US3644766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronous alternating current electrical machines
Assignee: Rolls Royce Power Engineering PLC
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Filing: 1970-08-07
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Granted: 1972-02-22
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Expires: 1990-08-07
Abstract
Abstract A synchronous AC generator has a DC excited superconducting field winding on the rotor and a nonsuperconducting armature winding on the stator. The armature winding is composed of active conductors and of reactance conductors connected in series with the active conductors and disposed in a magnetic shield surrounding the active conductors whereby the magnetic shield required to prevent large fields outside the machine due to the superconducting field winding also serves to provide the reactance necessary in the reactance conductors to limit short circuit currents.
Inventors
- 👤 Austin Hughes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:01
CPC Classifications
H; H02; H02K; H02K55/00; H02K55/02; H02K55/04; H02K19/00; H02K19/16; H02K19/36; Y; Y02; Y02E; Y02E40/00; Y02E40/60
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
110 words
A synchronous alternating current electrical machine comprising a rotor and a stator, a field winding of superconducting material on said rotor, means for supplying direct current to said field winding, means for maintaining said field winding at superconducting temperatures, an armature winding of nonsuperconducting material on said stator, and a magnetic shield on said stator, wherein said stator winding comprises active conductors disposed in a nonmagnetic environment adjacent the rotor, reactance conductors disposed in said magnetic shield, and end connections connecting the reactance conductors and the active conductors in series, said stator comprising nonmagnetic means supporting said active conductors and said magnetic shield surrounding said active conductors and said rotor.
Claim 2
Dependent Claim
110 words
A synchronous alternating current electrical machine comprising a rotor and a stator, a field winding of superconducting material on said rotor, means for supplying direct current to said field winding, means for maintaining said field winding at superconducting temperatures, an armature winding of nonsuperconducting material on said stator, and a magnetic shield on said stator, wherein said stator winding comprises active conductors disposed in a nonmagnetic environment adjacent the rotor, reactance conductors disposed in said magnetic shield, and end connections connecting the reactance conductors and the active conductors in series, said stator comprising nonmagnetic means supporting said active conductors and said magnetic shield surrounding said active conductors and said rotor.
Claim 3
Dependent Claim
36 words
An electrical machine as claimed in claim 1 in which the active and reactance conductors extend generally parallel to the axis of the rotor and the end connections extend in a plane transverse to said axis.
Claim 4
Dependent Claim
18 words
An electrical machine as claimed in claim 1 in which the active conductors form a double layer winding.
Claim 5
Dependent Claim
37 words
An electrical machine as claimed in claim 1 in which the portion of the armature winding formed by the reactance conductors has a number of poles different from that of the portion formed by the active conductors.
Claim 6
Dependent Claim
34 words
An electrical machine as claimed in claim 1 in which the magnetic shield comprises two coaxial cylinders of magnetic laminations having a gap therebetween and the reactance conductors are disposed in the said gap.
Claim 7
Dependent Claim
22 words
An electrical machine as claimed in claim 1 in which the magnetic shield has slots in which the reactance conductors are mounted.
Claim 8
Dependent Claim
94 words
An electrical machine as claimed in claim 1 wherein the armature winding is a three-phase winding, the active conductors extend parallel to the axis of rotation of the rotor and are arranged in pairs to form a double layer winding, the reactance conductors extend parallel to the axis of rotation of the rotor and the end connections are disposed at one end of the armature winding and so connect the active and reactance conductors in series that the portions of the winding formed by the active and reactance conductors have different numbers of poles.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-21 | 1975-08-23 | 1976-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-21 | 1979-08-23 | 1980-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-21 | 1983-08-23 | 1984-02-22 | $7700.00 | Window Closed / Lapsed |