US3904901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary electric machine with super-conducting winding
Assignee: Bpifrance Financement SA
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Filing: 1973-11-02
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Granted: 1975-09-09
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Expires: 1993-11-02
Abstract
Abstract An asynchronous rotary electric machine comprises a stator in which a field coil or inductor of superconducting material rotates. The field coil is in a cryostat rotating with it and has a purely electromagnetic coupling with an electrically conducting and amagnetic rotary assembly comprising a transmission shaft which delivers or receives mechanical power. The rotary assembly may be tubular and contains the cryostat and the field coil.
Inventors
- 👤 Michael Claude Albert Renard
- 👤 Alain Mailfert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:55
CPC Classifications
H; H02; H02K; H02K55/00; H02K55/02; H02K55/04; Y; Y02; Y02E; Y02E40/00; Y02E40/60
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
147 words
An asynchronous rotary electrical machine comprising, in combination: a stator having a normally conducting polyphase winding for providing a rotating field when electric currents circulate therein; a superconducting field winding located in a cryostat enclosure and mounted for rotation within said stator in synchronism with the rotating field of said stator; and a mechanical torque transmission shaft, rotatable with respect to said stator and said field winding, which shaft is purely electromagnetically coupled to said field winding and includes an annular portion located between said field winding and stator winding, said torque transmission shaft comprising a hollow cylinder of high mechanical resistance and low electric conductivity material internally lined with a high electrical conductivity material, said cylinder having internal longitudinal projections which hold the lining and said lining comprising a material selected from the group consisting of copper,, aluminum, aluminum base light alloys and zirconium base alloys.
Claim 2
Dependent Claim
147 words
An asynchronous rotary electrical machine comprising, in combination: a stator having a normally conducting polyphase winding for providing a rotating field when electric currents circulate therein; a superconducting field winding located in a cryostat enclosure and mounted for rotation within said stator in synchronism with the rotating field of said stator; and a mechanical torque transmission shaft, rotatable with respect to said stator and said field winding, which shaft is purely electromagnetically coupled to said field winding and includes an annular portion located between said field winding and stator winding, said torque transmission shaft comprising a hollow cylinder of high mechanical resistance and low electric conductivity material internally lined with a high electrical conductivity material, said cylinder having internal longitudinal projections which hold the lining and said lining comprising a material selected from the group consisting of copper,, aluminum, aluminum base light alloys and zirconium base alloys.
Claim 3
Dependent Claim
69 words
Rotary machine according to claim 1, comprising a closed circuit for cooling the tubular shaft, said circuit comprising means for injecting into the shaft water which forms a film against the inner wall when the shaft rotates, means for collecting the steam or the steam-water spray formed by boiling of the water in contact with the shaft, and means for cooling the water before reinjecting it into the shaft.
Claim 4
Dependent Claim
35 words
Machine according to claim 2, wherein the water cooling means are constituted by a heat exchanger with water supply from a boiler for the production of steam for driving a turbine coupled to the machine.
Claim 5
Dependent Claim
37 words
Machine according to claim 1, wherein the cryostat is constituted by an annular enclosure bounded by two metallic envelopes, the inner envelope being constituted in sufficiently strong manner to serve as a hoop for the field winding.
Claim 6
Dependent Claim
46 words
Machine according to claim 4, wherein the cryostat is extended axially by channeled or ribbed flanges, fixed to a central tube rotating in bearings mounted in the shaft and placed at an axial distance from the winding sufficient for the magnetic field therein to be weak.
Claim 7
Dependent Claim
23 words
Machine according to claim 5 wherein said flanges comprise channeled flanges. 7. Machine according to claim 5 wherein said flanges comprise ribbed flanges.
Claim 8
Dependent Claim
40 words
Machine according to claim 1, wherein the shaft is borne by end bearings placed at an axial distance from the field coil for the electromagnetic field in the bearings to be a small fraction of the field around said coil.
Claim 9
Dependent Claim
28 words
Machine according to claim 8, wherein the tubular shaft is forged in a single part with a solid extension of small diameter, for coupling with a drive turbine.
Claim 10
Dependent Claim
37 words
Machine according to claim 1, wherein the field winding is constituted of a plurality of layers, which extend parallel to the axis of the machine, of superconducting wire, which layers are hooped by spirally wound steel wires.
Claim 11
Dependent Claim
45 words
Machine according to claim 1, wherein the stator is constituted by electrical conductors insulated from one another, the diameter of each conductor being much smaller than skin depth at the working frequency and said conductors being transposed to avoid circulation currents and used in parallel.
Claim 12
Dependent Claim
33 words
Machine according to claim 11, wherein the conductors are twisted into groups containing between 17 and 150 wires, each group constituting a single conductor wound in conventional manner to constitute a stator winding.
Claim 13
Dependent Claim
30 words
Machine according to claim 1, comprising a screen arranged around stator of the machine at a distance therefrom at least equal to five times the radius of said field coil.
Claim 14
Dependent Claim
141 words
An asynchronous rotary electrical machine comprising, in combination: a stator having a polyphase normally conducting winding which comprises cylinders disposed in parallel to the axis and distributed angularly; a superconducting field winding located in a cryostat enclosure and mounted for rotation within said stator in synchronism with the rotating field of said stator; and a mechanical torque transmission shaft rotatable with respect to said stator and said field winding, and formed with electrically conducting means in a portion thereof located between said stator and said field winding; the arrangement of said cylinders of said stator winding being such that they encompass substantially the whole flux of the field winding, each cylinder being constituted so as to compensate for the third harmonic of the inductance reaction field at half the depth of penetration in said electrically conducting portion of the rotary shaft.
Claim 15
Dependent Claim
141 words
An asynchronous rotary electrical machine comprising, in combination: a stator having a polyphase normally conducting winding which comprises cylinders disposed in parallel to the axis and distributed angularly; a superconducting field winding located in a cryostat enclosure and mounted for rotation within said stator in synchronism with the rotating field of said stator; and a mechanical torque transmission shaft rotatable with respect to said stator and said field winding, and formed with electrically conducting means in a portion thereof located between said stator and said field winding; the arrangement of said cylinders of said stator winding being such that they encompass substantially the whole flux of the field winding, each cylinder being constituted so as to compensate for the third harmonic of the inductance reaction field at half the depth of penetration in said electrically conducting portion of the rotary shaft.
Claim 16
Dependent Claim
28 words
Machine according to claim 14, further comprising compensating conductors mounted in series opposition with the cylinders of the stator, and disposed between the cylinders and the rotary shaft.
Claim 17
Dependent Claim
23 words
Machine according to claim 14, wherein each cylinder comprises, over its whole length, a portion devoid of conductors close to the rotary shaft.
Claim 18
Dependent Claim
106 words
Asynchronous rotary electric machine comprising, in combination: a stator having a normally conducting polyphase winding for providing a rotating field when electric currents circulate therein; a superconducting field winding located in a cryostat enclosure and mounted for rotation within said stator in synchronism with the rotating field of said stator; and a mechanical torque transmission shaft rotatable with respect to said stator and said field winding and formed with an annular portion located between said stator winding and field winding, said portion carrying a polyphase winding cooled by circulation of a fluid and connected to sliding external contacts for exchanging electric power with an external circuit.
Claim 19
Dependent Claim
106 words
Asynchronous rotary electric machine comprising, in combination: a stator having a normally conducting polyphase winding for providing a rotating field when electric currents circulate therein; a superconducting field winding located in a cryostat enclosure and mounted for rotation within said stator in synchronism with the rotating field of said stator; and a mechanical torque transmission shaft rotatable with respect to said stator and said field winding and formed with an annular portion located between said stator winding and field winding, said portion carrying a polyphase winding cooled by circulation of a fluid and connected to sliding external contacts for exchanging electric power with an external circuit.
Claim 20
Dependent Claim
29 words
Electrical machine according to claim 17, wherein means connected to the sliding contacts enable the extraction of electrical power from the field winding and to supply it to it.
Claim 21
Dependent Claim
35 words
Electrical machine according to claim 17, wherein the outer wall of the cryostat is of a good electrically conducting material to constitute a damping screen for interfering fields produced by the winding of the stator.
Claim 22
Dependent Claim
23 words
Electrical machine according to claim 17, wherein the shaft is of electrically conducting material and is laminated perpendicular to its axis of rotation.
Claim 23
Dependent Claim
33 words
Machine according to claim 19 comprising means for supplying an energizing current to the field coil during the period of starting up of the machine until it operates at under steady state conditions.
Claim 24
Dependent Claim
30 words
Electrical machine according to claim 21, wherein the means supplying an energizing current are constituted by a direct current generator outside the machine, connected to the latter by sliding contacts.
Claim 25
Dependent Claim
30 words
Electrical machine according to claim 22, comprising a superconducting switch provided with actuating means to close the switch and to short circuit the field coil on itself at steady speed.
Claim 26
Dependent Claim
38 words
Electrical machine according to claim 17 wherein the shaft is fabricated of insulating material at least in the portion thereof subjected to a field rotating at the slip frequency of said shaft with respect to the field winding.
Claim 27
Dependent Claim
35 words
Electrical machine according to claim 10 wherein said layer is separated from the spirally wound steel wires which hoop it by a sheet of electrically insulating material formed with apertures for circulation of cooling liquid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |