US2284347A - Circuit interrupter - Google Patents

Description

y 6, 9 A. P. STROM 2,284,347

C IRCUIT INTERRUPTER Filed Sept. 8, 1938 6 Sheets-Sheet 5 INVENTOR y 26, 9 A. P. STROM 2,284,347

CIRCUIT- INTERRUPTER Filed Sept. 8, 1938 6 Sheets-Sheet 4 Fig /0.

WITNESSES: INVENTOR 7 "May 26, 1942. A. P. STRoM 2,234,347

CIRCUIT INTERRUPI'ER Filed Sept. 8, 1938 6 Sheets-Sheet 5 WITNESSES: lNVENTOR Z5. 4 fl/er/Pb'from WM 6- May 26, 1942.

WITNESSES:

A. P. STROM 2,284,347

CIRCUIT INTERRUPTER 6 Sheets-Sheet 6 Filed Sept. 8, 1938 INVENTOR /7/z9er/' fla /rain.

Patented May 26, 1942 omcul'r lNTEBRUPTER Albert P. Strom, Forest Hills, Pa., assignor to Westinghouse Electric 3; Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 8, 1938, Serial No. 228,931

27 Claims.

This invention relates to circuit interrupter's,

' and more particularly to high voltage, high power circuit breakers of the liquid immersed type.

Modern circuit breakers which are capable of interrupting a large number of volts per inch of contact separation employ various means for controlling the are after it is drawn. The first factors which are sought to be controlled are the location, elongation, restriction and relative motion of the arc with respect to the arc extinguishing liquid and the pressure within the arcing chamber.

A number of schemes have in the past been employed to obtain the requisite arc control as, for example, those which utilize the magnetic properties of the current in the circuit; those which utilize the thermal properties of the arc itself, those which use mechanical means independent of the circuit conditions or combinations of any two or all of the schemes mentioned.

The main object of my invention is the provision of a high power circuit breaker having improved interrupting ability and wherein are control is accomplished substantially by mechanical means. i

A further object of my invention is the provision of a circuit interrupter employing are extinguishing means wherein the arc to be extinguished is rapidly lengthened and subjected to a strong deionizing action along the entire length of the arc.

Another object of the invention is the provision of arc extinguishing means for high voltage, high power circuit interrupters wherein rapid deionization of the arc is obtained by squeezing the are into a very narrow slot or passage filled with are extinguishing liquid.

Another object of my invention is the provision of a high voltage circuit breaker having arc extinguishing means equally effective over a wide range of current values.

A still further object of my invention is the provision of a circuit breaker of the above named type employing a relatively small number of moving parts of light weight which may be accelerated rapidly to obtain high speed operation of the breaker without the expenditure of a large amount of power,

Other objects and advantages relate to the arrangement of the various parts of the breaker structure-and will appear more fully in the following description when taken in connection with the accompanying drawings, in which:

Figure 1 is a side assembly view partially in elevation and partially in section showing the circuit interrupter of my invention,

Fig. 2 is a sectional view of the arc extinguishing structure of the interrupter in Fig. 1, showing the interrupter in the closed circuit position,

Fig. 3 is a sectional view similar to that of Fig. 2, showing the interrupter in the open circuit position,

Fig. 4 is a fragmentary sectional view of the arc extinguishing device of my circuit interrupter taken along the line IV-IV of Fig. 2,

Fig. 5 is a cross sectional view of the are extinguishing device of my circuit interrupter taken along the line V--V of Fig. 2,

Fig. 6 is a fragmentary sectional view showing a modified form of arc extinguishing device which may be used in the interrupter housing shown in Fig. 1,

Fig. 7 is a cross sectional view of a modified form of an extinguishing device similar to that shown in Fig. 6, taken along the line VII-VII of Figure 9,

Fig. 8 is another sectional view of the interrupter shown in Fig. 6 taken longitudinally along the line VIII-VIII thereof,

Fig. v9 is a vertical sectional view of an arc extinguishing device showing a somewhat different are control arrangement than that shown in Fig. 6,

Fig. 10 is a sectional view of another form of arc extinguishing device constructed in accordance with the principles of my invention,

Fig. 11 is a cross sectional view of the arc extinguishing device of Fig. 10 taken along the line XIXI,

Fig. 12 is another cross sectional view of the arc extinguishing device of Fig. 10 taken along the line X1I-XII,

.Fig. 13 is an assembly view partially in elevation and partially in section showing a further form of circuit interrupter embodying my invention,

Fig. 14 is a longitudinal sectional view of the arc extinguishing structure in the closed circuit position of the circuit interrupter shown in Fig. 13,

Fig. 15 is a sectional view showing the arc extinguishing structure of Fig. 14 in the open circuit position,

Fig. 16 is a top view of the arc extinguishing structure shown in Fig. 14,

Fig. 17 is a cross sectional view of the are extinguishing structure of Fig. 14 taken along the line XVIIXVII thereof,

Fig. 18 is a view or the arc extinguishing device of Fig. 17 with certain of the operating levers removed to more clearly show the contact arrangement, and

Fig. 19 is a cross sectional view of the are extinguishing device of Fig. taken along the line XIX-XIX thereof.

In Figure 1, the reference numeral 2| designates a base having an upper supporting plate 23 to which is secured a cylindrical support and strain member 25. of insulating material. To the upper end of the cylindrical member 25 is secured an annular support plate 21 which in this instance serves to support the arc extinguishing structure of the circuit interrupter and also serves to support the external housing of the interrupter as will appear more fully hereinafter. Also mounted upon the support plate 23 is a flanged support member 29 which, in turn, carries a tubular weather-proof housing 3| preferably of porcelain or other suitable material. Between the housing 3| and the annular support plate 21 is disposed an annular expansion member 33 of C-shaped cross section for the purpose of maintaining the weather-proof housing 3| in compression. It will be understood that suitable sealing means as gaskets are employed between the tubular strain member 25 and the base 2| as well as between the outer housing 3| and the support flange 29 and the base 2| so as to prevent the escape of arc extinguishing liquid with which the housing structure is filled.

Suspended from the annular support plate 21 and projecting downwardly into the tubular strain member 25 is an arc extinguishing device generally indicated at 35 in 'Fig. 1 and more clearly shown in Figs. 2 to 5, inclusive. The are extinguishing structure 35 comprises a cylindrical housing 31 of insulating material, the

' upper end of which is provided with a metallic framework 39 by which the arc extinguishing device is supported from the annular plate 21.

A pair of contact supports 4| are positioned in diametrically opposed relation within the tubular housing 3'! and may be secured to the housing by means of bolts 43, as shown. The contact supports 4| each has an outwardly projecting portion at the lower end thereof which extends through the side walls of the housing 31 to form external terminals and 4?, respectively. The contact supports 4! also have an upwardly projecting arm 49 to which is pivoted a contact actuating arm 5|.

Each of the contact carrying arms 9| has a movable contact 53 secured to the lower end thereof. The two contacts 53 are adapted for cooperative engagement with each other and are maintained in spring pressed engagement by means of springs 55. Flexible shunts 51 provide a low resistance circuit from the respective contacts 53 to th terminal members.

Disposed immediately below the contacts 53 is a slot-like arc passage 59 of rectangular cross' section and preferably having its opposed inner walls formed of corrugations, as shown in Fig. 2. The are passage 59 may be formed by the use of a series of circular plates 6| and 63 ofinsulating material, alternately disposed to provide a stack and having a rectangular slot therein. The slot in the plate 6| is preferably narrower than the slot in the plate 63 so as to provide the corrugated inner surface previously mentioned. The corrugated arc passage wall is favored since it maintains a more liberal quantity of are extinguishing liquid adjacent the arc path during are extinction than is maintained by an arc pas sage wall having a smooth surface.

The plates BI and B3 are maintained in compression between the contact supports 4| and a piston chamber member 65 disposed at the lower end of the tubular housing 31. The member 85, the purpose of which will be more fully described hereinafter, may be held in place by an annular plate 81 bolted to a metallic flange 69 secured to the lower end of the casing 31, as shown.

Disposed within the casing 31 and adapted for longitudinal axial movement therein is a contact actuating and barrier member 1| which preferably is constructed of insulatingmaterial having a high dielectric strength and heat resistant properties when subjected to the direct action of an arc. The barrier member II is substantially the same width as the arc passage 59 and of thickness such that it provides preferably from to ,4 clearance on the longer sides thereof The barrier member H is also provided with a rectangular aperture I3 into which the moving contacts 53 project from opposite sides thereof to complete the electrical circuit through the interrupter. The upper end of the barrier member II is provided on each side thereof with cam surfaces I5 adapted to engage a roller 11 Jour- 'naled within the contact actuating arms 5|. The

cam surfaces 15 and the rollers I1 are also pref erably constructed of high dielectric strength insulating material so as to increase the open circuit resistance of the interrupter. The extreme upper end of the barrier member 1| is provided with a coupling member 19 adapted to be connected to a spring actuating mechanism generally indicated at BI and housed within the chamber 83 as shown in Fig. 1. The lower end of the barrier member extends through a snug fitting aperture in the piston chamber member 65 and is provided with a suitable coupling 85 to which the breaker actuating mechanism, a part of which is shown at 81, is connected.

From the foregoing description, it will be apparent that the actuating mechanism 91 when held in the position shown in Fig. 1, maintains an upward thrust upon the barrier member H which, in turn, holds the spring actuating mechanism 8| in compression ready to drive the barrier member H downwardly when the operating mechanism 8'! is tripped or released so as to effect a circuit opening operation. The electrical circuit through the interrupter as more clearly shown in Figs. 1 and 2 proceeds from a line terminal 89 projecting through the side wall of a cover 9| of the interrupter housing and continues by way of a flexible connection 93 to the support plate 2! which, in turn, is connected to a conductor 95 making connection with the terminal 45 of the contact support 4|. The connection then proceeds through the flexible shunt 51 to the left-hand movable contact member 53 and then to the right-hand contact 53, flexible shunt 51 and the fixed terminal 41. A conductor 97 connects the terminal 41 of the arc extinguishing device 35 to an external terminal 99 extending through the base 2|.

In the event that the circuit breaker, as shown in Fig. 1, is connected in a power circuit through the external terminals 89 and 99 and it is desired to interrupt the circuit, the operation of the breaker is as follows:

Upon tripping of the circuit interrupter which releases the operating mechanism 81, the spring means 8| forces the barrier member 'Il downwardly. The cam surfaces III on either side of the barrier member 1| engage the two -.rollers 'I'I carried by the contact actuating arms 5I so as to separate these arms and consequently separate the contacts 53. The leading edges of the cam surfaces ii are so proportioned in connection with the contact actuating arms 5I that the contacts 53 will have separated sufficiently by the time the upper edge of the aperture I3 in the barrier member 'II reaches the former contact position to permit the barrier II to pass between the contacts. Thus the arc is established between the contacts 53 and through the aperture Upon continued movement of the barrier II, the wedge-shaped upper edge of the aperture I3 is driven into the areand moves the same downwardly into the slot-like are passage 59, causing the arc to be lengthened rapidly and to be forced into the confined space on'either side of the barrier member. The relative position of the barrier member and contacts with respect to the arc passage upon reaching full open circuit position is shown in Fig. 3.

Inasmuch as the barrier member II immediately below the aperture I3 has a reduced width as shown in Fig. 4 so as to form shoulders IOI, arc extinguishing liquid is driven by virtue of these shoulders which serve as pistons, upwardly along the arc stream. Also, formation of the arc within the confined slot-like are passage produces considerable gas as a result of decomposition of the arc extinguishing liquid which, in escaping from the arc chamber 59, must flow longitudinally of the arc stream on either side of the barrier member II towards the upper and open end of the arc chamber. Thus substantially the entire length of the arc is subjected to a violent deionizing action which takes place substantially immediately upon formation of the are thereby hastening arc extinction. Arc extinction is also facilitated due to the fact that the arc is coninuously lengthened during the deionizlng process. Although the arc passage on either side of the barrier member II is extremely narrow, arcs of large as well as small current magnitude are successfully extinguished since the are core may spread out laterally in accordance with the current magnitude.

In order to rid the are passage 59 of undesirable products of decomposition of the are, I have provided a flushing arrangement adjoining the lower end of the chamber. The flushing arrangement in this instance comprises a piston I03 surrounding the barrier member II and operative within the piston chamber 65. The piston I03 is normally held by a spring I05 in the position shown in Fig. 2, that is in engagement with the upper wall of the chamber 65. The chamber 65 is provided with a plurality of passages I'I communicating with the lower end of the arc chamber 59.

59 exceeds a predetermined value, liquid in the lower portion of the chamber will be forced through the openings I01 into the chamber 65 and drive the piston I03 to the position shown in Fig. 3 against the bias of the spring I05. Upon extinction of the arc and subsidence of the pressure within the chamber 59, the spring I again returns the piston I03 to its uppermost position driving the oil previously collected above the piston through the passages I01 into the arc chamber 59 and upwardly through the open end thereof so as to flush out any sediment or other impurities which may have collected as a result of the circuit interrupting operation.

In the interrupter shown in Figs. 6 and 8, a barrier member I09 is illustrated of somewhat different form than the barrier member 'lI previously described. In the modified form the aperture I3 has been omitted and a contact bridging member III has been substituted therefor. The bridging contact member III, when the barrier member I08 is in the closed circuit position, is interposed in contacting engagement between a pair of contacts H3, each oiwhich is secured to the end of a contact support rod H5. The contact support rods H5 are. carried within the tubular support guides II! of the fixed contact terminals H9 secured on diametrically opposed sides of the tubular casing 31.

The contacts H3 are yieldingly maintained in engagement with the bridging contact member III by springs I2I surrounding the contact carrying rods H5. The are extinguisher arrangement shown in Figs. 6 to 9 also differs somewhat from that previously described, in that the shape of the slot-like are passage has been modified. In this instance the arc passage dimension has been decreased in the direction parallel to the I width of the barrier member I09 to substantially Thus during the circuit opening operation when the arc pressure within the chamber the width of the bridging contact member III, as shown at I23 in Fig. '7. The are passage I23 is defined by a plurality of alternate plates I25 and I21 of insulating material having slots therethrough the major portion of which have an outline conforming to the cross section of the barrier member I09 with the exception that the portion adjacent the bridging contact member III has been enlarged, the enlargement in the plates I21 being greater than in the plates I25 so as to provide an irregular surface.

Thus, when the barrier member I09 is moved downwardly carrying with it the bridging contact member III so as to move the bridging member out of contact engagement with the contacts H3, two arcs are drawnone on each side of the barrier member I09 into the arc passage I23. In this arrangement, the two separate arcs are confined respectively to a relatively long and narrow passage and are not permitted to spread laterally to the extent permitted in connection with the structure previously described.

The clearance between the moving barrier member I09 and the edge of the slot forming the arc passage I23 may vary from A; to inch. Movement of the contact bridging member III downwardly into the arc passage I23 also provides a longitudinal flow of arc extinguishing liquid upwardly which assists in extinguishing the arc. The provision of the bridging contact member III may under certain conditions be more effective than the arrangement shown in Fig. 2, in that it controls the lengthening of the are. In the device of Fig. 6, the two arcs are caused to elongate at a rate dependent upon the rate of travel of the barrier member I09, whereas in the arrangement shown in Fig. 2, the are drawn between the two separating contact members has a tendency to lengthen, due to magnetic action of the current flowing in opposite sides of the loop, and to advance more rapidly than the upper edge of the aperture I3 within the barrier member II, thereby producing somewhat higher pressures under certain conditions, within the arc passage tending to retard movement of the barrier member.

Fig. 9 shows an arc extinguishing device substantially of the same form as shown in Figs. 6

and 8 with the exception that an aperture I29 is provided in the barrier member I89 immediately above the bridging contact III. The provision of the aperture I29 provides a more turbulent flow of arc extinguishing liquid adjacent the bridging contact member III and for this reason may under certain current conditions be more eilective in bringing about are extinction. In other respects the operation of the interrupter shown in Fig. 9 is substantially the same as that shown in Figs. 6 and 8.

The are extinguishing device illustrated in Figs. 10 through 12 differs from the arrangement shown in Fig. 2 primarily in that it is specifically designed to bring about efiective arc extinction over a very broad range of current values. As shown in Fig. 10, a barrier member I3I is provided, the lower end of which is of wedge shape and is adapted to force the are formed between the separating contacts I33 into a wedge-shaped arc passage I35. A cam actuating mechanism for contact operation, as shown in Fig. 2, is here employed.

The V-shaped arc passage I35 is preferably formed of plates of insulating material I31, the slots therein being of rectangular cross section and varying in width from the uppermost plate to the lowermost plate so as to cause the passage to converge towards the lower end thereof. The inclined side walls of the passage I35 are also corrugated by providing the plates I31 with'slots of slightly difierent widths. The moving barrier member I3I may be actuated to the open and closed position by means of suitable mechanism connected to the operating rod I39 coupled to the side edges of the barrier member I3I by brackets I4I.

From the foregoingdescription it is apparent upon separation of the contacts I33 while the interrupter is carrying extremely high currents, the wedge shape portion of the barrier member I3I will not confine the arc to an appreciable extent during the initial part of the circuit interrupting operation. This permits ready escape of the products of decomposition of the are which fiow longitudinally along the arc stream, as it is lengthened by the barrier member I3I, so as to extinguish the are without causing the arc energy to be materially increased.

In the event that an arc is being interrupted of very small current magnitude, very little interrupting effect will be produced until the wedge shape portion of the barrier member I31 has moved the are a considerable distance into the wedge shape passage 335. However, as the barrier member. I3l approaches the lower limit of its stroke, the effective width of the arc passage on either side of the barrier member becomes very small, thus subjecting the lowcurrent arc to substantially the same deionizing action as is produced with currents of larger magnitude but where the arc passage is of a greater width.

It will be observed that the modifications shown and described in Figs. 6 through 12, inclusive, are also adapted for operation in a weather-proof housing of the low oil capacity type, as shown in Fig. 1. The respective barrier members in each of the modifications are also adapted to be actuated to their open circuit positions by means of spring actuated accelerating means, as shown at 8i in Fig. 1.

In Figs. 13 through 19, a circuit interrupter is shown having a contact arrangement adapted for operation with a barrier member and are extinguishing passage of the tubular form. In Fig.

13 the external housing of the interrupter is subsubstantially the same as that shown in Fig. 1 and need not be further described. The housing, as shown in Fig. 13, encloses an interrupting unit I45 which is more fully shown in Figs. 14 to 19. The are extinguishing structure I45 comprises a cylindrical casing member I41, the upper portion of which is provided with a support flange I49 across which is secured a conducting support I 5|. Centrally disposed of the support III and projecting axially within the casing I41 is a fixed contact rod I53.

'On diametrically opposed sides of the casing I41 are cutout portions I55 to provide suitable openings for the reception of an operating mechanism which will be more fully described hereinafter.

Within the casing I41 adjacent the lower edge of the cutout portions I55, is a fianged tubular metallic support I51 for carrying a movable contact assembly generally indicated at I59. The tubular support I51 carries a plurality of contact supporting brackets I65, each of which pivotally support a moving contact I61 at the lower end thereof. The contacts I61 are encircled by a plurality of springs I69 so as to yieldingly maintain the contacts in engagement with the lower end of the fixed contact rod I53. Disposed below the tubular support I51 are a plurality of plates I1I of insulating material, all of which have a circular aperture therethrough with alternate plates having apertures of a difierent diameter so as to produce an arc passage I13 having corrugated side walls. Joined to the lower end of the fixed contact rod I53 is a filling member I15 of insulating material having a diameter substantially equal to the diameter of the lower end of the contact rod. The filling member I15 extends to the bottom of the arc passage I13 and is adapted to register with a suitable opening in a plate I11 forming the bottom of the arc extinguishing passage.' Thus the side edges of the plates HI and the filling member I15 produce an arc extinguishing chamber of tubular cross section.

Surrounding the fixed contact rod I53 is a tubular barrier member I19 of insulating material which is adapted to be moved downwardly into the tubular arc passage I13 so as to move an arc established between the contacts I61 and the contact rod I53 into the arc passage. Movement of the barrier member 119 is accomplished by an operating mechanism supported upon an external flange iti encircling the casing I41.

The operating mechanism includes a collar H81 secured about the tubular barrier member H19 and to which one end of a pair of actuating links I83 is pivoted. The other end of the links I83 is pivoted by means of a shaft I85 to a pair of sliding block or bearing members I 81. The bearing members I81 are adapted to slide in elongated slots I89 provided in a pair of spaced upright brackets I 9I which are secured to a support plate I63 mounted on the flange I6I. The link members I83 are connected by a shaft I93 to one end of a pair of link members I 95 fixedly joined together by a sleeve I91 and through which a shaft I99 is adapted to pass so as to pivotally support the link members I95 to two upstanding brackets 21 secured to a second support plate I64 also mounted on the flange IIiI. The other end of the link members I 95 are joined by a shaft 203 to which an operating rod 265 of a suitable operating mechanism may be connected. As shown in Fig. 13,

the rod 205 extends downwardly between the arc extinguishing device I45; and the interrupter housing and connects to a bell crank 201 which is operatively coupled to a mechanism not shown, for actuatingthe interrupter to open and closed circuit positions.

The foregoing linkage including the members I83 and the link members I95, are disposed with respect to their pivotal connections such that upon rocking the links I95 about the shaft I93 in a counter-clockwise direction as viewed in Fig. 14, a substantially straight line motion in the downward direction, will be imparted to the tubular barrier member I19..

In order to prevent the lower end of the tubular barrier member I19 from striking the con-' tacts I61 means are provided for rocking these contacts about their pivotal supports out of engagement with the contact rod I53, thereby establishing an are between at leastone of the contact fingers I61 and the fixed. contact rod I53 and providing sufiicient clearance to permit the barrier member I19 to be moved downwardly into engagement with the arc and force the same into the tubular arc passage I13.

In order to rock the contact fingers I61 out of engagement with the fixed contact rod I53, the contact fingers are provided with outwardly extending projections 209 adjacent their pivoted ends. Immediately below the projections 209 is disposed an annular member 2 having two upstanding arms 2I3 fixedly secured thereto and disposed at diametrically opposed points thereon. Pivoted to the upper end' of each arm 2I3 is a bifurcated arm M5, the legs of which are preferably integrally joined together by a sleeve 2I1, which sleeve provides for the passage of a shaft 2I9 which, in turn, is journaled in the two upright support brackets MI.

The sleeve 2I1 has an upstanding arm 22I, the end of which is provided with a roller 223. The roller 223 is adapted to engage a cam surface 225 disposed upon the sleeve I91 joining the link members I95. With particular reference to Figs. 14 and 15, it will be noted that as the link members I95 are rotated counter-clockwise about the shaft I99, the cam surface 225 engaging the roller 223 will cause the arm 22I rigidly secured with respect to the arms 2I5, to be rocked in a clockwise direction about the shaft 2l9. This clockwise rotation of the arms 2I5 will raise the arms 2I3 and the annular member 2 which is brought into engagement with the projections 209 so as to rock the contacts I61 out of engagement with the contact rod I53 and thereby permit the-tubular barrier member I19 to proceed downwardly unobstructed into the tubular arc passage I13.

The circuit through the arc extinguishing device I45 proceeds from the contact member I5I through the fixed contact rod I53, the contact fingers I61 through the flexible shunts provided between these contact fingers and the contact support I65 and from the support I65 to the support plate I64 by a shunt connection 2I9. When the unit I45 is disposed in the housing, as shown in Fig. 13, the terminal support member I5I may be connected to an external terminal 222 by a flexible connector 224. The support plate I64 may be connected by a conductor 226 to an external terminal 221 extending through the base of the interrupter housing,

The arc extinguishing operation of the are extinguishing device I45 is similar to that previously described. From the foregoing description of the mechanics of the moving parts constituting the contact and barrier member operating neans, it is apparent that as the barrier member I19 is moved downwardly and the contacts I61 are withdrawn from the fixed contact I53, an arc is drawn between the separating contact surfaces. This arc is caused to be rapidly elongated by the downwardly movement of the barrier member I19 and consequently is driven into the tubular arc passage I13 and forced to play between the fixed contact member I63 and at least one of the contact fingers I61 while being looped over the lower end of the barrier member I13. From to clearance is preferably provided between the barrier member I19 and the side walls of the arc passage I13. It is thus seen that as the barrier member I13 is moved into the arc chamber I13, the elongated arc is confined to a high degree and subjected to the intense blast of the products of decomposition of the are which in escaping from the passage must flow in the direction opposite to that of movement of the barrier member. The barrier member also I produces a fiow of arc extinguishing liquid which it displaces upwardly due to its downward movement into the passage. Thus an are drawn by the contacts arranged in this manner in conjunction with the tubular barrier member is subjected to an intense deionizing action and efiectively extinguished.

The tubular form of arc passage is particu larly effective in extinguishing arcs covering a wide range of current values in that the arc core,

for a given current value, can spread out circumferentially of the passage in accordance with the current magnitude.

The lower end of the arc passage I13 15 in this instance as in the previous modifications illustrated, also provided with spring actuated flushing means constructed and arranged in the manner previously described in connection with the arc extinguishing device shown in Fig. 2. Although I have shown and described a specific circuit interrupting structure. and various arrangement of arc extinguishing devices therefor, it is to be understood that the same is for the purpose of illustration and that changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter of the liquid immersed type, a quantity of arc extinguishing liquid, an arc extinguishing structure immersed in said liquid, said arc extinguishing structure comprising means of insulating material defining an arc chamber open at one end and closed at the other, means for establishing an are outside of but'adjacent the open end of said are chamber, means for moving the arc into said arc chamber, and resilient means disposed at the closed end of said arcchamber movable in response to pressure created by the are within said are chamber to a predetermined position, said resilient means being returnable to its normal position upon subsidence of the pressure within 'said arc chamber to force arc extinguishing liquid entrapped in the closed end of said are chamber from the are chamber through the open end thereof.

2. In a circuit interrupter of the liquid immersed type, a quantity of arc extinguishing liquid, an arc extinguishing structure immersed in said liquid, said arc extinguishing structure comprising means of insulating material defining an arc chamber open at one end and closed at the other, means for establishing an are outside of but adjacent the open end of said are chamber, means for moving the are into said are chamber, means at the closed end of said are chamber for moving a quantity oi arc extinguishing liquid through said are chamber following arc extinction, and resilient energy storing means for actuating said liquid moving means, said energy storing means being stressed to store energy therein in response to are pressure within said are chamber.

3. In a circuit interrupter of the liquid immersed type, a quantity of arc extinguishing liquid, an arc extinguishing structure immersed in said liquid, said arc extinguishing structure comprising means of insulating material defining an arc chamber open at one end and closed at the other, means for establishing an arc outside of but adjacent the open end of said are chamber, means for moving the are into said are chamber, a. piston chamber communicating with the closed end of said arc chamber having a piston movable therein, and means biasing said piston toward one end of said piston chamber, said piston being moved in response to pressure within the arc chamber in a direction to stress said biasing means, said biasing means returnin said piston to its normal position in response to the subsidence of pressure within the arc chamber to move a quantity of arc extinguishing liquid through the arc chamber.

4. In a circuit interrupter, a quantity of arc extinguishing liquid, means of insulating material defining a narrow arc chamber of generally rectangular cross section open at one end and closed at the other end immersed in said liquid, a blade member at least partially of insulating material having a portion normally outside said are chamber and movable into the arc chamber during circuit interruption and a portion normally within said arc chamber movable through the closed end thereof during circuit interruption, a pair of contacts disposed adjacent the open end of said are chamber and adapted to be moved to open circuit position to draw an arc transversely of said are passage and in the path of movement of said portion of blade member normally outside said arc chamber, and operating means for sequentially separating said contactsfland moving said blade member into engagement with the arc to project the latter into said are chamber, said portion of the blade member being moved out of said arc chamber displacing less liquid than said portion being moved into the arc chamber to subject the arc to a flow of liquid to assist arc extinction.

5. In a circuit interrupter, a quantity of arc extinguishing liquid, means of insulating material defining a constricted arc passage of considerable length immersed in said liquid, said are passage being closed at one end and open at the other, a pair of separable contacts at least one of which is permanently positioned outside said are passage adjacent the open end thereof, a movable member of insulating material supporting the other of said pair of separable contacts, said movable member having a portion normally outside said are passage and a portion normally inside said passage, and means for moving said member of insulating material to establish an arc within said arc passage and to cause said portion outside said passage to move into 'said passage and said portion inside said passage to move through the closed end thereof, said portion normally outside said are passage displacing a more liquid than said portion normally inside said passage to provide a longitudinal flow of are extinguishing liquid along the arc to aid in ex-' tinguishing the arc.

6. In a circuit interrupter, a quantit of arc extinguishing liquid, means of insulating material defining an elongated arc passage open at one end but otherwise completely enclosed immersed in said liquid, a plunger member of insulating material movable into said are passage to provide an arc path of constricted cross section between the plunger member and one wall of said passage, a fixed contact disposed adjacent the open end of said are passage, a cooperating contact carried by said plunger member and movable therewith into said arc passage to establish an are along said constricted arc path, and a guide member movable with said plunger and extending from said cooperating contact through the closed end of said arc passage, the products of decomposition of the are being caused to flow longitudinally of the arc path towards the open end of said are passage, said guide member having a cross-section less than said plunger member to cause a flow of arc extinguishing liquid longitudinally of the arc to assist the products of decomposition of the arc in extinguishing the are.

'7. In a circuit interrupter, means of insulating material defining a constricted arc passage of considerable length, said are passage being closed at one end and open at the other, are extinguishing liquid in said passage, a pair of contacts permanently positioned outside said arc passage adjacent the open end thereof, a barrier member of insulating material disposed between said contacts and extending into said are passage and through the closed end thereof, said barrier member carrying a bridging contact normally disposed between said pair of contacts to interconnect the same, said bridging contact being movable with said barrier member into said are passage to establish an are on each side of said barrier member within the arc passage, the portion of said barrier member being moved out of said passage during the circuit interrupting operation having a cross-section less than the portion of said barrier being moved into said passage to cause a flow of arc extinguishing liquid longitudinally of the arcs toward the open end of said are passage.

8. In a circuit interrupter, means of insulating material defining an arc chamber having a generally rectangular cross section, said are chamber being open at one end but otherwise completely closed, two opposing walls of said arc chamber converging in a direction away from the open end thereof, means for establishing an arc across the open end of said are chamber, and a wedge member of insulating material movable into the arc chamber whereby the arc is progressively lengthened and constricted in cross section as it is forced into said are chamber by said wedge member.

9. In a circuit interrupter, means of insulating material defining an arc chamber having a generally rectangular cross section, said arc chamber being open at one end but otherwise completely closed, two opposing walls of said are chamber converging in a direction away from the open end thereof, a pair of separable contacts for establishing an arc across the open end of said are chamber, a wedge member of insulating material movable between said contacts for initiating arc movement into said are chamber, and an actuating mechanism for simultaneously operating said contacts to open circuit position and moving said wedge member into engagement with the arc, said actuating mechanism separating said contacts a distance sufficient to permit said wedge member to be moved therebetween without engaging the contacts.

10. In a circuit interrupter, a quantity of arc extinguishing liquid, a casing immersed in said liquid, means of insulating material disposed in one end of said casing. defining a tubular arc passage open at one end, a fixed contact disposed adjacent the open end of said tubular arc passage, a plurality of movable contacts cooperating with said fixed contact to establish the circuit through the interrupter, means for moving said movable contacts out of engagement with said fixed contact to establish at least one are radially across said tubular arc passage, and a tubular member of insulating material movable in surrounding relation with respect to said fixed contact into said tubular arc passage in response to the separation of said movable contacts from said fixed contact for causing said are to play in an extended loop within said tubular arc passage.

11. In a circuit interrupter, a quantity of arc extinguishing liquid, a tubular casing immersed in said liquid, an arc extinguishing chamber of circular cross section and open at one end disposed in one end of said casing, a filling member of insulating material disposed axially of said are chamber to provide an annular arc passage, a contact member coextensive with said filling member having a contact portion adjacent the open end of said are passage, pivotally mounted contacts adapted to cooperate with said contact portion to establish the circuit through the interrupter, means for rocking said contacts out of engagement with said contact portion to establish at least one are across said annular arc passage, a tubular barrier member of insulating material normally surrounding said contact member and slidable longitudinally thereof over said filling member into said annular arc passage, and means operative in unison for rocking said contacts and for moving said tubular barrier member into said annular arc passage to cause said are to be looped over the end of said barrier member and play in said annular arc passage. 12. In a circuit interrupter of the liquid immersed type, a quantity of arc extinguishing liquid, an arc extinguishing structure immersed in said liquid, said arc extinguishing structure comprising means of insulating material defining an arc chamber open at one end and closed at the other, means for establishing an are outside of but adjacent the open end of said arc chamber, means for moving the arc into said arc chamber,

'a piston member movable into said are chamber to establish a flow of arc extinguishing liquid along said are, a piston member movable into said are chamber to establish a fiow of arc extinguishing liquid along said are, and means adjacent the closed end of said arc chamber for moving an additional quantity of arc extinguishing liquid through said are chamber in accordance with predetermined pressure conditions in said are chamber.

13. In a circuit interrupter of the liquid immersed type, a quantity of arc extinguishing liquid, an arc extinguishing structure immersed in said liquid, said are extinguishing structure comprising means of insulating material defining an arc chamber, means for establishing an arc in said are chamber, a plunger at least partially of insulating material movable into said are chamber for confining the are between,

the plunger and a wall or said arc chamber and for causing a fiow of insulating liquid irf contact with the arc and means operative in response to predetermined pressure conditions within said are chamber for producing an additional fiow of arc extinguishing liquid through said are chamber.

14. In a circuit interrupterya pair of fixed, spaced members of insulating material defining an annular arc chamber therebetween, contacts adjacent one end of said are chamber, means for establishing an are between said contacts, and a tubular member at least partially of insulating material movable upon the striking of said arc between said contacts and into said annular arc chamber to substantially fill said chamber and for causing said are to play in the constricted space between said tubular member and opposite walls of said annular arc chamber.

15. In a circuit interrupter, means of insulat ing material defining an annular arc chamber, separable contacts for establishing an arc radially across said annular arc chamber and a tubular member at least partially of insulating material movable against said are into said annular arc chamber to substantially fill said chamber and for directing the are into said chamber and causing it to play in an extended loop about one end of said tubular member.

16. In a circuit interrupter, means of insulating material defining an annular arc passage open at one end, a fixed contact disposed adjacent the open end of said annular arc passage, a plurality of movable contacts cooperating with said fixed contact to establish the circuit through the interrupter, means formoving said movable contact out of engagement with said fixed contact to establish at least one are radially across said annular arc passage, and a tubular member of insulating material movable in surrounding relation with respect to said fixed contact into said annular arc passage in response to the separation of said movable contacts from said fixed contact for causing said are to play in an extended loop within said annular arc passage.

17. In a circuit interrupter, an arc extinguishing chamber of circular cross section and open at one end, a filling member of insulating material disposed axially of said are chamber to provide an annular arc passage, a contact member coextensive with said'filling member having a contact portion adjacent the open end of said are passage, pivotally mounted contacts adapted to cooperate with said contact portion to establish the circuit through the interrupter, means for rocking said contacts out of engagement with said contact portion to establish at least one are across said annular arc passage, a tubular barrier member of insulating material normally surrounding said contact member and slidable longitudinally thereof over said filling member into said annular arc passage, and means operative in unison for rocking said contacts and for moving said tubular barrier member into said annular arc passage to cause said are to be looped over the end of said barrier member and play in said annular arc passage.

18. In a circuit interrupter, a quantity of arc extinguishing liquid, means of insulating material defining'a tubular arc passage immersed in said liquid, separable contacts for establishing an arc adjacent one end of said are passage, a tubular member of insulating material movable into engagement with said are and into said tubular arc passage for causing the arc to be extended into said arc passage, said tubular member causing a flow of arc extinguishing liquid axially of said are passage to aid in extinguishing the arc, and means for causing an additional flow of arc extinguishing liquid axially of said are passage.

19. In a circuit interrupter, a quantity of arc extinguishing liquid, means of insulating material defining a tubular arc passage immersed in said liquid, said are passage being open at one end and closed at the other, separable contacts for establishing an arc radially across the open end of said are passage, a tubular barrier member of insulating material movable into said tubular arc passage for causing the arc to play in an extended loop about the end of said barrier member within said are passage, said barrier member causing a flow of arc extinguishing liquid longitudinally of the arc towards the open end of said are passage and means operative in response to predetermined pressure conditions within said are passage to cause an additional flow of arc extinguishing liquid through said are passage.

20. In a circuit interrupter, means of insulating material defining a narrow arc chamber open at one end and closed at the other end, separable contacts disposed outside of said arc chamber adjacent the open end thereof, means mounting said contacts for movement in paths outside of ,said chamber and extending across the open end thereof, means for operating said contacts to open circuit position to establish an arc across the open end of said are chamber, a member at least partially of insulating material movable upon separation of said contacts into engagement with said arc substantially transversely thereof and into said are chamber for moving said arc into said chamber and causing it to play in an elongated restricted path on opposite sides of said movable member, and means along said elongated restricted paths which gives off a gas when acted upon by an arc to aid in extinguishing the arc, the said walls of said are chamber and the closed end thereof causing said are extinguishing gas to flow longitudinally of the arc and across the space between said separable contacts at the open end of said chamber.

21. In a circuit interrupter, means of insulating material defining a narrow arc chamber open at one end and closed at the other end, separable contacts disposed outside of said are chamber adjacent the open end thereof, means mounting said contacts for movement in paths outside of said chamber and extending across the open end thereof, means for operating said contacts to open circuit position to establish an arc across the open end of said are chamber, a member at least partially of insulating material movable upon separation of said contacts into engagement with said are substantially transversely thereof and into said arc chamber for moving said are into said chamber and causing it to play in an elongated restricted path on opposite sides of said movable member, and a quantity of arc extinguishing liquid in said chamber, the side walls of said chamber being so arranged with respect to said member that movement of said member into the chamber towards the closed end thereof causes a flow of arc extinguishing liquid and the products of decomposition of the arc longitudinally of the arc and through the member of space betweensaid separable contacts at the open end of said chamber.

, 22. In a circuit interrupter having a pair of terminals, a first relatively stationary contact having a plurality of contact surfaces connected to one of said terminals, a plurality of pivoted contacts connected to the other terminal and resiliently urged into engagement with said contact surfaces, and means including a tubular insulating material telescopically movable over said first contact and operable to sequentially move said pivoted contacts away from said contact surfaces and interpose said member of insulating material between said pivoted contacts and said contact surfaces.

23. In a circuit interrupter having a pair of terminals, means of insulating material defining an elongated arc passage open at one end, a first relatively fixed contact having a plurality of contact surfaces disposed adjacent the open end of said passage and connected to one of said terminals, a plurality of pivoted contacts connected to the other terminal and biased into engagement with said contact surfaces, means for moving said pivoted contacts away from said contact surfaces to establish an arc, and a tubular member of insulating material telescopically movable over said first contact and movable in accordance with movement of said pivoted contacts between said pivoted contacts and said contact surfaces into said are passage to cause 1 said are to play in an extended loop between said member of insulating material and the walls of said are passage.

24. In a circuit interrupter, a quantity of arc extinguishing liquid, means of insulating material defining a narrow arc chamber open at one end and closed at the other end immersed in said liquid, a member at least partially of insulating material having a portion normally outside said are chamber and movable into the arc chamber during circuit interruption and a portion normally within said are chamber movable through the closed end thereof during circuit interruption, a pair of contacts disposed adjacent the open end of said are chamber and adapted to be moved to open circuit position to draw an arc adjacent the open end of said passageway, means including said member for projecting the are into said arc chamber, said portion of the member being moved out of said arc chamber displacing less liquid than said portion being moved into the arc chamber to subject the arc to a flow of liquid to assist arc extinction.

25. In a circuit interrupter, means of insulating material defining a narrow arc chamber, said chamber being open at one end and closed at the other, a member at least partially of insulating material having a portion normally outside said are chamber and movable into said chamber through the open end thereof during a circuit interruption and a portion normally within said chamber movable through the closed end thereof during a circuit interruption, separable contacts normally disposed adjacent the open end of said are chamber and adapted to separate to draw an are adjacent the open end of said chamber, means including said member for projecting the are into said chamber, said portion of said member being moved out of said are chamber having less displacement in said chamber than said portion being moved into the arc chamber to create a fluid pressure in said chamber in addition to that which may be created by the arc to subject the arc to a flow of fluid from said chamber out through the open end thereof.

26. In a circuit interrupter, means of insulating material defining an arc chamber, said arc chamber being open at one end but otherwise completely closed, at least two opposing walls of said are chamber converging in a direction away from the open end thereof, means for establishing an are adjacent the open end of said arc chamber, and a wedge member of insulating material movable into the arc chamber whereby the arc is progressively lengthened and constricted in cross section as it is forced into said are chamber by said wedge member.

27. In a circuit interrupter, means of insulating material defining an annular arc passage open at one end, spaced contacts adjacent the open end of said passage, a bridging contact cooperating with said spaced contacts to establish the circuit through said interrupter, means for striking an are between said spaced contacts, and a tubular member of insulating material movable between said spaced contacts and into said annular arc passage in response to the striking of said are for causing said are to play in an extended loop within said annular arc passage.

ALBERT P. STROM.

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