US2425147A - Circuit interrupter - Google Patents

Description

Patented Aug. 5, 1947 CIRCUIT INTERRUPTER Clinton L. Denault, Sharpsville, Pa., assignorvto Westinghouse Electric Corporation, East Pittsburgh, Pa.,- a corporation of Pennsylvania Application June 29, 1944, Serial No. 542,688

(C1, k2Il(l-'1`50) 6 Claims.

Thisv invention relates to circuit interrupters -inv general, andymore particularly, to arc-extinguishing structures therefor.

A general object of my invention is to provide an improved circuit interrupter in which more effective performance is achieved at increasing economical operation. This is obtained by providing an Uimproved construction wherein the fluid blast principle is used in a way which will permit a wide range of currents to be handled in a` given sized structure without Vthe use of ex- Cessive fluid quantities or uid driving pressures.

A more specific object of myinvention is to provide an improved circuit interruptor in which a discharge outlet is provided adjacent the established arc and to provide improved valve means, controlling the discharge Y outlet which will be'responsive to the pressurev in the arc region. Preferably the improved valve means comprises guide means for directing iiuid toward the arc in which the opening movement of the guide means will serveto decrease the quantity of iiuid directed toward the arc to'therebyy prevent the generation of excessive pressures within the arc region.

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

/ Figure l is a vertical sectional view of a circuit interrupter embodying my invention and shown in the closed circuit position, the arc-extinguish- "ingstructure being shown in full elevation;

Fig. Z is a vertical sectional view lthrough the improved arc-extinguishing structure of Fig. 1,

the parts being shown in the partly open circuit position; and

Fig. 3 is a modied type of arc-extinguishing structure which may be substituted for the arcextinguishing structure of Fig. l.

Referring to the drawing and, more particularly, to Fig. 1 thereof, the reference numeral I designates a tank filled to the level f2 with a suitable arc-extinguishing fluid 3, in this instance circuit breaker oil Depending from the cover 4 of the tank I are two insulating bushings 5, E through which. extend terminal studs l, 8. Threadedly secured to the lower end of the terminal stud l is a bracket `9 having secured there- Ato a slider Contact I, making contacting engagement with the conducting portion I I of the movable contact, generally designated by the reference numeral I2. The upper portion I3 of the movable Contact I2 is formed of insulating material and is vertically actuated in a reciprocal `manner during the opening and closing operations by suitable mechanism (not shown).

Insulating brackets I4, I5 rigidly support within Athe tank I the Varc-extinguisl'iing structure, generally designated by the reference numerall 6. Movable through the bottom plate 'II Aof the tank I vthrough suitable packing means I8, is an operating rod I9 at the upperend of whi-ch is secured a piston'Z movable within. a pistonrchamber"'2| and constitutingv fluid moving means. Preferably flap valvesA 22 are provided to permit agunidirectional flow of fluid through apertures '23 provided in the ipiston. 'Thus during the opening operation of the circuit interrupter when the piston 2i? is forced upwardly, the flap valve'22 will'remain closed. During a subsequent resetting il is pivotally connected at-8li to a link 8I,the

lower `end =of.which is pivoted at182 to a lever 33. The lever 83 is pivoted on a xedjpivot 84. The left-hand end of lever 83, as viewedrin Fig. 1, is pivotally connected at `85 to the lower end. of the operating rod I9.

Thus upward opening movement of 'the movable contact I2 by suitable means, not shown, simultaneously causes upward movement ofthe 'piston 2i) to force fluid toward the established arc. `During the downward closing movement of themovable Contact I2, the piston 20 is moved downwardly to be charged.

Referring, more particularly, to Fig. 2 which illustrates an enlarged, vertical sectional view through the arc-extinguishing structure IE, it will be observed that the casing 24 lof the` arc-extinguishing structure I5 is formed of insulatinglmateria] and-has an annular-recess 2,5, formed at its upper end. Secured between insulating brackets Il within the annular recess 25, is a ring-shapedy member 26 which cooperates with the recess '2t to forman annular discharge'outletc-r venting means, generallyldesignated by the reference numeral 2l. The annular discharge outlet or annular discharge means 21 permits a discharge or exhausting of fluid away from the arc` drawnl betweenr the movable IContact Il and the relatively stationary contact 29 within an elongated generally cylindrical substantially enclosed arc passage 86.

.An aperture 30 is centrally provided in the ringshaped member 26 and has an inwardly extending flange 3| disposed at its lower end. Slidably movable within the aperture 38 is a sleeve valve 32 constituting valve means responsive to the pressure within the arc passage and controlling the venting means 21. It may be either of insulating or metallic material but is herein shown as being of insulating material, having a flange 33 biased against the flange 3| by a compression spring 34, encircling the sleeve valve 32, The upper end of the compression spring 34 seats against a ring 35 secured by screws 36 within a recess 31 provided in the ring-shaped member 26.

It will thus be apparent that the sleeve valve 32 controls the exhausting of fluid out of the arcextinguishing structure I6 through the annular discharge outlet 21, the valve 32 being responsive to the pressure within the arc region and also responsive to the velocity of the fluid.

An annular recess 38 is provided at the lower end of the casing 24. An insulating bottom plate 39 is secured by bolts 40 to the casing 24. Disposed between the casing 24 and the bottom plate 39, is a conducting spider member 4| having apertures 42 provided therein, the spider 4| having an upstanding portion 43 internally threaded to rigidly support in place a conducting cylindrical member 44 which, in the closed circuit position of the interruptor, makes sliding contacting engagement with the movable contact The relatively stationary contact 29 is biased upwardly by a compression spring 45 so that a flange 45, integrally formed with the stationary contact 29, makes abutting engagement with a shoulder 41. Thus, in the closed circuit position the conducting cylindrical member 44 serves to carry the current through the interrupter, whereas during the opening operation, the stationary contact, 29 remains in following engagement with the movable contact I I until the iiange 46 strikes the shoulder 41, at which time the lower terminal between the cylindrical member 44 and the movl able contact Il.

The spider 4| has a terminal portion 48 to which is electrically attached a cable 49 by a screw 58. The upper end of the cable 49 is secured by nuts to the lower end of the terminal s stud 8.

From the foregoing description, it will be apparent that in the closed circuit position of the interrupter shown in Fig. l, the electrical circuit therethrough comprises terminal stud 1, conducting bracket 9, slider contact l0, conducting portion |2 of movable contact cylindrical member 44, spider 4|, terminal portion 48, cable 49, to terminal stud 8.

Inserted within the recess 38 against a shoulder 52, is a ring-shaped plate 53 composed of insulating material, having a central aperture 54, and having a plurality of outer apertures 55 formed therein. The plate 53 is maintained in place by a resilient ring clip 56 disposed in an annular groove 51 provided in the casing 24. The cylindrical member 44 has at its upper end a radially outwardly extending horizontal portion 58 which cooperates with the plate 53 to form an inwardly extending inlet passage, designated by the refer,-

il l) ance numeral 59. Also the plate 53 cooperates with the upper end of the recess 38 which extends inwardly to form a ring-shaped plate portion and thereby to form a second radially inwardly extending inlet passage, designated by the reference numeral 60. I provide the outer periphery of the horizontal portion 58 with a downwardly depending flange portion 6| to cooperate with the upper portion of the recess 38 to provide an annular inlet passage, generally designated by the reference numeral 62 in Fig. 2.

The operation of the embodiment of my invention shown in Figs. 1 and 2 will now be explained. During the opening operation, suitable means (not shown) causes both upward movement of the movable contact and upward movement of the operating rod I9 and piston 20 by the aforesaid linkage. An arc 28 is established between the contact 28 and the movable Contact I, the upward movement of the piston 26, flap valves 22 remaining closed, serving to force uid, in this instance oil, upwardly through the apertures 42 in spider member 4|, upwardly through the annular inlet passage 62, and radially inwardly through the passages 59, toward the arc 28. After contacting the arc 28, the fluid exhausts out through the discharge outlet 21, raising the sleeve valve 32 to an extent depending upon the pressure within the arc region. Following interruption, the movable contact preferably moves out of the arc-extingushing structure I6 to a position shown by the dotted line 63 in Fig. 1 to provide an isolating gap in the electrical circuit.

By the above construction, it will be apparent that I have provided a circuit interrupting structure where use is made of the uid blast principle in a way which will permit a wide range of currents to be handled in a given sized structure without the use of excessive fluid quantities or fluid driving pressures. The arc 28 is drawn within an arc passage 86 which is almost completely closed on the discharge side by the sleeve valve 32, spring-biased to its lower position. This valve 32 is responsive to both pressure and velocity. With this arrangement, a, wide range of currents can be handled in the arc chamber without having excessive pressures in the arc zone at the high currents, nor having excessive fluid loss at the low currents. As an additional feature, the control of the arc discharge area contributes a self-generated pressure control eiect in the arc zone, where a desirable moderate pressure is generated and maintained by the interaction of the uid ilow and discharge valve movement.

The embodiment of my invention, shown in Fig. 3, is generally similar in some constructional features with the embodiment shown in Fig. 2; consequently, similar reference numerals have, where possible, been employed. However, in this embodiment of my invention, the conducting cylindrical member 44 of Fig. 2 has been omitted and in its place has been provided an insulating cup-shaped member 64 constituting second valve means which serves to guide an insulating ringshaped member 65 which supports, by bolts 66 and their spacer sleeves 61, a plurality of spaced insulating ring-shaped plates 68, cooperating to provide a plurality of inlet passages, designated by the reference numeral 69 and disposed in superimposed relation axially along the path of movement vo1? the movable contact The spaced plate structure is operatively connected to the rst valve means 10 hereinafter described.

having" the upperportion 1| thereof ofsuch configuration that it controls by valve action the discharge outlet or venting means 2l. The ringshaped-member 26 forms-a'stationary valve -seat for thelfirst valve means 4lil' in `this embodiment of my invention. The cup-'shaped member 1D is guided by a cylindrical portion-1'2- of the casing 24. The region 15 below the ring-shaped member 65 is connectedbyconduit-16-to-thefregion outside of casing 24 to eliminate'-back-pressure on member 65.

In the embodiment of my invention shown in Fig. 3, an additional feature is incorporated in the structure. In this case the discharge duct valve is a part of the fluid duct guide and is so arranged that as the pressure in the arc chamber increases, the fluid entrance ducts 69 will be moved downwardly with respect to the fixed ecntact 29, so that, as the discharge outlet 21 opens up during high pressure, the fluid inlet passages 69 will be blocked by the second valve means 64 to a greater and greater extent, as the discharge opening 2l increases. This serves to reduce the quantity of oil flowing into the high current arcs, thereby preventing the generation of excessive pressures. It is probable that a denite minimum quantity of oil will be necessary. The stop 13 controls that feature.

From the foregoing description of the embodiment shown in Fig. 3, it will be apparent that I have provided an improved circuit interrupting structure in which annular guide means, generally designated by the reference numeral T4, and comprising the plates 68 and cup-shaped member 10, are provided which have the additional function of serving as a valve for the annular discharge means 21. The downward movement of the annular guide means M not only serves to open up the discharge means 2l, but also serves to decrease the number of inlet passages 69 available, thereby decreasing the quantity of fluid directed upwardly by the piston 20 toward the arc 28.

Although I have shown and described specific structures, it is to be clearly understood that the same were 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.

I claim as my invention:

l. In a circuit interrupter, means including a plurality of spaced ring-shaped plate members defining an elongated generally cylindrical substantially enclosed arc passage, a relatively stationary contact disposed at one end of the arc passage and substantially blocking the same at this end, a movable rod-shaped contact separable from the stationary contact to draw an arc through the arc passage, fluid moving means for forcing fluid radially inwardly toward the arc between the spaced ring-shaped plate members, venting means disposed adjacent the other end of the arc passage, and valve means responsive to the pressure within the .arc passage and disposed adjacent the other end of the substantially enclosed arc passage to control the exhaust of fluid out of the venting means.

2. In a circuit interrupter, means including a plurality of relatively fixed spaced ring-shaped plate members defining an elongated generally cylindrical arc passage, means for establishing anarc axially Withinv the arc-passage,-meansvsub stantia'lly enclosing Ithearc passage at one end thereofjfluid moving means'for moving fluid ra- `diallyV inwardly between the spaced ring-shaped plate ymembers along the arcy passage, venting Vmeans disposed adjacent the other end'of the arc passage, and valve means responsive to the-pres- 'surewithin the arc passage l to control -the exhaust `of fluid out the venting means.

SIJIn;v a 'circuit interrupter, means defining a substantially enclosed arc passage, meansforestablishing an arc withinthe arcpassage, venting means disposed adjacent `one end of the arc passage, valve means responsive to the pressure within the arc passage for controlling the exhaust of fluid out of the arc passage through the venting means, means at least lpartially of insulating material defining a plurality of fluid passages operatively connected to the valve means, second valve means for successively yclosing the fluid passages upon continued opening movement of the first-mentioned valve means, and fluid moving means for forcing fluid through the fluid passages into the arc passage to effect the extinction of the arc established therein.

4. In a circuit interrupter of the fluid type, means defining a substantially enclosed arc passage, means including a rod-shaped movable contact for establishing an arc within the arc passage, means defining a, stationary valve seat, a movable orifice-shaped valve, means biasing the movable orifice-shaped valve against the stationary valve seat to make the valve responsive to the pressure Within the arc passage, spaced plate structure secured to and movable with the movable valve to define a plurality of fluid passages spaced axially along the arc passage, means for forcing iiuid through the fluid passages into the arc passage to effect extinction of the arc therein, and relatively stationary valve structure for successively blocking olf the fluid passages upon continued opening movement of the movable valve, the arrangement functioning to reduce the quantity of fluid directed into the arc passage upon the attainment of excessive pre-ssurethere- 1n.

5. In a circuit interrupter, means defining a substantially enclosed arc passage, means closing the arc passage adjacent one end thereof, means for establishing an arc within the arc passage including a rod-shaped movable contact movable toward the other end of the arc passage, venting means for the arc passage disposed adjacent the other end of the arc passage, valve means responsive to the pressure within the arc passage for controlling the venting means and including 'a movable valve, annular guide means defining a plurality of radially inwardly extending inlet passages disposed in superposed relation axially along the path of movement of the movable contact and secured to and movable with the movable valve, second valve means for successively closing the inlet passages upon continued opening movement of the movable valve, and fluidmoving means for forcing fluid through the passages into the arc passage to effect extinction of the arc therein.

6. In a circuit interrupter, means dening a substantially enclosed arc passage, means for establishing an arc within the arc passage, venting means disposed adjacent one end of the arc passage, valve means including an orifice-shaped movable valve responsive to the pressure within the arc passage for controlling the exhaust of fluid out of the arc passage through the venting means, a, plurality of spaced ring-shaped insulating plates secured to and movable with the movable valve, means for forcing uid radially inwardly between the plates into the arc passage, and a relatively fixed cup-shaped member disposed in surrounding relation to the plates so that as the movable valve opens the plates progressive- 1y enter the relatively fixed cup-shaped member,

the arrangement thus functioning to diminish 10 uid 110W toward the arc as the pressure increases to open the movable valve.

CLINTON L. DENAULT.

REFERENCES CITED The following references are of record in the file of this patent:

OTHER REFERENCES A. P. C. application of Kesselring et al., Serial No. 219,932, published May 18, 1943.

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