US3301937A - Liquid nitrogen cooled beryllium superconductor - Google Patents

Liquid nitrogen cooled beryllium superconductor Download PDF

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Publication number
US3301937A
US3301937A US408276A US40827664A US3301937A US 3301937 A US3301937 A US 3301937A US 408276 A US408276 A US 408276A US 40827664 A US40827664 A US 40827664A US 3301937 A US3301937 A US 3301937A
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United States
Prior art keywords
beryllium
conductor
liquid nitrogen
cooled
temperature
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Expired - Lifetime
Application number
US408276A
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English (en)
Inventor
Burnier Pierre
Bonmarin Jacques
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Pechiney SA
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Pechiney SA
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/24—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors with channels or ducts for cooling medium between the conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2876—Cooling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F36/00—Transformers with superconductive windings or with windings operating at cryogenic temperature
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/20—Electromagnets; Actuators including electromagnets without armatures
    • H01F7/202—Electromagnets for high magnetic field strength
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/02—Windings characterised by the conductor material
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/22—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors consisting of hollow conductors
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
    • 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
    • Y10S505/884—Conductor
    • Y10S505/885—Cooling, or feeding, circulating, or distributing fluid; in superconductive apparatus
    • Y10S505/886—Cable

Definitions

  • This invention relates to coils, conductors and connectors formed of beryllium and cooled to a temperature below 150 K. for use in electrical devices intended for the production of electrical, magnetic or mechanical energy or for the conversion of electrical energy.
  • the resistivity of the metal is the sum of two independ-' ent terms; the ideal resistivity which corresponds to the inter-action of electrons with the thermal vibrations of the crystalline structure, and the residual resistivity due to the presence of impurities and faults in the structure of the crystalline network.
  • the ideal resistivity can be reduced by reductions in temperature whereas the residual resistivity is, in principle, independent of temperature.
  • the cold-conductor concept has been applied to conductors formed of sodium, copper, or alumium having a high degree of purity and cooled to a temperature of about 20 K. in order to take advantage of the exceptional conductivity of these metals at very low temperatures.
  • FIG. 1 is a graph which relates resistivity P, expressed in microohms-cm., versus absolute temperature for various metals;
  • FIG. 2 is a graph representing the value of the ratio P/P as a function of the absolute temperature for various metals
  • FIG. 3 is a cross-sectional elevational view of an assembly embodying a conductor in accordance with the prac' tice of this invention
  • FIG. 4 is a cross-sectional view of a stator for an alternating current rotary machine embodying the features of this invention
  • FIG. 5 is a cross-sectional view of a coil or winding in a transformer or circuit breaker embodying the features of this invention.
  • FIG. 6 is a diagrammatic illustration of an installation for the use of a cold conductor embodying the features of this invention.
  • beryllium can be used as a cold conductor in a manner to provide for marked improvements in electrical machinery which makes use of cold conductors.
  • Such improvements result from the ability to make use of industrial grades of beryllium and operation of the conductors formed thereof at temperatures even higher than those of liquid hydrogen or neon.' This result is entirely unexpected because beryllium of industrial grade is not particularly pure, and, as shown in FIG. 1, the lowering of the resistivity at very low temperatures is much lesser with beryllium than in the case of copper or aluminum.
  • FIG. 1 which relates the fluctuation in resistivity p, expressed in microohms-cm., for various metals, as a function of absolute temperature, it can be seen that the resistivity of extra pure aluminum, copper and sodium drops in proportion to the temperature from ordinary levels to that of 20 K., for example, which corresponds to the boiling point of hydrogen under atmospheric pressure.
  • the determination of minimum resistivity of the con ductor is not adequate to give an exact idea of the gain in power obtained by machines which make use of cooled conductors. This power gain is partially offset by the necessary expenditure of power for operating the refrigerator, the efficiency of which diminishes as the working temperature is lowered.
  • the refrigerant receives the heat produced by Joules effect in the winding at a temperature T Kelvin, and disperses the heat at a temperature close to the ambient temperature, i.e. approximately 300 K.
  • beryllium of industrial grade offers a ratio of P/P of the order of 0.5 at the temperature of 150 K. and of the order of 0.15 between 6080 K.
  • aluminum for example, containing only 40 parts-per million of impurities, does not reach a ratio of the same magnitude until approximately 25 K. and offers nothing of interest at approximately 80 K.
  • beryllium having impurities present in an amount greater than 0.1% by weight. It contains approximately 1,000 parts per million of beryllium oxide, 90 parts per million of iron, 25 parts per million of aluminum, 2.0 parts per million of silicon, 1(l parts'per million of nickel, 10 parts per million of chromium and 5 parts per million of manganese.
  • liquid nitrogen is relatively inexpensively produced from liquefaction of air and liquid nitrogen in large quantities is currently available at relatively low cost as a by-product in the liquefaction of air to provide liquid oxygen used in the production of steel by oxygen converters.
  • Liquefied nitrogen offers many other advantages over other liquefied gases or refrigerants in that it is relatively low in cost and readily available; it is non-toxic; it is non-corrosive to the conductors, and it is an excellent electrical insulating material. Thermal insulation is much easier to achieve and maintain at the temperatures of liquid nitrogen than at the temperatures of liquid neon or liquid hydrogen.
  • liquid nitrogen at atmospheric pressure is preferred as the refrigerant for use in the practice of this invention
  • other liquid or gaseous refrigerants can be used at pressure above or below atmospheric pressure for cooling beryllium conductors.
  • Example 1 In FIG. 3, illustration is made of a conductor 1 fabricated of beryllium and contained in a heat-insulating sheath.
  • the conductor is intended for the continuous production of magnetic energy to energize a large synchronous machine.
  • the conductor 1 has direct current passing through it, it can be solid, i.e. non-foliated.
  • a longitudinal duct 2 extends through the conductor 1 and liquid nitrogen is circulated through the duct at a pressure within the range of 0.2 to 10 atmospheres absolute.
  • Thermal insulation 3 such 'as aluminized polyethylene-terephthalate reflector screens, is arranged in the space between the two fluid-tight spacedwalls 5 and 6 which is maintained under a vacuum of l0- Torr.
  • Wall 5 is housed in the recess 4 in the machine.
  • Example 2 In FIG. 4, illustration is made of an alternating current rotary machine embodying the features of the present invention.
  • An alternating current is passed through the conductor 17 and the conductor is placed in an alternating magnetic field.
  • the conductor is formed of a stack of thin sheets of beryllium in order to obviate the unfavorable influence of Foucault currents and of the pellicular effect.
  • the conductor could also be made of fine berylium wires insulated one from the other and formed into a cable.
  • Liquid nitrogen is circulated as a refrigerant through conduits 12 arranged externally of the conductor.
  • This assembly is housed within a sheath 16 of insulating or low conductivity material'that is impermeable to liquid nitrogen.
  • the space between the inner sheath 16 and the outer sheath 15, the latter of which is made of similar material, is provided with heat-insulat ing material 13, such as reflector screens, and a very high vacuum is maintained in the space between the two she
  • Example 3 In FIG. 5, illustration is made of a winding 21 consisting of thin sheets of fine wires of beryllium which are insulated one from the other and immersed in liquid nitrogen 22.
  • the winding can be used as a winding of a'transformer to produce a magnetic field or ,as the coils of a circuit breaker for converting alternating electrical energy.
  • the liquid nitrogen 22 functions as the refrigerating medium and as a dielectric medium since it embodies the dielectric properties required for such an application.
  • the assembly ishoused in a double-walled vessel formed of walls 25 and 26 to define a sealed space provided with thermal insulation 23 and maintained under high vacuum.
  • Example 4 In FIG. 6, illustration is made of an installation produced to embody the features of this invention and capable of being used for application of the devices described in the preceding examples.
  • a refrigerant apparatus 7 is adapted to feed the electrical appliance 8 with liquid nitrogen flowing through the heat-insulated interconnecting ducts 9.
  • a pump 11 maintains the desired vacuum in the insulated spaces of the refrigerator 7, the electrical appliance 8 and the ducts 9 and 10.
  • an electrical device which makes use of a cooled conductor
  • the improvement which comprises a conductor formed of beryllium, a fluid impervious wall surrounding the conductor, a liquefied gas circulated in heat exchange relationship with the conductor within the fluid impervious wall, another wall spaced from the said fluid impervious wall to define an open space in between, a thermal insulating material in the space between the walls, and in which the beryllium conductor is cooled to a temperature within the range of 40150 K.
  • An electrical device as claimed in claim 4 in which the liquid nitrogen is maintained at a pressure of 0.2 to 10 atmospheres.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Coils Of Transformers For General Uses (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Particle Accelerators (AREA)
US408276A 1963-11-08 1964-11-02 Liquid nitrogen cooled beryllium superconductor Expired - Lifetime US3301937A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR953119A FR1382328A (fr) 1963-11-08 1963-11-08 Utilisation du béryllium comme conducteur électrique

Publications (1)

Publication Number Publication Date
US3301937A true US3301937A (en) 1967-01-31

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Family Applications (1)

Application Number Title Priority Date Filing Date
US408276A Expired - Lifetime US3301937A (en) 1963-11-08 1964-11-02 Liquid nitrogen cooled beryllium superconductor

Country Status (7)

Country Link
US (1) US3301937A (enrdf_load_stackoverflow)
BE (1) BE655372A (enrdf_load_stackoverflow)
CH (1) CH421268A (enrdf_load_stackoverflow)
DE (1) DE1296229B (enrdf_load_stackoverflow)
FR (1) FR1382328A (enrdf_load_stackoverflow)
GB (1) GB1034165A (enrdf_load_stackoverflow)
SE (1) SE323119B (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3515793A (en) * 1966-12-29 1970-06-02 Comp Generale Electricite Cryogenic polyphase cable
US3675042A (en) * 1968-02-07 1972-07-04 Gulf Oil Corp Apparatus for power transmission utilizing superconductive elements
US4079192A (en) * 1973-06-12 1978-03-14 Bernard Josse Conductor for reducing leakage at high frequencies
US4528609A (en) * 1982-08-23 1985-07-09 Ga Technologies Inc. Method and apparatus for protecting superconducting magnetic energy storage systems during rapid energy dissipation
US4947007A (en) * 1988-11-08 1990-08-07 General Atomics Superconducting transmission line system
US4966886A (en) * 1988-04-01 1990-10-30 Junkosha Co., Ltd. Superconducting cable with continuously porous insulation
US6262375B1 (en) * 1992-09-24 2001-07-17 Electric Power Research Institute, Inc. Room temperature dielectric HTSC cable

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU748918A1 (ru) * 1977-12-26 1980-07-15 Московский Ордена Ленина Энергетический Институт Устройство дл индукционного нагрева

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3515793A (en) * 1966-12-29 1970-06-02 Comp Generale Electricite Cryogenic polyphase cable
US3675042A (en) * 1968-02-07 1972-07-04 Gulf Oil Corp Apparatus for power transmission utilizing superconductive elements
US4079192A (en) * 1973-06-12 1978-03-14 Bernard Josse Conductor for reducing leakage at high frequencies
US4528609A (en) * 1982-08-23 1985-07-09 Ga Technologies Inc. Method and apparatus for protecting superconducting magnetic energy storage systems during rapid energy dissipation
US4966886A (en) * 1988-04-01 1990-10-30 Junkosha Co., Ltd. Superconducting cable with continuously porous insulation
US4947007A (en) * 1988-11-08 1990-08-07 General Atomics Superconducting transmission line system
US6262375B1 (en) * 1992-09-24 2001-07-17 Electric Power Research Institute, Inc. Room temperature dielectric HTSC cable

Also Published As

Publication number Publication date
CH421268A (fr) 1966-09-30
SE323119B (enrdf_load_stackoverflow) 1970-04-27
DE1296229B (de) 1969-05-29
GB1034165A (en) 1966-06-29
BE655372A (enrdf_load_stackoverflow) 1965-05-06
FR1382328A (fr) 1964-12-18

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