatic reclosing circuit breaker, comprising, a liquid container, separable contacts mounted in said container below the liquid level thereoflat least one of said contacts being movable in a predetermined generally vertical path into andout of engagement with the other contact, overload-responsive means for moving said movable contact to open the circuit, said movable contact being biased to engage the other of said contacts to automatically reclose the circuit following a circuit interrupting operation, tubular means of insulating material open at both ends and supported in a vertical position with said tubular means located entirely below the liquid level in said container to receive said movable contact during its movement to aid in extinguishing the arc, a vent opening through said tubular means at one side at a point intermediate said contacts when at their open circuit position and remote from the open ends of said tubular means, the other of said contacts being supported at a position below said vent opening, whereby during a circuit opening operation said movable contact moves from a position below said vent opening upwardly past the vent opening and the gas bubble formed by the action of the are on the liquid rises from a position below the vent opening upwardly past said but above said interrupting chamber and having 'v nt opening to cause movement of theliquid a liquid intake facing said chamber, and means upperend of said tubular means. of said dashpot means.

4. A circuit breaker, comprising, a container 7. An automatic reclosing circuit breaker, for an arc extinguishing liquid, an upright tubucomprising, a liquid container fixed contact endsisupported in said container entirely below uid level therein contact means movable in a mounted for generally upward movement away 111 tubular means located entirely below the liquid spaced above said stationary contact means, and tion and which moves upwardly a predetermined movement of the liqiud out through said vent end thereof and having an opening for slidably opening.

interrupter chamber which is open at both ends 8. An automatic reclosing circuit breaker comsupported in said container below the liquid level prising, a liquid container, fixed contact means thereof and spaced from the bottom of said conmounted in said container below the liquid level tamer, spaced stationary contact means suptherein, contact means movable in a geneially mounted for generally upward movement away 40 lating material open at both ends and supported opening. ing for slidably receiving said piston means, a 6. An automatic reclosing circuit breaker, side opening for said dashpot cylinder above said comprising a liquid container, separable concover and inwardly thereof said piston means v level thereof, overload-responsive means having a short dashpot cylinder having a closed top and circuit interruption operation, an interrupting closely successive operations of the breaker to circuit interrupting operation, dashpot means of operations.

for delaying at least certain of the movements 9. An automatic reclosing circuit breaker comof said operating part in any series of closely prising, a liquid container fixed contact means successive circuit interrupting and reclosing mounted in said container below the liquid level operations, said dashpot means being supported therein, contact means movable into and out of in said container below the liquid level thereof engagement with said fixed contact means, overload-responsive means ,having an operating part biased to a position from which it moves a predetermined distance before movingsaid movable contact means to open the circuit, said movable contact means being biased to automatically close the circuit following a circuit interrupting operation, a first dashpot cylinder receiving piston means on said operating part, said piston means having a short enlarged piston portion, a short dashpot cylinder having a closed end and an open end for receiving said enlarged piston portion at the fully open position of the breaker to momentarily delay reclosing of the breaker, and counting means responsive to a series of closely successive operations of the breaker to render the first-mentioned dashpot cylinder piston means ineffective and efiective to delay movement of said part on different predetermined operations, respectively, in any such series of operations.

1 References Cited in the file of this patent UNITED STATES PATENTS Number 20 Number Div. 37.)

16 Name Date 7 Hilliard Oct. 12, 1926 Paul Mar. 21, 1933 Ronnberg Nov. 12, 1935 Walle Jan. 26, 1937 Nye May 19,1942 Wallace Nov. 2, 1943 Wallace June 20, 1944 Slepian Dec. 19, 1944 Rawlins et a1. Aug. 13, 1946 Kyle, Jr. et al Jan; 18, 1949 Kyle, Jr. et al July 26, 1949 Wallace Oct. 13,1950 Rawlins et a1 Apr. 17, 1951 Van Ryan et al. July 10, 1951 Van Ryan et a1. July 17, 1951 Hubbard Sept. 18, 1951 FOREIGN PATENTS Country Date Great Britain 1913 Great Britain Mar. 2, 1922 OTHER REFERENCES An Improved Automatic M. Wallace, AIEE, tech- (November 1946). (Copy in

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