Patent US42537A successfully refreshed from Google Patents.
Patent US3705331A successfully refreshed from Google Patents.
US3705331A
Expired / Lapsed
US
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Ac generator system including differential protection of exciter
Assignee: Westinghouse Electric Corp
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Filing: 1972-03-16
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Granted: 1972-12-05
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Expires: 1992-03-16
Abstract
Abstract A differential protection system is connected to detect and indicate faults in an exciter by comparing signals developed from the exciter field and from the generator armature. A first signal is developed representing the magnitude of the voltage on the exciter field winding and a second signal is developed representing the vectorial sum of the current and voltage on the armature winding. These signals are compared and a fault indication produced when the magnitude of their difference is at least of a certain value. The differential protection in brushless exciters permits avoiding the use of a fuse in series with each diode of a rotating rectifier.
Inventors
- 👤 William H South
- 👤 Thayer L Dillman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:06
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/06; H02H7/065
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
105 words
An A.C. generator system including differential protection of exciter elements comprising: an alternating current generator having inductively related D.C. field winding and A.C. armature winding; an exciter connected with said field winding of said generator, said exciter having a D.C. field winding; a differential protection system including first means to develop a first signal representing the magnitude of the voltage on said exciter field winding, second means to develop a second signal representing the vectorial sum of the current and voltage of said A.C. armature winding, and third means to produce a third signal representing the difference in magnitude of said first and second signals.
Claim 2
Dependent Claim
105 words
An A.C. generator system including differential protection of exciter elements comprising: an alternating current generator having inductively related D.C. field winding and A.C. armature winding; an exciter connected with said field winding of said generator, said exciter having a D.C. field winding; a differential protection system including first means to develop a first signal representing the magnitude of the voltage on said exciter field winding, second means to develop a second signal representing the vectorial sum of the current and voltage of said A.C. armature winding, and third means to produce a third signal representing the difference in magnitude of said first and second signals.
Claim 3
Dependent Claim
55 words
The subject matter of claim 1 wherein: said first means includes a first resistive impedance of a magnitude to compensate for gain of said exciter; said second means includes a second resistive impedance of a magnitude to compensate for the synchronous reactance of said generator; and said first and second signals are both direct currents.
Claim 4
Dependent Claim
68 words
The subject matter of claim 2 wherein: said third means includes means responsive to a given minimum level of difference between said first and second signals to produce a fault indication, and said third means includes time delay means to limit the response of said responsive means to instances in which said minimum level of difference between said first and second signals endures for a given minimum time.
Claim 5
Dependent Claim
81 words
An A.C. generator system comprising: an alternating current generator having inductively related D.C. field winding and A.C. armature winding; a brushless excitation system including an alternating current exciter and a rotating rectifier assembly, said rotating rectifier being connected with said generator field winding, said exciter having a D.C. field winding and an A.C. armature winding; a differential protection system connected to detect and indicate faults in said exciter by comparing signals developed from said exciter field and from said generator armature.
Claim 6
Dependent Claim
81 words
An A.C. generator system comprising: an alternating current generator having inductively related D.C. field winding and A.C. armature winding; a brushless excitation system including an alternating current exciter and a rotating rectifier assembly, said rotating rectifier being connected with said generator field winding, said exciter having a D.C. field winding and an A.C. armature winding; a differential protection system connected to detect and indicate faults in said exciter by comparing signals developed from said exciter field and from said generator armature.
Claim 7
Dependent Claim
29 words
The subject matter of claim 4 wherein: said rotating rectifier assembly comprises at least one semiconductor diode directly connected between said exciter armature winding and said generator field winding.
Claim 8
Dependent Claim
22 words
The subject matter of claim 5 wherein: the direct connection of said diode to said windings is without any fuse element therein.
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) | 1975-12-05 | 1976-06-05 | 1976-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-05 | 1980-06-05 | 1980-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-05 | 1984-06-05 | 1984-12-05 | $7700.00 | Window Closed / Lapsed |