US3002073A - Electric circuit interruption device and method - Google Patents

Description

Sept. 26, 1961 J. D. COBINE 3,002,073

ELECTRIC CIRCUIT INTERRUPTION DEVICE AND METHOD Filed April 1a, 1958 Jr) ventor':

Jam DCob'ne, .byjrZF is Attorney.

United States Patent i ce 3,002,073 ELECTRIC CIRCUIT INTERRUPTION DEVICE AND METHOD James D. Cobine, Rexford, N.Y., assignor to General Electric Company, a corporation of New York Filed Apr. 16, 1958, Ser. No. 728,815 Claims. (Cl. 200-150) The present invention relates to electric circuit inter-,

rupting devices and methods and, more particularly, to devices and methods for interrupting high current elec Patented Sept. 26, 1961 ing chamber wall A second movable arc electrode 5 abuts against fixed electrode 4 and is mounted upon electrode rod 5a which extends through the opposite end of breaker housing 1, and through a second orifice 7 in insulating chamber wall 3. A first electrical ter 7 minal strap 8 is connected to the exterior end of arc electrio arcs very rapidly without the use of complicated ap- 1 paratus.

In the electrical generation and transmission arts, it very often becomes necessary to interrupt current in high-voltage high-current circuits, because the circuit becomes overloaded or a particular piece of equipment fails, among other reasons. In these instances, a circuit interrupting device is generally utilized. .Such devices generally comprise a pair of arc electrodes which, when mechanically separated, serve as terminal points for a inder 16 having therein afluid driving piston 17 conhigh-current electric arc. The electrical circuit becomes finally interrupted when this are is extinguished. The efficiency and value of an electric circuit interrupting device is often measured by the time taken to extinguish the are between the arc electrodes. For many reasons,

the more rapidly the arc is interrupted and extinguished,

the greater the value and utility of the arc interrupting device. expedients to interrupt high current arcs; Thus, for example, the arcs are often bent by magnetic fields,

Prior art are interrupting devices utilize many nected to a piston arm 18 having a laterally extending end member 19. A surge tank or reservoir 20, is also located within housing 1. Reservoir 20 is connected with cylinder 16 by means of a fluid conduit 21. Cylinder 16 is connected with are chamber 2 by means of an oil-center fluid conduit 22, terminating in orifice 23.

Fluid which passes from are chamber 2 flows to surge tank 20 by means of fluid conduit 24. The apparatus thus contains a complete fluid flow loop comprising cylinder 16, conduit 22, are chamber 2, conduit blown by high pressure gas blasts, or forced across in- A further object of the present invention is to provide a simple, rapidly-acting electric circuit breaker.'

In accord with the present invention, an electric circuit interrupting device includes a pair of arc electrodes, at least one of which is movable relative to the other. These electrodes are surrounded by an arc chamber.

24, reservoir 20, and conduit 21. In the unactuated or cocked position, piston 17 is maintained in the uppermost portion of cylinder 16, away from fluid conduit 22, and is held latched by pawl 25 which is pivotally rotatable and is latched under laterally extending member 19 on the actuating end of piston rod 18. Pawl 25 may be rotated by actuation of solenoid 26, connected between a pair of terminals 27 and 28. Solenoid 13, which actuates pawl 11, releasing movable arc electrode 5 is connected to a suitable source of electric power connected with terminals 29 and 30 and is connected through a switch 31, actuated by actuating arm 32 connected to the operating end of piston arm 18. Piston arm 18 is spring biased inwardly by means of spring 33 connected between actuating arm 32 and housing 1.

In operation, the interrupting device is cocked, either manually or electrically by means well known to the art, moving piston 17 outwardly within cylinder 16, so

that pawl 25 may be locked under member 19 on piston Means are provided to establish a fluid vortex within 1 the arc chamber and for establishing an. electric arc in the arc chamber by separating the arc electrodes. The fluid vortex rapidly and efficiently removes energy from the electric are, causing the rapid extinction thereof.

The novel features believed characteristic of the present invention are set forth in the appended claims. The

invention itself, together with further objects and advantages thereof, may best be understood with reference to the following description taken in connection with the appended drawing in which:

FIG. 1 is a vertical view partially in cross section of i one device constructed in accord with the present in vention, FIG. 2 is a vertical cross section along the lmes in FIG. 1, and

FIG. 3 is a vertical view, partially in cross section of i of a suitable electrically insulating material and having the torrnot a pro'late spheroid with open ends. A first fixed arc electrode 4 is located within the wall of breaker housing 1 immediately adjacent one orifice 6 in insulatrod 18. At the same time, electrode rod 5a isrnoved inwardly so that movable electrode 5 abuts against fixed electrode 4 and pawl 11 is caught upon member 10.

When it is desired to interrupt the electrical circuit including terminal straps 8 and 9 and electrodes 4 and 5, as for example, upon the exceeding of a particular current value, solenoid 26, which may carry a current proportional to the current passing through the arc electrodes, is actuated. Pawl 24 isrotated, releasing piston 17, which .is actuated under the-bias of spring 33 inwardly within cylinder 16. The fluid in the lower half of cylinder 16 is urged into arc chamber 2 tangentially, leaving the arc chamber through orifices 6 and 7 which act as nozzles. A fluid vortex is-established Within arc chamber 2 due to the tangential motion of fluid entering chamber 2 through orifice 23 prior to the separation of terminals 4 and 5. As piston 17 continues to descend within cylinder, 16, actuating arm 32 closes switch 3-1, actuating solenoid 13 and causing pawl 11 to rot-ate about pin 12. Spring 14 then moves electrode rod 5a outwardly, urging movable electrode 5 away rfrom fixed electrodes 4, causing the establishment of a high current electric are.

As may be noted from FIG. 1, an are established .between movable electrode 5 and fixed electrodes 4 is established within the throat of nozzle 6, defined by insulating material 3, a region of high turbulence. Thus,

there exists a high current are surrounded by an axial fluid vortex of continuously moving fluid. This vortex rapidly absorbs energy from the are by direct radiation of thermal energy from. the arcto the cooler fluid constituting the vortex, by ambipolar diffusion of electrons and ions into the vortex, thus giving up all of their thermal, kinetic, and potential energy, and by the vaporization of water splashed or otherwise physically urged into the arc column. By these means, the arc column rapidly loses energy to the fluid vortex which, being composed of a fluid in motion, is not appreciably raised in temperature. The fluid of which the vortex is constituted may be any suitable non-conducting fluid, as for example, deionized water or oil.

As the arc column loses energy, the arc voltage between the electrodes of the device rapidly rises to a value above the system sustaining voltage, and the arc is consequently extinguished. Arc chamber 2 illustrated inthe device of FIG. 1, is, in eflect, a double-ended device. This means that there are: two orifices or nozzles 6 and 7 within which a large amount of energy may be removed from the arc column established between electrodes 6 and 7. It is possible therefore, to remove movable electrode to such an ex tent that energy is being extracted from the are at nozzles 6 and 7, thus intensifying the energy removal. A doubleended device is not, however, necessary in accord with the invention, and most arcs may be interrupted using only a single ended device, as for example, one including only the nozzle adjacent fixed electrode 4.

As illustrated. in FIG. 1, the device has been shown utilizing a nozzle formed by the smaller end of a substantially conical-1y shaped arc chamber. While, in its preferred embodiment, the present invention contemplates utilizing the added turbulence and added water velocity obtained through the use of a conically shaped arc chamben and a nozzle in the vicinity of the fixed arc electrode, sucha. structure is not necessary in all cases. Thus, the normal turbulence 'gained by the establishment of a fluid vortex within a substantially cylindrical arc chamber maybe suflicient to extinguish many arcs. Accordingly, while, in its preferred embodiment, my invention contemplates the use of conical arc chambers with nozzles adjacent the fixed electrodes, substantially cylindrical arc chambers may beutilized as well.

In FIG. 2 of the drawing there is shown a partial vertical cross sectional view taken along the lines 2-2 in FIG. 1. As may be seen from FIG. 2, fluid conduit 22 from cylinder '16 enters the arc chamber defined by insulating material 3 tangentially, causing the fiuid to rotate in a circular path, forming a vortex, and exit through orifices 6 and 7 in the arc chamber.

In FIG. 3' of the drawing, there is shown an alternative embodiment of the invention. The device of FIG. 3 is a single-ended circuit interrupting device which differs functionally from the device of FIG. 1 primarily in that the operation of the movable arc electrode is controlled by the fluid which forms the vortex, and the arc electrodes are separated by the action of the fluid forming the vortex. In FIG. 3, the arc interrupting device includes a housing 40 having therein an arc chamber 41 surrounded by a conically shaped insulating member 42 and terminating at one end thereof in a nozzle 43. Meeting within nozzle 43 are a fixed arc-electrode'44' and a movable arcelectrode 45. Movable arc-electrode 45 is connected with, and mounted upon, an arc actuating plate 46 having outwardly extending orifices 47 therein. Actuating plate 47 is mounted upon electrode shaft 48 which is suitably journaled within bearing 49 and connected to a terminal strap 50. Electrode actuating plate46 is urged against insulating member 42 adjacent nozzle 43 by a suitable compression spring 51.

The device of FIG. 3 also includes a fluid storage cylinder'SZ having therein a piston 53 mounted upon a piston rod 54, a surge tank or reservoir 55 and suitable inter- 4 l I connecting conduits 56, 5'7, and 58 all analogous to like parts in the device of FIG. 1. In the device of FIG. 3, a complete fluid circuit then comprises cylinder 52, conduit 58, are chamber 41, orifice 43, orifices 47, conduit 56, reservoir 55, and conduit 57.

Piston rod 54 terminates in an outwardly extending member 59 which is juxtaposed with a pawl 60 pivotally rotatable about pin 61 and actuated by solenoid 62 con nected between terminals 63. A fixed terminal strap 64 is connected to the outwardly extending end of fixed arc electrode 44.

To cock the device of FIG. 3, piston rod 54 is pulled upwardly until pawl 60 engages member 59. Movable electrode 45 is automatically urged into abutment with fixed electrode 44 by the action of compression spring 51. In operation, let it be assumed that the device is to be actuated by a current overload through conductors 50 and 64 and are electrodes 44 and 45. A current representative, and proportional to, the main current flows through solenoid 62, actuates pawl 60 allowing piston 53 to be urged into cylinder 52 by means of tension spring 65. Fluid contained; cylinder 52 is urged tangentially into arc chamber 41 through orifice 66. A vortex is established therein, the portion of greatest turbulence existing at orifice 43. The fluid forced into arc chamber 41 through orifice 66 escapes therefrom through orifices 47 in electrode actuation plate 45, both of which are insufficient to allow all ofthe fluid to escape therethrough. Under these conditions, fluid pressure builds up within arc chamber 41 and electrode actuation plate 45 is lifted from its seat, against the pressure of compression spring 51, allowing fluid to flow through conduit 56 to reservoir 55. As electrode actuation plate 45 leaves its seat, movable arc electrode 45 is separated from fixed arc electrode 44, and an electric arc is established therebetwecn. This electric are rapidly loses energy to the fluid vortex, partio ularly to the turbulent portion existing at nozzle 43 inthe same fashion as in the device of FIG. 1, and the arc is readily extinguished.

In the embodiments of both FIGS. 1 and 3 of the drawings, the means which is responsive to energization to force fluid into the arc chamber to establish a fluid vortex therein is shown to be a reciprocating piston. This means is not, however, unique and could equally as Well be any other means for forcing fluid from a storage chamber into the arc chamber before an arc is struck. Such means include a rotating eccentric pump or other similar means.

While the invention has been set forth hereinbefore, with respect. to particular embodiments thereof, many modifications and changes will readily occur to those skilled in the art. Accordingly, I intend by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.

What I claim is:

1. An electric circuit interrupting device comprising: a pair of arc-electrodes, at least one of which is movable to separate said electrodes and cause the initiation of .an electric arc therebetween; an arc chamber surrounding said electrodes and having an orifice within the wall thereof; means associated with said orifice for causing a fluid flow therethroughand tangentially within said chamber to establish therein an arc-extinguishing fluid vortex, the walls of said arc chamber tapering in the region thereof laterally surrounding said arc-electrodes in circuit-closed position to create thereat a nozzle in which fluid is forced past said electrodes when in circuit opened position at high velocity creating a region of high fluid turbulence to rapidly extract energy from said arc; and means responsive to a flow of fluid within said chamber for separating said arc-electrodes to initiate said are after the establishment of'said vortex.

2. An electric circuit interrupting device comprising: a pair of arc-electrodes at least one of which is movable to separate said electrodes and cause the initiation of an electric arc therebetween, a tapered arc chamber having an orifice in the wall thereof surrounding said electrodes and forming a minimal diameter region adjacent to the intersection of said electrodes to define thereat, a nozzle, said nozzle approximately surrounding the junction between said electrodes when in contact-making position, and means associated with said orifice for causing a stream of fluid to flow therethrough and tangentially within said chamber to establish therein an arc-extinguishing fluid vortex, said vortex creating at said nozzle a region of high her having an orifice in the wall thereof surrounding said electrodes and defining in the region of the intersection of said electrodes, a nozzle, said nozzle approximately surrounding the junction between said electrodes when in contact-making position; moans associated with said orifice for causing a fluid flow therethrough and tangentially into said chamber to establish therein an arc-extinguishing fluid vortex having a restricted diameter portion in said nozzle, causing fluid to be forced past the arc at high velocity establishing a region of high fluid turbulence surrounding said are which rapidly extracts energy therefrom; and means responsive to a flow of fluid within said chamber for separating said are electrodes to initiate the are after the establishment of said vortex. a 4. An electric circuit interrupting device comprising: a pair of arc-electrodes at least one of which is movable to separate said electrodes and cause the initiation of an electric arc therebetween, a substantially conical are! chamber having an orifice in the wall thereof surrounding said electrodes and defining, in the region of the intersection of said electrodes, a nozzle; means associated with said movable arc electrode for substantially closing the throat of said nozzle; and means associated with said orifice for causing a fluid flow therethrough and tangentially within said chamber to establish therein a fluid vortex; said means "for closing said nozzle being responsive to a flow of fluid within said chamber to open the throat of said nozzle and concurrently therewith separate said electrodes to establish said are. n

5. An electric circuit interrupting device comprising: a pair of arc-electrodes at least one of which is movable to separate said electrodes and cause the initiation of an electric are between, a tapered arc chamber having an orifice in the wall thereof surrounding said electrodes and forming a minimal diameter region laterally surrounding the intersection of said electrodes to define thereat a nozzle, and means for establishing Within said tapered arc chamber an are-extinguishing fluid vortex having a restricted diameter portion in said nozzle, causing fluid to be forced past said are at high velocity establishing a region of high fluid turbulence surrounding said are to rapidly extract energy therefrom, said means including an orifice in the wall of said chamber and means for causing a stream of fluid to flow therethrough and tangentially in said chamber thereby establishing said vortex, the axis of said vortex corresponding substantially with the line of motion of said movable electrode.

References Cited in the file of this patent UNITED STATES PATENTS 1,820,928 Whitney et a1 Sept. 1, 1931 2,061,945 Koppelmann et a1 Nov. 24, 1936 02,109,685 Ainsworth Mar. 1, 1938 2,279,040 Grosse Apr. 7, 1942 2,310,093 Korndorfer Feb. 2, 1943 2,391,826 Flurscheim Dec. 25, 1945 2,517,136 Schneider Aug. 1, 1950 2,533,545 Ainsworth et a1 Dec. 12, 1950 FOREIGN PATENTS 319,019 Great Britain Dec. 11, 1930 638,145 Germany Nov. 10, 1936 477,231 Great Britain Dec. 24, 1937 679,327 Germany Aug. 5, 1939 723,076 Germany July 30, 1942 960,111 Germany Mar. 14, 1957

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