US3705144A - Vacuum interrupter or switch for electric power networks - Google Patents

Vacuum interrupter or switch for electric power networks Download PDF

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Publication number
US3705144A
US3705144A US208209A US3705144DA US3705144A US 3705144 A US3705144 A US 3705144A US 208209 A US208209 A US 208209A US 3705144D A US3705144D A US 3705144DA US 3705144 A US3705144 A US 3705144A
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Prior art keywords
interrupter
contact elements
contact
armature
elements
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US208209A
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Pierre Genequand
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Battelle Memorial Institute Inc
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Battelle Memorial Institute Inc
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Priority claimed from CH1902970A external-priority patent/CH543170A/fr
Priority claimed from CH1694571A external-priority patent/CH560963A5/fr
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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
    • 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
    • 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
    • H01H33/662—Housings or protective screens
    • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations

Definitions

  • FIG. l2 VACUUM INTERRUPTER OR SWITCH FOR ELECTRIC POWER NETWORKS Filed Deo. l5, 1971 '7 Sheets-Sheet L1 FIG. l2
  • the invention relates to a vacuum single-pole interrupter or switch for alternating electric current, having a plurality of contact elements operating in series, said contact elements belonging to first and second contact armatures capable of moving in relation to each other along an axis of displacement, the contact elements of one armature cooperating with those of the other armature so as together to form a chain of contact elements constituting, when the interrupter is closed, a conduction path alternately passing through the contact elements of said two armatures and forming, when the interrupter is open, a series of interrupting gaps alternately defined by said contact elements, the two end elements of this chain being electrically connected to the one and the other, respectively of two terminals for connection of this interrupter to an electrical network.
  • the problem of breaking a high voltage alternating current circuit has long existed, particularly in grid systems.
  • the problem consists in imparting to the medium in which the contact elements operate and in which ilashes the discharge resulting from a break, the ability to recover very quickly, after the current has dropped to zero, suflicient dielectric strength to enable a potential difference of some 100 kv. to be set up across the contact elements without causing the discharge to be restarted.
  • it is the phenomenon of the dielectric restoration of the medium in which the discharge flashes that constitutes one of the key elements of the problem.
  • vacuum interrupters are characterized by a small gap between the contact elements, of the order of 1 cm. This provides substantial advantages as regards the control mechanism since the 'ice latter is only required to move the contact elements over short distances. The forces of inertia to be overcome are thus small so that the vacuum interrupter can be made to operate with little noise.
  • Reece cones Whose apexes are located on the cathode and form the cathodic spots mentioned earlier. These cathodic spots move by sweeping across the cathode, somewhat like gas molecules, at speeds of some 10 to m./s., and the corresponding Reece cones, which have a very short life, something of the order of 1 microsecond to 1 millisecond, keep going through subdivision. They each convey a current of not more than 30 to 100 a. Under these diffuse arc flow conditions, the cathode is subjected to little erosion, not exceeding 50 to 100 rtg/as.
  • the current is conveyed by a single column resulting from a regrouping of the Reece cones.
  • This single column which carries all of the current, has little mobility and as a result causes destructive fusion of the contact elements.
  • the molten regions give rise to much evaporation of the metal, so that the discharge comes to behave like a high pressure arc. Dielectric restoration is then adversely affected and the discharge starts up again after the current has dropped to zero.
  • Dielectric restoration is then adversely affected and the discharge starts up again after the current has dropped to zero.
  • the heat conductivity of the metal from which the contact elements are made is such as not to enable the heat generated at the point of impact of the discharge to be removed sufficiently quickly.
  • any interrupter when open, must be able to withstand disruption, i.e. to bear a high potential difference without any discharge flashing across its contact elements.
  • the best possible surface conditions are very rapidly affected by the erosive action of the discharges occurring when interrupter is being opened.
  • the dielectric strength of the medium it is dependent on the pressure prevailing therein. This pressure must remain such that the mean free path of a charged particle be suiciently long to prevent this particle from being accelerated to the point of generating an avalanche process (Paschen discharge).
  • Vacuum switch or interrupter designers thus have to contend with two contradictory requirements, i.e. a short distance between the electrodes to prevent the discharge from being restarted after the current has dropped to zero, and a large distance between the contact elements to ensure resistance at high voltage.
  • a suitable and economical compromise must therefore be found between these two requirements and the interrupter according to the present invention provides a novel compromise of this nature.
  • each of the said contact elements is provided with screening means that are electrically connected therewith and that are placed in such a manner as to separate from one another those of the interrupting gaps of said series which are delimited by said contact elements and as to prevent any electrical ield line to extend through more than one of these interrupting gaps.
  • FIG. 1 is a side view, partly in section, of the iirst form of embodiment
  • FIG. 2 is a section through part of the interrupter illustrated in FIG. l, with the interrupter shown in a rst particular position;
  • FIG. 3 is a similar section, with the interrupter shown in a second particular position
  • FIG. 4 is an enlarged view of part of FIG. 3, illustrating the operation of the first form of embodiment
  • FIGS. 5 to 9 are diagrams relating to various arrangements that some parts of this first form of embodiment can have;
  • FIGS. and 1l illustrate, partly in section, two variants ofthe first form of embodiment
  • FIG. 12 is a side view, partly in section, of the second form of embodiment
  • FIGS. 13 to 15 are partial sections of some elements visible in FIG. 12;
  • FIG. 16 shows on an enlarged scale a variant of a par of FIG. l2;
  • FIG. 17 shows, partly in section, like FIGS. 1 and 3, another variant of the rst embodiment
  • FIG. 18 is a horizontal section along line XVIII-XVIII of FIG. 17;
  • FIG. 19 is a section like that of FIG. 16, of a variant similar to that shown in FIG. 17 applied to the second embodiment.
  • the interrupter comprises a fluidtight exhausted enclosure 1 which rests on a base 2 forming the bottom of the lower half 1b of the enclosure and into which enters via a iluidtight bellows sealing member 3 a conductive actuating rod 4 serving to operate the movable armature of the interrupter.
  • This movable armature is made up of a series of three circular metal shells 5, 6 and 7, which are coaxially suspended on the actuating rod 4 one inside the other.
  • These shells are isolated from each other by insulating spacers 8 and 9 and, except for the outer shell 5, they are isolated from the actuating rod 4 by shoulders 10 and 11 formed in the spacers and by an insulating washer 12 placed between the head 13 of the rod 4 and the inner shell 7.
  • the shells 5, 6 and 7 and the insulating elements 8, 9 and 12 are pressed against the head 13 by a nut 14 which at the same time applies the outer shell 5 against the shoulder 15 of the rod 4 to ensure electrical contact between the rod and the outer shell.
  • the rod 4 is uidtightly secured by a welding 16 to the top of the bellows 3 and the latter is fastened to the upper half 1a of the enclosure 1 by a welding 17.
  • the stationary armature of the interrupter is formed in similar manner by a series of three metal shells 18, 19 and 20 which are coaxially mounted inside each other and which are fixed to the base 2 by a threaded conductive rod 21.
  • These shells are isolated from each other and from the base 2 by insulating spacers 22, 23 and 24 and, except for the inner shell 20, they are isolated from the threaded rod 21 by shoulders 25 and 26 formed in the spacers 22 and 23 respectively.
  • the threaded rod 21 is moreover isolated from the base 2 by an insulating washer 27 having a shoulder 28.
  • the inner shell 20 iS clamped beneath the head 29 of the threaded rod 21 so as to be in electrical contact with the latter.
  • a nut 30 simultaneously to assemble together the shells 18, 19 and 20 and the insulating elements 22, 23, 24 and 27, to ix these components to the base 2 and to ensure electrical contact between the inner shell 20 and the threaded rod 21.
  • the base 2 carries a threaded stud 31 which is electrically connected thereto by a welding 32.
  • the two halves 1a and 1b of the enclosure 1 are secured to each other by a welding 33.
  • the air contained in the enclosure 1 is removed through a withdrawal pipe 44 which, when the pressure reaches the lowest possible value (of the order of 10*s torr and below), is sealed by nipping and is made fluidtight by a welding 45.
  • the threaded rod 21 acts as one of the terminals of the interrupter, which terminal has secured thereto by a nut 34 a conductor 35, the latter thus being electrically connected to the inner shell 20 of the stationary armature.
  • the stud 31 acts as the other ternnnal of the interrupter and this terminal has secured thereto by a nut 36 a conductor 37, the latter thus being electrically connected to the outer shell 5 of the movable armature.
  • Each of the armature carries a series of contact elements of circular shape around the axis 52 of the interrupter.
  • the contact element of the outer shell 5 of the movable armature is shaped in the form of a crown 38 laid ilat and projecting inwardly of the shell.
  • the contact element of the inner shell 20 of the stationary armature is shaped in the form of a crown 39 laid ilat, but projecting outwardly of the shell.
  • the contact elements of the other shells are formed by circular components of T-shaped cross-section, alternately in upstanding and upside down positions.
  • the shells 18 and 19 of the stationary armature have contact elements 40 and 41,
  • the shells 6 and 7 of the movable armature have contact elements 42 and 43, respectively, which are of upstanding T cross-section.
  • 'Ihese circular components are secured at the middle of their horizontal portions to the edges of their associated shells so that these horizontal portions should extend outwardly and inwardly of their associated shell.
  • the contact elements are so sized that their horizontal portions 46 should overlap each other so as to come into contact when the movable armature is pressed against the stationary armature (closed position of the interrupter, FIG. 2), while their vertical portions 47 form screens which prohibit any direct sighting between contiguous contact elements, even when the movable armature is moved away from the stationary armature (open position of the interrupter, FIG. 3).
  • the displacements of the movable armature are controlled by a mechanism not shown, which operates the actuating rod 4, the latter being axially movable in relation to the enclosure 1 by virtue of the bellows sealing members 3.
  • a high vacuum is created in the interrupter by connecting the withdrawal pipe 44 to a high vacuum pumping unit with which a pressure of less than 10-8 torr can be obtained. While pumping is in progress, intensive degassing is performed, through heating, to reduce as far as possible any subsequent degassing, either while the interrupter is in storage or while it is in use. As will be explained later the pressure in the enclosure 1 must not rise above a limit p1 defined by torr. cm., the length d being that of the longest field line likely to appear in the interrupter.
  • the described interrupter operates as follows. Be it supposed that the interrupter is closed 'with its contact elements occupying the positions shown in FIG. 2. Then the movable armature moves away from the stationary armature and disengages the contact elements (FIG. 3), the voltage across two contiguous contact elements is equal to the potential difference between the conductors 35 and 37 divided by the number of interrupting gaps appearing between the contact elements, i.e. by the total number of shells minus one (in the described example), there are three shells (5, 6, 7) for the movable armature and three shells (18, 19, 20) for the stationary armature, i.e. six in all, hence five interruptions along the chain (38, 40, 42, 41, 43, 39).
  • this reduced voltage only produces a discharge of the diffuse are type, formed by several parallel conical columns (termed Reece cones) Whose apexes are located on that one of the contact elements which happens to be at negative potential in relation to its neighbour.
  • the polarities are those indicated in FIG. 3.
  • the diffuse arc discharges that come into being are as shown on an enlarged scale in FIG.
  • the vertical portions 47 of the intermediate contact elements prevent any direct sighting from one interrupting space to another.
  • the vertical portions firstly prevent a particle from passing from one interrupting space to the next, this corresponding to prohibition of a direct sighting in the optical meaning of the expression direct sighting, and secondly prevent field lines from passing through more than one interrupting gap or join two non adjacent contact elements, this corresponding to the electrical meaning of the expression direct viewing.
  • the field lines which are located in the interrupting gap between two contiguous contact elements like the field line 274 (FIG.
  • the described interrupter prevents the restarting phenomenon from occurring, improves resistance to disruption and reduces the time taken to read this resistance to disruption.
  • the characteristic features of the described interrupter lie: in the fact that the interruption of the circuit is not localized, but is spread over several interruptions that give rise to a cascade of series mounted discharge paths; in the presence of bafiles which prevent direct sighting from any one discharge path of a neighbouring discharge path; and in the presence of shells so arranged as to provide screens prohibiting the existence of long field lines or field lines causing a large potential drop.
  • the baffles are simple insofar as each contact element, except for the terminal contact elements 55 and 56, carries only one bafiie, this bale being symmetrically disposed in relation to this element, as shown by the element 57 and its baffle 58 which have been drawn in thicker lines.
  • Other arrangements can be conceived, like that of FIG. 6 where the non terminal contact elements are all identical and are provided, like the element '59, with a single baffle i60, this baffle being placed asymmetrically.
  • FIG. 7 and 8 illustrate diagrammatically the case where some of the contact elements like the elements 61 and 64, respectively, are provided with two baves 62, 63 and 65, 66, respectively, whereas others, like the elements 67 and 68, respectively, have none; in the case of FIG. 7, the baffles 62 and 63 are symmetrically disposed on the element 61; in the case of FIG. 8, the baffles l65 and 66 are asymmetrically disposed on the element 64.
  • FIG. 9 shows the case where some elements, such as the element ⁇ 69, are provided with three symmetrically disposed bailies, like the bailies 70, 71 and 72, whereas others, like the elements 73, have none.
  • the interrupted illustrated in FIG. 1 comprises three contact elements per armature, to wit the elements 38, 42 and 43 on the movable armature and the elements 39, 40 and 41 on the stationary armature, thus producing ve circuit interruptions. It will be clear that this number of three elements per armature is not imperative and that, according to circumstances, for instance the power to be conveyed by the circuit and the voltage, use can be made of a larger number of contact element, thereby splitting up to a greater extent the circuit interrupting action.
  • the shells may be of advantage to increase the resiliency of the shells to enable the contact pressure to be more evenly distributed over the entire periphery of the contact elements.
  • the contact element 79 of the stationary armature is split into two parts 79a and 7912 which are supported by the shells 79a and 79'b that are connected to a common central portion 79".
  • This arrangement enables the two parts 78a and 78b to move in relation to each other so that they can cooperate independently of one another with the contiguous contact elements S3 and 255 of the movable armature.
  • the same applies to the two parts 79a and 79b of the contact element 79 which can thus cooperate independently of each other with the contiguous contact elements 255 and 54 of the movable armature.
  • the T-shaped cross-section, Whether upstanding or inverted, of the contact elements in the interrupter illustrated in FIG. 1 is only one possibility among others and other cross-sections can be conceived, e.g. U-shaped, whether upstanding or inverted, with the limbs of one set being inserted between the limbs of the others.
  • Some of the arrangements discussed earlier in particular that which is diagrammatically illustrated in FIG. 1, are derived from shapes of this kind.
  • FIG. 12 illustrates a second form of embodiment in which the contact elements, instead of being distributed in a common plane, over increasing diameters, as is the case with the first form of embodiment visible in FIG. l, are axially distributed and have identical diameters.
  • This interrupter comprises an enclosure 80 mounted on a base 81 and capped by a cover 182, these elements being fluid tightly assembled together, as by welding.
  • the stationary armature comprises a stack of identical dishes 83 to 88 which are separated from each other by insulating spacers ⁇ 89 to 91 of tubular shape. These dishes have a radial cross-section as shown, on an enlarged scale, in FIG. 13. They are formed with a central limb 92 having a rounded outline with the concave side thereof facing the axis of revolution 97, a at crown-shaped portion 93, a median groove 94, a conical portion 95 and a plane disc-shaped portion 96 which is placed at a level beneath that of the flat portion 93, to the same side thereof as the groove 94.
  • the distance between the limb 92 and the groove 94 is such that the intervening space acts as a centering recess for receiving the associated tubular spacer.
  • the dishes within the stack are arranged in pairs, like the pair 84, and the pair 86, 87, and the two dishes of a pair are in inverted relationship so that their central limbs 92 together constitute an anti-euvium screen of concave form, with the concave side facing the inside of the tube formed by the stack of spacers 89, and 91, and so that the median groves 94 together constitute tield suppressing screens on the outside of this tube.
  • the groove of the lowermost dish 183 caps an axial rim 98 provided at the centre of the base 81, inside the enclosure 80, whereas the groove of the uppermost dish 88 accommodates a clamping piece 99 which is welded to the top end of a clamping tube 100.
  • This clamping tube is subjected to a pulling stress by means of a nut 101 which is screwed onto a threaded member 102 fastened to the lower part of this tube.
  • the nut 101 beats on a flat support 103 on which the base 81 rests through the intermediary of a splined insulating sleeve 104.
  • the movable armature comprises a series of three shells 105, 106 and 107 which are formed by the outer portions of bell-shaped members having as their axis of revolution the axis 97 of the interrupter.
  • each bell includes a flat central boss 108, a conical bottom 109 which is connected to the central boss 108 by a conical flank 110, an inner peripheral boss 111, a flat crown-shaped portion 112, an outer peripheral boss 113, a connecting edge 114 and a conically ilared skirt-shaped outer portion 115 which constitutes the shell mentioned earlier.
  • the bells 116, 117 and 118 to which belong the shells 107, 106 and 105 are fitted inside one another and are kept separate from each other by insulating sleeves 119, 120 and 121, each sleeve bearing on the hat crownshaped portion of the associated bell (as shown by the chain line outline 122 in FIG. 14 from which may also be observed that the distance between the peripheral bosses 111 and 113 is such that the intervening space acts as a centering recess for the associated sleeve).
  • each of these members is circularly shaped around the axis 97 of the interrupter and comprises a flat central boss 126, a conical flange 127 which is connected to the central boss 126 by a conical flank 128, an inner peripheral groove 129, a flat crown-shaped plate 130, and an outer peripheral groove 131, the distance between these peripheral grooves being such that the intervening space acts as a centering recess for a sleeve, as shown by the chain line outline 132.
  • the dimensions of these various parts and their conicities are such that the supporting members t exactly against the bottoms of the associated bells, so that the fitting of the peripheral grooves 129 and 131 in the supporting members with the peripheral bosses 111 and 113 in the bells forms two field suppressing screens located on opposite sides of the junction between two consecutive insulating sleeves, as will be observed from FIG. 12 as regards the supporting members 124 and the bell 118.
  • the lower supporting member 116 rests, through the intermediary of a central spacer 133, on an auxiliary shell 134 having a conical ange 135 which is parallel to the ange of this supporting member, and a conical skirt 136 which is parallel to the skirt of the inner bell '7.
  • the hub of this auxiliary shell 134 comprises a central portion 137 surrounded by a crown 138.
  • the central portion 137 is secured to the top end of an actuating rod 139, made of metal or other material, which is housed inside the clamping tube 100, its diameter being such as not to touch this tube.
  • the crown 138 is connected, through the intermediary of a fluidtight bellows 140, to the clamping piece 99, this connection being effected in iluidtight manner, by welding at each end of the bellows 140.
  • the upper supporting member 125 bears on a dished member 141 having a rim 142 and a central stud 143.
  • the rim 142 is connected, through the intermediary of a fluidtight bellows 144, to the cover 82, this connection being effected in fluidtight manner, by welding at each end of the bellows 144.
  • the central stud 1143 slides in a recess 145 formed in a threaded stopper 146 which is in turn accommodated in a threaded hole 147 in the cover 82.
  • a spring 148 is prestressed between the stopper 146 and the bottom of the dished member 141.
  • the clamping piece 99 is welded to a glass tube 1149 which surrounds the clamping tube 100 and which is terminated at its lower end by a pleated folded-back sleeve 150.
  • This sleeve in which the pleats are only made to provide for heat expansion, is welded to the lower end of a uidtight metal bellows 151 whose top end is tluidtightly connected to the base 81 of the interrupter.
  • the glassmetal welding 152 is surrounded by a peripheral screening hood 153 having an inner part 154 and an outer part 155.
  • the contact elements carried by the stationary and movable armatures are distributed in three identical superposed stages 156, 157 and 158, each of which is constructed as shown on an enlarged scale in FIG. 16.
  • Each stage e.g. stage 156, comprises a part 159 which is attached to the movable armature, and two parts, 160 and 161, which are attached to the stationary part.
  • Each of these parts is of circularly symmetrical cross-section about the axis 97 of the interrupter.
  • the member 159 which is ⁇ attached to the movable armature is shaped like an asymmetrical inverted U with unequal limbs 162 and 163, the longer limb 162 being remote from the axis 97 and the shorter limb being closer to this axis.
  • the longer limb 1-62 of this member 159 extends into the peripheral channel formed by the first, 160, of the two members which are attached to the stationary armature, the cross-section of this first member being shaped like an asymmetrical U having a longer limb 164 remote from the axis and a shorter limb 165 nearer the axis.
  • the shorter limb 163 of the member 159 extends into the peripheral channel formed by the second, 161, of the two members which are attached to the stationary armature, the cross-section of this second member being shaped like an asymmetrical U having a shorter limb 166 remote from the axis and a longer limb 167 nearer the axis, this longer limb being extended downwards by an appendage 168.
  • the members 159, 160 and 161 each comprise a fastening rim 169, 170 and 171, respectively, by means of which it is fastened to the associated armature.
  • the member 159 of stage 156 is fastened by the fastening rim 169 to the tip of the shell 105, the member 160 of this selfsame stage is attached by the fastening rim 170 to the plane portion 9683 of the dish 83 and the member 161 is attached by the fastening rim 171 to the plane portion 9684 of the dish 84.
  • the interrupter is closed, the electrical connection between the contact elements of the stage 1516 is established via the bottom 172 of the peripheral channel formed by the member 160, the tip 173 of the outer edge 162 of the inverted peripheral channel formed by the member 159, the tip 174 of the inner edge 163 of this selfsame channel and the bottom 175 of the peripheral channel formed by the member 161.
  • the members 159 belonging to the stages 156, 157 and 158 constitute the contact elements of the movable armature
  • the lower U-shaped members belonging to one stage e.g. the U-shaped member 16011 of the stage 15
  • the upper U-shaped members belonging to the sub-jacent stage e.g. the U-shaped member 161 of the stage 156
  • the dishes to which are secured these members c g. the dishes 87 and 86 and the dishes 85 and 84, respectively
  • this second form of embodiment is in respects similar to that of the first form of embodiment illustrated in FIG. l.
  • the edges 164 and 165 (FIG. 16) of the peripheral channel formed by the part 160 and the edges 166 and 167 of the peripheral channel formed by the part 161 constitute within any one stage the baffles that prevent direct sighting of one interrupting gap from another, e.g. of the interrupting gap 182 from the interrupting gap 181 in the stage 156 illustrated in this ligure.
  • the cylindrical screen which has as its cross-section the appendage 168 (FIG.
  • auxiliary shell 134 it simultaneously constitutes, firstly, another, additional, anti-vapour screen and, secondly, an additional baflie for preventing direct sighting between the clamping piece 99 and the inner shell 107.
  • the nut 101 serves to clamp the members making up the stationary armature and to iix them to the support 103 and to the base 81.
  • the threaded stopper 146 it serves to adjust the prestressing of the spring 148, this spring urging the movable armature against the stationary armature. It is therefore this spring which exerts the contacting pressure between the contact elements of the stages 156 to 158 and it is against the action of this spring that the actuating rod 139 has to be moved when it is required to separate the contact elements upon opening the interrupter.
  • this second form of embodiment has the advantage, in relation to the first, of being produced from a limited number of standard parts, thereby reducing the number of machining operations.
  • the dishes 83 to 88 are identical and are easily made by stamping.
  • the contact elements of the various stages only comprise three types of diiferent parts, i.e. the parts 159, 160 and 161, which parts only differ from one stage to the next as regards the diameter of their fastening rims 169, 170 and 171, respectively. Simple lathe operations will easily impart to these diameters the values they are required to have in the stages for which they are intended.
  • the bells :5, 106 and 107 are all identical as regards their profile, which profile is very well suited to production by stamping.
  • the arrangement that has been adopted for this second form of embodiment avoids having to expose to the vacuum for no good purpose purely mechanical components.
  • the clamping spring 148 and the device 146, 147 for modifying its prestressing are located outside the exhausted enclosure 80.
  • the clamping device of the stationary armature i.e. the nut 101, the member 102 and the tube 1100.
  • the actuating rod 139 is not subjected to any pull: it only operates on a thrust basis against the action of the force exerted by the spring 148 so that even when the switch is closed it remains subjected to a compressive force and never to a pulling force.
  • cathodic barrier the discharge confinement device called cathodic barrier and described in Swiss patent application No. 17,52'6/70.
  • FIG. 16 This is what is diagrammatically illustrated in FIG. 16 in which are to be seen, for the purpose of confining the discharge within the interrupting gap 181, the annular cathodic barriers 184 and 185 provided on the part 160 and the cathodic barriers 186 and 187 provided on the contact element 159, and, for the purpose of confining the discharge in the interrupting gap i182, the annular cathodic barriers 188 and 1-89 provided on the contact element 159 and the cathodic barriers 190 and 191 provided on the part 161.
  • the screened contact elements like the element 159 (FIG. 16) of the stage 156 (the latter being screened by virtue of the fact that its flanges 162 and 163 ⁇ are trapped in the peripheral channels i116() and 161, respectively), with helicoidal slots like the slots 195 formed on the outer flange 162, and like the slots 196 formed on the inner flange 163 of this contact element 159.
  • helicoidal slots like the slots 195 formed on the outer flange 162
  • these parts are preferably formed on the surfaces of these parts lying opposite the surfaces between which the discharges take place. Along these surfaces they have helicoidal or spiral outlines such that the current being channelled by these grooves sets up a magnetic field having a component capable of causing the discharge to travel along the contact elements in a circular translationary movement centered on the axis 97 of these elements.
  • the grooves are formed in the surfaces of the contact elements lying opposite the bafes (or screening flanges) 47.
  • the grooves are formed on the underneath surface of the element 41 and on the top surfaces of the elements 42 and 43.
  • the value S/d must be made as high as possible for each of the interrupting gaps. This is what the above described forms of interrupter achieve.
  • the contact elements should therefore be adapted so as to prevent without fail the current from reaching during the transitory state the critical value that leads to the formation of a single column, in other words be adapted to start, between the pairs of contact elements being moved apart, a plurality of discharges under diffuse fiow conditions with the current having to flow in the interrupting gaps set up between these Contact elements being divided up between them.
  • this amounts to increasing the simultaneity of the breaking action between all points of the two contact elements being moved apart, whilst maintaining a high pressure at all of these points when the contact elements are in contact in the closed position of the interrupter. This is what is achieved by the variants depicted in FIGS. 17 and 18 in relation to the first embodiment, and in FIG. 19, in relation to the second embodiment, it being assumed that one of the two armatures is movable and the other is stationary.
  • the contact elements of the stationary armature are splitting by cutting therein radial slots, such as the slots 239 in the case of the contact element 39, the slots 240 in the case of the contact element 40 and the slots 241 in the case of the contact element 41.
  • each Contact element fraction forms the tip of a contact fingen
  • the fractions 339 of the contact element 39 form the tips of contact fingers 220.
  • This arrangement imparts to the adjacent fractions of any one contact element an individual -fiexiblity which endows them with some mobility in relation to each other, such mobility multiplying, -when the interrupter is in the closed position, the points at which a stationary contact element touches the two movable contact elements that are adjacent thereto and with which it cooperates: it is then each fraction which touches, individually, these two contact elements.
  • the machining tolerances may be less tight and the heating action due to current throughfiow is better distributed and less large.
  • the splitting up of the stationary contact elements has another advantage which is most important when the armature is being opened: it is that the extra breaking current that springs between the contact elements when the latter are being separated is distributed between several parallel partial discharges, with at least one per finger, so that each only conveys a limited amount of current. If the current at each discharge starting point does not exceed a limiting value (of the order of 5 ka. in the case of contact elements made of copper), the corresponding discharges are bound to start up in diffuse arc form. This however supposes that each of the fractions into which the stationary contact elements are divided separate simultaneously.
  • the fingers In practice, during this time lag, the fingers must not be allowed time to follow the movable contact element in its breaking movement. This amounts to giving to the mass of the various fractions and to the elasticity of the corresponding fingers values such that the vibration period of these fingers is much greater than the time taken by the movable contact element to move away therefrom.
  • the fingers of one shell can be angularly offset in relation to the fingers of another shell: thus the fingers 218 formed in the outer shell 18 are angularly offset by half a width in relation to the fingers 219 formed in the shell 19.
  • the angular width of the fingers of one shell is not necessarily equal to the angular width of the fingers of another shell: if the fingers 218 have the same angular width as the ngers 2119, the fingers 220 of the inner shell 20 have a double angular width.
  • the interrupter has contact elements in the form of annuli stacked on top of each other into a substantially cylindrical tubular structure, like that shown in FIG. 12,.
  • the splitting up of the stationary contact elements leads to the arrangement shown in FIG. 19. It will be observed from the latter, which must be compared with FIG. 16, how the radial slots formed on the contact elements are arranged.
  • the annulus is provided with radial slots of which may be seen the portions 251 located on its outer flank 1164, the portions 252 on its inner flange 1165 and the portions 253 located on its mounting annulus '170.
  • the annulus 161 is also provided with radial slots of which may be seen the portions 261 located on its outer lflange 166, the portions 262 located on its inner liange '167 and the portions 263 located on its mounting annulus 171.
  • each of the stationary annuli 160, 161 belonging to one stage (here stage 156) is split up into sections which form the tips of contact fingers, such as the lingers 270 in the case of the annulus 1-60 and the lingers 271 in the case of the annulus 161.
  • a vacuum single-pole interrupter for alternating electric current having a plurality of contact elements operating in series, said contact elements belonging to irst and second contact armatures capable of moving in relation to each other along an axis of displacement, the contact elements of one armature cooperating with those of the other armature so as together to form a chain of contact elements constituting, when the interrupter is closed, a conduction path alternately passing through the contact elements of said two armatures and forming, when the interrupter is open, a series of interrupting gaps alternately defined 'by said contact, the outermost two elements of this chain being electrically connected to the rst and second, respectively, of a pair of terminals serving to connect the interrupter to an electric network, characterized in that each of said contact elements is provided with screening means which are electrically connected therewith and which are arranged so as to separate from each other those interrupting gaps which, within said series, are defined by this contact element and so as to prevent any one electric field line from extending through more than one of these interrupting
  • each of the said contact elements consists of a circular conductive crown which has at least one annular contacting surface and which is located at the periphery of a round conductive support, at least one of the crowns of at least one of the two armatures being provided with at least one dange substantially at right angles to the contacting surface of said crown, and the supports bearing the crowns of at least one of said armatures having a concave shape enabling them to fit into one another, in that within each of said armatures the supports are arranged in coaxial positions, that are aligned along said axis of displacement, and are attached to each other by fastening means which isolate them electrically from one another, the flanges being in all of the crowns of this armature oriented in a common direction, and in that, within any one armature, the concave supports are tted into each other, the arrangement being such that, when the interrupter is closed, the contact surfaces borne by the crowns of one
  • crowns are coaxial crowns of substantially equal diameters which are stacked one above the other and which alternately belong to one then the other of said armatures, said crowns together forming a substantially cylindrical tubular structure coaxial with said axis of displacement.
  • An interrupter according to claim 2 characterized in that the said outermost two elements of said chain belong to different armatures, whereby the interrupter may be connected to the network through the intermediary of these two armatures.
  • An interrupter according to claim 2 characterized in that the said outermost two elements of said chain belong to one armature, whereby the interrupter may be connected to the network through the intermediary of this one armature.
  • each of said armatures includes at least one crown having at least one of said flanges.
  • An interrupter according to claim 2 characterized in that, within at least one of the armatures, at least one of said crowns is split into two concentric parts of which one includes one of the contact surfaces of this crown and is secured to the edge of a first circular member, and of which the other includes the other contact surface of this crown and is secured to the edge of a second circular member, said two circular members being connected to each other at the central portions thereof so as together to form a composite support enabling relative movement of one of the contact surfaces of said crown in relation to the other.
  • each of the coaxial crowns of the lirst of said armatures is shaped like two superposed Us, the bottoms of these Us respectively constituting the cross-section of either of the two contact surfaces of this crown and the limbs of these Us forming the cross-section of each of two pairs of flanges, with one pair encircling one of said contact surfaces and with the other pair encircling the other contact surface, and in that the crosssection of each of the coaxial crowns of the second of said armatures is shaped like an inverted U having unequal limbs, the ends of these limbs respectively constituting the cross-sections of either of the two contact surfaces of this crown, said crowns being so arranged that the limbs of the inverted U of the cross-section of the crown of the second armature extend into the respective Us of the cross-sections of the crowns of the rst armature.
  • An interrupter according to claim 2 characterized in that said contact elements are provided with cathodic barriers so arranged as to delimit the contact surfaces of each said element.
  • An interrupter according to claim 1 characterized in that some portions at least of said contact elements are provided with lines along which the resistance oiered to electric current flow is increased, pairs of said lines delimiting in said portions paths of lesser resistance which channel the electrical current flowing therein, the shape of these lines being so selected that the electromagnetic action exerted by this current on the discharges occurring in said interruption gaps will impart to these dischargers a circular translationary movement along these contact elements.
  • An interrupter according to claim 16 characterized in that said lines of increased resistance are formed by grooves.
  • each contact element consists of a plurality of sections which are attached to this armature by elastic elements that render these sections movable in relation to each other in planes passing through said axis of displacement, the mass of these sections and the elasticity of these elastic elements being chosen so that when the interrupter is closed each of the sectioned contact elements of the stationary armature touches each of the corresponding contact elements of the other armature at at least one point per section, and so that when the interrupter opens the inertia of these sections prevents them from accompanying the contact elements of the other armature while they are moving away.
  • each of the sections belonging to one Contact element of said stationary armature has the shape of an annulus sector, each of these sectors being secured to the tip of a radial finger consisting of the portion of said round support lying between two adjacent slots belonging to a plurality of meridian slots formed in said support from its outer edge, the axis of said support corresponding to said displacement axis and said radial fingers constituting said elastic elements, the flexibility of said lingers being determined by the radial depth of the slots.

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  • Manufacture Of Switches (AREA)
  • Slide Switches (AREA)
  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
US208209A 1970-12-24 1971-12-15 Vacuum interrupter or switch for electric power networks Expired - Lifetime US3705144A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH1902970A CH543170A (fr) 1970-12-24 1970-12-24 Interrupteur monopolaire à vide pour réseaux électriques de puissance
CH1694571A CH560963A5 (en) 1971-11-22 1971-11-22 Vacuum interruptor for AC current - with contact elements in two assemblies forming conducting path or interrupting gaps

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US3705144A true US3705144A (en) 1972-12-05

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US (1) US3705144A (de)
DE (1) DE2163900A1 (de)
FR (1) FR2120815A5 (de)
GB (1) GB1382817A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3818166A (en) * 1972-03-06 1974-06-18 Westinghouse Electric Corp Contacts for vacuum interrupter of small outside diameter
US3953693A (en) * 1974-09-09 1976-04-27 Allis-Chalmers Corporation Vacuum switch with integrated capacitor shield
US4553002A (en) * 1983-12-05 1985-11-12 Westinghouse Electric Corp. Axial magnetic field vacuum-type circuit interrupter
US20210304987A1 (en) * 2013-12-18 2021-09-30 Hubbell Incorporated Single bottle interrupter
US20230215674A1 (en) * 2021-12-31 2023-07-06 Schneider Electric Industries Sas Movable contact bracket assembly and contactor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3302226C2 (de) * 1983-01-24 1985-01-03 Siemens AG, 1000 Berlin und 8000 München Kontaktanordnung für Vakuumschalter

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3818166A (en) * 1972-03-06 1974-06-18 Westinghouse Electric Corp Contacts for vacuum interrupter of small outside diameter
US3953693A (en) * 1974-09-09 1976-04-27 Allis-Chalmers Corporation Vacuum switch with integrated capacitor shield
US4553002A (en) * 1983-12-05 1985-11-12 Westinghouse Electric Corp. Axial magnetic field vacuum-type circuit interrupter
US20210304987A1 (en) * 2013-12-18 2021-09-30 Hubbell Incorporated Single bottle interrupter
US11600459B2 (en) * 2013-12-18 2023-03-07 Hubbell Incorporated Single bottle interrupter
US20230215674A1 (en) * 2021-12-31 2023-07-06 Schneider Electric Industries Sas Movable contact bracket assembly and contactor
US12087532B2 (en) * 2021-12-31 2024-09-10 Schneider Electric Industries Sas Movable contact bracket assembly and contactor

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Publication number Publication date
DE2163900A1 (de) 1972-06-29
GB1382817A (en) 1975-02-05
FR2120815A5 (de) 1972-08-18

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