US2445442A - Circuit interrupter - Google Patents

Description

y ,1948. w. M. LEEDS ETAL 2,445,442

' CIRCUIT INTERRUP'IER Filed Aug. 31, 1944 Sheets-Sheet 1 Fly. 1.

Insulation WITNESSES: INVENTORS a: wmthrop M Leeds and Ruben; E. Wiedrl'ch.

July 20, 1948. w. M. LEEDS ETAL 2,445,442

cmcun, m'rmurmn FiledAug. 31, 1944 2 Sheets-Sheet 2 wlmzsszsz mvzmons Z Winthrop M. Leeds and Robert E Friedrich Patented July 20, 1948 I uNrrsofsrArEs PATENT orrica CIRCUIT INTERBUPTER Winthrop M. Leeds, Forest Hills, andv Robert E.

Friedrich, Pittsburgh, Pa minors to Westing'hous'e Electric Corporation, East Pittsburgh,

Pa, a corporation of Pennsylvania Application August 31, 1944, semi No. 552,132

9 Claims.

This invention relates to circuit interrupters in general and, more particularly, to are extinguishing structures therefor. v

A general object of our invention is to provide an improved circuit interrupter in which interruption of the circuit passing therethrough is obtained in an improved manner. 7

Another object is to provide a circuit interrupter of the type establishing both a pressuregenerating arc and an interrupting arc, and to provide an improved interrupting structure ad- Jacent th pressure-generating break to facilitate low curre t interruption.

Another object is to provide a circuit interrupter of the foregoing type in which both a first and second piston means are provided to facilitate circuit interruption. Preferably the first piston means has the arcing pressure equalized on both sides thereof to be operative both during low and high current interruption; whereas, the second piston means is preferably of the type which is operative only during low current interruption and may be used for flushing purposes during high current interruption.

Another object is to provide an improved circuit interrupter in which improved operating mechanism is provided to charge piston means associated therewith.

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 an elevational' view of a complete circuit interrupter embodying our invention and shown in the closed circuit position;

Fig. 2 is an enlarged vertical sectional view through the left-hand arc extinguishing unit of Fig. 1, the parts being shown in the partly open circuit position;

Fig. 3 is a fragmentary vertical sectional view taken substantially on the line III-III of Fig. 2;

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

Fig. 5 is a sectional view taken substantially on the line V-V of Fig. 2.

Referring to the drawings and more particu- 'larly to Fig. 1 thereof, the reference numeral l designates a tank in which a suitable arc extinguishing fluid 2, in this instance circuit breaker oil, fills the tank to the level 3. Depending from the cover 4 of the tank i are two insulating bushings], 6 through which extend terminal studs 1, 8. Threadedly secured to the lower ends of the terminal studs I, l are contact feet 9, II which support identical arc extinguishing units generally designated by the reference numeral ii. A conducting bridging member l2 reciprocally operable in a vertical direction by an insulating operating rod It serves to electrically interconnect the two are extinguishing units II in the closed circuit position of the interrupter as shown in Fig. 1.

Referring to Fig. 2 it will be observed that the contact foot 9 is formed as an extension of a suitably shaped casting It, the interior of which forms a housing for contact structure more fully described hereinafter. A pressure-generating contact l5 cooperates with an intermediate contact I! to establish a pressure-generating arc ll within a pressure-generating chamber or passage it as shown more clearly in Figs. 2 and 3. The pressure-generating contact It has a hole it formed therein which is guided by an extension 20 threaded into the casting It. A conductor 21 electrically interconnects the pressure-generating contact is with the casting It.

Two pins 22, only one of which is shown in Fig. 2, are secured to the contact l6 and pass through slots 23 formed through the legs 24 of a bifurcated member 25 pivotaly, mounted at 26 and actuated externally of the unit Ii by two.integrally formed actuating arms 21, only one of which is shown in Fig. 2. The arms 21 have slots 28 through which passes a pin 28. The pin 29 passes through an elongated slot 30 provided in an insulating operating rod 3|. A compression spring 32 encircles the rod 3i and is disposed between a' flange 33 integrally formed with the rod 3i and the arms 2'l. 'In the closed circuit position of the interrupter the compression spring 32 provides the requisite contact. pressure between the several contacts. A compression spring 34 has its upper end seated against an extension 2! of the casting It, and has its lower end resting on a flange 36 integrally formed with rod 3i. -Thus it will be observed that the spring 34 biases the rod 3| downwardly.

Fixed to and movable with the rod ii is a first piston member 3'! operable within a piston chamber 38 defined by a cylindrical member 39. The piston member 31 moves downwardly during the opening stroke to send oil through the passage 42 and through two inlet passages ll towardthe pressure-generating are it.

The composite plate structure forms an orifice 42 adjacent each inlet passage, thereby causing the oil to flow through the inlet passages ll through the orifices 2 thus contacting the pressure-generating are it. The pressure created at haust passages 48 and downwardly through a verticali'loQw passage 44 through a plurality of inlet passages 45 toward an interrupting are 48 drawn between the intermediate contact I! and the lower movable contact 41 within an interrupting chamber 85. This fluid passes through orifices 42 to exhaust out venting passages 48 more clearly shown in Fig. 5.

Associated with the lower movable contact 41 is a second piston member 48 operable within a piston chamber 50 defined by a cylindrical member ii. The upper end oi the piston chamber in is vented to the region exteriorly oi the unit ll by vent passages 52, 53 more clearly shown in Fig. 3. Consequently. during high current interruption the piston member 48 may be maintained in its raised position against the biasing action of a compression spring 54 tending to bias the piston member 48 downwardly. When the piston member 49 does move downwardly it iorces oil to flow upwardly through the passages 55 through check valves 56 and through the inlet passages 48 towards the interrupting are 48.

Check valves 51 are also provided to allow clean oil to be drawn in through vents 58 when piston 48 is raised during a closing operation, check valves 58 blocking back flow from passages 44 and 4|. A compression accelerating spring 59 has its upper sea-t against a plate 68 and has its lower seat against a flange Bl integrally formed with the contact 41. The conducting bridging member I! serves during the closing stroke to operate both the lower movable contact 41 and the operating rod II to thereby effect an engagement between the several contacts.

It will be observed that the arcing pressure is applied to both the top and bottom of the piston member 31. Thus the piston member 31 is a circulating piston and is operable both during low and high current interruption. The piston member 49. on the other hand, may be stalled during high current interruption by the arcing pressure. and is operable thereafter to flush contaminated oil out of the vents 48 upon a subsidence oi pressure within the unit I I.

Circuit interrupters oi the type establishing both a pressure-generating arc and an interrupting are have maximum interrupting effectiveness on low currents such as magnetizing and linecharging currents when mechanically driven pistons are used to supplement the normal flow. Preferably also the arc in the pressurebreak as well as the interrupting are at the main break is subjected to deionizing oil flow. Where one piston is used to drive oil into the two breaks in serles a very high driving pressure is required. This invention covers a novel method oi. utilizing two pistons. a circulating piston attached to the operating rod 8| sending oil through the upper pressure break while a second piston 48 is used to supplement the oil flow in the main break. The check and intake valves '58. I1 assure unidirectional flow or clean all into the unit II by operation or the lower piston 49. On high current interruption this piston 49 may be stalled by high back pressure, but subsequent flushing takes place after the pressure i'alls.

It is to be noted that the upper circulating piston 81 is acted upon by are pressure on both top and bottom. This balancing efl'ect permits the piston 81 to be rigidly attached to the operating rod 8| without having the motion appreciably slower on high current than on low current intea-ruption. In fact, the high current perfo mshoe is improved by keeping fresh oil in closer proximity to the pressure-generating arc.

The arrangement herein shown has proved very eilective on tests. Charging currents from 45 to amperes at 68 kv. across one unit II were interrupted without restriking.

In the patent application filed May 27, 1943, Serial No. 488,624, now United States Patent 2,424,343, issued July 22, 1947, to Roswell C. Van Sickle, Robert E. Friedrich and Francis J. Fry and assigned to the assignee of the instant application there is disclosed a circuit interrupter similar in construction to the foregoing type in which a circulating piston is provided surrounding the intermediate contact and having the arcing pressure equalized on both sides thereoi to render the same operative both during high and low current interruption.

The broad concept oi jetting iluid toward the pressure-generating break is disclosed and claimed in United States patent application illed May 28, 1943, Serial No. 488,847 by Winthrop M. Leeds, now United States Patent 2,422,569 issued June 1'7, 1947, and assigned to the assignee of the instant application.

In the closed circuit position of the interrupter as shown in Fig. 1, the electrical circuit therethrough comprises terminal stud 1, contact ioot 8, casting l4, conductor 2|, pressure-generating contact ll, intermediate contact I'I, lower movable contact 41, conducting bridging member l2. through the right-hand uni-t II in an identical manner to the right-hand terminal stud I.

To open the circuit passing through .the interrupter the operating rod II is moved downwardly by suitable mechanism, not shown. Thi lowers the bridging member I! to permit the compression spring 59 to cause a separation between the contacts ll, 41 to establish an interrupting arc 48. Simultaneously, the bridging member I! permits downward movement oi the rod II to take place rota-ting the bifurcated member II and causing a separation between the contacts l4. II to establish a pressure-generating arc II. The

- two arcs are drawn substantially simultaneously.

Pressure created at the pressure-generating arc ll assisted by the circulation of oil caused by the movement of the piston 81 eilects during high current interruption an extinction oi the interrupting are 48.

During low current interruption the piston 4| moves and assists the piston 31. the piston 81 tending to eilect the-extinction of the. pressuregenerating arc II and the piston 48 tending to eilect extinction of the interrupting are 48. The check valves II, I! insure that the oil flow will be in the right direction. Following extinction of the arcs and a consequent breaking of the circuit through the interrupter, the bridging member l2 separates from the disconnect fingers 82 provided at the lower end oi the contact 41 to eilect an isolating gap in the circuit as shown more clearly in Pig. 1.

During the closing operation the bridging member 1! moves upwardly sliding between the disconnect fingers I! and causing a raising of both the movable contact 41 and the operating rod II. The contact 41 makes engagement with the intermediate contact I! at substantially the same time that the pressure-generating contact ll makes contact with the intermediate contact II, the compression spring 32 providing the requisite contact pressure between the several contacts.

Although we have shown and described a sue,-

cific structure, itis to be clearly understood that the sarne was merely for the purpose of illustration and that changes and mod-ifications 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, means defining a pressure-generating chamber and an interrupting chamber, means for establishing a pressuregenerating are within the pressure-generating chamber and an interrupting arc within the interrupting chamber, the pressure-generating are forcing fluid toward the interrupting arc to efiect the extinction thereof, means forming at least two inlet passages at different levels leading toward the pressure-generating arc, means forming two orifices adjacent the pressure-generating are through which it is drawn, one orifice associated with each inlet passage, and means for forcing fluid through the inlet passages toward the pressure-generating arc.

2. In a circuit interrupter, means defining a pressure-generating chamber and an interrupting chamber, means for establishing a, pressure-generating are within the pressure-generating chamber and an interrupting are within the interrupting chamber, the pressure-generating arc forcing fluid toward the interrupting arc to effect the extinction thereof, means forming at least two inlet passages at different intervals leading toward the pressure-generating arc, means forming two orifices adjacent the pressure-generating are through which it is drawn, one orifice associated with each inlet passage, and piston means for forcing fluid through the inlet passages toward the pressure-generating arc.

3. In a circuit interrupter, means defining a pressure-generating chamber and an interrupting chamber, a pressure-generating contact separable trom an intermediate contact to establish a pressure-generating arc within the pressuregenerating chamber, a movable contact separable from the intermediate contact to establish an interrupting are within the interrupting chamber, means forming at least two inlet passages at diflerent levels leading toward the pressure-generating arc, means forming an orifice associated with each inlet passage through which the pressure-generatin arc is drawn, operating means for the pressure-generating contact, and piston means actuated by the operating means for forcing fluid through the inlet passages toward the pressure-generating arc.

4. In a circuit interrupter, means -defining a pressure-generating chamber and an interrupting chamber, a pressure-generating contact separable from an intermediate contact to establish a pressure-generating are within the pressuregenerating chamber, a movable contact separable from the intermediate contact to establish an interrupting are within the interrupting chamber, means forming at least two inlet passages at different levels leading toward the pressure-generating are, means forming an orifice at an intermediate level associated with each inlet passage through which the pressure-generating arc is drawn, operating means for the pressure-generatingcontact,-piston means actuated by the operating means for forcing fluid through the inlet passages toward the pressure-generating arc, and means for equalizing the arcing pressure on both sides of the piston means.

5. In a circuit interrupter of the fluid flow type, means defining a pressure-generating chamber,

means for establishing a pressure-generating are within the pressure-generating chamber. means defining an interrupting chamber, means for astablishing a serially related interrupting arc within the interrupting chamber, means forming a plurality of orifices at a plurality of different levels through which the pressure-generating arc is drawn, means forming an inlet passage on one side of .a plurality of said orifices leading toward the pressure-generating arc, means defining at least one exhaust passage leading away from the pressure-generating arc between two orifices at an intermediate level, the exhaust passage leading toward the interrupting are within the interrupting chamber, and means for forcing fluid under pressure through the inlet passages and longitudinally of the pressure-generating are through the plurality of orifices to exhaust away from the pressure-generating are through the exhaust passage.

6. In a circuit interrupter of the fluid type, means atleast partially of insulation forming a pressure-generating arc passage, means for establishing a pressure-generating arc within the arc passage, the are passage having formed therein a plurality of pockets at spaced intervals along the arc passage, means forming a plurality of inlet passages leading into at least two pockets so that fluid may flow through the inlet passages into the pockets and be directed toward the pressure-generating arc at spaced intervals therealong, means defining an interrupting chamber, means for establishing an interrupting are within the interrupting chamber, means forming an exhaust passage leading away from the pressuregenerating arc passage at an intermediate interval and directed into the interrupting chamher, and piston means for forcing fluid under pressure first through the plurality of inlet passages toward the pressure-generating arc, then out of the pressure-generating are passage through the exhaust passage and in serial manner on into the interrupting chamber.

'7. In a circuit interrupter of the fluid flow type, means defining a pressure-generating chamber, means for establishing a pressure-generating are within the pressure-generating chamber, means I defining an interrupting chamber, means for establishing a serially related interrupting arc within the-interrupting chamber, means formin a plurality of orifices at a plurality of different levels through which the pressure-generating arc is drawn, means forming an inlet passage on one side of a plurality of said orifices leading .toward the pressure-generating arc, means defining at least one exhaust passage leading away from the pressure-generating are between two orifices at an intermediate level, the exhaust passage leading toward the interrupting arc within the interrupting chamber, and piston means for forcing fluid under pressure through the inlet passages and longitudinally of the pressure-generating are through the plurality of orifices to exhaust away from the pressure-generating are through the exhaust passage.

8. In a circuit interrupter of the fluid fiow type. means defining a pressure-generating chamber, means for establishing a, pressure-generating are within the pressure-generating chamber, means 7 side or a plurality of said oriflces leading toward the pressure-generating are, means deflning at least One exhaust passage leading away from the pressure-generating are between two oriflces at anintermediate level, the exhaust passage leading toward the interrupting are within the interrupting chamber, piston means ior forcing fluid under pressure through the inlet passages and longitudinally oi the pressure-generating are through the plurality of orifices to exhaust away from the pressure-generating are through the exhaust passage, and means for equalizing the arcing pressure on both sides oi the piston means.

9. In a circuit interrupter oi" the fluid type, means at least partially of insulation forming a pressure-generating arc passage, means for establishing a pressure-generating are within the arc passage. the arc passage having formed therein a lurality or pockets at spaced intervals along the arc passage, means forming a plurality of inlet passages leading into at least two pockets so that fluid may flow through the inlet passages into the pockets and be directed toward the pressuregenerating are at spaced intervals therealong, means defining an interrupting chamber, means for establishing an interrupting are within the interrupting chamber, means forming an exhaust passage leading away from the pressure-generating arc passage at an intermediate interval and directed into I the interrupting chamber, piston means for iorcing fluid under pressure flrst through the plurality or inlet passages toward the pressure-generating arc, then out of the pressurea generating arc passage through the exhaust passage and in serial manner on into the interrupting chamber, and means for equalizing the arcing pressure on both sides of the piston means.

WINTER/OP M. LEEDS. ROBERT E. FRIEDRICH.

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

Number Re. 21,848 2,020,995 20 2,102,768 2,155,263 2,258,226 2,292,547 2,387,589

Number 488,050 500,731

UNITED STATES PATENTS

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