EP0014766A1 - Dispositif d'amenée de courant pour une bobine magnétique supra-conductrice - Google Patents

Dispositif d'amenée de courant pour une bobine magnétique supra-conductrice Download PDF

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Publication number
EP0014766A1
EP0014766A1 EP79105293A EP79105293A EP0014766A1 EP 0014766 A1 EP0014766 A1 EP 0014766A1 EP 79105293 A EP79105293 A EP 79105293A EP 79105293 A EP79105293 A EP 79105293A EP 0014766 A1 EP0014766 A1 EP 0014766A1
Authority
EP
European Patent Office
Prior art keywords
contact part
contact
supply device
power supply
cooled
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP79105293A
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German (de)
English (en)
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EP0014766B1 (fr
Inventor
Hans Hieronymus
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
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Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0014766A1 publication Critical patent/EP0014766A1/fr
Application granted granted Critical
Publication of EP0014766B1 publication Critical patent/EP0014766B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/62—Heating or cooling of contacts

Definitions

  • the invention relates to a power supply device for a superconducting magnet coil cooled by a cryogenic medium, the coil ends of which are to be short-circuited via a continuous current switch, with a separating device per coil end, which has a stationary contact part connected to the respective coil end and also cooled by the cryogenic medium, and a movable part contains a contact part connected to a power supply device and a mechanical actuating device for joining the contact parts with a predetermined contact force or for separating them after the magnetic coil has been short-circuited.
  • Power supply devices are used for feeding current into magnetic coils with frozen superconductors tion required via which an electrical current is supplied to these conductors from a power supply unit located at a higher temperature level, for example at room temperature.
  • the conductors of the magnetic coil are kept at a temperature level below the so-called transition temperature of their superconducting material with the aid of a cryogenic medium, for example with liquid helium. Since this transition temperature of the known superconducting materials is far below room temperature, conductor parts made of electrically normal-conducting material such as copper or aluminum are used to bridge the corresponding temperature differences in the current supply devices. These normally conductive conductor parts are then connected to the superconductors of the magnetic coil at a point which is also kept at a temperature level below the transition temperature of the superconductor material.
  • the power supply device can therefore be provided with a separating device in order to supply electrically and thermally highly conductive conductor parts of the power supply, which are connected to the power supply device to room temperature, during continuous operation of the magnet coil of conductor parts which are in the cryogenic medium separate (see, for example, the magazine "Elektrie", Vol. 19 (1965), No. 4, page 179).
  • a corresponding separating device generally contains a stationary, cold contact part and a movable, warm contact part as well as a mechanical actuating device with which the contact parts are to be joined together with a predetermined contact force or are to be separated from one another after the magnetic coil has been short-circuited.
  • the object of the invention is therefore to provide a power supply device with a separating device in which these difficulties are substantially reduced.
  • the temperature of the connection point to the superconductor should be kept so low immediately after the hot contact part has been joined to the cold contact part that, with appropriate cooling of the supply line parts, there is practically no immediate risk of the superconductor becoming normal.
  • a shape of the cooled contact part which is elongated in the direction of current conduction is to be understood to mean a shape whose length between the contact area and the connection point for the superconductor is substantially greater than its mean extent in directions perpendicular thereto.
  • the advantages of this design of a power supply device are, in particular, that when the contact parts are separated, there is practically no heat introduced into the cryogenic medium via the power supply device, and even when the contact parts are joined together, the heat input is relatively low, since, due to the large mass ratio chosen between hot and cold Contact part can only transfer a correspondingly small amount of heat from the warm to the cold contact part. In addition, this amount of heat does not reach the connected superconducting coil end directly, because the cooled contact part is designed to be relatively elongated and has a predetermined minimum thermal resistance.
  • a temperature gradient advantageously forms over the cold contact part, and the amount of heat transferred to the cold contact part is largely released to the cooling cryogenic medium at its end facing away from the contact area before it connects the connected superconducting medium Can heat coil end.
  • the risk of the superconductor of the magnet coil becoming normally conductive is therefore low.
  • the time until the cold contact part has completely cooled down is also proportional short and is, for example, only a few 10 seconds if the thermal resistance of the cooled contact part per 1000 A to be transmitted is at most 3 K / W.
  • the mass ratio between the warm and cold contact part is advantageously chosen to be very large and is, for example, at least 10: 1.
  • the upper limit of this mass ratio is determined in particular by the mechanical strength of the smaller, warm contact part under the influence of the contact force.
  • the contact force in the closed state of the separating device can advantageously be at least 500 N, preferably at least 1000 N.
  • At least one of the contact surfaces of the two contact parts can be curved, preferably spherical cap-shaped. Under the influence of a relatively large contact force, a low contact resistance between the two contact parts of the separating device is achieved.
  • This contact resistance is particularly low if the mutually facing sides of the contact parts, which consist for example of copper, are each provided with a contact piece made of fine silver.
  • the current supply device can advantageously be associated with a short-circuit switch which is parallel to the continuous current switch and a mechanical actuating device which detects the short circuit depending on the switching state of the contact parts of the disconnecting device switches open when contact parts are joined together and keep closed when contact parts are separated. It is thus prevented that an unintentional or premature opening of the permanent current switch of the excited solenoid coil when the contact parts of the power supply devices have not yet been connected causes damage or even destruction of the permanent current switch and high electrical voltages at the coil ends.
  • a superconducting magnetic coil can be connected to a power supply device, also not shown, which is at room temperature.
  • the magnet coil is located within a cryostat in a bath 2 of a cryogenic medium such as liquid helium, with which the superconducting conductors of the coil are kept below the jump point from the superconducting to the normal conducting state which is characteristic of their superconducting material.
  • the power supply device includes a fixed, substantially in the bath 2 running and thus cooled contact part 3 with an elongated, fully cylindrical component 4 in the current carrying direction, which merges into a disc-shaped, horizontally extending component 7 at its upper end, which projects out of the bath 2 and faces a contact area 5.
  • this disk-shaped component facing the contact area 5 is provided with a contact piece 8 with a flat contact surface 9.
  • a contact piece 8 with a flat contact surface 9 Where the contact portion 5 facing away from the end 10 of the Langge - stretched component 4 of the contact part 3, multiple cooling fins are secured, of which in the illustration of Figure 1, only two vanes 11 and 12 are visible.. According to the cross section shown in FIG. 2 through these cooling vanes, however, further cooling vanes 13 and 14 can also be attached to the lower end 10 of the contact part 3. With the help of the cooling lugs, large cooling of the lower end 10 of the contact part 3 is achieved, so that this end always has at least approximately the temperature of the cryogenic medium in the bath 2. A superconducting end piece 16 of the magnetic coil can therefore advantageously be connected to this end.
  • the fixed position of the cooled contact part 3 is ensured with the aid of a thin-walled, vertically running steel tube 18, the upper end of which is connected to a housing (not shown in the figure) and the lower end of which is connected to a disc-shaped component 7 of the contact part 3 lying outside the bath 2 connected plate 19 is attached.
  • Movable contact part 22 of the power supply device is arranged in the actuating device, not shown in the figure.
  • This contact part contains a likewise fully cylindrical component 23, which is provided at its lower end facing the contact region 5 with a contact piece 24 with a curved, preferably slightly spherically curved contact surface 25.
  • the upper end of the contact part 22 facing away from the contact area 5 is widened to form a disk-shaped component 26, to which an electrical feed line 28 is connected, via which the contact part 22 is connected to the external power supply unit.
  • This supply line consists, for example, of a copper network, the cross section of which is predetermined due to the Joule losses that arise and which is cooled by evaporating helium.
  • This feed line 28 is surrounded concentrically by a thin-walled, rigid steel tube 29 fastened to the outer edge of the disk-shaped component 26, which represents a mechanically fixed connection between the actuating device (not shown in the figure) and the contact part 22.
  • the contact part 22 is advantageously pressed or separated from the contact piece 8 of the fixed, cold contact part 3 with a force of at least 500 N, preferably of at least 1000 N, for example 2000 N.
  • the temperature of the warm contact part 22 can be influenced when pulled up.
  • the components 23 and 26 of the contact part 22 and the components 4 and 7 of the contact part 3 and also the cooling vanes 11 to 14 are advantageously made of a normally conductive, electrically and thermally highly conductive material such as copper.
  • the mass of the lower contact part 3, which is kept at a low temperature by the helium bath 2 is very large in comparison to the upper, movable, warm contact part 22.
  • the mass ratio between these contact parts should be at least 5: 1, preferably at least 10: 1.
  • the upper limit of this ratio is determined by the mechanical stability of the warm contact part 22 under the influence of the predetermined contact force. This measure ensures that when the still warm contact part 22 is joined to the cold contact part 3, a correspondingly limited amount of heat is transferred to the contact part 3.
  • the cold contact part 3 is also designed such that it has a thermal resistance of at least 0.2 K / W, preferably of at least 0.5, per 1000 A of current to be transmitted K / W has.
  • the upper limit of the thermal resistance is mainly determined by the Joule heat generated and the maximum permissible time for the contact part 3 to cool down. Values above 3 K / W, preferably above 1 K / W, per 1000 A current are expediently not exceeded. It is ensured in this way that the contact part 3 is also within a relatively short time, for example less than 1 minute sufficiently cooled with the end connected to the movable contact part 22.
  • the desired thermal resistance of the contact part 3 is achieved with given material properties in that its length l in the vertical direction is at least twice as large as its mean extent in the horizontal direction.
  • the cold contact part 3 therefore contains an elongated, fully cylindrical component 4 with a small horizontal extent a. Due to the additional attached to its lower end 10 cooling lugs 11 to 14 it is ensured that this end 10 is always at least approximately at the temperature of the helium bath 2 with the superconducting end piece 16 of the magnetic coil connected to it.
  • a temperature gradient then forms over the elongated component 4 of the contact part 3 shortly after the two contact parts 3 and 22 have been joined together, which temperature gradient is practically completely reduced again in a relatively short time.
  • a sudden increase in temperature on the conductors of the magnet coil is thus prevented by the thermal resistance of a predetermined size between the joined contact surfaces 9 and 25 on the one hand and the superconducting connection 16 of the magnet coil on the other hand.
  • the contact parts 3 and 22 essentially consist of electrolytic copper with soldered-on contact pieces 8 and 25 made of fine silver.
  • the contact surface 9 is flat, while the contact surface 25 is spherical with a sphere radius of approximately 80 to 100 mm.
  • the mass of the cold contact part 3 including the cooling vanes 11 to 14 is approximately 300 g, while the movable contact part 22 has a mass of approximately 30 g Has.
  • the cooling surface of the cooling vanes is approximately 100 cm 2 , and the thermal resistance between the contact point and the connection point of the superconductor 16 is between 0.5 and 1 K / W. If the warm contact part 22, which is initially at a temperature of approximately 280 to 300 K, is then joined to the cold contact part 3 at the temperature of the helium bath 2 of approximately 4 K, the resulting temperature gradient along the cold contact part 3 builds up about 30 seconds.
  • two current supply devices 30 and 31 are indicated in the form of a longitudinal section, which correspond to the current supply device according to FIG. 1 and which are connected to ends 33 and 34 of a superconducting magnet coil 35. These coil ends 33 and 34 can be electrically short-circuited via a continuous current switch 37.
  • the continuous current switch 37 is a further short-circuit switch 38 connected in parallel, which is connected to the movable contact parts 22 of the current supply devices 30 and 31 by means of a mechanical actuating device 40 only indicated in the figure such that it can only be opened when the contact parts 3 and 22 of the current supply devices are closed is, however, always remains closed immediately before and during a separation of these contact parts. This measure prevents that in the disconnected state of the power supply devices, if a continuous current flows through the coil 35 and the continuous current switch 37, if these switches are accidentally opened, they are damaged or even destroyed and very high electrical voltages occur at the coil ends 33 and 34.

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  • Containers, Films, And Cooling For Superconductive Devices (AREA)
EP79105293A 1979-01-18 1979-12-20 Dispositif d'amenée de courant pour une bobine magnétique supra-conductrice Expired EP0014766B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2901892 1979-01-18
DE19792901892 DE2901892A1 (de) 1979-01-18 1979-01-18 Stromzufuehrungsvorrichtung fuer eine supraleitende magnetspule

Publications (2)

Publication Number Publication Date
EP0014766A1 true EP0014766A1 (fr) 1980-09-03
EP0014766B1 EP0014766B1 (fr) 1983-05-18

Family

ID=6060873

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79105293A Expired EP0014766B1 (fr) 1979-01-18 1979-12-20 Dispositif d'amenée de courant pour une bobine magnétique supra-conductrice

Country Status (3)

Country Link
US (1) US4314123A (fr)
EP (1) EP0014766B1 (fr)
DE (1) DE2901892A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3844053A1 (de) * 1988-12-28 1990-07-05 Calor Emag Elektrizitaets Ag Supraleitungsschalter
US7383688B2 (en) 2004-12-01 2008-06-10 Siemens Atkiengesellschaft Superconducting device having a cryogenic system and a superconducting switch

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4544979A (en) * 1984-03-22 1985-10-01 Cryomagnetics, Inc. Automatic current lead retractor system for superconducting magnets
US5148046A (en) * 1990-10-09 1992-09-15 Wisconsin Alumni Research Foundation Superconductive switching device and method of use
DE19947410A1 (de) * 1999-10-01 2001-04-12 Abb Research Ltd Tieftemperaturvorrichtung
DE10131235C1 (de) * 2001-06-28 2003-01-30 Siemens Ag Stromzuführungsvorrichtung für eine zu kühlende elektrische Gerätschaft mit elektrischer Trenneinrichtung sowie Verwendung der Vorrichtung
DE10324500B3 (de) * 2003-05-26 2004-11-18 Siemens Ag Geregelte kryogene Stromzuführung
DE102004057204B4 (de) 2004-11-26 2012-06-14 Siemens Ag Supraleitungseinrichtung mit Kryosystem und supraleitendem Schalter
US9182464B2 (en) * 2012-07-27 2015-11-10 General Electric Company Retractable current lead
DE102014221013A1 (de) * 2014-10-16 2016-04-21 Siemens Aktiengesellschaft Supraleitende Spuleneinrichtung mit Spulenwicklung und Kontaktstück sowie Verfahren zu deren Herstellung
LU101151B1 (de) 2019-02-25 2020-08-26 Vision Electric Super Conductors Gmbh Übergangsstück, das einen Normalstromleiter mit einem Supraleiter elektrisch leitend verbindet

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3551861A (en) * 1969-07-28 1970-12-29 North American Rockwell Persistent switch means for a superconducting magnet
DE2451949A1 (de) * 1974-10-31 1976-05-20 Fuji Electric Co Ltd Stromzufuehrungsvorrichtung fuer supraleitende einrichtungen
DE2324371C3 (de) * 1973-05-14 1977-10-27 Siemens AG, 1000 Berlin und 8000 München Kurzschlußelement zum Schließen eines supraleitenden Strompfades
DE2707589A1 (de) * 1977-02-22 1978-08-24 Siemens Ag Dauerstromschalter zum kurzschliessen eines supraleitenden magneten

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3278808A (en) * 1962-12-07 1966-10-11 Bell Telephone Labor Inc Superconducting device
GB1163271A (en) * 1965-08-06 1969-09-04 English Electric Co Ltd Circuit Interrupters
US3521207A (en) * 1968-09-27 1970-07-21 Atomic Energy Commission Power supply for superconducting magnet
US3689856A (en) * 1971-09-15 1972-09-05 T Bar Inc Switch having opposed dome and flexible bifurcated contacts
GB1404682A (en) * 1972-01-12 1975-09-03 Oxford Instr Co Ltd Superconducting magnets and leads thereto

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3551861A (en) * 1969-07-28 1970-12-29 North American Rockwell Persistent switch means for a superconducting magnet
DE2324371C3 (de) * 1973-05-14 1977-10-27 Siemens AG, 1000 Berlin und 8000 München Kurzschlußelement zum Schließen eines supraleitenden Strompfades
DE2451949A1 (de) * 1974-10-31 1976-05-20 Fuji Electric Co Ltd Stromzufuehrungsvorrichtung fuer supraleitende einrichtungen
DE2707589A1 (de) * 1977-02-22 1978-08-24 Siemens Ag Dauerstromschalter zum kurzschliessen eines supraleitenden magneten

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
ELEKTRIE, Band 19, Nr. 4, 1965, Berlin, F. LANGE "Supraleiter - Anwendung in der Starkstromtechnik, Teil 2", Seiten 176 bis 182. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3844053A1 (de) * 1988-12-28 1990-07-05 Calor Emag Elektrizitaets Ag Supraleitungsschalter
US7383688B2 (en) 2004-12-01 2008-06-10 Siemens Atkiengesellschaft Superconducting device having a cryogenic system and a superconducting switch

Also Published As

Publication number Publication date
DE2901892A1 (de) 1980-07-31
DE2901892C2 (fr) 1987-07-30
EP0014766B1 (fr) 1983-05-18
US4314123A (en) 1982-02-02

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