US4442480A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective circuit for thyristor controlled systems and thyristor converter embodying such protective circuit
Assignee: United States Department of Energy
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Filing: 1982-02-24
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Granted: 1984-04-10
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Expires: 2002-02-24
Abstract
Abstract A snubber circuit coupled across each thyristor to be gated in a chain of thyristors determines the critical output of a NOR LATCH whenever one snubber circuit could not be charged and discharged under normal gating conditions because of a short failure.
Inventors
- 👤 Francis H. Downhower, Jr.
- 👤 Paul T. Finlayson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:44
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/08; H03K17/081; H03K17/0814; H03K17/08144; H03K17/10; H03K17/105
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
144 words
In an array of thyristors serially connected and sharing a voltage common to said array, the thyristors being controlled independently and selectively for conduction by natural commutation under said common voltage, the provision of: a plurality of capacitor means each associated individually with a corresponding one of said thyristors, said capacitor means being adapted to be charged under said common voltage when the associated thyristor is non-conductive, and adapted to be discharged through the associated thyristor when the latter is turned ON; a like plurality of means responsive to a discharge condition of a corresponding one of said capacitor means for generating a representative pulse; and means responsive to the respective said representative pulses for detecting the absence of at least one of said representative pulses as an indication of thyristor failure under a shorted condition in one of the thyristors of said array.
Claim 2
Dependent Claim
144 words
In an array of thyristors serially connected and sharing a voltage common to said array, the thyristors being controlled independently and selectively for conduction by natural commutation under said common voltage, the provision of: a plurality of capacitor means each associated individually with a corresponding one of said thyristors, said capacitor means being adapted to be charged under said common voltage when the associated thyristor is non-conductive, and adapted to be discharged through the associated thyristor when the latter is turned ON; a like plurality of means responsive to a discharge condition of a corresponding one of said capacitor means for generating a representative pulse; and means responsive to the respective said representative pulses for detecting the absence of at least one of said representative pulses as an indication of thyristor failure under a shorted condition in one of the thyristors of said array.
Claim 3
Dependent Claim
14 words
The thyristor array of claim 1, with said detecting means being digital in nature.
Claim 4
Dependent Claim
97 words
The thyristor array of claim 2, with each said representative pulse generating means being a pulse transformer having a primary for passing the discharge of the associated capacitor means, and a secondary for generating a corresponding voltage signal; said digital detecting means including a plurality of A/D converters each associated with a corresponding one of said transformer secondaries; a NOR device coupled to all of said A/D converters; and means being provided responsive to said NOR device when said NOR device is in a critical condition indicative of a short thyristor failure for indicating such critical condition.
References Cited (Backward Citations)
US3593038A
Cited
US3623054A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-10 | 1987-10-10 | 1988-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-10 | 1991-10-10 | 1992-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-10 | 1995-10-10 | 1996-04-10 | $7700.00 | Window Closed / Lapsed |