US3432713A - High current vacuum gap devices with slotted electrode vanes - Google Patents

High current vacuum gap devices with slotted electrode vanes Download PDF

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US3432713A
US3432713A US639844A US3432713DA US3432713A US 3432713 A US3432713 A US 3432713A US 639844 A US639844 A US 639844A US 3432713D A US3432713D A US 3432713DA US 3432713 A US3432713 A US 3432713A
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vanes
electrode
arc
current
electrode assembly
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James M Lafferty
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General Electric Co
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General Electric Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
    • H01H33/66—Vacuum switches
    • H01H33/664—Contacts; Arc-extinguishing means, e.g. arcing rings
    • H01H33/6646—Contacts; Arc-extinguishing means, e.g. arcing rings having non flat disc-like contact surface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T2/00—Spark gaps comprising auxiliary triggering means
    • H01T2/02—Spark gaps comprising auxiliary triggering means comprising a trigger electrode or an auxiliary spark gap
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T7/00—Rotary spark gaps, i.e. devices having one or more rotating electrodes

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  • Vacuum gap devices adapted for very high current usage include a first inner electrode having outwardly disposed thin vanes and a second outer electrode having inwardly disposed thin vanes. Vanes of inner electrode are slotted to define a folded-back path of current conduction therein. Folded-back current path causes flux lines caused thereby to move arcing paths within interelectrode gaps to large mating vane area and permit high currents to pass between electrodes without high current density at any given point, thus avoiding anode spot formation.
  • the present invention relates to improved high power, high current vacuum gap devices, particularly those of the triggered vacuum gap and vacuum switch types, suitable for the attainment of very high power and current ratings without the development of anode spots and the attendant destructive erosion thereof. 7
  • Vacuum gap devices in particlar vacuum switches and fixed vacuum gaps of the triggered vacuum gap type, have recently been the subject of intense technological and commercial interest. After nearly 40 years of developmental evolution, commercial vacuum switches at high power ratings are presently being manufactured. Similarly, since the advent of the triggered vacuum gap disclosed and claimed in my US. Patent No. 3,087,092, issued Apr. 29, 1963, and entitled Gas Generating Switching Tube, gaps of this type which avoid the previously existing problems of instabilities and nonuniform breakdown voltages have been adapted for a number of commercial applications.
  • Both vacuum switches and triggered vacuum gaps are often limited in their ability to operate at high power levels and, particularly, to carry currents of the hundreds of thousands of ampere range for more than one half cycle, by the inability of conventional anodes to withstand destructive melting caused by the formation of intense anode spots which are the anode footpoints of individual electric arcs existing between cathode and anode. In gaps wit-h closely spaced electrodes, the destructive melting also occurs at the cathode electrode, because of intense radiation and heating from the anode spots.
  • a further object of the present invention is to provide vacuum gap devices, including vacuum switches and fixed gap devices which are adapted to operate at high current and power levels for long duty cycles without the formation of anode spots and thereby exhibit long-lifetime characteristics.
  • a further object of the present invention is to provide improved triggerable vacuum gap devices suitable for operation at higher currents and higher voltage levels than heretofore obtainable, without the incidence of anode spots.
  • Yet another obejct of the present invention is to provide improved high current, high power vacuum switches which may be utilized for a greater number of circuit interruptions than heretofore obtainable without the occurrence of anode spots therein and the ultimate destruction of the electrodes thereof.
  • I provide a vacuum gap device including, as essential elements thereof, a pair of primary electrodes which may define therebetween a plurality of parallel vacuum gaps. More specifically, in accord with the present invention the electrodes of the primary gap are interleaved between one another and contained within an evacuable envelope which, during arcing is substantially filled with an electron-ion plasma, which provides an infinite number of current carrying paths, none of which has sufficient current density to cause destructive melting of either anode or cathode electrodes and, specifically, of the anode electrode.
  • one primary electrode constitutes a plurality of outwardly depending radial fins attached at the center thereof to a centerpost and the other primary arc-electrode comprises a plurality of inwardly depending radial fins interleaved between the outwardly depending radial fins and connected to the outward edges thereof together so as to form an electrically unitary electrode structure.
  • the electrode structure as described hereinbefore, is permanently juxtaposed so as to define a plurality of fixed gaps and current is initiated between the two primary electrode structures by the pulsing of a trigger apparatus associated therewith to cause the injection into the primary gap of a charged electron-ion plasma to cause the breakdown thereof.
  • the electrode structure has one movable with respect to the other so that the central electrode apparatus, for example, may be moved with respect to the outer electrode apparatus, either by a longitudinal motion or by rotation thereof.
  • plasma to form a conduction path between the primary arc-electrode is produced by the arc struck upon circuit interrupting and the vaporizing and ionization of electrode material.
  • the initial arc is struck upon a separation of the two electrode apparatus and the are rapidly diffuses over the many parallel surfaces of the electrode structures so that the evacuated volume containing the electrode is rapidly filled with an electron-ion plasma which conducts high currents at high power levels until the occurrence of a current zero, at which time the discharge is extinguished.
  • FIGURE 1 is a vertical cross sectional view with parts broken away of a fixed gap triggerable vacuum device constructed in accord with the present invention
  • FIGURE 2 is a perspective view of the inner electrode assembly of the device of FIGURE 1,
  • FIGURE 3 is a vertical cross sectional view with parts broken away of a variable gap vacuum switch constructed in accord with another embodiment of the present invention
  • FIGURE 4 is a vertical cross sectional view, with parts broken away, of yet another device constructed in accord with a further embodiment of the present invention
  • FIGURES 5, 6, 7, 8, and 9 represent alternative structures to the lower central electrode assembly of the device illustrated in FIGURE 2 of the drawing.
  • FIGURE 10 is a vertical cross sectional view, with parts broken away, of a device constructed in still another alternative embodiment of the present invention.
  • a triggered vacuum gap constructed in accord with one embodiment of the invention and illustrated in FIG- URE 1 of the drawing comprises an evacuable envelope 1 containing therein a pair of primary electrode assemblies including a central electrode assembly 2 and an outer electrode assembly 3.
  • Central electrode assembly 2 comprises a plurality of outwardly-depending radial vanes 4, each of which is thin, having a small thickness dimension as compared with its length and width dimensions, and is substantially perpendicular to a transverse plane, and which are fastened at the lowest ends to a plate or disc 5 which is connected to and supported upon an electrode support member 6.
  • Electrode assembly 2 is also illustrated in FIGURE 2 of the drawing in perspective, showing the inter-relationship of vanes 4, plate 5, and support member 6.
  • outer electrode assembly 3 comprises a hollow, cylindrical member 7 and a plurality of inwardly depending radial vanes 8 physically and electrically connected thereto. Vanes 8 are also thin, having a small thickness dimension as compared with their length and width dimensions and substantially perpendicular to the same traverse plane. Electrode assemblies 2 and 3 are juxtaposed so that the individual, inwardlydepending vanes 8 and the individual, outwardly-depending vanes 4 define a plurality of electrically parallel breakdown gaps therebetween. Each of the electrically parallel gaps is substantially of equal dimension to the others. Vanes 8 of arc-electrode assembly 3 extend for substantially the entire length of the discharge space within envelope 1.
  • vanes 4 of arc-electrode assembly 2 are somewhat shorter as is consistent with the necessity of maintaining the space between arc-electrodes 2 and apertured end wall members 9 and 10 of such length to prevent a spurious arcing, since members 9 and 10 are of the same electrical potential as arc-electrode 3.
  • vanes 4 are at least one-half of the length of vanes 8.
  • the thinness of vanes 4 and 8 is such that essentially no appreciable increase in electrical resistivity is incurred, but due to the thinness, a large number of parallel primary breakdown gaps, none of which is overloaded by extreme current densities, may be formed in a relatively small volume.
  • each of vanes 4 of arc-electrode assembly 2 is slotted, horizontally at slot 11 at a distance that is at least approximately twothirds of the length of the vanes 4 from the end thereof at which breakdown first occurs.
  • Vertical slot 12 intersects horizontal slot 11 and is located at a region at least approximately two-thirds of the width of vane 4 to the center post. The function of slots 1 and 12 in vane 4 of arc-electrode assembly 2 is to provide a folded-back path for current flow within vane 4.
  • any path of current conduction from vanes 8 of electrode assembly 3 to a portion of vane 4 of arc-electrode assembly 4 causes a current path which passes upwardly over the upper tip of slot 12 and downwardly along the center post causing a folded-back current conduction path.
  • This folded-back current conduction path causes the flux lines of the magnetic field caused thereby to reinforce the magnetic field caused by current paths within the external arc-electrode 3, to force the paths of current conduction radially outwardly from the point of initial breakdown adjacent the source of electron-ion plasma injected into the interelectrode space and upwardly along the large areas of vanes 4 and 8.
  • Envelope 1 of the device of FIGURE 1 contains a metallic, substantially cylindrical sidewall member 7 and a pair of oppositely disposed end caps 9 and 10, respectively. Both sidewall and end wall members are composed of a suitable conductive material, as for example high purity cooper, or the equivalent.
  • the cylindrical sidewall member may be the cylindrical portion 7 of exterior electrode assembly, as illustrated, or, alternatively the electrode assembly may be firmly mechanically and electrically connected to the interior thereof.
  • the aperture in upper end wall member 9 is hermetically closed with a suitable trigger electrode assembly 13 having a trigger anode 14, a trigger cathode 15, and a trigger gap therein (not shown) for supplying a pulse of gaseous ion-electron plasma or vaporized and ionized electrode material to cause breakdown between primary electrode assemblies 2 and 3 upon the initiation of a suitable electrical signal to trigger electrode assembly 13.
  • Electrode assembly 13 is suitably brazed to end plate 9.
  • Suitable trigger electrode assemblies are illustrated, disclosed and claimed in my aforementioned US. Patent and in my copending applications, Ser. No. 516,914, Ser. No. 516,942; and Ser. No. 516,943, all filed Dec. 28, 1965 and assigned to the assignee of the present invention.
  • the trigger electrode assembly 13 is surrounded by a conductive cylindrical member 16 which is brazed to end plate 9 and which may be an intermediate electrical connection therebetween and electrical terminal conductor 17.
  • An insulated trigger electrode lead 18 passes through cylinder 16 to allow for connection of trigger electrode assembly 13 to a suitable source of pulsed voltage (not shown).
  • Central electrode support rod 6 passes down through aperture 20 in end wall member 10, through a ferruled breakdown shield 21 and is supported by a closure disc 22 which is hermetically sealed to a ceramic insulator bushing 23, which in turn is hermetically sealed to end closure by means of a suitable annular chrome-iron or equivalent alloy sealing flange 24.
  • a central tubulation in support rod 6 permits the evaculation of envelope 1 and is sealed into an exterior tubulation 26 which extends through the end of support rod 6 and is pinched off at 27 to complete the evacuation and sealing of envelope 1.
  • FIGURE 3 of the drawing illustrates in vertical cross section with parts broken away, another embodiment of the invention.
  • an evacuable envelope 1 comprises a general cylindrical metallic sidewall member and a pair of upper and lower end wall members 9 and 10, respectively.
  • the aperture in end plate 10 is closed by an hermetic seal between an annular sealing flange member 28 of a suitable Fe-Ni- Co alloy, or equivalent, and a ceramic insulating bushing 29.
  • Ceramic insulating bushing 29 is closed by an annular apertured end plate 30 which is hermetically sealed by ceramic-to-metal sealing techniques thereto and welded, brazed, or otherwise suitably fastened to a longitudinally flexible bellows 31 which is capped by an annular end piece 32 which is sealed around and, by an hermetic seal, sealed to electrode support member 6 to complete a vacuum-tight envelope.
  • a first central primary electrode assembly 2 comprising a plurality of slotted outwardly-depending, radial vanes 4 is interdigitated between the inwardly-depending radial vanes 8 of an outer electrode assembly 3 which is substantially the same as that illustrated in the embodiment of FIGURE 1 of the drawing and which is electrically and mechanically a portion of the outer electrode assembly 3.
  • Vanes 4 and 8 are thin, as described hereinbefore, define a plurality of electrically-parallel gaps and are substantially perpendicular to the same transverse plane.
  • vanes 4 are slotted with horizontal and vertical slots 11 and 12, as in the embodiment of FIGURE 1 and illustrated more particularly in FIGURE 2 of the drawing, in order to cause current conduction therethrough to be folded-back to cause the interaction of the magnetic fields with the conduction current paths to force conduction current paths outwardly from the center of envelope 1, downwardly along the surface of vanes 4 and 8 in order to prevent the concentration of conduction paths at any given point, primarily the corner of vanes 4 by electromagnetic bunching and the establishment of a destructive anode spot upon the periphery of vane 4 to cause erosion and melting thereof. Additionally, due to the method of initiating herein, vanes 4 are attached to support member 6 only at the upper portion thereof to provide a doubly foldedback current path.
  • a metallic contact ring 33 rests in electrical and mechanical contact with the inner surface of the lower metallic end plate 10, and is also, electrically, a portion of electrode assembly 3.
  • the device of FIGURE 3 may be evacuated to a central tubulation in electrode support member 6 which terminates in a tubulation which, after evacuation, is sealed to vacuum by a pinch.
  • the device of FIGURE 3 constitutes a vacuum switch or circuit interrupter.
  • the two primary electrode assemblies 2 and 3 are brought into electrical circuit-making position by a downward thrust upon annular flange 34 surrounding the lower end of electrode support member 6 or an equivalent force supplied by means not illustrated.
  • the lower end edges of the outwardly depending radial vanes 4 of central electrode apparatus 2 impinge upon, and make electrical contact with, annular contact ring 33.
  • a circuit to be switched is connected through the switch in series circuit relationship therewith by making one device terminal to the lower end of electrode support member 6, as represented by arrow A.
  • the other terminal may be made at suitable connecting studs attached to the outward portion of lower end plate 10, contact studs being represented by arrows B. Between these terminals, a source of alternating voltage may be connected in series circuit relationship with an electric load to be switched.
  • the electrode support member 6 is moved longitudinally upward, as permitted by bellows 31, separating the lower portions of vanes 4 of electrode assembly 2 from the upper surface of contact ring 33. A plurality of arcs are thereby struck between each of the vanes and the contact ring. Since the path of current through support member 6, electrode assembly 2, the arc, contact ring 33, lower end plate 10, and a plurality of peripheral terminal lugs at B constitutes a loop, magnetic forces cause a concentration of flux at the center of the loop which urges the arc upwardly between the vanes of the inwardly depending outer electrode assembly and the outwardly depending, inward electrode assembly, thus tending to render the entire surface of the vanes available as contact surfaces on the electric arc.
  • slots 11 and 12 cause the path of current within vanes 4 of arc-electrode assembly 2 to be folded-back upon itself. This causes a further reinforcement of the magnetic field to act in conjunction with the current paths across the interelectrode gap, to cause any tendency of the current paths to bunch at the corners of the vanes 4 of arc-electrode 2 to eliminated and forces the conduction paths upwardly along the entire surface of vanes 4 of arc-electrode assembly 2.
  • FIGURE 4 of the drawing illustrates, in vertical cross sectional view, a multiple-stage, cascaded, triggered vacuum gap device constructed in accord with the present invention.
  • the device of FIGURE 4 is an improvemen upon the multiple stage trigger vacuum gap device disclosed and claimed in my aforementioned copending application, Ser. No. 586,751, filed Oct. 14, 1966 and includes an evacuable envelope indicated generally as 35, including a pair of insulating cylindrical sidewall envelope members 36 and 37 disposed along a common axis and connected by an annular ring electrode support member 38 by a pair of annular flange ceramic-to-metal seals 39 and 40.
  • evacuable envelope 35 The ends of evacuable envelope 35 are closed by a pair of apertured cup members 41 and 42', each of which is fastened to the respective juxtaposed cylindrical insulating body by an annular collar 43 and an annular metallic-to-ceramic sealing flange 44.
  • a trigger electrode assembly 45 is disposed within the aperture in cup member 41 and hermetically sealed thereto.
  • a trigger electrode assembly 46 is disposed within the aperture in end cup 42 and hermetically sealed thereto.
  • a trigger electrode lead wire 47 is used to supply an electrical signal to trigger electrode assembly 45 and a similar trigger electrode lead 48 supplies a signal to trigger electrode assembly 46.
  • Each of trigger electrode leads 47 and 48 is passed in insulating relationship through trigger electrode assembly 45 or 46 through respective insulating bushings 49 and 40.
  • First triggerable gap stage 60 includes an outer electrode assembly 61 including a cylindrical outer member 62 and a plurality of relatively thin extended area inwardly-dependent radial fins 63 which are parallel with the longitudinal axis of the device of FIGURE 4, which axis may be described as a line passing through the central portions of trigger electrode assemblies 45 and 46, about which the cylindrical insulating members 36 and 37 are concentric.
  • a second electrode assembly 64 within triggerable gap stage 60 include a plurality of outwardly-depending thin, relatively large area, radial vanes 65. Vanes 65 are disposed so as to be interposed between adjacent vanes 63 of electrode assembly 61 and are equidistant from adjacent ones thereof. The length thereof is slightly less than the length of the inwardly dependent vanes 63 of outer electrode assembly 61.
  • the vanes 65 are each supplied with slots 11 and 12, as is the device of FIGURE 1, for insuring that the electric discharge paths within stage 60 are evenly dispersed over the entire surface of the vanes, as in the device of FIGURE 1.
  • Electrode assembly 64 is mechanically and electrically connected to an annular support member 66 at the lower portions thereof, which annular support member is, in turn, electrically and mechanically connected to and supported by annular member 38, which constitutes a portion of the evacuable envelope 35.
  • annular support member 66 joins support member 38
  • support member 38 also is joined by a short cylindrical annular shield member 67, the prime purpose of which is to prevent the passage of metallic particles out from the interelectrode space so as to short-circuit the insulating cylinder 36 by causing the coating thereof with metallic particles.
  • this shield member is shown as being relatively short, it may be of any desired length and configuration sufficient to shield insulator 36 and to prevent an electric field from occurring in the area where 35 and 39 join.
  • the construction of the second triggerable vacuum gap stage of the device of FIGURE 4 represented generally by 70 is substantially identical with that of the first stage 60 and like elements thereof are indicated by the corresponding numerals of the 70 series to those elements indicated in the 60 series in first triggerable gap stage 60 of FIGURE 4.
  • first stage 60 of FIGURE 4 the inwardly-depending, outer radial vanes are shown in full and the outwardly-depending, inner radial vanes are shown in partial section.
  • stage 70' on the other hand, the inner outwardly-depending electrode vanes are shown in full view and the outer inwardly-depending vanes are shown in partial section.
  • a plasma transfer tube 80 which is a cylindrical member, is connected between the inner electrode support members 66 and 76 and is electrically connected to the inner electrode assemblies 64 and 74. It presents an open, unimpeded path for the conduction of electron-ion plasma between the interaction spaces of stages 60 and 70 during operation.
  • Means are provided by contacts 81 and 82 to provide connection with an electrical load circuit to be protected, switched, or otherwise controlled by the operation of the triggerable vacuum gap device of FIGURE 4.
  • Means for applying a triggering pulse to trigger electrode assemblies 45 and 46 are provided by a pair of separate, but simultaneously controlled, pulse sources 86 which are connected to the associated trigger electrode lead 49 or 50 and to cup members 41 and 42.
  • members 36 and 37 are a high voltage insulator, as for example, a fosterite ceramic, Pyrex glass, or high density alumina.
  • Electrode assemblies 61, 64 and 71 and members 66, 67 and 76 and 77 and 74 are made of extremely high purity, preferably zone-refined material, as for example copper having less than 1 part 10 of gas, or gas-forming impurities, particularly oxygen or oxygen-containing impurities.
  • Such material may, for example, be prepared in accord with the method set forth in US. Patent No. 3,234,351, issued Feb. 8, 1966 to M. H. Hebb.
  • the other metallic members as for example, end cap members 43 and 44 and support member 38' should be constructed of high purity metals, as for example, copper, stainless steel, or nickel which are out-gassed to preclude the presence of concentrations of gas or gas-forming materials, but need not have the extremely high purity of the electrode materials themselves.
  • the device Before operation, the device is evacuated to a pressure of 10 mm. of mercury or less to obtain the high hold-01f and rapid recovery characteristics of vacuum.
  • the device is to be used to switch from a nonconducting to a conducing condition between a high voltage applied between terminals 81 and 82.
  • the voltage divider comprising capacitors 83 and 84 causes a division of the applied voltage between the two series interelectrode gaps of stages 60' and 70.
  • approximately half the applied voltage is across the capacitor 83 and similarly, is applied across the vanes of electrode assemblies 61 and 64.
  • the remaining half of the applied voltage is across the capacitor 84 and, similarly, is applied across the vanes of electrode assemblies 71 and 74.
  • a predetermined control causes a positive pulse of from 50 to 5,000 volts, for example, depending upon the magnitude of the voltage being held off and the dimensions of the interelectrode gaps between the primary electrode assemblies, to be applied to the trigger electrode leads 47 and 48 respectively. If the applied line voltage is a unidirectional voltage, only one of the primary arc-electrodes 61 or 71 is associated with the two trigger assemblies 45 and 46 and will be negative. A positive trigger voltage applied to the trigger associated 'with the negative electrode cause a trigger breakdown between that electrode assembly and the trigger anode of the as sociated trigger assembly.
  • the voltage applied to terminals 81 and 82 is an alternating voltage
  • one of the two primary electrode assemblies 61 and 71 is more negative than the other and the associated trigger assembly, either 45 or 46, will break down, causing the injection of an electron-ion plasma into the interelectrode space between the associated primary electrodes.
  • a pulse of ion-electron plasma is injected into the interelectrode spacing between electrodes assemblies 61 and 64, causing the establishment of a high voltage are therebetween.
  • the charge from capacitor -83 discharges through the connections to the respective electrodes, thus preventing the extinction of the arc and permitting the establishment of a diffuse arc over the wide area of the narrow vanes 63 and 65 of electrode assemblies 61 and '64.
  • the electron-ion plasma generated thereby is propelled through arc transfer tube 80 and into the interelectrode spacing between the vanes of the electrodes of triggered gap sections 70, namely electrode assemblies 71 and 74.
  • substantially the entire voltage between the terminals 81 and '82 is transferred across capacitor 84.
  • the erosion upon any given arc electrode is minimized or substantially eliminated by causing the slots in the inner, outwardlydisposed arc-electrode vanes to cause a folding-back of the current conduction path with a resultant magnetic field which causes the arc currents to be diffused uniformly over the surfaces of the respective arc-electrode vanes rather than bunohing together at the corners of the vanes and causing the establishment of a destructive and eroding anode footpoint thereat.
  • FIGURE 5 of the drawing an alternative arrangeelectrode assembly 74 of FIGURE 6, wherein the horizontal slot 11 is at least two-thirds of the distance from the bottom of the vane 75.
  • the slotting of the vanes illustrated heretofor is entirely suitable to avoid the formation of anode spots in accord with the present invention. This is particularly so, irrespective of the material from which the arc-electrodes are fabricated. In particular, no further measures need be taken if the arc-electrodes are fabricated from an alloy that has a particularly high strength, as for example copper with minor additions of beryllium, nickel, tin or lead. It should be appreciated, however, that the same magnetic forces that cause the arcing paths to be moved around the corner of the inner, outwardly-disposed vanes, to avoid the formation of an anode spot upon the outer corner of the vane, also cause enormous forces to be exerted upon the vanes themselves.
  • FIGURE 7 of the drawing a central electrode assembly is illustrated which overcomes the aforementioned difficulty.
  • horizontal slot 11 does not extend to the edge of the vane 4 but, rather, extends to within approximately thereof.
  • the configuration of the slots in the vane 4 of FIGURE 7 is substantially the same as that illustrated in FIGURE 6. It has been found that the main path of current utilizing the vane slot configuration illustrated in FIGURE 7 does not substantially differ from that utilizing the vane slot configuration of FIGURE 5.
  • FIGURE 8 illustrates an alternative vane slot configuration to that illustrated in FIGURE 7 which accomplishes the same purpose.
  • the slots are cut as in FIGURE and a hole 90 is bored through the upper end of the plate 5 downwardly through vane 4 and through the slot.
  • a small stainless steel pin 91 having a reduced area portion 92 therein is placed into the hole with the reduced area portion 92 adjacent the slot and not in contact with the vane thereat.
  • the illustrated stainless steel pin in FIGURE 8 of the drawing is sufficient to withstand the magnetic forces tending to move the slotted portion of the vane outwardly under magnetic stress, and yet is not such as to cause any change in the electric current path within the vane, so that the vane operates substantially as that illustrated in FIGURE 6 of the drawing, but without any distortion due to the magnetic field and its effect upon the vane.
  • any poor conductor or insulator which has sufficient strength may be used.
  • FIGURE 9 of the drawing illustrates an alternative slotting, wherein the slot is cut in the form of a gentle curve which may be advisable from a manufacturing standpoint since a single cut with a band-saw may accomplish this fabrication.
  • the slot pattern illustrated in FIGURE 9 of the drawing is the substantial equivalent of that shown in FIGURES 5 and 6. Since, however, the same forces which operate on these vanes may tend to force the remote portion of the vane outwardly during arcing if the material is soft, it may be advisable to utilize the same technique in FIGURE 9 as is illustrated in FIGURE 8, drilling a hole through plate 5 into vane 4 and inserting a suitable stainless steel or other high-strength, poorly electrical conductive material to keep the vane from being distorted.
  • FIGURE of the drawing illustrates yet another alternative embodiment of the invention.
  • a vacuum switch embodying the invention operates to move from a circuit-making to a circuit-breaking position in response to a rotational motion of the central electrode assembly.
  • the envelope of the device of FIGURE 10 is composed of a substantially cylindrical, metallic side wall member 100, an upper closed end plate 101 and a lower, dished, or upwardly flanged, apertured end plate 102.
  • Member 100 is composed of a highly conductive material, as for example, copper.
  • Members 101 and 102 are composed of a suitable gas impervious insulating dielectric material as for example, an alumina ceramic.
  • Apertured end wall member 102 is fastened hermetically to cylindrical side wall member 100 by means of an annular sealing flange 103, preferably of a fernico alloy.
  • a vacuum-tight sleeve bearing104 permitting limited rotation of the central electrode assembly is connected and hermetically sealed with central electrode support rod 105 and comprises a sleeve member 106 which is hermetically sealed to ceramic end Wall member 102 by means of an annular ceramic-to-metal sealing flange member 107.
  • Electrical contact is made to the respective primary electrode apparatus by making contacts to electrode support member 105, as represented schematically by arrow 108, and by making contact to cylindrical side wall member 100 at terminal lug 109, as represented schematically by arrow 110.
  • An alternating current source 111 and a suitable load impedance 112 may be disposed in series or parallel circuit relationship between these points, as indicated schematically.
  • the device In operation, the device, once having been fabricated and evacuated. to a pressure of less than 10* mm. of mercury, is caused to move from a circuit-making condition in which the electrodes are in substantial mating position to a circuit-breaking position, by a slight rotation of the central electrode apparatus.
  • Contact is made between coupled thin contact vanes each of which is substantially perpendicular to the same transverse plane at the abutting edges thereof.
  • both inner and outer vanes are beveled at the ends to meet fiushly with the mating vane. It is along these beveled surfaces that a plurality of parallel arcs are struck upon separation of the electrodes.
  • slots 11 and 12 in the outwardly projecting vanes of the inner electrode assembly cause magnetic forces to move the arcs over the entire surfaces of the respective vanes, preventing the formation of destructive anode spots.
  • I provide improved vacuum gap devices, such as triggerable vacuum gap and vacuum switch devices, having a pair of arc-electrodes in which a first inner electrode has a plurality of outwardly-disposed electrode vanes and a second outer electrode with inwardly-disposed electrodes vanes which avoid the formation of anode spots.
  • anode spot formation is avoided by causing the vanes of the inner electrode assembly to be appropriately slotted, thus causing currents therein to be folded-back, causing magnetic flux lines to force current conduction paths to diffuse evenly over a large area of the electrode vanes.
  • a vacuum gap discharge device comprising:
  • a first primary arc-electrode assembly supported within said envelope and including a first plurality of thin substantially planar vanes projecting therefrom and being substantially perpendicular to a transverse plane through said envelope;
  • vanes of said first primary arc-electrode assembly and the vanes of said second primary arcelectrode assembly being interleaved alternatively between one another so as to define a plurality of electrically-parallel gaps between said first and second primary arc-electrode assemblies to cause electrical breakdown between said primary arc-electrode assemblies to occur simultaneously at a multiplicity of points whereby the formation of high current density anode spots is avoided;
  • slots comprise a first slot substantially perpendicular to the longitudinal axis of said device and at least approximately two-thirds of the distance from the end of said assembly at which said electron-ion plasma is first produced and a second slot which is substantially parallel with the longitudinal axis of said device and intersects said first slot.
  • said slots comprise a first slot substantially perpendicular to the longitudinal axis of said device and a second slot substantially parallel to the longitudinal axis of said device, intersecting said first slot, and disposed at a distance of at least approximately two-thirds of the distance from the active edge thereof which is closest to said other electrode assembly.
  • the device of claim 1 wherein the device is a fixed gap device with stationary electrode assemblies and the means for supplying said plasma is a trigger electrode assembly which is operative to an external electrical pulse to inititate breakdown.
  • the device is a vacuum switch with at least one electrode assembly movable in response to an external force to separate the vanes of said electrode assemblies, said separating of said vanes constituting means for establishing an electron-ion plasma between said arc-electrode assemblies.
  • said slots comprise a first slot substantially perpendicular to the longitudinal axis of said device and at least approximately two-thirds the length of said vanes from the end thereof at which said plasma first appears and said second slot is substantially parallel to the axis of said device and at least approximately two-thirds the width of said vanes from the edge thereof which is closest to said outer arc-electrode assembly and intersects said first slot.
  • said first slot does not extend entirely to the edge of said vane, but is terminated at a distance therefrom which is sufficient to leave a quantity of said vane between portions thereof on either side of said slot which is mechanically strong enough to prevent deformation of said vane due to concentrated magnetic forces but which is narrow enough so as to have negligible elfect upon said folded-back current paths within said vane.
  • said first slot extends to the edge of said vane and a bore is made through said vane passing through said slot and substantially parallel to the longitudinal axis of said device and a pin having high strength, but poor electrical conductivity is inserted therein bridging said slot and preventing deformation of said vane during operation by magnetic forces.

Landscapes

  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
  • Plasma Technology (AREA)
  • Microwave Tubes (AREA)
US639844A 1966-03-21 1967-05-19 High current vacuum gap devices with slotted electrode vanes Expired - Lifetime US3432713A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US53594866A 1966-03-21 1966-03-21
US63984467A 1967-05-19 1967-05-19

Publications (1)

Publication Number Publication Date
US3432713A true US3432713A (en) 1969-03-11

Family

ID=24136484

Family Applications (1)

Application Number Title Priority Date Filing Date
US639844A Expired - Lifetime US3432713A (en) 1966-03-21 1967-05-19 High current vacuum gap devices with slotted electrode vanes

Country Status (7)

Country Link
US (1) US3432713A (de)
JP (1) JPS4520657B1 (de)
DE (1) DE1765425A1 (de)
FR (2) FR1511467A (de)
GB (2) GB1162423A (de)
NL (2) NL6702544A (de)
SE (1) SE376125B (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970810A (en) * 1975-03-06 1976-07-20 General Electric Company Electric circuit breaker comprising parallel-connected vacuum interrupters
US3970809A (en) * 1975-02-10 1976-07-20 General Electric Company Electric circuit breaker comprising parallel-connected vacuum interrupters

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2896104A (en) * 1954-06-11 1959-07-21 Sedlacek Franz Lightning arrester

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2896104A (en) * 1954-06-11 1959-07-21 Sedlacek Franz Lightning arrester

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970809A (en) * 1975-02-10 1976-07-20 General Electric Company Electric circuit breaker comprising parallel-connected vacuum interrupters
US3970810A (en) * 1975-03-06 1976-07-20 General Electric Company Electric circuit breaker comprising parallel-connected vacuum interrupters

Also Published As

Publication number Publication date
DE1640202A1 (de) 1970-05-27
GB1162423A (en) 1969-08-27
SE376125B (de) 1975-05-05
JPS4520657B1 (de) 1970-07-14
NL6702544A (de) 1967-09-22
FR94441E (fr) 1969-08-14
GB1228905A (de) 1971-04-21
DE1640202B2 (de) 1975-12-04
NL6807064A (de) 1968-11-20
DE1765425A1 (de) 1971-07-29
FR1511467A (fr) 1968-01-26

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