US2039054A - Oil circuit breaker contact - Google Patents

Description

April 28, 1936 s. H.' BODEN E-r AL 2,039,054

OIL CIRCUIT BREAKER CONTACT Original Filed Feb. 1,' 1933 3 Sheets-Sheet 1 'ATToRN Y April 28, 1935 s. H. BODEN ET' AL 2,039,054

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April 28, 1936. s, H. BODEN Er AL.

OIL CIRCUIT BREAKER CONTACT 3 Shets-Sheet 5 Original Filed Feb. 1, 1935 .0a ma@ M www .m WQLMv ,.m. 15.5 d f @9B mm sa Patented Apr. 28, 1936 UNITED STATES PATENT oFFIcE OIL CIRCUIT BREAKER CONTACT sylvania Application February 1, 1933, Serial No. 654,626 Renewed April 18, 1934 29 claims. (o1. zoo-150) Our invention relates to circuit interrupters and more particularly to oil-immersed circuit breakers which utilize arc extinguishers of the side-vented chamber type.

One form of this type of arc extinguisher comprises a stack of plates of insulating materiall between which are placed a plurality of plates of magnetic material at spaced intervals. Aligned slots are provided in both the insulating plates and the iron plates, and on assembly these slots form an elongated passage within which the arc is drawn. The arc is moved transversely in the passage due to the distortion of the magnetic eld about the arc by the slotted magnetic plates. Oil is retained adjacent the path of movement of the arc by means of openings or pockets which form a part of the insulating plates, and, during the extinguishing operation, this oil is decomposed and gives oif a large volume of gas which passes turbulently through the arc stream, thereby cooling and extinguishing it.

In the previous structures of this type, it has been customary to provide vents positioned longitudinally along the passage wherein the arc is drawn and extending transversely outwardly from this passage in substantially the opposite direction to that in which the arc is moved by the magnetic plates. This form of construction Works very satisfactorily for most values of current, but, under certain abnormal overload conditions, it has been found that the absence of vents extending outwardly from the passage where-in the arc is drawn so as to permit ow of fluid in the same direction that the arc is moved results in the entrapping of sufficient gas ahead of the arc to prevent its movement by the magnetic forces resulting from the `presence of the magnetic plates. This condition is especially noticeable during the interruption of very heavy current overloads because for those values of current the magnetic plates are substantially saturated and the increased arc energy which must be dissipated in gasifying the oil adjacent the arc path does not result in a corresponding increase in the force available for moving the arc.

One object of our invention, therefore, is to provide arc extinguishing structure of the sidevented chamber type wherein vent passages are provided in that portion of the chamber toward which thejarc is moved.

Another object of our invention is to provide an improved, substantiallyV completely enclosed contact structure particularly suitable for use with the above-mentioned type of arc extinguisher; our improved contact structure to include means for so directing the escape of the arc gases formed Within the closure during the interruption operation that the arc is caused to move from the current-carrying members of the contact structure onto an arcing member.

A further object of our invention is to provide improved venting means for an arc extinguishing device adapted for use With our improved l5 contact structure; our improved venting means to cause the outflowing gas from the contact closure to aid in moving the arc within the passage in the arc extinguisher, and, at the same time, to aid in the extinguishment of the arc by providing an additional flow of un-ionized gas through the ionized arc stream.

A further object of our invention is to provide an improved arc extinguisher of the above-mentioned type that shall be provided with a continuous opening in one side in order to permit the entry of a portion of the moving contact and so minimize the necessary movement of that member.

A still further object of our -invention is to provide an improved arc extinguisher that shall be more economical to manufacture, and that shall be more effective in operation than the previous structures of this type.

Since our invention is particularly adapted for use with oil-immersed circuit breakers, we shall hereinafter describe an embodiment of our invention as applied to such circuit breakers Without, in any way, intending to restrict the scope of our invention, except as indicated in the appended claims.

The features of our invention which We believe to be new are particularly pointed out in the appended claims. For a fuller understanding of the principles of the invention, reference may be had to the accompanying drawings, in

' which:

Figure 1 is a sectional view through a circuit breaker embodying our invention; certain of the parts have been shown in elevation to more clearly point out the structural details involved;

Fig. 2 is a sectional view through the preferred form of our arc extinguishing device taken on the line II-II of Fig. 3;

Fig. 3 is a sectional view of our arc extinguishing device taken on the line III- III of Fig. 2;

Figs. 4 to 12 inclusive are plan views of the various individual plates which are utilized in the preferred form of our are extinguishing device;

Fig. 13 is a sectional view taken on the line XIII-)H11 of Fig. 14, showing one of the contact structures and arc extinguishing devices shown in` Fig. 1;

Fig. 14 is a side elevation of the contact structure and part of the are extinguisher shown in Fig. 13;

Fig. 15 is a sectional view takenv on the line XV--XV of Fig. 13; and,

Fig. 16 is a sectional view taken on the line XVI-XVI of Fig. 15.

Referring to the drawings, the circuit breaker I includes a liquid-tight tank 3 which is partially filled with oil or other insulating liquid 5. Current conductors 9 extend through insulating bushings 1 which are secured by flanged collars Il to the top of the tank. The lower end of each of the conductors is provided with an adapter I3 which is utilized to connect the lower end of each of the conductors 9 with the stationary contact assemblages |5. An arcextin guishing device |1 is bolted to the lower portion of each of the stationary contact assemblages I5. Electrical connection is made between the two contact assemblages |5 by means of a bridging member |9 having upstanding contactportions 2|. The bridging member I9 is moved to open or to close the circuit by a suitable operating mechanism (not shown) which is connected to the operating rod 22.

Each of the arc-extinguishing structures I1, which are shown particularly in Figs. 2 and 3, comprises a stack of plates held together by retaining means, such as the metal bolts 23 about which are disposed tubes of insulating material 25 and 21 as shown particularly in Fig. 3, the heads of the bolts 23 are embedded in a molded insulating material covering 24. The upper end of each of the bolts 23 extends through a suitable opening in the base of one of the frame members 1|, 'which form part of the stationary contact assemblages, and are retained in position by nuts 29.

The individual pl-ates which are used to form this embodiment of our invention are shown in detail in Figs. 4 to l2, inclusive. The top plate 3| (Fig. 4) and the bottom plate 35 (Fig. 11) each have four suitably spaced openings 33 to permit passage of the retaining bolts 23. The

top plate 3| has a centrally disposed slot 39 to permit the passage of they contact portion 2l of the bridging member I9 and also to provide an opening for the arcing member |01.

Immediately adjacent the top plate 3| are two plates 43 (Fig. 5). Each of the plates 43 has a centrally disposed slot 45 and six openings 41 which are utilized to form oil pockets in the assembled interrupter. The slot 45 has a portion 49 which extends to the edge of the plate 43, and is utilized to provide a Ventilating passage from the interior of the arc-extinguishing chamber.

A plate 5| (Fig. 6) ofinsulating material is positioned immediately beneath the .plates 43.

This plate has an opening 53 which aligns with the corresponding portions of the openings 45 and 39 to provide the passage within the arc extinguisher through which `the contact portion 2| moves. The opening 55 connects directly with the opening 53, in order that the are may be moved transversely within the extinguishing chamber.

Beneath the plate 5| is positioned a slotted plate 51 (Fig. 9) of magnetic material, preferably iron, which is provided with a liner plate 59 (Fig. 12) of insulating material. The liner plate 59 is substantially the same thickness as the magnetic plate 51 and is utilized for protecting the edges of the magnetic plate from the arc. The liner plate 59 has openings 53 and 55 similar to the plate 5|, and it will be noted, that the opening 53 does not extend to the edge of either of the plates 5| or 59. The passage wherein the arc is drawn is thus closed in the upper portion of the stack except for the vents provided by the openings 49 in the plates 43. A second plate 5| is positioned .beneath the magnetic and liner plate combinations.

Two more plates 43, a plate 5|, a magnetic plate 51 and its associated liner plate 59, another plate 5|, and two plates 44 comprise the next units in the arc-extinguishing structure.

Each of theplates 44 (Fig. 7) is provided with the common .opening 53 and, in addition, includes four of the pocket openings 41. Adjacent the lower plate 44 is positioned a plate 6| (Fig. 8) of insulating material. The plate 6| is exactly the same as the insulating plates 5I except that the slots 53 extend to the edge of the plate. Beneath the first plate 6| is another of the magnetic plates 51 and a liner plate 33 (Fig. 9). The liner plate B3 is similar to the liner plate 59 except that the slot 53, as in the case of the plate 3|, extends to the edge of the plate. A second plate 6| is disposed beneath the liner plate 33 and its associated magnetic plate 51.

Two plates'55 (Fig. 10) of insulating material are positioned beneath the second plate 5|. Each of the plates 65 is similar to the plates 44 except that the opening 53 extends to the edge ofthe plate. A third plate 6| is positioned beneath the secon-d plate 65. Following this is a magnetic plate 51 with its liner plate 63, a fourth plate BI, two more plates B5 and the bottom plate 35. The bottom plate 35 is provided with the common opening 53, which opening extends, as for the plates 6|, 63, and 65, to the edge of the plate.

Each of the plates 43, 44, 5|, 59, 6|, 63, and 65 is provided with suitable aligned openings 56 to permit the passage of the bolt 23 and its associated insulating tubes 25 and 21 during the assembling of the stack structure. Each of the magnetic pl-ates 51 is provided with cutout portions 68 which are adapted to abut against the insulating tubes 21 and thus accurately position the magnetic plate-liner plate combinations within the arc extinguisher.

It should be noted at this point that the removal of the portion B1, which closes the outer end of the slot 53 in the plates in the top portion of the stack, from the plates in the lower portion of the stack provides a continuous opening which extends longitudinally along the side of the passage wherein the contact portion 2| of the bridging member I9 moves and wherein the arc is drawn. This side opening makes possible a very appreciable saving in the size of the tank and in the operating mechanism used to actuate the bridging member I9, because it permits the use of abridging member having relatively small upstanding contact portions 2|.

Previously, it wascommon practice in the art to make a Contact portion 2| of the bridging member |9 at least as long as the passage in the arcextinguishing structure. In the higher voltage installations this necessitated a very large tank and a relatively expensive operating mechanism, due to the great length of the stack structure for those higher voltages.' Our arc-extinguishing however, makes is unnecessary for the main -portion of the bridging member I9 to be moved any great. distance beneath the bottom of the arc extinguisher itself.

The stationary contact assemblage |5 of our invention is shown particularly in Figs. 13 to 16, inclusive. 'I'he assemblage includes a pair of frame members II which are adapted to form the two opposing halves of a substantially closed chamber. A slight gap 'I3 (as shown particularly in Fig. 13) may exist between the opposing edges of the two halves I| due to inaccuracies in machining, but in view of the large volumes of gas which are generated by the arc, the venting effect of this gap is negligible. The upper portions of the opposing frame members 'I I define a substantially rectangular opening into which the end l5 of the adapter i3 lits. Lugs 'I'I having suitable openings to permit the passage of the bolts 'i9 are provided for :fastening the two frame portions il onto the end l5 of the adapter i3.

Suitable openings are provided in each of the frame members lli to permit the passage of a pivot pin di which supports a contact finger 9S. The opening ill in each of the lingers t3 through which the pin lli passes is made somewhat larger than the pin. This makes the lingers substantially self aligning. Each of the contact fingers 83 is provided with a recess t5 adapted to engage the end of a spring lili and is further provided with a stud t9. As shown particularly in Fig. 16, the stud t9 extends through a suitable opening 9i in the side of each of the frame members lll and is restrained in position by a castellated nut 93 which limits the movement of the fingers @il under the biasing action of the springs A cotter pin @il serves to lock the nut in 'posi-s tion.

The fingers @t oppose each other and provide a very satisfactory means for maintaining good contact pressure-upon the contact portions 2l of the bridging member i9. The opposing lingers @il are particularly effective in this regard in that they engage the sides of the contact portions 2i of the bridging member. That is, they engage surfaces which are not used for establishing the arc, and which are, therefore, not liable to become roughened or otherwise injured by the action of the arc.

Each of the contact lingers 83 is provided with a flexible conducting shunt 95 preferably of laminated copper which is brazed or otherwise electrically connected to the upper -portion of the lingers B3. The shunts 95 are bolted directly to the portion 'I5 of the adapter I3 by means of bolts 97. The width of the shunts 95 is substantially the same as the distance between the lugs 'II and since the clearance between the lingers 83 and the frame halves II is very small, the shunts serve to substantially completely seal the upper portion of the contact closure.

On the tank side of the contact assemblage, a support member IUI is fastened to the two halves II by means of bolts |03. The support member IUI, as shown particularly in Fig. 15, has a. downwardly extending portion |05 which is adapted to engage the top plate 3| of the arc-extinguishing structure and to seal the slot 39 with respect to the closure about the contact fingers. An arcing member |91 is bolted to the portion |95 of thesupport member through the agency of a bolt |09. The arcing member |91 has a slanting portion III of arc resisting material which is disposed closely adjacent to the lower portion of the lingers 83, and another portion I I3 which is of substantially the same width as the slot 39 in the top plate 3| and which is adapted to extend downwardly into the passage within the arc-extinguishing structure.

The unpivoted end of each of the fingers 83 is provided with an arcing portion ||5 of arc resisting material, and the upper end II'I of the Contact portion 2| is likewise ofl arc resisting material. We prefer to use a silver-tungsten alloy composed of 40% of the former and 60% of the latter for the portions IH, H5, and H1; any arc resisting conducting material would be equally suitable however.

The bridging member i9 is shown in the partly closed position in Fig, 3. It will be noted that a passage extending through the arc-extinguishing Istructure is provided by the aligning slots 53 and d5, and the slot 39 in the top plate 3|. The transverse length of this passage is several times its transverse width. It-will also be noted that the removal of the enclosing portion from the lower plates provides a continuous opening extending longitudinally along the lower portion of the arc extinguisher in order to permit the pamage of the body portion M9 of the bridging member i9. This, as previously pointed out, reduces the necessary length of travel of the bridging member, and permits the use of a smaller tank enclosure and a less complicated operating mechanisrn. When the circuit breaker is in the fully closedposition, the passage 'through the arc-extinguisher is substantially closed by the contact portion El of the bridging member lili The central portion M9 of the bridging member either abuts against or is very close to the portion dl o the plate l-l, and thus substantially oompletely encloses the arc-extinguishing structure except for the vent openings i9 in the plates it should be noted that the vent openings are positioned in the tanls side of each of the stacks.

This prevents the co-rningling of the arc gases during normal operations of the breaker and is of great value in preventing breakdowns between the stack structures, Electrical contact for conducting the current when the breaker is in closed position is made between the opposing surfaces i126 of the Contact lingers 33 and the sides 25 of the contact portion 2|, contact pressure being secured by the springs lil which bias the pivoted lingers toward each other.

During the opening operation the bridging member I9 is moved downwardly by the circuit breaker operating mechanism. The contact surfaces I2| disengage the cooperating surfaces |25 and just before the arc is established the tip portion II'I contacts the lower portions ||5 of the opposed lingers 83. The arc is then established between the arc resisting portion Ill'I and the arc resisting portions I 5, thereby preventing any in- .jury to the normal current-carrying surfaces.

Simultaneously with the establishing of the arc the oil which is entrapped in the closure about the stationary contacts begins to gasify, and the gas formed moves upwardly Within the closure, thereby bringing new oil in contact with the arc. This gasitying of the oil proceeds at a very rapid rate and the chamber is almost immediately lled with the gas resulting from the arcing action. These gases can vent directly only through the venting openings 49 in the upper plates 43 of the arcextinguishing structure, the lower end of the passage through which the contact portion 2l of the bridging member I9 moves being substantially closed by the presence of that member. The venting of the gas in this manner causes'a transverse blast oi outfiowing gas and oil through the arc stream and almost immediately moves the end of the arc from the portions IIB of the contact lingers 83 onto the slanting portion III o! the arcing member |01. The end oi' the arc is then moved downwardly onto the lower horizontal f portion I I3 of the arcing member |01.

Coincident with the establishing of the arc the7 vent openings 49 disposed in that portion of the arc extinguisher toward which the arc is moved. The combined result oi the gasifying of the oil as a result of the high temperature of the arc and the directing of the outflowing gas is to cause a rapid and positive extinguishing of the arc, usually at the nrst or second zero point in current cycle.

While the usual operation o! the arc extinguisher results in a complete extinguishment of the arc in the upper and middle portions of the stack structure and before'the passage 5I in the plates 6I, 63, and 65 is uncovered by the contact portion 2i of the bridging bar I9, under certain conditions the arc is drawn into the lower portion of the stack. Here the transverse movement oi the arc is continued, due to the presence of the slotted iron plates 51, and the oil entrapped in the pockets 41 in the plates 65 is gasiiled exactly the same as in the upperportion of the structure. This gas, however, is compelled to vent in the opposite direction to that in which therarc, is moved, and this results,` in combination with the movement of the gas in the upper portion of the structure, in extreme turbulence immediately adjacent the arc path. Arc extinction follows almost immediately.

The venting of the arc extinguisher in the same direction that the arc is moved in the upper portion of the stack is of great value in securing a rapid movement ,of the arc during the initial .stages of the extinguishing process, chiefly because it prevents the building up of gas pressure ahead of the path of movement of the arc. At the same time, when used in combination with the substantially totally enclosed stationary contact assemblage, such as disclosed in this embodiment of our invention, it provides an additional means for directing the outowing gases resulting from the arc, andthe oil moved by the gas, in order to secure a movement of the end oi' the arc from the contact members onto an arcing member.` During the usual operation ofthe arc extinguisher, a further advantage arises from the fact that the gases generated in the upper and middle portions'oi the structure are compelled to vent upwardly and rearwardly, thus flowing through the arc stream in a direction that substantially coincides with the longitudinal axis of the arc. This, of course, is most effective in securing a rapid cooling and deionizing of the arc itself.

It will thus be seen that we have provided an improved arc extinguisher, and an improved, substantially totally enclosed contact assemblage, particularly adapted ior use with the preferred embodiment of our arc extinguisher. Our improved arc extinguisher includes novel venting means for preventing the building up of gas pressure during the movement of the arc within the passage in the arc extinguisher; it includes means for so directing the outilowing gases formed by the arc within the closure surrounding the stationary contacts that the arc is moved from those contacts onto an arcing member; it includes a longitudinal opening in the side of the arc extinguisher for reducing the necessary amount of travel oi' the moving contact member and thereby decreasing the size oi the tank closure; and, in addition, it includes means for utilizing practically all of the gas formed by the arc for arc extinguishing purposes.

While in accordance with the patent statutes we have disclosed one embodiment of our invention,

the principles herein involved are applicable to other structures, and we desire, therefore, that the language of the accompanying claims shall be accorded the broadest reasonable construction, and that our invention be limited only by what is explicitly stated in the claims and by the prior art.

We claim as our invention:

1. In an arc-extinguishing structure, means defining a' groove that is closed on two sides, means for establishing an arc within said groove, means along said groove for giving off gas when acted upon by the arc, means for magnetically moving said arc in said groove, and means providing a restricted vent for said groove adjacent that portion toward which said arc is moved for causingk a stream of uid to ilow through the are and out said vent.

2. In an arc-extinguishing structure, means at least partly of insulating material defining a groove, means along said groove for giving oi gas when acted upon by an arc means including a contact member having an arc horn on which one end of the arc is movable for establishing an arc within said groove, said groove being substantially closed while the arc is initially established except for restricted venting means adjacent the end of said arc horn away from said contact member for causing the flow of iluid toward the venting means to move the end of the arc on the arc horn toward the venting means.

3. In an arc extinguishing structure, means defining a groove, means along said groove for giving oi gas when acted upon by an arc, means for establishing an arc within said groove, means on which one end of said arc is movable in said groove, and an opening providing the main vent from said groove, said opening being only adjacent one end of said means on which one end oi said arc is movable.

4. In an arc-extinguishing structure for a circuit interrupter, means defining a passage having a substantially enclosed portion, means along said passage which gives off gas when acted upon by an arc, means for drawing an aro within said passage, means for magnetically moving the arc in said passage, and means for venting said passage, said venting means being of small crosssectional area comparedfto the largest cross-sectional area of said passage and being disposed adjacent that portion of said passage toward which said arc is moved. l

5. In an arc-extinguishing structure for a circuit interrupter, means defining a passage having a substantially enclosed portion, the transverse length of said passage being several times its transverse width, means for drawing an arc within said passage, both ends of said passage being substantially closed during at least a portion of the arc-extinguishing process, means along said passage for giving off gas when acted uponby an arc means on which one end of the arc may be moved transversely in said passage, and means for venting said passage on the side toward which the arc is movable and only adjacent said means on which one end of the arc may be moved.

6. In an arc extinguishing structure for a circuit interrupter, means dening a passage, means for establishing an arc within said passage, said means including a contact member having an arc horn at one side thereof on which one end of the arc is movable, said passage being substantially closed at the end where the arc is initially established, means for magnetically moving the arc in said passage, and means providing a restricted vent for said structure, said venting means including a passage extending along the surface of the arc horn on which the arc is movable to the outside surface of said structure in substantially the same direction as said arc is moved magnetically.

7. In an arc extinguishing structure, means of insulating material defining a passage, means along said passage for giving oli gas when acted on by the arc means for establishing an arc within said passage, means including a plurality ofv members of magnetic material for moving said arc in said passage, said` members of magnetic material being insulated from the arc by said means of insulating material, said passage being closed on two opposite sides and means for venting the side of said passage toward which said arc is moved.

8. In an arc-extinguishing structure, means dening a passage which is closed on at least two sides, means for establishing an arc within said passage., means including a plurality of plates of magnetic material spaced along, and substantially perpendicular to, the longitudinal axis of said passage for moving said arc in said passage, means for insulating said plates of magnetic material from the arc and means dening a venting passage between some of said plates of magnetic material, said venting passage extending outwardly from said passage wherein the arc is drawn in the same direction that said arc is moved.

9. In an arc-extinguishing structure, means of insulating material defining a passage, means for establishing an arc within said passage, means including at least one substantially U-shaped plate of magnetic material insulated from the arc by being embedded in said insulating material and disposed in a plane substantially perpendicular to the longitudinal axis of'said passage for moving the arc in said passage, said passage being closed along the sides of said U, and means dening at least one Ventilating passage adjacent the closed end of said U.

10. In a circuit interrupter, a pair of relatively movable contact members for opening and closing the circuit, and means deiining a chamber wherein one of said contact members is disposed. said chamber having an arcing member associated therewith, an opening in said chamber to permit the entry of the other of said contact members, said opening being substantially closed by said other contact member during a substantial part of the circuit interrupting operation, a vent opening in said chamber adjacent said arcing member and said chamber being otherwise closed for so directing the escape oi' the fluid caused to ow by the operation of said interrupter that one end of the arc is moved thereby from said Contact member disposed in the chamber to said arcing member.

11. In a circuit interrupter, an arc-extinguishing structure including means defining a sidevented passage, a substantially completely enclosed contact chamber positioned adjacent said arc-extinguisher and open only where said passage in said arc extinguisher engages said contact chamber, means for drawing an arc within said passage, an arc terminal means on which one end of said arc is movable, and the vent from said passage being adjacent said arc terminal means for causing one end of said arc to be moved on said arc terminal means by the outiiowing gases generated Within said chamber by said arc.

12. In a circuit interrupter, a stationary contact assemblage, and a cooperating moving contact member for opening and closing the circuit, said stationary Contact assemblage including a contact portion for engaging and disengaging said moving Contact member, an arcing portion,

' and means forsubstantially completely enclosing said assemblage during a substantial part of the movement of said moving contact member, said means enclosing said stationary contact assemblage including a vent adjacent to said arcing portion for causing the Youtiowing gases resulting from the arc formed incident to the operation of said interrupter to move one end of said arc from said contact portion onto and along said arcing portion.

13. In a circuit interrupter, a stationary contact assemblage, a cooperating moving contact for opening and closing the circuit, and an arc-extinguishing structure associated with said stationary contact assemblage, said arc-extinguishing structure including means defining a passage wherein said cooperating contact moves, arc terminal means on which one end of the arc is movable and means for venting said passage along the side thereof vadjacent said arc terminal means, said stationary contact assemblage being substantially completely enclosed except where it engages said passage, said venting means and said contact assemblage causing the arc established incident to operation of said circuit interrupter to be'moved in said arc extinguisher by the outflowing gases from said stationary contact assemblage.

14. In a circuit interrupter, a stationary contact assemblage, a cooperating moving contact for opening and closing the circuit, and an arcextinguishing structure associated with said stationary contact assemblage, said arc-extinguishing structure including means dening a passage wherein said cooperating contact moves. theV an arcing horn extending into said passage, and means for substantially completely enclosing said assemblage except adjacent the arcing horn in said passage, said means enclosing said stationary contact assemblage except where it engages said Passage, and having means associated therewithA for causing said arc to be moved, during the initial stages of the circuit interrupting process, from said contact engaging means onto said arcing horn, and thence into said arc extinguisher, by the outilowing gases from the enclosures for said stationary contact assemblage.

15. In an arc extinguishing structure, means defining a passage that is substantially closed on two opposite sides, said passage having an opening on a third side and venting means on the fourth side opposite the side having said opening, and the ends of said passage being substantially closed during the extinguishing of the arc.

16. In a circuit interrupter, relatively movable contact members for opening and closing the circuit, and an arc-extinguishing structure associated with one of said contact members, said arc-extinguishing structure including means delining a passage that is substantially closed at its ends and on two opposite sides, that has a continuous opening for a portion of its length on a third side through which said other contact member moves, and that has vent openings on the fourth side.

17. In a circuit interrupter, a stationary contact s member and a movable contact member for opening and closing the circuit, and an arc-extinguishing structure, associated with said stationary contact member, said arc-extinguishing structure including means deinlng a passage that is substantially closed at its ends and on two opposite sides and wherein said movable contact member moves longitudinally to establish the arc, said passage having a continuous opening extending longitudinally along a. portion of a third side, a partv ot said movable contact member moving within said continuous opening during at least a portion of the opening operation, said arc-extinguishing structure having means associated therewith for defining at least one vent opening on the fourth side of said extinguisher.

18. In a circuit interrupter, a body of liquid, a stationary contactimember and a movable contact member for opening and closing the circuit, and an arc-extinguishing structure associated with said stationary contact member and immersed in said liquid, said arc-extinguishing structure including means flning a passage that is closed on two sides and wherein said] movable contact member moves longitudinally to establish the arc, said passage having a continuous opening extending longitudinally along a portion of a third side, a part of said movable contact member moving within said continuous opening during at least a portion of the opening operation, said arcextinguishing structure having means including at least one substantially U-shaped plate of magnetic material disposed in a plane substantially ary contact assemblage including means for engaging said moving contact member, and means for substantially completely enclosing said assemblage except in the path of movement of said cooperating contact members, said arc extinguishing structure dening a passage substantially enclosing a part of, the path of movement of said contact member and connecting at one end With said means enclosing said contact assemblage, said passage having a slot in one side of said moving contact member and said slot being substantially closed by said moving contact member during at leastna part of the opening operation of said interrupter, said passage having at least one transverse vent in its side opposite said opening for the moving contact member, said means enclosing said stationary contact assemblage causing the outiiowing gases resulting from the arc formed incident to the operation of said interrupter to ow outwardly through said transverse vent and to thereby move the arc within said passage.

20. In a circuit interrupter, a pair of conducting means between which an arc may play, an arc extinguishing chamber around the arc space between said conducting means, said arc extinguishing chamber being substantially closed during at least a part of the circuit interrupting operation except for a restricted vent opening adjacent to one side only of one of said conducting means, said conducting means adjacent the vent opening having an arc horn on which one end of the arc is movable, said arc horn extending toward the outer end of said vent opening, and

means for causing a ow of fluid from the chamber out said vent opening for moving the end of the arc along said arc horn toward the outer end of. the vent opening and for extinguishing the arc.

21. In a circuit interrupter, a stationary con- `tact member and a moving contact member, said stationary contact member having a portion for normally engaging and conducting current to said moving contact member and having another portion forming an arc horn on which one end of the arc is movable, an are extinguishing chamber in which the arc is drawn between said stationary and moving contact members, said arc extinguishing chamber having one end thereof closed except for an opening through which said moving contact member is actuated and having an opening adjacent the other end providing the only large vent from the chamber during at least the first part of the circuit interrupting operation, means in said chamber for causing pressure to be built up upon the establishment of the arc and causing a flow of iiuid outof said vent, said vent being positioned to cause the Iiow of iluid to move one end of the arc along the arc horn toward the open end of the vent and extinguish the arc.

22. In a circuit interrupter, a stationary con- -tact member and a moving contact member, said stationary contact member having a portion for normally engaging and conducting current to said moving contact member and having another portion forming an arc horn on which one end of the arc is movable, an arc extinguishing chamber in which the arc is drawn between said stationary and mov-ing contact members, said arc extin- .guishing chamber being substantially closed except for an opening adjacent one end through which the moving contact is actuated and which is substantially closed by said moving contact when it moves therein and except for a vent Cil opening adjacent the side of the arc horn portion which is away from the normal current conducting portion of said stationary contact member, and said arc extinguishing chamber having a quantity of liquid therein and one or more plates of insulating material extending generally transversely of the arc for retaining said liquid along the arc where it may be acted upon by the arc and cause pressure to be built up in the chamber and force uid to flow along said arc horn and out said vent opening, thereby moving the end of the arc along vsaid arc horn toward the outer end of said vent opening.

23. In a circuit interrupter, a stationary contact member and a moving contact member, said stationary contact member having a portion fornormally engaging and conducting current tosaid moving contact member and having another portion forming an arc horn on which one end of the arc is movable, an arc extinguishing chamber in which the are is drawn between said stationary and moving contact members, said arc extinguishing chamber being substantially closed ex-k cept for an opening adjacent one end through which the moving contact is actuated and which is substantially closed by said moving contact when it moves therein and except for a vent opening adjacent the end of the chamber opposite the opening for the moving contact and adjacent the side of the are horn portion which is away from the normal current conducting portion of said stationary contact member, said vent opening causing the hot are products to avoid flowng across said normal current conducting portion of said stationary contact member and to flow along said arcing portion of said stationary contact member and move one end of. the arc therealong.

24. In a circuit interrupter, a stationary contact member and a moving contact member, said stationary contact member having a portion for normally engaging and conducting current to said moving contact member and having another portion forming an arc horn on which one end of the arc is movable, an arc extinguishing charnber in which the arc is drawn between said stationary and moving contact members, said arc extinguishing chamber being substantially closed except for an opening adjacent one end through which the moving contact is actuated and which is substantially closed by said moving contact when it moves therein and except for a vent open= ing adjacent the side of the arc horn portion which. is away from the normal current conducting portion of said stationary contact member, said vent opening causing the hot arc products to avoid flowing across said normal current conducting portion of said stationary contact member and to ow along said arcing portion of said stationary contact member and move one end of the arc therealong, and means of insulating material forming the inside of said chamber and providing one or more pockets for retaining an arc extinguishing liquid along the arc pat h Where it may be acted upon by the arc and cause a flow of duid out said vent opening to extinguish the arc.

25. In a circuit interrupter, a body of arc extinguishing liquid, an arc extinguishing chamber immersed in said liquid, said chamber having inner'walls of insulating material, a stationary contact mounted adjacent one end of said chamber, said end of the chamber being substantially closed except for a vent opening, said stationary contact having an arc horn extending from the portion of said contact where the arc is established to said vent opening, the other end of said chamber being substantially closed except for an opening for a moving contact, and a contact movable in said opening into and out of engagement with said stationary contact.

I26. In a circuit interrupter, a body of arc extinguishing liquid, an arc extinguishing chamber immersed inv said liquid, said chamber having inner walls of insulating material, ai stationary contact mounted adjacent one end of said chamber, said end of the chamber being substantially closed except for a vent opening, said stationary contact having an arc horn extending from the portion of said contact Where the arc is established to said vent opening, the other end of said chamber being substantially closed except for an opening for a moving contact, and a contact movable in said opening into and out of engagement with said stationary contact and the inner walls of insulating material having one or more pockets for retaining said liquid along the arc drawn between said contacts.

27. ln a circuit interruptor, an arc extinguishing chamber having inner walls of insulating material, a stationary contact mounted in one end portion o the chamber, said stationary contact having an arc horn extending from the portion thereof at which lthe arc is iirst established, a vent opening in the chamber adjacent the outer end of said. arc horn, said vent opening being of small cross-sectional area compared to the cross-sectional area of the interior of the chamber, an opening in the other end of said chamber and a contact movable therein into and out of engagement with said stationary Contact member, said chamber being substantially closed except for said vent opening and said opening for the movable contact, a material along the inner walls of said chamber which gives off gas when the arc is drawn whereby pressure is built up in said chamber to cause a now or" i-luid along said arc horn and out said vent opening.

28. in a circuit interrupter, an are extinguislin ing chamber having inner walls of insulating materiai, ,a body of liquid in said chamber which when acted upon by an arc gives off gas, a sta= tionary contact mounted in one end of said chainber, said stationary contact having an arc horn portion onto which one end of the are is movable, a vent opening in the chamber adjacent said arc horn portioi'i, said vent opening being or small cross-sectional area compared to the largest cross-sectional area of the interior of said chamber, a second opening in the chamber and a contact movable therein into and out of engagement with the stationary contact, said charnber being substantially closed except for said vent opening and said opening for the moving contact, and said opening for the moving contact being closed by the moving contact during the first portion of the movement thereof to such an extent that the main flow of fluid in the chamber is toward said vent opening for moving the end of the arc on said arc horn.

29. In a circuit interrupter, an arc extinguishing chamber having inner walls of insulating material, a body of liquid in said chamber which when acted upon by an arc gives off gas, a stationary contact mounted in one end o-f said chamber, said stationary contact having an arc horn portion onto which one end of the arc is movable, a vent opening in the chamber adjacent the outer end of said arc horn portion, said vent opening being of small cross-sectional area compared to the largest cross-sectional area of the interior of said chamber, a second opening in the other end of the chamber and a contact movable therein into and out of engagement with the stationary contact, said chamber being substantally closed except for said vent opening and said opening for the mving contact, one or more pockets formed in said chamber for retaining 10 some of said liquid along the path of movement of said moving contact, and said opening for the moving contact being closed by the moving contact during the first portion of the movement thereof to such an extent that the main ow of fluid in the chamber is toward said vent opening SAMUEL H. BODEN.

STANLEY T. scHoFIELD. 10

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