US3423824A - Method for fixing superconducting magnetic coils - Google Patents

Method for fixing superconducting magnetic coils Download PDF

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Publication number
US3423824A
US3423824A US542322A US3423824DA US3423824A US 3423824 A US3423824 A US 3423824A US 542322 A US542322 A US 542322A US 3423824D A US3423824D A US 3423824DA US 3423824 A US3423824 A US 3423824A
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United States
Prior art keywords
coil
wire
fixing
wound
superconducting
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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.)
Expired - Lifetime
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US542322A
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English (en)
Inventor
Louis Weil
Bernard Bonnin
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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Publication of US3423824A publication Critical patent/US3423824A/en
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Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S505/00—Superconductor technology: apparatus, material, process
    • Y10S505/825—Apparatus per se, device per se, or process of making or operating same
    • Y10S505/917—Mechanically manufacturing superconductor
    • Y10S505/924—Making superconductive magnet or coil
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49014—Superconductor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4981—Utilizing transitory attached element or associated separate material
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4998—Combined manufacture including applying or shaping of fluent material

Definitions

  • the present invention relates to a method for fixing superconducting magnetic coils and to coils obtained through said method.
  • the critical currents of superconducting coils have proved to be considerably less than those of uncoiled short samples made of the same wire and submitted to the same tests (externally applied transverse magnetic field).
  • Such a phenomenon is termed current degradation and one usually refers to a so-called degradation factor viz the ratio of the critical current of a given coiled wire to that of a short-sample made of the same wire, the upper limit of said factor being therefore unity.
  • the present invention relates to a fixing method by means of which are obtained superconducting coils having substantially no training and the degradation factor of which is substantially unity, said method consisting in introducing, between the successive turns of a wire in the process of being wound into a coil, a heterogeneous fixing mixture constituted by a granulated material having a Youngs modulus of at least 1l.5 l0 lbs./sq.in. (8,000 kg./mm. in suspension in a material which, whereas it is viscous while said wire is being Wound, is brought to the solid state at very low temperatures.
  • the method according to the present invention it is possible to cause the hard granulated material, which may also be a good thermal conductor, to penetrate deeply into the coil when it is most necessary, which is not possible in the case of conventional fixing methods according to which the fixing step does not take place until the coil is formed' Moreover, if the suspension material used, which is brought to the solid state at very low temperatures, can resume its viscous initial state (in particular through a temperature rise), the method according to the present invention permits to recover the superconducting wire (should, for instance, a breakdown occur), which is most advantageous since superconducting wires are very costly.
  • the present invention also relates to the superconducting magnetic coils obtained through the above method.
  • the granulated material of the heterogeneous impregnating mixture used is preferably a substance both hard and a very good conductor of heat: it may be a hard amorphous substance, for instance crushed glass, but it is preferable to resort to a substance in the crystalline state, e.g. silica sand, alumina in powder form or beryllium oxide.
  • the heat granulated material used must necessarily have a Youngs modulus of at least 1l.5 10 lbs./sq.in. (8,000 kg./mm.
  • the granules used will thus have for instance a diameter of from 1 to 2 mils (25 to 50 microns).
  • the suspension material must both be fluid enough for allowing the addition thereto of the granulated material and have enough consistence to prevent said granulated material from forming a deposit when being applied to the wire. Cup-grease seems to be specially suitable.
  • the fixing materials used to this day have a Youngs modulus not much higher than 1.4)(10 lbs/sq. in. (1,000 kg./mm. which is for instance the case with ice or frozen oils
  • the heterogeneous impregnating mixture according to the invention in view of its hard granules having a high Youngs modulus, enables the superconducting coils to withstand the electromagnetic stresses exerted upon them and which might be the cause of more or less abrupt movements of the coil turns, thus creating flux jumps leading to degradation.
  • the wire used is a niobium-titanium wire, the characteristics of which (when in the state of a short sample) would be plotted, in the figure, as a curve located between curves numbered 1 and 2, depending upon the manufacturing conditions of said wire.
  • a coil having a diameter of 1.2 in. (30 mm.) is made with said wire and, according to the invention, a heterogeneous fixing mixture is introduced between the successive turns of the wire in the process of being wound, said mixture being constituted by siilca sand granules having a diameter of about 1 mil (25 microns) in suspension in cup-grease.
  • the coil thus manufactured is cooled down to the temperature of liquid helium and the tests carried out show that this coil exhibits a critical current which provides a magnetic field of 87,000 oersteds along the coil axis (and of about 88,500 oersteds on the first inner layer of the coil), as shown by curve 3 of the chart, where the log of current in amperes is plotted against magnetic fields in kilo-oersteds, it being assumed that the coil is submitted to an outer magnetic field of 40 kilo-oersteds.
  • Curve 4 and point B correspond to the results obtained with the same coil but with no outer magnetic field.
  • Hatched area C brings out the advantage of the method according to the invention, since it shows that superconducting magnetic coils according to the prior art exhibit degradation factors which never go beyond 0.85.
  • the coils according to the invention show a better stability when undergoing uctuations of the magnetic field.
  • a method for fixing superconducting magnetic coils comprising the step of introducing between the successive turns of a wire in the process of being wound into a coil, a heterogeneous mixture of a high thermally conductive granulated non-metallic material having a Youngs modulus of at least 11.5 lbs/sq. in. (8000 kg./mm. in suspension in a material which is vicous while said wire is being wound and is solid at very low temperatures, said granulated material providing maximum discharge condition for the heat generated during flux jumps within the coil and said material fixing the turns of the magnetic coil.
  • a method for impregnating superconducting magnetic coils consisting in introducing, between the successive turns of a wire in the process of being wound into a coil, a heterogeneous impregnating mixture constituted by a crystalline granulated non-metallic material, the granules of which have a diameter of from 1 to 2 mils, and having a high thermal conductivity and a Youngs modulus of at least 1l.5 10 l bs/sq. in. (8,000 kg./mrn. in suspension in a material which, whereas it is viscous While said wire is being wound, is brought to the solid state at very low temperature.
  • a method for impregnating superconducting magnetic coils consisting in introducing, between the successive turns of a wire in the process of being wound into a coil, a heterogeneous impregnating mixture constituted by a granulated non-metallic material, the granules of which have a diameter of from 1 to 2 mils (25 to microns), and having a Youngs modulus of at least 11.5)(10 lbs/sq. in. (8,000 kg./mm. in suspension in a material which, whereas it is viscous while said wire is being wound,-is brought to the solid state at very low temperature.
  • a method for impregnating superconducting magnetic coils consisting in introducing, between the successive turns of a wire in the process of being wound into a coil, a heterogeneous impregnating mixture constituted by a granulated non-metallic material having a Youngs modulus of at least 11.5 l0 lbs/sq. in. (8,000 kg./mm. in suspension in a material which, at the temperature at which said wire is being wound into a coil, is fluid enough for allowing the addition thereto of said granulated material but has enough consistence to prevent said granulated material from forming a deposit when being applied to said wire, and which is brought to the solid state at very low temperatures.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Manufacture Of Motors, Generators (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
US542322A 1965-04-21 1966-04-13 Method for fixing superconducting magnetic coils Expired - Lifetime US3423824A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR14050A FR1441588A (fr) 1965-04-21 1965-04-21 Procédé d'imprégnation des bobines supraconductrices à l'aide d'un imprégnant hétérogène

Publications (1)

Publication Number Publication Date
US3423824A true US3423824A (en) 1969-01-28

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US542322A Expired - Lifetime US3423824A (en) 1965-04-21 1966-04-13 Method for fixing superconducting magnetic coils

Country Status (7)

Country Link
US (1) US3423824A (forum.php)
BE (1) BE679532A (forum.php)
CH (1) CH455042A (forum.php)
ES (1) ES325730A1 (forum.php)
FR (1) FR1441588A (forum.php)
GB (1) GB1089580A (forum.php)
LU (1) LU50919A1 (forum.php)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2786330B2 (ja) * 1990-11-30 1998-08-13 株式会社日立製作所 超電導マグネットコイル、及び該マグネットコイルに用いる硬化性樹脂組成物

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2167215A (en) * 1937-04-24 1939-07-25 American Mach & Foundry Sponge rubber roller and method of making the same
US2203937A (en) * 1938-05-18 1940-06-11 Barco Corp Method of punching or cutting impregnated fabrics
US2641879A (en) * 1951-07-11 1953-06-16 Internat Glass Company Inc Mounting method
US2841866A (en) * 1954-02-10 1958-07-08 Daystrom Inc Method of forming thin-walled tubing into a desired shape
US2914840A (en) * 1954-12-31 1959-12-01 Micro seconds
US3068533A (en) * 1958-12-08 1962-12-18 Ciba Ltd Method of impregnating and covering electric windings
US3078186A (en) * 1960-07-26 1963-02-19 Westinghouse Electric Corp Ceramic potting composition and method of encapsulating an electrical article therewith
US3243871A (en) * 1963-08-12 1966-04-05 Nat Res Corp Method of making ductile superconductors
US3264713A (en) * 1962-01-30 1966-08-09 Evans J Gregg Method of making memory core structures
US3296684A (en) * 1962-09-24 1967-01-10 Nat Res Corp Method of forming intermetallic superconductors
US3322871A (en) * 1963-08-29 1967-05-30 Rca Corp Method of forming a pattern

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2167215A (en) * 1937-04-24 1939-07-25 American Mach & Foundry Sponge rubber roller and method of making the same
US2203937A (en) * 1938-05-18 1940-06-11 Barco Corp Method of punching or cutting impregnated fabrics
US2641879A (en) * 1951-07-11 1953-06-16 Internat Glass Company Inc Mounting method
US2841866A (en) * 1954-02-10 1958-07-08 Daystrom Inc Method of forming thin-walled tubing into a desired shape
US2914840A (en) * 1954-12-31 1959-12-01 Micro seconds
US3068533A (en) * 1958-12-08 1962-12-18 Ciba Ltd Method of impregnating and covering electric windings
US3078186A (en) * 1960-07-26 1963-02-19 Westinghouse Electric Corp Ceramic potting composition and method of encapsulating an electrical article therewith
US3264713A (en) * 1962-01-30 1966-08-09 Evans J Gregg Method of making memory core structures
US3296684A (en) * 1962-09-24 1967-01-10 Nat Res Corp Method of forming intermetallic superconductors
US3243871A (en) * 1963-08-12 1966-04-05 Nat Res Corp Method of making ductile superconductors
US3322871A (en) * 1963-08-29 1967-05-30 Rca Corp Method of forming a pattern

Also Published As

Publication number Publication date
CH455042A (fr) 1968-04-30
GB1089580A (en) 1967-11-01
FR1441588A (fr) 1966-06-10
ES325730A1 (es) 1967-04-01
BE679532A (forum.php) 1966-09-16
LU50919A1 (forum.php) 1966-06-20

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