US2477781A - Circuit interrupter - Google Patents

Description

1949. a. P. BAKER ETAL 2,477,781

CIRCUIT INTERRUPTER Filed Oct. 7, 1946 a sheds-sheet 1 WITNESSES:

INVENTORS z fienjamtn Pfia/rer and am es /I, (z/ m my M Aug. 2, 1949.

B. P. BAKER ETAL CIRCUIT INTERRUPTER s Sheets-Sh aet 2 Filed 001;. 7, 1946 INVENTORS fienjamin P5 and James /7. ('umm ny- WITNESSES: 1

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Aug. 2, 1949. B. P. BAKER ETAL 7 CIRCUIT INTERRUPT Filed Oct. 7, 1946 3 Sheets-Sheet 3 WITNESSES: INVENTdRS fiery am 1'27 Ffia/Fer a James /7. Cumming? 704M BY 4 ATTORNE Patented Aug. 2; 1949 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER Benjamin P. Baker and James M. Cumming, Turtle Creek, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 7, 1946, Serial No. 701,846

9 Claims. (01. 200-150) This invention relates to circuit interrupters, in general, and, more particularly, to arc-extinguishing structures therefor.

Circuit interrupters of the prior art employed to interrupt high voltage circuits have employed a number of serially related breaks to minimize the voltage to be interrupted at each break. However, the prior art circuit interru'pters involving a number of breaks have been complicated, costly to manufacture because of their complexity and wasteful of longitudinal space.

The principal object of our invention is to pro vide a simplified, compact circuit interrupter hav-- ing a considerable number of serially related breaks especially adaptable for the interruption of high voltage circuits such as a 287 k. v. circuit in three or less cycles, and to arrange the breaks in an advantageous manner to minimize longitudinal space. However, certain features of our invention are also adaptable for the interruption of low voltage circuits.

Another object of our invention is to provide an improved circuit interrupter in which the arcextinguishing units are of improved construction and also in which the contact means may be readily inspected and replaced if necessary.

Another object is to provide an improved circuit interrupter in which the several parts thereof are of simplified construction and may be readily repeated for high voltage application.

Another object is to provide an improved circuit interrupter of very compact construction comprising a plurality of serially related superimposed arc-extinguishing units in which the contact separation is effected in a simplified and positive manner.

Another object is to provide an improved circuit interrupter involving one or more arc-extinguishing units in which a pressure-generating arc is established within a substantially annular pressure-generating arc passage and is utilized to direct fluid toward an interrupting are which is established within a segmental portion of an annular vented interrupting passage.

Still another object is to provide an improved piston construction for a circuit interrupter of the high voltage type to facilitate low current interruption.

Further objects and advantages will readily become apparent upon a reading of the following specification taken in conjunction with the drawings, in which:

Figure 1 is a. side elevational' view, partly in section, of a circuit interrupter embodying our 2 invention and shown in the closed circuit position;

Fig. 2 is an enlarged vertical sectional view through the right-hand arc-extinguishing assemblage of the interrupter of Fig. 1, the contact structure being shown in the closed circuit position;

Fig. 3 is an enlarged vertical sectional view through our improved arc-extinguishing unit, taken along the line III-'III of Fig. 6, the contacts being shown in the closed circuit position;

Fig. 4 is an enlarged sectional view taken along the line IVIV of Fig. 2;

Fig. 5 is a sectional view taken along the line VV of Fig. 3;

Fig. 6 is a sectional view taken along the line VI-VI of Fig. 3;

Fig. 7 is a sectional view taken along the line VII-VII of Fig. 3;

Fig. 8 is a sectional view taken along the line VIII-VIII of Fig. 3; and

Fig. 9 is a perspective view of our improved relatively stationary bridging contact construction showing how it may be easily removed from and inserted into the arc-extinguishing assemblage.

Referring to the drawings, and more particularly to Fig. 1, the reference numeral I designates a tank filled to the level 2 with a suitable arcextinguishing fluid 3, in this instance circuit breaker oil. Depending from the cover 4 of the tank I are two insulating terminal bushings designated by the reference numerals 5, 6 to the lower ends of which are secured identical arcextinguishing assemblages, generally designated by the reference numeral 1. A conducting bridging member 8 electrically interconnects. the two arc-extinguishing assemblages l in the closed circuit position of the interrupter .as shown in Fig. 1. An insulating actuatingrod 9 is employed for effecting vertical reciprocating motion of the bridging member 8. Suitable mechanism (not shown) is utilized for effecting motion of the actuating rod 9.

Referring to Fig. 2 which shows in more detail our improved arc-extinguishing assemblage 1, it will be observed that the assemblage 1 includes a plurality of arc-extinguishing units generally designated by the reference numeral I0 and disposed in serially related superimposed abutting relationship. The units H] are mounted in stacked relation to each other upon a casting member 34, a circular insulating plate member 14 being disposed therebetween. Insulating .tie

rods ll may be employed for maintaining the several arc-extinguishing units l rigidly in position. The upper ends of the insulating tie rods ii are enlarged and fixed to a metallic plate l2, the latter being secured by bolts l3 to a top casting M. The upper portion of the casting l4 forms a piston means including a piston chamber I5 in which reciprocally moves a piston member 1 6, the latter being spring-biased downwardly by a compression spring H. The piston means including the piston member i 6 operable in the piston chamber i5 is charged against the downward biasing action exerted by the compression spring H by the upward movement of a movable contact carriage generally designated by the reference numeral i8 and including a Pair of parallel operating rods, generally designated by the reference numerals l8 and 28.

The operating rods i9, are secured together at their lower ends by a cross-head 2| of conducting material having a recess 22 formed therein,

which recess is in abutting relation with the upper end of a movable disconnect contact 23. The disconnect contact 23 is secured at the extremity of the conducting bridging member 8, as more clearly shown in Figs. 1 and 2. Upward movement of the movable disconnect contact 23 causes upward movement of the contact carriage 118 against the downward biasing action exerted by the accelerating springs 24 disposed at the lower end of the assemblage l.

The construction of the operating rods i9, 20 is such as to provide a zig-zag current path through the assemblage 7, as shown more clearly in Fig. 2. More specifically, each operating rod 59, 20 has alternately disposed conducting portions 25 and insulating portions 26. These portions 25, 2B are supported by elongated insulating operating rods 21, which extend upwardly through both operating rods I9, 20. The insulating portion 28 includes an insulating sleeve 28 surrounding the insulating operating rod 21. Ihe conducting portion 25 includes an interiorly positioned conducting sleeve 29 immediately surrounding the insulating operating rod 2?. However, the conducting sleeve 29 is in turn surrounded by an insulating sleeve 30. Disposed between the insulating sleeves 28 and 30 is a ringshaped movable contact 3| which makes engagement with relatively stationary bridging contact means 32 disposed at the upper end of each unit ill.

Fig. 9 shows more clearly the construction of the relatively stationary bridging contact means 32. It will be observed that an elongated conducting bar 33 is provided having a central portion 35 removed therefrom. Disposed within the cutout portion 35 are a pair of opposed relatively stationary contact segments 36, more clearly shown in Fig. 5. Each of the contact segments 36, is biased inwardly by a compression spring 3'! disposed between the wall of the cutout portion 35 and the inner end of a recess 38 provided in each stationary contact segment 36 as shown in Fig. 5.

It will be observed that the bridging contact means 32 may be easily removed from the assemblage I by lateral movement thereof upon the downward removal of the two operating rods i9, 20. This method of holding the contact structures 32 in position is more clearly shown in Fig. 5. After the relatively stationary bridging contacts 32 have been placed into position between the opposed insulating plates 39 (Fig. 5), the upward movement of the operating rods 19, 20 into the ends of the cutout portion 35 of the Contact structure 32 securely holds the contact structure 32 in position while at the same time permitting the mounting to be sufficiently flexible to accommodate any variations present on the rods II, 20.

In the closed circuit position of the interrupter shown in Figs. 1-3, the electrical circuit therethrough includes the terminal stud (not shown) passing interiorly through the terminal bushing 6, top casting l4, slider contact fingers 40 (Fig. 2) supported by the casting l4, conducting sleeve 4!, ring-shaped movable contact 3i, relatively stationary bridging contact 32, upper right-hand movable ring-shaped contact 3! associated with the right operating rod l5, conducting sleeve 29, ring-shaped contact 3!, to the left through relatively stationary bridging contact 32 and so forth, in a zig-zag manner to the lower end of the assemblage l. The current path extends from the lowermost bridging contact 32 through the lower ring-shaped movable contact 3| associated with the left-hand operating rod 20, through the conducting sleeve 42 to the conducting cross-head 2|, from whence the circuit passes through the movable disconnect contact 23 to the conducting cross-member 8. The circuit passes through the left-hand arc-extinguishing assemblage 1 (Fig. l) in an identical manner to the terminal stud passing through the left-hand terminal bushing 5 of the interrupter.

During the opening operation, suitable means (not shown) but which may be responsive either to manual operation or to excessive current passing through the interrupter, causes downward motion of the lift rod 9. The downward movement of the lift rod 9 causes corresponding downward movement of the conducting cross-member 8 and hence downward movement of the two movable disconnect contacts 23 secured to the opposed extremities of the conducting cross-bar 8.

Considering only the right-hand arc-extinguishing assemblage I, referring to Fig. 2, it will be apparent that the accelerating compression springs 24 initially cause downward following movement of the movable contact carriage IS in response to lowering of the movable disconnect contact 23. The downward motion of the movable contact carriage l8 causes corresponding downward motion of the two operating rods IS, 20 to simultaneously establish a pair of serially related arcs in each arc-extinguishing unit HI, the construction of which will be described hereinafter. It will be observed that the downward motion of the operating rods 19, 20 permits the compression springs H to cause downward motion of the piston I6 within the piston chamber l5, ii the current being interrupted is not too high. Circuit interruption soon occurs and the conducting cross-head 2| in striking a dash pct 43 disposed at the lower end of the assemblage l permits separation to take place between the recess or relatively stationary disconnect contact 22 and the upper tip of the movable disconnect contact 23.

The dash pct 43 comprises a movable piston 44 having apertures 45 provided therein which are closed off by an upstanding cylindrical portion 43 of a lower ring plate 4'! threadedly secured at 48 to the lower end of a ring-shaped conducting casting 49. Preferably, the piston 44 is biased upwardly by a compression spring 50 seated upon a lower cap 5| secured by bolts 52 to the lower ring plate 41.

The dash pct 43 is effective to cushion the stopping of the downward movable contact'carriage H} at the end of its opening movement. As mentioned previously, the circuit has been interrupted when the conducting cross-head 2i strikes the dash pct 49 to be arrested thereby, thus permitting the movable disconnect contact 29 to separate from the recess or contact 22 to insert an isolating gap into the circuit, as more clearly shown by the dotted lines in Fig. 1.

The internal construction of the arc-extinguishing units In will now be described. Referring to Fig. 3, which shows enlarged a vertical sectional view through the arc-extinguishing unit i0 taken on the line III-DI of Fig. 6, it will be observed that the unit in is formed by the use of a plurality of suitably configured insulating plates disposed in superimposed contiguous relationship and held in place by the insulating tie rods Ii. The top flow plate 53 of the unit I. has a configuration more clearly shownin Fig. 7. It will be observed that the insulating now plate 59 has two apertures 54 provided therein together with a centrally disposed cutout portion 55. On the same level as the plate 53 is a centrally disposed round plate 55 having a lower projection 51 which is employed to hold it in position.

It will be observed that the flow plate 59 permits a flow .of fluid to take place between the pressure-generating are (not shown) which is drawn within a substantially annular pressuregenerating arc passage, generally designated by the reference numeral 58 and the interrupting are (not shown) which is established within a segmental portion of an annular interrupting arc passage, generally designated by the reference numeral 59 in Fig. 3.

Immediately below the insulating flow plate 53 is an insulating partition plate 55, more clearly shown in Fig. 6. The partition plate 50 has the apertures 54 provided therein and also has an aperture 6| formed therein closely confining the insulating operating rod l9. It will be observed that there is some clearance provided between the aperture GI and the operating rod l9 to permit a flow of liquid to take place past the partition plate 69. The partition plate 50 also has an aperture 62 formed therein to closely confine the operating rod 28. The aperture 92 has a notch 63 formed therein, the purpose for which will appear more clearly hereinafter.

Immediately below the insulating partition plate 80 is an insulating vent plate 54, the configuration of which is more clearly shown in Fig. 6. The insulating vent plate 64 has apertures 54 provided therein which communicate with a pair of intersecting inlet passages 65, the latter leading toward the substantially annular pressuregenerating arc passage 58 to form a pool of liquid 15 therealong. Also the vent plate 54 has a vent passage 66 formed therein to permit venting of the substantially annular interrupting passage 59 to the region exterior of the unit It.

Immediately adjacent to the vent plate 54 is a second insulating partition plate 58 having a construction identical to the partition plate 55 previously described. Below the second insulating partition plate 60 is a second flow insulating plate 53 having a configuration the same as previously described and shown more clearly in Fig. 7. Below the second insulating flow plate 53 is a barrier insulating plate 81, the configuration of which is more clearly shown in Fig. 7. The barrier insulating plate 61 has apertures 54 provided therein and also apertures 58, which closely confine the insulating sleeves 28, 88 of operating rods i9, 20, respectively. Below the barrier insulating plate 61 is a pocket insulating plate 55,

which also has apertures 54 provided therein. The configuration of the pocket insulating plate 59 is more clearly shown in Fig. .8.

It will be observed that the insulating plate 59 has annular recesses Ill provided therein which prevent loss of fluid pressure downwardly along the side walls of the annular arcing passages 59, 59. Below the plate 89 is a second barrier insulating plate 81 which is in turn followed by a second pocket insulating plate 59. most plat in the unit I! is a barrier insulating plate 81 which has a configuration as previously described.

It will be apparent that upon alignment of the several plates there will be provided passage means including two vertically extending passages, generally designated by the reference numeral ll, interconnecting the piston chamber 15 with the several units ID.

During the opening operation, assuming the current conditions to be high, it will be apparent that two arcs (not shown) are drawn in each unit H) in the substantially annular restricted pressure-generating arc passage 59 and in the restricted segmental portion of the annular interrupting arc passage, 59 as defined by the notches 69. Since the units In are immersed in oil, there is a readily available quantity of oil disposed adjacent the arcs within the recesses provided by the several plates and especially in the liquid pools I5. Referring to Fig. 3, it will be apparent that the pressure are drawn in the pressure passage 58 will react upon the oil disposed therealong and especially in the pool 15 to force liquid to flow through the connecting passages (Fig. '7) in the two flow plates 59 toward the interrupting arc which is drawn within the interrupting passage 59 as defined .by the notches 69. The notches 69 provided in the two partition plates 60 force the interrupting arc to be drawn therein, thereby preventing the interrupting are from being displaced around the surface of the insulating sleeve 30 adjacent the open side of the vent passage 66. The oil which passes through the connecting passages 12 provided in the flow plates 59 must pass upwardly and downwardly through the two notches 93 adjacent to the interrupting are before it is vented out of the unit I. by means of the vent passage 65.

It will be apparent that by providing substantially annular arc passages 58, 59 with the operating rod members I9, 20 substantially filling said are passages, a desirable restricting of the two serially related arcs is provided in each unit 19. During the interruption of high currents, the pressure generated adjacent the pressure arc will act backwardly through the inlet passages 55 and upwardly through the vertical flow passages H to prevent downward movement of the piston l5 within the piston chamber l5. In other words, during the interruption of high current, the back pressure is too great to permit operation of the piston means. It is only during the interruption of relatively low power that the pressure is sumciently low to permit the compression spring I! to force the piston l5 downwardly within the piston chamber l5 to force oil downwardly through the vertical flow passages II and into the inlet passages 55 provided in each unit I 0 by the insulating vent plate 54. Thus, the pressure are in each unit I8 is acted upon by oil driven from the piston means through the inlet passages 65. This oil flow increases the pressure generated at the pressure-generating arc and also tends to eflect the extinction of the The lowersame. As previously mentioned, the resulting oil flow from the pressure arc passes through the connecting passages i2 provided in the two plates $3 of each unit it) toward the interrupting are drawn within the interrupting passage 59. The oil in passing through the notches 63 comes into intimate engagement with the interrupting arc to pass out of the unit In through the vent passage 56.

By the time the operating rods 19, 20 and the cross-head 2i strike the dash-pot 43, arc extinction has already transpired, and the tip of the movable disconnect contact 23 is forceably withdrawn from the stationary disconnect contact 22 provided in the conducting cross-head 5!. Certain features of the disconnect arrangement are more fully set forth and claimed in United States patent application, Serial No. 696,571, filed September 12, 1946, now U. S. Patent 2,460,450, issued Februar 1, 1949, to James M. Cumming, and assigned to the assignee of the instant application. Also certain features of the interrupting structure herein set forth are illustrated and claimed in United States patent application, Serial No. 465,244, filed November 11, 1942, now U. S. Patent 2,406,469, issued August 27, 1946, by Leon R. Ludwig, Winthrop M. Leeds and Benjamin P. Baker, and assigned to the assignee of the instant application.

It will be observed that certain features of the pressure-generating arc passage 58 are similar to those of the interrupting structure set forth and claimed in United States Patent 2,253,009, issued August 19, 1941, to Benjamin P. Baker, entitled Circuit interrupter" and assigned to the assignee of the instant application.

From the foregoing description, it will be apparent that we have provided an improved circuit interrupter of the type drawing pressure and interrupting arcs in which more effective interrupting conditions are brought to bear upon both the pressure are and the interrupting arc in each extinguishing unit ill. By the provision of the operating rods i9, 20 having sleeve portions 28, 30 therealong which closely confine the two serially related arcs, effective interrupting conditions are brought to bear upon both arcs. During the interruption of low power, the piston means is operative to send fluid through the inlet passages 65 toward the pressure arc to increase the pressure thereabout and to tend to effect the extinction of the same.

The construction is simplified inasmuch as by withdrawal of the two operating rods I9, 20 downwardly out of the assemblage 1, the relatively stationary contact structures 32 may be laterally removed from the assemblage '1 between the insulating plates 39. Upon their replacement, they are merely held in position by the presence of the rods I9, 28 which may be moved upwardly into the several cutout portions 35 provided in the several relatively stationary contact structure" 32. In the fully open circuit position, shown by the dotted lines 73 of Fig. 1, two isolating gaps are provided in the circuit and fresh oil within the tank I is permitted to enter the several units In through the vent passages 66.

Although we have shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. In a circuit interrupter, an arc-extinguishing assemblage including a plurality of arc-extinguishing units each having two openings therethrough, contact means associated with each arcextinguishing unit, a pair of axially movable spaced operating rods each extending through one of the openings in each unit of the assemblage, and each operating rod having alternately disposed conducting portions and insulating portions, said conducting portions being covered with insulation except at the end portions thereof which coact with the several contact means so as to provide a zig-zag current path through the assemblage.

2. In a circuit interrupter, means defining at least a pair of arc-extinguishing units disposed in abutting relationship, each of said arc-extinguishing units having two openings therein, relatively stationary bridging contact means disposed at one end of each unit, a pair of axially movable spaced operating rods extendin within the two openings in the units, each operating rod having alternately disposed a conducting portion and an insulating portion, each of said conducting portions being covered with insulation except at the end portions thereof which coact with the several bridging contact means, and said conducting portions and bridging contact means providing a zig-zag current path through the units in the closed circuit position of the interrupter.

3. In a circuit interrupter, means defining at least a pair of arc-extinguishing units disposed in abutting relationship. each of said arc-extinguishing units having two openings therein, relatively stationary bridging Contact means disposed at one end of each unit, a pair of axially movable spaced operating rods extending within the two openings in the units, each operating rod having alternately disposed a conducting portion and an insulating portion, each of said conducting portions being covered with insulation except at the end portions thereof which coact with the several bridging contact means and said conductin portions and bridging contact means providing a zig-zag current path through the units in the closed circuit position of the interrupter, and each relatively stationary bridging contact means being laterally removable from it unit following withdrawal of the two operating rods. from the units.

4. In a circuit interrupter, an arc-extinguishing assemblage including a plurality of arc-extinguishing units having two parallel openings therein, a, pair of axially movable spaced operating rods extendin within the said two parallel openings, each operating rod having at least a conducting portion and an insulating portion, relatively stationary bridging contact means associated with each unit, and the conducting portion of one operating rod being opposite to the insulating portion of the other operating rod and coacting with the bridging contact means so as the provide a zig-zag current path through the assemblage in the closed circuit position thereof.

5. In a circuit interrupter, an arc-extinguishing assemblage including a, plurality of serially related arc-extinguishing units having two parallel openings therein, an axially movable contact carriage including a pair of axially movable parallel disposed operating rods each in one of said openings, each operating rod having a conducting portion and an insulating portion disposed in end-to-end relationship, relatively stationary bridging contact means associated with each unit, the conductin portions of the operating rods being alternately disposed and cooperating with the stationary bridging contact means to establish a zig-zag current path through the assemblage, and disconnect means separable from the contact carriage for actuating the movable contact carriage, the disconnect means separating from the contact carriage in the fully open cirerating arc passage and a substantially annular interrupting passage within the unit, the pair of parallel operating rods being movable along the arc passages, each rod having a movable contact secured to and movable therewith, the pair of movable contacts makin engagement with the bridging contact in the closed circuit position of the interrupter, a vent plate configured to permit venting of the interrupting arc passage and to provide a pool of liquid along the Walls of the pressure are passage adjacent to the pressuregenerating arc, and a pair of partition plates on opposite sides of the vent plate having apertures therein closely confining the two operating rods.

7. In a circuit interrupter, an arc-extinguishing unit immersed in an arc-extinguishing liquid, a relatively stationary bridging contact disposed at one end of the unit, suitably configured insulating plate structure including a pair of parallel operating rods for defining a substantially annular pressure-generating arc passage and a substantially annular interrupting passage within the unit, the pair of parallel operating rods movable along the arc passages, each'rod having a movable contact secured to and movable there- 'with, the pair of movable contacts making engagement with the bridging contact in the closed circuit position of the interrupter, a vent plate configured to permit venting of the interrupting arc passage and to provide a pool of liquid along the walls of the pressure are passage adjacent to the pressure-generating arc, a pair of partition plates on opposite sides of the vent plate'having apertures therein closely confining the two operating rods, and a flow plate on the opposite side of each partition plate providing communication between the two are passages.

lating plate structure including a pair of axially movable parallel operating rods for defining a substantially annular pressure-generating arc passage and a substantially annular interrupting passage within the unit, the pair of parallel operating rods movable along the arc passages, each rod having a movable contact secured to and movable therewith, the pair of movable contacts making engagement with the bridging contact in the closed circuit position of the interrupter, a vent plate configured to permit venting of the interrupting arc passage and to provide a pool of liquid along the walls of the pressure arc passage adjacent to the pressure-generating arc, a pair of partition plates ,on opposite sides of the vent plate having apertures therein closely confining the two operating rods, 9, fiow plate on the opposite side of each partition plate providing communication between the two arc passages, and the two partition plates having notches provided therein to position the interrupting are on the opposite side of the operating rod from the vent passage in a segmental restricted portion of the arc passage.

9. In a circuit interrupter, an arc-extinguishing unit, a bridging contact disposed at one end 01 the unit including a conducting bar having a cut-out portion, a pair of opposed contact segments positioned within the cut-out portion, and a pair of operating rods carryin a pair of movable contacts movable through the ends of the cut-out portion.

BENJAMIN P. BAKER. JAMES M. CUMMING.

REFERENCES crrnn The following referenices are of record in the file of this patent:

UNITED STATES PATENTS

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