Patent US4034245A successfully refreshed from Google Patents.
US4034245A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronous electrical machine having a superconductive field winding
Assignee: Bpifrance Financement SA
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Filing: 1975-05-05
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Granted: 1977-07-05
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Expires: 1995-05-05
Abstract
Abstract A synchronous electrical alternator has a superconducting field winding and armature windings. An auxiliary winding is carried by the shaft receiving motive power and a source circulates in the auxiliary winding a D.C. current of such amplitude that it compensates the torque tending to rotate the field winding with respect to the shaft.
Inventors
- 👤 Alain Mailfert
- 👤 Michel Renard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:31
CPC Classifications
H; H02; H02K; H02K55/00; H02K55/02; H02K55/04; Y; Y02; Y02E; Y02E40/00; Y02E40/60; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/876; Y10S505/877; Y10S505/878
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
125 words
A ployphase synchronous electrical machine comprising a superconducting D.C. field winding for providing a rotating, at least bipolar magnetic field, stationary windings adapted to produce a field which rotates about the longitudinal axis of the machine when a polyphase alternating current flows through said windings; means for rotatably supporting said field winding inside said stationary windings coaxially of a rotating torque transmission shaft carrying an auxiliary winding; and an exciting circuit for circulating in the auxiliary winding a field-producing D.C. current and for adjusting said D.C. current delivered by an external source in the auxiliary winding at a value so related to the power component of the current flowing through the stationary windings as to maintain synchronism between the field winding and the auxiliary winding.
Claim 2
Dependent Claim
125 words
A ployphase synchronous electrical machine comprising a superconducting D.C. field winding for providing a rotating, at least bipolar magnetic field, stationary windings adapted to produce a field which rotates about the longitudinal axis of the machine when a polyphase alternating current flows through said windings; means for rotatably supporting said field winding inside said stationary windings coaxially of a rotating torque transmission shaft carrying an auxiliary winding; and an exciting circuit for circulating in the auxiliary winding a field-producing D.C. current and for adjusting said D.C. current delivered by an external source in the auxiliary winding at a value so related to the power component of the current flowing through the stationary windings as to maintain synchronism between the field winding and the auxiliary winding.
Claim 3
Dependent Claim
26 words
A machine according to claim 1, wherein the shaft is hollow and a cryostat in which the field winding is disposed is located inside the shaft.
Claim 4
Dependent Claim
40 words
A machine according to claim 1, having means for flowing water at a temperature near the ambient temperature or a cryogenic liquid at a temperature intermediate the ambient temperature and the temperature of the field winding in the auxiliary winding.
Claim 5
Dependent Claim
27 words
A machine according to claim 1, having an electrical protection and damping screen carried by the shaft and located between the field winding and the stationary windings.
Claim 6
Dependent Claim
37 words
A machine according to claim 4, wherein the field winding is located radially inwardly of the screen, the screen is radially inwardly of the auxiliary winding and the auxiliary winding is radially inwardly of the stationary windings.
Claim 7
Dependent Claim
25 words
A machine according to claim 4, wherein the shaft is formed with radial slots receiving electrical conductors of the auxiliary winding and of the screen.
Claim 8
Dependent Claim
29 words
A machine according to claim 1, wherein the field winding is secured to the shaft by supports which are of reduced mechanical strength and high resistance to heat flow.
Claim 9
Dependent Claim
53 words
A machine according to claim 7, wherein the exciting circuit has means for detecting any torque tending to rotate the field winding relatively to the shaft and means operatively connected to said detecting means for continuously adjusting the current in said auxiliary winding to a value such that said torque is substantially zero.
Claim 10
Dependent Claim
63 words
A machine according to claim 1, wherein the field winding is freely rotatable relatively to the shaft and the exciting circuit has means for adjusting the current in the auxiliary winding to a value such that the angular offset between the auxiliary winding field and the field produced by the field winding does not exceed a predetermined value which is less than 90°.
Claim 11
Dependent Claim
15 words
A machine according to claim 9, characterized in that the predetermined value is about 60°.
Claim 12
Dependent Claim
27 words
A machine according to claim 9, wherein the adjusting means are arranged to alter the auxiliary-winding current when the offset departs from a predetermined range of values.
Claim 13
Dependent Claim
20 words
A machine according to claim 11, characterized in that the adjusting means comprise a stationary detector of the angular offset.
Claim 14
Dependent Claim
20 words
A machine according to claim 1, having a D.C. generator providing current to the field winding at least at starting.
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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) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |