NO122850B

NO122850B -

Info

Publication number: NO122850B
Application number: NO478769A
Authority: NO
Inventors: B Dalmo; H Landhult; C Roennevig; O Tjernstroem; J Franked; B Nordberg
Original assignee: Asea Ab
Priority date: 1968-12-05
Filing date: 1969-12-04
Publication date: 1971-08-23
Also published as: GB1282057A; CH509687A; DE1960546A1; SE315042B; DE1960546B2

Description

Fullmektig: Siv.ing. Joh. C. Holst. Authorized representative: Siv.ing. Joh. C. Holst.

Direkte kjølt elektrisk leder for væskekjølt vikling. Direct cooled electrical conductor for liquid cooled winding.

Foreliggende oppfinnelse angår en for en væskekjblt vikling beregnet direkte kjblt elektrisk leder som inneholder et av en lederskinne omsluttet og i dennes lengderetning anordnet kjolerbr, samt en fremgangsmåte for fremstilling av en slik leder. The present invention relates to a direct-heated electric conductor intended for a liquid-cooled winding which contains a conductor rail enclosed by a conductor rail and arranged in its longitudinal direction, as well as a method for producing such a conductor.

Ved vannkjblte elektriske maskiner, ovner, magnetspoler for akseleratorer med meget mer anvendes ofte hulledere av kobber hvor kjblevannet kommer i direkte kontakt med kobberet. For water-cooled electrical machines, ovens, magnet coils for accelerators and much more, hollow copper conductors are often used where the cooling water comes into direct contact with the copper.

Dette forer til at den tillatte vannhastighet blir liten på grunn av risikoen for erosjon. Videre foreligger stor risiko for ero-sjonskorosjon på grunn av elektrolyse. Ved skjoting av slike ledere er man vanligvis henvist til lodding med derav fblgende risiko for lekkasje i skjbtene. 0This leads to the permitted water velocity being small due to the risk of erosion. Furthermore, there is a great risk of erosion corrosion due to electrolysis. When splicing such conductors, you are usually referred to soldering, with the resulting risk of leakage in the joints. 0

For å unngå disse ulemper er det utviklet en framgangsmåte, ifblge hvilken et rustfritt ror legges mellom to halvdeler i en delt In order to avoid these disadvantages, a procedure has been developed, according to which a stainless rudder is placed between two halves in a divided

leder. manager.

Denne fremgangsmåte er fullt godtagbar ved nå vanligvis forekommende strdmtettheter i lederen. This method is fully acceptable for current densities in the conductor that are now usually present.

Ved laboratorieundersøkelser utfort i forbindelse med det utviklingsarbeide som har fort frem til oppfinnelsen, har man imidlertid kunnet konstatere at en med kjolerbr forsynt og ifdlge ovennevnte fremgangsmåte fremstilt leder ikke er tilfredsstillende ved de ekstreme strbmtettheter som er'aktuelle i visse forbindelser, fremfor alt i dempningsv ik1 inger for asynkron start av synkronkompensatorer og motorer for pumpekra ftverk..Ved et modellforsbk med en sterkt strbmbe1 astet lederstav viste det seg at store og helt uregelmessige temperatura vv ike1ser oppsto mellom punkter med forskjellig anbrin-gelse i stavens lengderetning. Man antok at temperaturspissene oppsto på steder, hvor kontakttrykket mellom kjolerbr og leder ikke hadde tilstrekkelig hby verdi. Beregninger viser at nevnte temperaturav-vikelser i det vesentlige er proporsjonale med kvadratet av strøm-tettheten, hvilket innebærer at man ved ekstreme strømtettheter bor rette en skarp oppmerksomhet mot områder med redusert varmeovergang mellom kjolerbr og leder og i mindre grad enn ved hittil kjente direkte kjolte ledere nbye seg med at den gjennomsnittlige varmetran-sport mellom kjolerbr og leder gir en godtagbar middeltemperatur for viklingen. During laboratory investigations carried out in connection with the development work that has led to the invention, it has, however, been possible to establish that a conductor provided with a collar and produced according to the above-mentioned method is not satisfactory at the extreme current densities that are relevant in certain connections, above all in damping In a model test with a highly stressed conductor rod, it was found that large and completely irregular temperature changes occurred between points with different placements in the lengthwise direction of the rod. It was assumed that the temperature spikes occurred in places where the contact pressure between the skirting board and conductor did not have a sufficient hby value. Calculations show that the aforementioned temperature deviations are essentially proportional to the square of the current density, which means that at extreme current densities, one should pay close attention to areas with reduced heat transfer between the jacket and the conductor and to a lesser extent than with previously known direct jackets conductors rely on the fact that the average heat transfer between the sheath and the conductor gives an acceptable average temperature for the winding.

En direkte kjolt leder ifblge oppfinnelsen utmerker seg ved at lederskinnen langs en overveiende del av viklingens totale lederlengde er utfort med et sammenhengende og udelt tverrsnitt og at kjblerbret er ekspandert for å danne varmeledende kontakt med lederens innvendige overflate. A direct sheathed conductor according to the invention is distinguished by the fact that the conductor rail along a predominantly part of the winding's total conductor length is extended with a continuous and undivided cross-section and that the cable strip is expanded to form heat-conducting contact with the conductor's inner surface.

En fremgangsmåte ifblge oppfinnelsen utmerker seg ved at et kjolerbr av et materiale, hvor forholdet strekkgrense/elastisitetsmo-dul er mindre enn for 1edermater i a 1et, innfores i aksiell retning i nevnte hulrom, idet kjblerbret er slik dimensjonert at det gir så stor klaring mellom hulrommets vegger og den ytre kjSlerbrf late , at den ved innfbringen anvendte, i kjblerbrets lengderetning virkende kraft, ved en rett lede rstrekning som i det minste er like stor som den lengste rette ledestrekning i nevnte vikling, er mindre enn den trekkraft, ved hvilken den anvendte rbrtype passerer flytegrensen, hvoretter kjblerbret og derved ogsa lederskinnen utsettes for sa stor ekspanderende trykkv i rkning at en vesentlig elastisk deformering av lederskinnen gjenstår når nevnte ekspanderende trykkv i rkning til slutt A method according to the invention is distinguished by the fact that a skirting board made of a material, where the ratio of tensile strength/elasticity modulus is smaller than that of the outer material in the a 1et, is introduced in the axial direction into said cavity, the skirting board being dimensioned in such a way that it provides such a large clearance between the cavity's walls and the outer insulation board, so that the applied force acting in the longitudinal direction of the insulation board during installation, with a straight conductor length that is at least as large as the longest straight conductor length in said winding, is less than the tensile force at which the cable type passes the yield point, after which the cable board and thereby also the conductor rail is exposed to such a large expanding pressure in the impact that a significant elastic deformation of the conductor rail remains when said expanding pressure in the impact finally

bringes til å opphore. brought to opphora.

Mens termisk kontakt mellom 1 edermater i a 1et og kjblerbret for ovennevnte kjente ledere bevirkes ved at to med spor forsynte 1ederha1vde1 er presses mot det mellomliggende kjolerbr, anvender man ifblge oppfinnelsen radielt utover, mot kjblerbrets innerside virkende krefter til dette formål, hvilket innebærer at lederen ikke må være slisset opp. Innleggingen av kjblerbret behbver allikevel ikke med-fbre noe vanskelig arbeidsmoment, fordi det finnes kjblerbrmateriale som foruten å oppfylle kravets angjeldende strekkgrense og elastisi-tetsmodul, samt korosjons- og erosjonsbestandighet, også tåler en betydelig plastisk deformering. Man kan da velge kjolerbr, hvis ytter-dimensjoner i ikke ekspandert tilstand skiller seg såvidt meget fra tilsvarende innvendige diemensjoner av lederskinnen av flere meter lange kjolerbr kan skyves inn i lederskinner med samme lengde uten noen vanskelighet. Hvis man f.eks. av standardiser ingshensyn bnsker å anvende et noe tykkere ror, kan man i stedet trekke kjblerbret inn i lederskinnen, f.eks. ved hjelp av en stålwire. Også i dette tilfelle må man imidlertid ha en forholdsvis stor klaring fordi man ikke kan tillate at i nntrekk ingen medfbrer flytning i kjb1 erormateri a 1et. While thermal contact between 1 surface in the a 1et and cable board for the above-mentioned known conductors is effected by two grooved conductors being pressed against the intermediate cable board, according to the invention forces acting radially outwards, towards the inside of the cable board are applied for this purpose, which means that the conductor does not must be slotted up. However, the insertion of fiberboard does not require any difficult work, because fiberboard material is available which, in addition to meeting the requirement's tensile strength and modulus of elasticity, as well as corrosion and erosion resistance, can also withstand significant plastic deformation. One can then choose skirting boards, whose outer dimensions in the unexpanded state differ very little from the corresponding internal dimensions of the conductor rail. Skirting boards several meters long can be pushed into conductor rails of the same length without any difficulty. If you e.g. for reasons of standardization, if you want to use a somewhat thicker rudder, you can instead pull the cable board into the guide rail, e.g. using a steel wire. In this case too, however, one must have a relatively large clearance because one cannot allow that no draft causes movement in the kjb1 erromaterie a 1et.

Oppfinnelsen skal beskrives nærmere i det fblgende under hen-visning til tegningene, hvor fig. 1 i snitt gjennom lederens senterlinje viser i nn 1 edningsstad iet ved fremstillingen av en direktekjblt leder ifblge oppfinnelsen og fig. 2 og 3 viser samme Ider etter full-fort fremsti 11 ingsprosess i snitt gjennom, hhv. loddrett på lederens senterlinje. The invention will be described in more detail below with reference to the drawings, where fig. 1 in section through the center line of the conductor shows in section 1 the finishing stage in the production of a directly connected conductor according to the invention and fig. 2 and 3 show the same Ider after a full-speed production process in average throughout, respectively. perpendicular to the leader's centerline.

På tegningene betegner 1 en lederskinne av kobber med et sentralt hulrom 2, hvori er anordnet et kjolerbr 3. Ved en fremgangsmåte ifblge oppfinnelsen skyves eller trekkes forst kjblerbret 3 inn i lederskinnen 1. Klaringen mellom kjolerbr bg lederskinne er valgt så stor at den til dette nedvendige kraft ikke utsetter kjblerbret for noen deformering av betydning. Kjblerbret 3 er noe lenger enn lederskinnen og anordnes med begge ender stikkende ut i forhold til denne. Lederskinnen anordnet deretter mellom hbytrykks hy1 se ne 5 og 6, idet kjblerbrsendene omsluttes av disse. Hbytrykkshylsene er festet til en stiv stålplate 4 ved hjelp av skruebolter antydet med strek-trukne linjer 7 og tetter mot kjblerbrets utside ved hjelp av gummi-ringer 8 og elastisk ettergivende ringer 9 av forholdsvis hardt materiale, hvilke er utfort med koniske endeflater. Hylsen 6 er forsynt med luftekanal 10 med stengeskrue 11. Hylsen 5 er tilkoblet en trykk- In the drawings, 1 denotes a conductor rail made of copper with a central cavity 2, in which a skirting board 3 is arranged. In a method according to the invention, first the conductor board 3 is pushed or pulled into the conductor rail 1. The clearance between the skirting board and conductor rail is chosen so large that for this necessary force does not expose the cable tray to any significant deformation. Kjblerbret 3 is somewhat longer than the conductor rail and is arranged with both ends protruding in relation to this. The conductor rail is then arranged between high-pressure heads 5 and 6, as the cable ends are enclosed by these. The high-pressure sleeves are attached to a rigid steel plate 4 by means of screw bolts indicated by dashed lines 7 and seal against the outside of the kiblerboard by means of rubber rings 8 and elastically yielding rings 9 of relatively hard material, which are fitted with conical end faces. Sleeve 6 is provided with air channel 10 with closing screw 11. Sleeve 5 is connected to a pressure

ledning 12, gjennom hivlken et trykkmedium med meget hoyt trykk på line 12, through the plane a pressurized medium with very high pressure

ca. 2000 ato pumpes inn i kjblerbret 3. Det fbrste som da skjer er at kjblerbret 3 ekspanderes på strekningen mellom tetningsr ingene 9 helt til trykket opptas av den innvendige grenseflate av lederskinnen 1. Hvis klaringen til å begynne med er forholdsvis stor, foregår flytning i kjblerbret allerede på dette stadium av ekspansjonen. En ytterligere bkning av trykket medfbrer en elastisk deformering av lederskinnen 1 og tilsvarende bkning av den plastiske deformering av kjblerbret 3. Trykket bkes så meget at en vesentlig elastisk deformering finner sted i lederskinnens ytre lag, hvilket ofte, om enn ikke nodvendigv is , innebærer at flytning oppstår i dets innerste lag. På grunn av det hbye trykk presses kjolerorma ter i a let også inn i mindre groper i lederskinnen og de mot hverandre liggende kontaktfla-ter blir fullstendig kongouente. Deretter reduseres trykket i det innpumpede trykkmedium til 0, hvorved kjb1 erbrtve rrsni11et qg lederskinnens innvendige tverrsnitt reduseres. about. 2000 ato is pumped into the cable tray 3. The first thing that then happens is that the cable tray 3 expands in the section between the sealing rings 9 until the pressure is taken up by the internal boundary surface of the conductor rail 1. If the clearance to begin with is relatively large, movement takes place in the cable tray already at this stage of expansion. A further bending of the pressure causes an elastic deformation of the conductor rail 1 and a corresponding bending of the plastic deformation of the cable board 3. The pressure bends so much that a significant elastic deformation takes place in the outer layer of the conductor rail, which often, although not necessarily, implies that movement occurs in its innermost layer. Due to the high pressure, the wear worms are easily pressed into smaller pits in the conductor rail and the contact surfaces lying against each other become completely congruent. The pressure in the pumped-in pressure medium is then reduced to 0, whereby the internal cross-section of the conductor rail is reduced.

Hvis man forst forestiller seg at de to konsentriske legemer var utfort av samme materiale og at de fikk trekke seg sammen uten å påvirke hverandre, ser man at deres tverrsnittsreduksjoner ville bli like store. Ingen nevneverdig spenning ville da virke i berbr ingsf 1 a-t e n. If one first imagines that the two concentric bodies were made of the same material and that they were allowed to contract without affecting each other, one sees that their cross-sectional reductions would be the same. No appreciable voltage would then act in the bearing 1 a-t e n.

Ved fremstilling av en direkte kjblt leder ifblge oppfinnelsen velges ledermateriale, kjo1erormateri a 1e og anvendt pumpetrykk på en slik måte at den innvendig målte tilbakefjæring av ledertverrsnit-tet ved en uhindret tilbakefjæring blir storre enn tilbakefjæringen fra maksimal dimensjon av kjblerbret når dette trykkbe1 astes ut over flytegrensen. Denne betingelse oppfylles f.eks. hvis man velger kobber som ledermater i a le og rustfritt stål som kjb1erormater ia 1e. When manufacturing a directly coiled conductor according to the invention, the conductor material, cooling element material and applied pump pressure are selected in such a way that the internally measured rebound of the conductor cross-section in the case of an unobstructed rebound is greater than the rebound from the maximum dimension of the coil board when this pressure load is exceeded the yield point. This condition is fulfilled e.g. if one chooses copper as conductor feeder in a le and stainless steel as copper conductor feeder in 1e.

Som nevnt må man regne med at kjblerbret alltid deformeres As mentioned, it must be taken into account that the kibler board is always deformed

ut over flytegrensen hvis klaringen skal være tilstrekkelig stor til å tillate innskyvning av kjblerbret i lederskinnen. Vil man være sik-ker på at man oppnår det maksimalt mulige kontakttrykk mellom kjolerbr og lederskinne, må man sbrge for at sistnevnte under ekspansjonen deformeres helt til begynnende flytning i det innerste laget. Under disse forutsetninger kan man regne med at man alltid oppnår et gjen-stående trykk mellom lederskinne og kjolerbr hvis man velger de res-pektive materialer på en slik måte at den maksimalt oppnåelige elas-tiske strekking pr. lengdeenhet er mindre for kjb1erbrmater i a let enn for ledermateri a let. Denne betingelse kan også uttrykkes på fblgende måte: beyond the yield point if the clearance is to be sufficiently large to allow the cable board to be pushed into the conductor rail. If you want to be sure that you achieve the maximum possible contact pressure between the skirting board and the conductor rail, you must ensure that the latter is deformed during the expansion until it starts to move in the innermost layer. Under these conditions, it can be assumed that a residual pressure is always achieved between the conductor rail and the skirting board if the respective materials are chosen in such a way that the maximum achievable elastic stretching per length unit is smaller for cable materials in a light than for conductor material in a light. This condition can also be expressed in the following way:

Forholdet strekkgrens e/e lastisitetsmodu1 skal være mindre The ratio tensile strength e/e modulus of elasticity 1 must be smaller

for kjd1erormater i a 1 et enn for 1edermater i a 1et. for core feeders in a 1 et than for 1eder feeders in a 1et.

Ved dimensjoneringen av en direkte kjblt leder ifblge oppfinnelsen må man passe seg for å overdrive sin iver for å oppnå så stort kobbertve rrsni11 og så stort kjb1ekana 11verr sn i11 som mulig, fordi hvis man derved kommer til å redusere kjblerbrets veggtykkelse for meget, blir spennkraften mellom lederskinne og kjolerbr så liten at man i virkeligheten bevirker en svekkelse av lederens egenskaper da det jo er åpenbart at kontakttrykket avtar i omtrent samme forhold som veggtykkelsen reduseres. Som et veiledende dimensjoner ingseksempe1 kan nevnes at en kvadratisk lederskinne med en bredde på 18 mm passende kan forsynes med et kjolerbr, hvis ytre diameter er 12 mm og veggtykkelse ér 1 mm. When dimensioning a directly cabled conductor according to the invention, one must be careful not to exaggerate one's eagerness to achieve as large a copper cross section and as large a copper cross section as possible, because if one thereby reduces the wall thickness of the cable board too much, the tension force becomes between conductor rail and skirting board so small that in reality it causes a weakening of the conductor's properties, as it is obvious that the contact pressure decreases in roughly the same ratio as the wall thickness is reduced. As an indicative dimensioning example1, it can be mentioned that a square conductor rail with a width of 18 mm can be suitably provided with a skirt bridge, whose outer diameter is 12 mm and wall thickness is 1 mm.

Ved en fremgangsmåte ifblge oppfinnelsen kan ekspansjon av kjblerbret også bevirkes på annen måte enn beskrevet ovenfor. Man kan f.eks. trekke et antall dorer med bkende dimensjoner gjentatte ganger gjennom roret. Fremgangsmåten gir imidlertid ikke den samme fullkomne forbindelse mellom kontaktflatene som en hydraulisk fremgangsmåte og medfbrer dessuten lett at visse partier av kjblerbret får en utillate-lig stor reduksjon av veggtykkelsen. In a method according to the invention, expansion of the fiberboard can also be effected in a different way than described above. One can e.g. pull a number of dors of varying dimensions repeatedly through the rudder. However, the method does not provide the same perfect connection between the contact surfaces as a hydraulic method and also easily results in certain parts of the boiler board having an impermissibly large reduction in wall thickness.

Videre kan ekspansjon bevirkes ved at en trådformet spreng-ladning anordnes i kjblerbret og antennes når rbrendende i stbrre eller mindre grad er tettet igjen. En slik fremgangsmåte innbærer imidlertid en betydelig fare for sprekkdannelser i kjblerbret. Furthermore, expansion can be effected by placing a wire-shaped explosive charge in the pipe and igniting when the pipe is sealed to a greater or lesser extent. However, such a method entails a significant risk of cracks forming in the plywood.

Claims

1. Directly sheathed electrical conductor for liquid-cooled winding containing a conductor rail (3) enclosed by a conductor rail and extending in its longitudinal direction, characterized in that the conductor rail (1) along a major part of the winding's total conductor length is extended with a continuous and undivided cross-section (fig. 3) and that the boiler tube is expanded to form heat-conducting contact with the inner surface of the conductor.

2. Electrical conductor according to claim 1, characterized in that the contact pressure between the conductor and the skirt is so great that a relative displacement in the longitudinal direction - at least over the longest straight stretches occurring and in case of winding temperature - cannot be caused by a pulling force in the boiler rudder which is below the value at which the type of rudder used passes the yield point.

3. Method for the production of a directly cooled electric conductor for liquid-clad winding comprising the production of an undivided conductor rail (1) with a central cavity (2) in the longitudinal direction of the conductor, which essentially has a constant cross-section, characterized in that a sheath tube ( 3) of a material, where the ratio tensile strength/module of elasticity is smaller than that of the conductor material, is inserted in the axial direction into the said cavity, the skirt being dimensioned in such a way that it provides such a large clearance between the walls of the cavity and the outer skirt surface, that upon insertion applied, in the longitudinal direction of the rudder, the <v>acting force, with a straight conductor stretch that is at least as large as the longest straight conductor stretch in said winding, is less than the pulling force at which the type of rudder used passes the yield point, after which the skirt rudder and thereby also the guide rail are exposed to such a large expanding pressure effect that a significant elastic deformation of the guide rail remains when said expanding pressure effect is finally brought to an end.

4. Method according to claim 3, characterized in that the said expanding pressure effect is caused by the skirt tube arranged in the guide rail being sealed at one end and at the other end a fluid is supplied under very high pressure.