US3592986A

US3592986A - Multicontact vacuum-type high-voltage circuit breaker utilizing a liquid metal and drawing a plurality of series arc

Info

Publication number: US3592986A
Application number: US889516A
Authority: US
Inventors: Russell E Fox
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1969-12-31
Filing date: 1969-12-31
Publication date: 1971-07-13
Anticipated expiration: 1988-07-13
Also published as: DE2064787A1; CA919747A

Abstract

A high-voltage vacuum-type circuit breaker is provided having multiple spaced contacts, or electrodes, which are sequentially removed, or withdrawn from a pool of a liquid metal, such as gallium, or its alloys. A multiplicity of series arcs are thereby established, which are moved from the end electrodes to the adjacent surfaces of the intervening spaced electrodes. This enables a high-voltage circuit to be interrupted by the establishment of a number of arcs in series. If desirable, magnetic means may be employed to effect lateral movement of the established arcs. Gallium is particularly favorable for my circuit breaker application because of its extremely low vapor pressure in vacuum. In another circuit breaker arrangement, an insulating rotating disc, or wheel carries a number of spokelike contacts, or electrodes, which are sequentially withdrawn from the pool of liquid metal to establish a plurality of series arcs.

Description

I United States Patent [72] Inventor Russell E. Fox 3,052,783 9/1962 Buron 200/145 Pittsburgh, Pa. 3,462,573 8/1969 Rabinowitz et al. 200/144 (B) [21] pp M 89.5 FOREIGN PATENTS [221 PM 288,195 10/1915 Germany 200/144 (AP) [45] Patented July 13, 1971 [73] Assignee Westinghouse Eleflric Corporation 341,486 10/1921 Germany 200/144 (AP) pmsburgmpa. 25,451 12/1899 Great Britain 200/144 (AP) Primary Examiner-Robert S. Macon Amr v --A. T. Stratton. Cl m m L. M H l d s4 MULTICONTACT VACUUM-TYPE morrt g 6 e c a e w'nard VOLTAGE CIRCUIT BREAKER UTILIZING A M LI UID METAL AND W I Y F sEgms ARC DRA ING A PLURAL T 0 ABSTRACT: A high-voltage vacuum-type circuit breaker is 11 Claim D provided having multiple spaced contacts, or electrodes, "wing [gs which are sequentially removed, or withdrawn from a pool of U.S. a metal uch as gallium or its alloys. A multiplicity of ZOO/145, 200/ 152 series arcs are thereby established, which are moved from the Int. end electrgdes to the adjacent surfaces of the intervening H01 h 29/00 spaced electrodes. This enables a high-voltage circuit to be inof terru ted the establishment ofa number of arcs in eries 15210, 152 desirable, magnetic means may be employed to effect lateral movement of the established arcs. Gallium is particularly [56] References cued favorable for my circuit breaker application because of its ex- UNITED STATES PATENTS tremely low vapor pressure in vacuum. 437,412 9/1890 Deprez 200/153 (.10) In another circuit breaker arrangement, an insulating rotat- 468,Il9 2/1892 Thomson 200/144 (AP) ing disc, or wheel carries a number of spokelike contacts, or 532,838 895 h m n 200/ I44 (AP) electrodes, which are sequentially withdrawn from the pool of 535,077 3/1895 Potter 200/ 144 (AP) liquid metal to establish a plurality of series arcs.

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CLOSED POSITION CONDUCTING SUC JPR? sALuuM PATENTEU JUU 3 Ian 3 592 9 8 6 sum 3 0F 5 A 'LS v I 4 i 3 44A 5A A- 5A CONDUCTING 9 /LIQUID FULLY-OPEN POSITION PATENTED JUL 1 3 |Q7i SHEET Q UF 5 OPERATING MECHANISM CONDUCT lNG 5Q LIQUID PATENTED JUL-13M 3,592,986

SHEET 5 0F 5 FULLY- CLOSED POSITION FIG. I4

FULLY- OPEN POSITION MULTICONTACT VACUUM-TYPE HIGH-VOLTAGE CIRCUIT BREAKER UTILIZING A LIQUID METAL AND DRAWING A PLURALITY OF SERIES ARC CROSS-REFERENCES TO RELATED APPLICATIONS perties of gallium and its alloys, and, additionally, some circuit breaker applications thereof.

BACKGROUND OF THE INVENTION The use of gallium and its alloys has been set forth in the prior art as used as a medium in connection with circuit breakers. Reference may be made to the following U.S. Pats. Nos. 1,948,687; 2,250,212; 2,732,464; 3,331,937; 3,369,094, which teach the use of gallium broadly as a circuit breaker medium. In addition, reference may be ,.had to the aforesaid patent application by Fox et al. Ser. No. 496,008 for additional uses of gallium in circuit breaker applications.

However, for high-voltage interruption, it is desirable to establish a plurality of arcs in series so that the voltage per arc may be reduced. In other words, for high-voltage application of circuit breakers, it is highly desirable to break the arc gap into a number of arc segments, such that the voltage will be distributed equally among the different gaps. The characteristics of some liquid metals, such as gallium and its alloys, with very low vapor pressure makes it possible to dothis simply by the means hereafter described.

SUMMARY OF THE INVENTION It is, accordingly, a general object of the present invention to provide an improved high-voltage circuit interrupter utilizing a liquid metal, such as gallium, for example, and establishing a plurality of arcs in series.

Still a further object of the present invention is to provide an improved circuit breaker utilizing means for sequentially withdrawing contacts, or electrodes out of a liquid pool of gallium, or its alloys.

Another object of the present invention is the provision of an improved gallium-type circuit interrupter utilizing a transverse magnetic field for facilitating lateral movement of the established arcs in the manner proposed by the instant application.

Still a further object of the present invention is the provision of an improved gallium-type circuit interrupter in which a rotating wheel, or disc member is utilized to successively rotate a plurality of spaced electrodes, or contacts out of the liquid pool of gallium, or its alloys.

According to a preferred embodiment of the invention, a movable contact assembly, comprising a plurality of laterally spaced and insulated electrodes having different lengths, is linearly moved upwardly out of a pool of liquid gallium, so that the end electrodes first establish a pair of arcs. Subsequently, the intervening spaced electrodes are withdrawn from the same pool of gallium, and the end arcs are preferably laterally moved from the pool to the adjacent side surfaces of the intervening electrodes. As a result, a plurality of seriallyrelated arcs are established, the number of arcs being equal to the number of contacts or electrodes employed.

An additional embodiment of the invention utilizes a rotating insulating disc, or wheel carrying along its periphery spokelike radially extending electrodes, or contacts, which again are successively withdrawn from the liquid pool of gallium, or its alloys.

Further objects and advantages will readily become apparent upon reading the following specification taken in con-. junction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front elevational view of a three-phase circuit breaker embodying the principles of the present invention;

FIG. 2 is a side elevational view of the circuit breaker construction illustrated in FIG. I;

FIG. 3 is a considerably enlarged vertical sectional view taken through one of the circuit breaker pole-units of the present invention, the contact structure being shown in the closed-circuit position;

FIGS. 4-7 show, in successive arrangement, the progressive establishment of the arcs during an opening operation, with FIG. 7 illustrating the fully open circuit position of the circuit breaker unit of the present invention;

FIG. 8 is a vertical sectional view taken through a modifiedtype of circuit breaker unit employing the principles of the present invention, the contact structure being illustrated in the closed-circuit position;

FIG. 9 is a detailed fragmentary view taken along the line IX-IX of FIG. 8 illustrating the rack-and-pinion gear-driving arrangement;

FIG. 10 is a side sectional view taken substantially along the line XX of FIG. 8, the contact structure being shown in the closed circuit position; and,

FIGS. lI-I4 show successive opening positions of the circuit breaker unit of FIG. 8, with FIG. 14 illustrating the fully open circuit position of the interrupter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, and more particularly to FIGS. 1 and 2 thereof, the reference numeral 1 designates a circuit breaker of the three-phase type including, generally, an upper interrupting compartment 2 and a lower mechanism compartment 3. Associated with each pole-unit A, B or C of the circuit breaker l is a pair of spaced terminal bushings 6, 7 extending through the upper cover plate 8 of the unit. The lower ends of the terminal bushings 6, 7 have cable, or strap connections 11, 12 connected to the enclosed vacuum-type circuit breaker unit utilizing gallium 14 in its lower portion. In addition to gallium, various alloys thereof may be used, as set forth in U.S. Pat. application Ser. No. 496,008.

Side-frame supports l6, 17 may be utilized to support the upper and

lower compartments

2, 3, as shown in FIGS. 1 and 2. The details of the operating mechanism are not important to the present invention, it merely being observed that there is provided a horizontally extending main operating shaft 18 having a plurality of

crank arms

19, 20 and 21 secured thereto, one crank arm being provided for each interrupting unit A, B or C to effect the vertical reciprocal movement of a operating rod, designated by the reference numeral 23, and illustrated more clearly in F IG.3 of the drawings.

As viewed in FIG. I, the left-hand end of the main horizontally extending operating shaft 18 may have a main crank lever 24 secured thereto, having its free outer end pivotally con nected to a vertically extending operating rod 25, which extends downwardly into the mechanism compartment 3, and may be operated by any suitable operating mechanism disposed therein.

The operating mechanism within the compartment 3 may be of any type, reference being had to U.S. Pat. application filed May 22, I968, Ser. No. 730,983, and assigned to the assignee of the instant invention for one particular type.

With reference to FIG. 3, it will be observed that, generally, there is provided an evacuated housing 27, composed of a suitable metal having nonmagnetic properties. Extending downwardly through the upper end of the evacuated metal housing 27 is a pair of spaced

terminal bushings

29, 30, the lower ends of which have

cable connections

31, 32 connecting to the outer ofa plurality of spaced

electrodes

33, 34 secured to an movable with a movable contact assembly, the latter being designated by the reference numeral 35. The operating rod 23, causing the vertical linear movement of the movable contact assembly 35, is sealed to the upper end of the housing 27 by a metallic bellows 37. The upper end of the operating rod 23 is connected to the crank arm 19 of the operating mechanism (not shown), which has generally the characteristics hereinbefore described in connection with FIGS. 1 and 2.

Disposed in the lower end of the housing 27 is the gallium 14, or its alloys, which provides a conducting path for the

end electrodes

33, 34 in the closed circuit position of the device illustrated in FIG. 3. It will be observed that there is provided a series blowout coil assembly 40 such that the pole-plates 40a thereof provide a transverse magnetic field extending through the evacuated housing 27, the purpose of which will become more apparent hereinafter.

During the opening operation, suitable means is provided to efiect upward opening movement of the operating rod 23, which successively draws the electrode structure 35 upwardly out of the liquid pool of gallium metal 14. FIGS. 4--7 show successively the arrangement in which initially a pair of end arcs 42, 43 are established, which are transformed by the transverse magnetic field to the side surfaces 44, 45 of the intervening

electrodes

44A, 45A. When the intervening

electrodes

44A, 45A are withdrawn from the liquid pool 14, as shown in FIG. 6, two additional arcs 48, 49 are established, there resulting thereby four arcs 42, 43, 48, 49 in series. The arcs are quickly extinguished because of the low-vapor pressure of the gallium, or its alloys.

FIG. 7 shows the fully open circuit position of the circuit breaker unit A in which all of the spaced

electrodes

33, 34, 44A, 45A are withdrawn from the gallium pool 14.

During the closing operation, suitable means causes a lowering of the movable contact assembly 35 downwardly into the liquid gallium pool 14 to a position illustrated in FIG. 3, in which the electrical circuit'is closed between the line terminal connections L L of each pole unit A, B and C.

It will be observed that in the closed circuit position of the interrupter l, the metallic housing 27 is at line potential, and

' for this reason it is desirable to support the evacuated housing structure 27 upon a pair of

post-type insulators

52, 53 from the horizontally extending frame 54, which of course, is at ground potential.

FIG. 8 illustrates a modification of the invention 56, in which instead of a linearly movable contact assembly 35, a rotating disc, or wheel 58 is utilized. As shown more clearly in FIGS. -44, an insulating wheel 58 is rotated by a rack-andpinion arrangement 60, illustrated in FIG. 9, with the operating rod 23 having the same sealed construction 37, as described heretofore. A lateral support 70 may be provided to resist lateral thrust of the gear-driving arrangement.

The

cable connections

31, 32 from the lower ends of the

terminal bushings

29, 30 are illustrated more clearly in FIG. 10 of the drawings, being attached to the

outer electrodes

62, 63. As shown in FIGS. 10-- 14, the rotation of the wheel 58, as effected by upward movement of the operating rod 23, and the transmission of rotative movement by the rack-and-pinion means 60 causes a successive withdrawing of the electrodes, or

spokelike contacts

62, 63 and 64 out of the liquid pool of gallium 14 to draw the

arcs

65, 66, 67, as shown in FIGS. 10 13 of the drawings. These arcs are again extinguished by the low vapor pressure of the gallium.

FIG. I4 illustrates the fully open circuit position of the modified-type of interrupter 56 in which the rotating disc 58 has completely withdrawn all of the

spokelike electrodes

62, 63, 64 out of the liquid pool of gallium 14 to the open circuit position.

The closing operation is provided by a reverse rotation of the insulating disc 58 to bring the electrodes 62--64 back again into the liquid pool 14 to the position shown in FIG. 10, wherein the line circuit is again completed through the circuit breaker unit 56 of FIG. 8.

From the foregoing description, it will be apparent that there hovel been provided novel circuit breaker structures A" and 56 adaptable for high-voltage application, in which a number of series arcs are established. The advantages of such a system are that the liquid metal 14 does not require smooth surfaces for good contact; therefore, erosion, due to arcing. is

not a serious problem. In addition, the liquid metal gallium ing the electrodes to be made simply and economically. I

Finally, welding of the contacts upon reclosure is eliminated by the use of the liquid metal.

It is to be clearly understood that although there have been illustrated four electrodes in the embodiment of FIG. 3, and three electrodes in the modification 56 of FIGS. l0-l3, nevertheless, there is no reason why a greater number of intermediate electrodes could not be used, if so desired.

From the foregoing description, it will be apparent that there has been provided a novel means of establishing rapidly a number of series arcs utilizing a suitable liquid metal, such as gallium, or its alloys and adaptable for high-voltageapplications.

Although there has been illustrated 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 invention..

lclaim:

l. A circuit interrupter comprising, in combination, means defining an evacuated enclosure containing a pool of a conducting liquid metal, a movable contact assembly disposed within said enclosure and having a plurality of spaced electrodes insulatingly supported from each other, line terminal connections for the circuit interrupter, means conductively connecting the line terminal connections of the interrupter with the end electrodes of the movable contact assembly, means immersing the end electrodes of the movable contact assembly into the pool of liquid metal to close the electrical circuit to the line terminal connections, and said last-mentioned means being operative to withdraw the electrodes of the movable contact assembly successively out of the pool of liquid metal to establish a plurality of series arcs.

2. The circuit interrupter combination of claim 1, wherein the liquid metal comprises gallium or its alloys.

3. The circuit interrupter combination of claim 1, wherein the movable contact assembly is linearly movable and comprises electrodes of different length.

4. The combination of claim 3, wherein there are at least four electrodes and the end electrodes are shorter in length than the two intervening electrodes.

5. The combination of claim I, wherein the end electrodes of the movable contact assembly are shorter in length than the intervening electrodes.

6. The combination of claim 1, wherein the movable contact assembly comprises a rotatable insulating disc carrying the electrodes radially therefrom.

7. The combination of claim 1, wherein a transverse magnetic field is provided to assist in arc movement.

8. The combination of claim 6, wherein a rack-and-pinion drive effect rotating of the insulating disc.

9. The circuit interrupter combination of claim 1, wherein all of the end electrodes are immersed into the pool of liquid metal to close the electrical circuit in the closed circuit position of the device.

10. The combination according to claim 1, wherein the lastmentioned means is operative to withdraw at least one of the end electrodes of the movable contact assembly out of the pool of liquid metal prior to at least one other electrode to establish a plurality of serially related arcs.

11. The circuit interrupter combination of claim 10, wherein the. linnirl mptal rnmnricnc Mm... A. "11......

Claims

2. The circuit interrupter combination of claim 1, wherein the liquid metal comprises gallium or its alloys.
3. The circuit interrupter combination of claim 1, wherein the movable contact assembly is linearly movable and comprises electrodes of different length.
4. The combination of claim 3, wherein there are at least four electrodes and the end electrodes are shorter in length than the two intervening electrodes.
5. The combination of claim 1, wherein the end electrodes of the movable contact assembly are shorter in length than the intervening electrodes.
6. The combination of claim 1, wherein the movable contact assembly comprises a rotatable insulating disc carrying the electrodes radially therefrom.
7. The combination of claim 1, wherein a transverse magnetic field is provided to assist in arc movement.
8. The combination of claim 6, wherein a rack-and-pinion drive effect rotating of the insulating disc.
9. The circuit interrupter combination of claim 1, wherein all of the end electrodes are immersed into the pool of liquid metal to close the electrical circuit in the closed circuit position of the device.
10. The combination according to claim 1, wherein the last-mentioned means is operative to withdraw at least one of the end electrodes of the movable contact assembly out of the pool of liquid metal prior to at least one other electrode to establish a plurality of serially related arcs.
11. The circuit interrupter combination of claim 10, wherein the liquid metal comprises gallium or its alloys.