US2042335A - Circuit interrupter - Google Patents

Description

May 26, 1936. P. J. GLAISTER ET AL CIRCUIT INTERRUPTER Filed Nov. 3, 1934 2 Sheets-Sheet l 5 R O T. N E V m Patented May 26', 193

UNITED STATES PATENT OFFICE Paul J. Glaister, Edgewood, and Herbert L.

Bawlins, Wilkinsburg, Pa., assignors to. Weak inghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 3, 1934. Serial No. 751,306 24 Claims. (01. zoo-r50) Our invention relates to circuit interrupters and particularly to expulsion circuit breakers of the type which utilize an expulsive blast of are extinguishing gas for eifecting the extinguishment of the are which is established incident to the opening of the controlled circuit.

Expulsion circuit interrupters provide the solution to a problem which has, in the past, presented great difliculties to the art, namely, the provision of a reliable yet inexpensive. circuitin terruptingdevice of large arc extinguishing capacity. The commercial forms of these devicesvary widely, but essentially, each comprises means for defining the walls of a chamber or are passage, means for establishing an are therein, and means for producing an expulsive blast ber of a material which is capable of evolving a suitable gas when placed in proximity to an electric arc.

In the operation of these devices, it has been observed that large current magnitude arcs are extinguished much more efliciently and within a much shorter interval of time than low current magnitude arcs. In fact, certain designs of expulsion circuit interrupter-s while capable of efficiently extinguishing arcs of very large current magnitude are incapable of extinguishing low current magnitude arcsat all.

This apparent phenomenon has been carefully investigated and its cause has been determined. The blast of arc extinguishing gas which isproduced during the circuit opening operation is, generally speaking, a function of the current magnitude of the arc. ever, holds true only when the arc is so confined by the walls of the arc extinguishing chamber that intimate contact between the arc of the gas evolving lining of that chamber is effected. Thus, when small current magnitude arcs are drawn within arc passages of large cross sectional area, an insufficient volume of gas is evolved to assure their extinguishment.

Knowing the source of the, dimculty, it would appear that the whole problem could be solved through the provisionoi a chamber having a suihciently small cross sectional area to assure intimate contact between the lining of that chamber and the smallestcurrent magnitude arc which might be drawn therein." Unfortunately,

from being developed within an expulsion device during its operation in interrupting heavy currents, it has been found necessary to provide a chamber which has a cross sectional area not substantially smaller than the cross sectional area of the largest current magnitude are which may be established therein during the operation of the interrupter.

It is thus necessary to utilize a chamber of substantial size, and as a result efllcient operation of the prior art devices at low, currents is precluded. To overcome this limitation and to assure eificlent operation over a wide range of arc current values, is the principal object of the present invention.

One means for overcoming the difllculty discussed above is to utilize an expulsion type cir- This relationship, howhowever, the problem is not so. simply solved.

' In order to prevent reasonably high pressures -magnitude is low, the volume cuit interrupter which is provided with a plunger having a conducting portion for establishing the are within the arc passage, and an insulating portion which is movable into the passage subsequent to the establishing of the arc therein 4 to restrict its volume and to assure intimate contact'between the arc and the gas evolving walls, which define the arc passage. is shown in application Serial No. 718,267 of H. L. Rawlins, which was flied on March 30, 1934, and which is assigned to the assignee of the present invention.

in this device, a single means is utilized for moving both thearc drawing and the volume restricting portions of the plunger. A much greater range oi. satisfactory operation over the earlier devices has thereby been obtained, but even this structure still falls short of accomplishing absolutely reliable operation over as wide a range of current magnitudes as is sometimes desired.

'In the preferred embodiment of the present invention a structure resembling the Rawlins device is utilized. The arc drawing means and the volume restricting means comprise, however, sep-,

Such a structure is automatically moved into the arc passage, so as to assure intimate contact between the arc stream and the gas evolving lining of the passage. The operation of the volume restricting means is controlled either by a means which is responsive to the volume of gas evolved from the gas evolving lining of the arc passage, or it is controlled by some suitable electro-responsive means or the like. Through this arrangement, efficient operation over a very wide range of current magnitudes is assured, and the prolonged arcing which heretofore accompanied the opening of high voltage circuits carrying low magnitude currents by high capacity expulsion devices is obviated.

Another object of our invention is to provide an improved wide range, expulsion type circuit interrupting device which shall be low in cost, simple to manufacture and maintain, and reliable in operation'at all times.

A further object of our invention is to provide an improved expulsion type circuit interrupter which shall utilize a single arc passage and means whereby the volume of that passage may be varied upon the occurrence of predetermined conditions, the volume controlling means being efiected by either an electro-responsive, a time-responsive or a pressure responsive means.

These and other objects of our invention will be made more apparent by reference to the following drawings and description of a preferred embodiment thereof. Referring to the drawings:

Figure 1 is a sectional view, partially in elevation, of a single-pole double-break circuit breaker, wherein are embodied the principal elements of our invention; a

Fig. 2 is an enlarged sectional view through one of the arc extinguishing structures associated with the circuit breaker shown in Fig. 1;

Fig. 3 is a sectional view taken on the line IIIIII of Fig. 2;

Fig. 4 is a sectional view taken on the line IV-IV of Fig. 2;-

Fig. 5 is an enlarged fragmentary View showing the details of the contact structure utilized in conjunction with the circuit breaker illustrated in the other figures of the drawings;

Fig. 6 is a sectional view corresponding to Fig. 2 of a modified form of our invention;

Fig. '7 is an enlarged sectional view on the lin VIIVI I of Fig. 6;

Fig. 8 is a fragmentary sectional view, similar to Fig. 6, showing the details of a modified form of latch and latch releasing mechanism for use with the arc extinguishing device shown in Figs. 6 and 'l; and

Fig. 9 is a fragmentary perspective view showing the armature and latch assemblage utilized in conjunction with the device illustrated in Figs. 6 and 7.

The circuit breaker illustrated in Fig. 1 is of the single-pole, double-break type and includes a suitable cylindrical tank I, which is provided with a cover 3 rigidly aflixed thereto by means, such as the stud bolts 5. A pair of insulator bushings I extend through the cover 3 into the interior of the tank, and are supported thereon by means of flanges 9 and bolts II. A plate member l3 of insulating material closes the lower end of the tank I, and suitable vent openings I are provided for venting the entire structure to the at mosphere.

' A combined arc extinguishing device and con- "tact structure I5 is supported upon the lower end of each of the control conductors l6 which forms the electrical circuit through the breaker.

a part of the bushings I. These devices are adapted to cooperate with a bridging member I'l, having a pair of upstanding contact portions 19, in order to permit the opening or the closing of The bridging member I! is actuated by a suitable pull-rod 2| and operating mechanism (not shown). In order that the various structural details of the arc extinguishing and contact structures l5 may be more clearly visible, these devices have not been illustrated in exact proportion, but have been enlarged somewhat from their normal size.

The preferred form of the are extinguishing and contact structure is shown particularly in Figs. 2, 3, 4, and 5. It includes a cast metallic outer casing .23 which is substantially cylindrical in form, and which is adapted to serve as a support for the remaining portions of the device, and a plurality of plates 25 of insulating material which are assembled, one upon the other, in order to define the walls of an arc passage 21, (excepting a top plate which is provided with a slotted vent opening cut therein). Each of the plates comprises a flat circular member of hard fibre or other insulating material which is formed from an insulating material which is capable of evolving an arc extinguishing gas when placed in proximity to an electric arc. Five circular openings are provided in each of these plates, the outer openings serving to engage insulating studs 29 which are utilized for holding the plates together, and for aflixing them to a flange member 3| which is rigidly secured to the lower end of the casing 23. The central openings in each of the plates align to define the arc passage proper 21. These central openings are slightly larger in cross-sectional area than the upstanding contact portions [9 of the bridging member I! which are adapted to move therethrough during the normal operation of the device. In order to facilitate the entry of these contact portions I9 into the arc passage 21, the lower end of the central opening in the bottom plate 25 is flared.

The upper plate 25 is provided with a cut out portion 33 which serves to form a vent opening for preventing the building up of dangerous high pressures in the arc passage during the circuit interrupting operation. Insulating materials other than hard fibre may be used for forming its insulating qualities, particularly recommends that material.

, The contact structure associated with each of the devices l5, as shown particularly in Figs. 2, 4 and 5, comprises a pair of pivotally supported finger members 35, biased toward each other by suitable springs 31 which engage recesses in the contact members and in the walls of the casing 23. Each of the fingers 35 is provided with a downwardly projecting portion 38 which is adapted to cooperate with the edges of recesses 39 formed in the flanged portion of the main casing in order to limit the motion of the fingers toward each other. Suitable flexible shunts 4| connect the fingers with the casing 23, and when the breaker is in the closed circuit position, as is shown in Figs. 4 and 5, each set of opposed lin-- gers 35 engage opposite sides of each of the cooperating upstanding contact portion I 9 of the bridging member.

A supporting clamp 43 is cast integral with each of the main casings 23 in order to permit the combined contact structure and are extinguishing devices I to be supported on the lower end of the conductors I5 extending through the insulating bushings I. The upper end of each of the casings 23 is closed by means of a cap 'member 45 which is screwed thereon, .this cap member being provided with an adjustable, spring biased valve 41 of the ball type for controlling the rate at which air may be drawn into or taken from the upper portion of thechamber 49 within the casing 23.. The interior portion of the capmember 45 comprises a tubular member 5I, the outer edges 53 of which are threaded for engaging a spring 55 which is positioned within the casing, and the interior of which is machined drical chamber 51 formed in the cap member in order to give a dashpot action during its .operation. The spring 55 engages the upper surface of the guide member SI and serves to bias the insulating member 59 in the direction of the arc passage.

In the several figures of the drawing the various structural features of thecircuit interrupter are shown in the closed circuit position. Upon the occurrence of an overload or other condition, which is capable of causing the circuit breaker actuating means to move the bridging member I1 toward the open circuit position, the upstanding contact portion I9, which engages each of the two pairs of cooperating contact fingers 35, is moved toward the open circuit position, and when those portions disengage the cooperating fingers, an arc is estab within each of the arc passages 21. The insulating rod 59,'which comprises the volume restricting means for each of the devices, does not move downwardly into the adjacent arc passage 21v immediately following the movement of the" upstanding contact portion normally abutting thereagainst, because of the restraining action of the dashpot formed by the cooperating piston and cylinder portions 63 and. 51.

If the overload producing the operation of the breaker is one 0! large current magnitude, "the are which is established in each of the are passages is of large cross-sectional area and thereby causes the evolution 01' a large amount fof are extinguishing gas from the gas evolving lining of each of the two passages. This gas creates a pressure which is transmitted to the lower-surface of the guide member SI for the volume restricting means, and if the magnitude of the arc is sufliciently large that the volume restricting means is not necessary to efi'ect its extinction, the movement of that means into the arc passage is entirely prevented, the spring 55 being properly calibrated with respect to the other dimensions of the device.

If, however, the are which is a olished within each of the arc passages is 0; low current magnitude, a comparatively small amount of gas would be evolved, and the pressure resulting from this will be incapable of effecting any substantial retarding oi the normal downward movement of the volume decreasing means, and as soon as the dashpot action has persisted for a predetermined time, depending upon the setting of the spring valve 41, that means will be free to move into the associated arc passage under the influence of its biasing spring. The immediate result of this movement is to decrease the dimensions of the arc passage very'materlally and to assure an intimate contact between the arc and the gas evolving lining of the arc passage. As a'result, an adequate volume of arc extinguishing gas is made available for effecting the extinguishment of each of the two arcs within a short period of time.

The amount of time delay introduced into the operation of the volume decreasing means by the dashpot means is variable over a comparatively wide range, but is usually adjusted so as to introduce a delay of perhaps 3 to cycles in the operation of that means. Since large current arcs are usually extinguished within not more than two or three alternations, this assures that the operation of the device will be reasonably uniform as to arcing time, and will 'be equally eflicient upon either high or low currents.

The provision of the vent in the upper plate immediately adjacent the point at which the arc is initially established aids in preventing the.

rapid development of undesirable high pressures within the arc extinguishing device during its operation, and, in addition, it causes the outwardly flowing arc extinguishing gas to flow through the arc passage substantially longitudinally, thus efiecting an extremely turbulent intermixing of the arc with the arc extinguishing gas, and as is well known in the art, thereby aiding the process of arc extinction.

i If desired, the dimensions of the guide portion 5| oi the volume restricting means may be made sufiicientlylarge to prevent any piston action between that member and the casing 23. This arrangement has av tendency to speed up the operation of the breaker somewhat, but either arrangement is quite satisfactory.

The modified form of our invention illustrated in Figs. 6 through 9 operates in essentially the same manner as the previously described structure. Each of the combined arc extinguishing and contact structures II5 comprise a cylindrical metallic casing I23 which is closed at its upper end by a suitable cap member I45 and is pro-v vided with a. flanged member I3I for supporting the associated are extinguishing device. The dimensions of this flanged portion I3I are the same as those of the similar member 3I in the previously describedemb'odiment, and a plate type are extinguishing structure of exactly the same form is preferably utilized therein. 'Likewise, the contact structure is essentially the same and comprises a pair of pivoted fingers I biased toward each other by suitable springs I31.

The arrangement of the volume decreasing means is, however, somewhat difierent. The volume decreasing member I59 which enters the arc passage 21 is a cylindrical rod of insulating material, such as hard fibre, which is supported upon a metallic guide rod I15 to which is affixed a latch engaging member I11 intermediate its ends and a piston member I6I at its upper end. The piston member IBI is adapted to engage the walls of the upper portion of the main easing I23 and is biased downwardly in the direction of,

the associated arc passage 21 by means of a the cap portion I45. The volume decreasing means is prevented from moving under the biasing action of this spring by an electro-responsive trip unit I19, which includes a pivoted latch member I8I.

' The latch I8I, mentioned above, is pivotally supported at the inner end of this casing I83 and is released by movement of an armature I85, shown particularly in Fig. 9. A compression spring I81 biases this armature toward the latched position and it is moved to the unlatched position by the attraction of a coil I89 which is energized by suitable relay means only during the occurrence of moderate overloads. By this means the biasing spring I81 is effective to hold the device in the latched position except when the magnitude 01' the current flowing in the controlled circuit lies within a predetermined range, which range is determined by the operational characteristics of the device.

The operation of the preferred form of our invention is essentially the same as that described above- Upon the occurrence of an abnormal condition capable of effecting an operation of the main breaker mechanism, the :bridging means I1 automatically moves downwardly, taking with it the upstanding contact portions I9. An arc is thus immediately established between the contact fingers I35 and the upper end of each of these contact portions, which are is progressively lengthened within each of the arc passages 21 as the opening operation progresses. If the current magnitude of these arcs is sufficiently large, the relay means for effecting the energization of the holding coil I 89 for each of the latches I8I does not operate, and as a result the two latches remain in the latched position, thereby preventingany movement of the volume decreasing means during the operation 01' the breaker. The range of currents during which the coils I89 are energized to effect the release of the latches I8I is carefully calibrated in order that the volume decreasing means shall be restricted from movement only when the current magnitudeof the overload is sufllciently large to assure rapid extinction of each of the arcs drawn within the arc passages 21.

As a further means for preventing the operation of the device from taking place at a too rapid rate, the piston portion I6I of the volume decreasing means fits tightly against the adjacent walls of the main casing. The pressure of the gas which is evolved within the arc passage during the operation of the device is thus transmitted directly to the volume decreasing means, and that means is prevented from moving when the large current magnitude arcs have been established therein, even if the latch means should become inoperative.

In certain applications, it is'desirable that the volume decreasing means shall not move into the arc passages until a predetermined time interval has elapsed subsequent to the'establishing of an are within those passages. In the latched type of device just described, this may be conveniently accomplished through the provision of a dashpot piston I9I and a cylinder I93, as is shown in Fig. 8. With this arrangement, the downward movement of the member I 59. which decreases the volume of the arc passages 21, is positively prevented from taking place until a certain deflnite interval of time has elapsed subsequent to the establishing of an are within each of those passages.

The volume reducing members 58 and I! are preferably formed of hard fibre or similar material. By doing this the maximum possible amount of arc extinguishing gas is made available during each circuit opening operation, and the maximum possible efliciency of the device is attained. Refractory insulating material may likewise be used, however, with reasonable success, but regardless of what material is used there should be some clearance between the volume reducing means and the walls of the arc passage when that means moves therein. Through theprovision of clearance it is possible for the arc extinguishing gas to flow freely through the arcstream, and snufiing of the arc, with the undesirable resultant voltage transients, is pre vented.

From the foregoing, it will be seen that we havedisclosed the details of an improved form of expulsion circuit interrupting device which is capable of satisfactory operation over a very wide range of current magnitudes. Our improved breaker includes means for defining the walls of an arc passage of a fixed volume and a separate means for decreasing the volume of that passage upon the occurrence of certain predetermined conditions, in order to assure intimate contact between the walls if the arc passage and the arc stream itself. Preferably, the arc passage is lined with a gas evolving material in order to assure an adequate volume of arc extinguishing gas during the operation of the device.

In one form of our invention, the volume decreasing means is operable to move into the arc passage only after a predetermined time delay, which depends, in part, upon the amount of arc extinguishing gas which is evolved from the lining of the arc passage, the amount of this gas being one measure of the operational ability of the breaker.

In another modification of our invention, the movement ofthe volume decreasing means is made responsive to the electrical conditions in the controlled circuit, and in a further modification, it is made responsive to the electrical conc ditions in that circuit, and at the same time is controlled in its operation by a time delay means.

It will be apparent to those skilled in the art that numerous modifications of our invention may be made without departing from the broad principles which we have disclosed. It is our intention, therefore, that the language of the accompanying claims shall be accorded the broadest reasonable construction, and that our invention shall be limited only by what is expressly stated therein and by the prior art.

We claim the following as our invention:

1, In a ,circuit interrupter, rigid means for defining the walls of a passage having substantially fixed dimcnsions,-means for establishing an are within said passage, means, normally disposed without said passage, which is movable into said passage to decrease the volume thereof during the operation of said interrupter, and actuating means for said movable means including means whereby said movable means is moved into said passage only following the establishing of a low current magnitude arc therein.

2. In a circuit interrupter, means defining a passage having substantially fixed walls, means for establishing an are within said passage, means movable into said passage to decrease the volume thereof during the operation of said interrupter, and actuating means for said movable means including means operable a predetermined time after arcs of predetermined current magnitudes have been established within said passage to move said movable means therein.

3. In a circuit interrupter, means defining a passage having substantially rigid walls, at least a'portion of said passage being lined with a material capable of evolving an arc extinguishing gas when placed in proximity to'an electric arc, means for establishing an are within said passage, means movable into said passage during the operation of said interrupter to decrease the volume of said passage and to effect an intimate engagement between the arc and said gas evolving lining, and actuating means for said movable means including means for causing a predetermined time interval to elapse subsequent to the establishing of said arc before said movable means is moved into said passage.

4. In a circuit interrupter, means defining the walls of an arc passage, means for establishing an arc within said passage, means, normally positioned without said passage, which is movable into said passage to decrease the volume thereof during the operation of said interrupter, actu-' I ating means for said movable means, and electroresponsive means for preventing said actuating means from moving said movable means into said are passage except during the existence of certain predetermined conditions.

5. In a circuit interrupter, means defining the walls of an arc passage, means for establishing an are within said passage, means, normally positioned without said passage, which is movable into said passage to decrease the volume thereof during the operation of said interrupter, means for biasing said movable means into said passage, and electro-responsive means forpreventing said biasing means frommoving said movable means into said are passage except upon the occurrence of predetermined conditions.

6. In a'circuit interrupter, means defining the walls of an arc passage, means for establishing an are within said passage, means movable into said passage to decrease the volume thereof during the operation of said interrupter, actuating means for moving said movable means into said passage, and means including a dashpot for limiting the speed at which said movable means may be moved by said actuating means.

'7. In a circuit interrupter, means defining the walls of an arc passage, means for establishing an are within said passage, means, movable into said passage to decrease the volume thereof during the operation of said interrupter, actuating means for moving said movable means into said passage, and time delay means for preventing said actuating means from moving said movable means intb said passage until a predetermined period of time 'has elapsed following the establishing of an arc therein.

8. In a circuit interrupter, rigid means, at least partially of insulating material, for defining the walls of an arc passage, means for establishing an' arc within said passage, a plunger means, which is at least partially of insulating material,

and which is adapted to be moved into said are passage to decrease the volume thereof during the operation of said interrupter, and actuating means for said interrupter including means opera able after a predetermined time interval has elapsed following the establishing of an arc within said passage to move said plunger means therein.

9. In a circuit interrupter, means for defining the walls of an arc passage which is lined with insulating material, means for establishing an arc decrease the volume thereof during the opera-- tion of said interrupter, actuating means for moving said plunger means into said passage, and time delay means for preventing said actuating means from moving said plunger means into said passage until a predetermined period of time has elapsed following the establishing of an arc therein.

10. In a circuit interrupter, fixed means, at least partially of insulating material, for defining the walls of an arc passage, means for establishing an arc within said passage, a plunger means, which is at least partially of insulating material, and which is adapted to be moved into said arc passage to decrease the volume thereof during the operation of said interrupter; spring means for biasing said plunger means into said passage and electro-responsive means for preventing said actuating means from moving said movable means into said passage until a predetermined period of time has elapsed following the establishing of an arc therein, I ii. In a circuit interrupter, means defining a passage having substantially rigid walls, at least a portion of said passage being lined with a material capable of evolving an arc extinguishing gas when placed in proximity to an electric are, means for establishing an are within said passage, means, normally disposed without said passage, which is movable into said passage during the operation of said interrupter to decrease the volume of said passage and to effect an intimate engagement between the arc and said gas evolving lining, actuating means for said interrupter including means for moving said movable means,

and electro-responsive means for preventing said movable means from being moved into said passage except during the existence of certain predetermined conditions.

12. In a-circuit interrupter, means defining a, passage having substantially fixed walls, at least a portion of said passage being lined with a material capable of evolving an arc extinguishing 'said movable means except upon the occurrence of predetermined conditions. l

13. In a circuit interrupter, means defining a passage having substantially fixed walls, at least a portion of said passage being lined with a material capable of evolving an arc extinguishing gas when placed in proximity to an electric arc, means for establishing an arc within said passage, means movable into said passage during the operation of said interrupter to decrease the volume of said passage and to effect an intimate en- 'gagement between the arc and said gas evolving 1s lining, actuating means for moving said movable means into said passage, and time delay means for preventing said actuating means from moving said movable means into said passage until a predetermined period of time has elapsed following the establishing of an arc therein.

I 14. In a circuit interrupter, rigid means for defining the walls of an arc passage, means for establishing an are within said passage, means for producing a pressure within said passage following the establishing of an arc therein, means movable into said passage to decrease the volume thereof during the operation of said interrupter, and means operable a predetermined time subsequent to the establishing of said are to move said movable means into said passage provided that the pressure existing therein does not exceed a predetermined value.

15. In a circuit interrupter, rigid means for defining the walls of an arc passage, means for establishing an arc within said passage, means for producing a pressure within said passage follow-.

ing the establishing of an arc therein, means movable into said passage to decrease the volume thereof during the operation of said interrupter, means for biasing said movable means into said passage, and means for preventing said biasing means from moving said movable means into said passage except upon the occurrence of predetermined conditions, said motion preventing means including a piston, a guide means for said piston, and means for subjecting said piston to the pressure developed within said passage.

16. In a circuit interrupter, rigid means for defining the walls of an arc passage which is lined with insulating material, means for establishing an are within said passage, means, at least partially of insulating material, which is normallydisposed without said passage and which is movable into said passage to decrease the volume thereof during the operation of said interrupter, means capable of evolving an arc extinguishing gas when placed in proximity to an electric are disposed so as to contact the are which is established within said arc passage, the gas which is evolved from said means producing a pressure within said arc passage, and means responsive to the pressure developed within said passage for moving said movable means into'said passage.

17. In a circuit interrupter, rigid means for defining the walls of an arc passage which is lined with insulating material, means for establishing are passage, the gas which is evolved from said' means producing a pressure within said are passage, which is substantially proportional to the current magnitude of the arc which is established within said arc'passage, means responsive to the pressure developed within said passage for moving said movable means into said passage, and time delay means for preventing said pressure responsive means from moving said movable means into said passage until a predetermined period of time has elapsed following the establishing of an arc therein.

18. In a circuit interrupter, means defining the walls of an arc passage, means for establishing an are within said passage, means for producing a pressure within said passage following the estab posed without said passage, which is movable into said passage to decrease the volume thereof duringthe operation of said interrupter, operating means actuable to move said movable means into said passage, and means responsive to the pressure developed within said passage for preventing said means from moving said movable means into said are passage except when said pressure falls below a predetermined value.

19. In a circuit interrupter, rigid means for defining the walls of an arc passage, means for establishing an arc within said passage, means for producing a pressure within said are passage following the establishing of an are therein, said pressure being proportional to the current magnitude of the arc, rigid means of insulating material, normally disposed without said passage, which is movable into said passage to decrease the volume thereof during the operation of said interrupter, means for moving said movable means into said passage and means responsive to the pressure developed within, said passage for controlling the operation of said means for moving said rigid volume restricting means.

20. In a circuit interrupter, rigid means for defining the walls of an arc passage, means for establishing an arc within said passage, means,

at least partially of insulating material, which is normally disposed without said passage and which is movable into said passage to decrease the volume thereof during the operation of said interrupter, means capable of evolving an are extinguishing gas when placed in proximity to an electric are disposed so as to contact the are which is established within said are passage, the gas which is evolved from said means producing a pressure within said are passage, which is substantially proportional to'the current magnitude of the are which is established within said arc passage, means for biasing said movable means into said arc passage, and means responsive to the pressure developed within said are passage during the circuit opening operation for preventing said biasing means from moving said movable means except upon the occurrence of predetermined conditions.

21. In a circuit interrupter, rigid means for defining the walls of an arc passage which has a length at least several times its greatest width, means for establishing the arc incident to eachopening operation of said interrupter within said passage, means of insulating material which is normally disposed without said passage and which is movable longitudinally into said passage to decrease the volume thereof during the operation of said interrupter, actuating means for said movable means, and means whereby said actuating means is prevented from moving said movable means into said are passage except when the current magnitude of the are which is estab lished therein is less than a predetermined value and said are has existed within said arc-passage for a predetermined interval of time subsequent to its establishment therein. 22. In a circuit interrupter, rigid means for defining the walls of an arc passage which has the general form of a prism, the length of said passage being at least several times its greatest cross sectional dimension, a. rod member normally disposed without said passage and movable longitudinally into and through said passage t0 decrease the volume thereof during the operation of said interrupter, said r d. member being formed at least in part of insulating material and havingacross sectionalareawhichislessthanthe cross-sectional area of said are pasage, actuating means for moving said rod member and means whereby said actuating means is prevented from moving said rod member into said are passage except when the current magnitude of said are is less than a predetermined value and said are has existed within said are passage for a predetermined interval of time subsequent to its establishment therein.

23. In a circuit interrupter, rigid means for defining the walls of an arc passage which is substantially cylindrical in form, contact means movable through said are passage to establish the arc incident to each.opening operation of said interrupter therewithin, a cylindrical rod member normally disposed without said passage and movable longitudinallyinto and through said passage to decrease the volume thereoi during the operation of saidinterrupter, said rod member being formed at least in part of insulating material, havinga less cross sectional area than said are passage, and being adapted to be positioned concentric with said are passage when it is moved into and through that passage, actuating means for said movable rod member, and means whereby said actuating means is prevented from moving said rod member into said arc passage except when the current magnitude of said are is less than a predetermined value and said archasexistedwithin saidarcpassageiorapredetermined interval of time subsequent to its establishment therein.

24. In a circuit interrupter, rigid means for defining the walls 0! an arc pasage which has the general term of a prism, the length of said passage being at least several times its greatest crow-sectional dimension and at least a portion of said passage being lined with a material capable oi. evolving an arcextinguishing gas when placed in proximity to an electric are, means for establishing the arc incident to each opening operation of said interrupter longitudinally within said passage, a rod member formed at least in part of insulating material which is movable longitudinally into and through said passage during the operation of said interrupter to decrease the volume of said passage and to eiIect an intimate engasemcnt between the arc and said gas evolving lining, said rod member being normally disposed without saidare passage and having a cross-sectional area which is less than the cross-sectional area of said passage. actuating means for moving said movable means, and means whereby said actuating means is prevented from moving said movable means into said are passage except when the current magnitude of said are is less than a predetermined value and said are has existed within said passage for a predetermined interval of time subsequent to its establishment therein.

' PAUL J. GIAISTER.

HERBERT L.

. DIJSCLAIMEIR v 2,042,335.Paul J. Glaister; Edgewood, and Herbert, L. 12mm, Wfikinsburg, Pa.

'CIRCUIT INTERRUP'IEB. Patentdatod May 26, 1936. Disclaimer filedgctober 31, 1936, by the assignee, Westinghouu E'edfic d: Mdnujaduring Hereb enters this disclaimer to claims 1, 4, 5, 11 and 12 of the specification. v

[ Gazette December 1, 1986.1

DlgQLAlM ER 2,042,385.Pau'l J. 01am"; Edgewood, and Herbert, L. Rdwlim, Wflldnsburg', Pa.

'Gmcm'r ln'r'nnnur'rnn. Patenfldated May 26, 1936. Disclaimer filedgcfober 31, 1936, by the aesignee, Wafinghouge Hedi-i0 d: Mdmgfacturing ompany.

Hereb entera this disclaimer to claims 1, 4, 5, 11 and 12 of the specification.

[ v Gazette Decembcr 1, 1986.]

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