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US3525857A
Expired / Lapsed
US
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Load-frequency control system without proportional windup
Assignee: Leeds and Northrup Co
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Filing: 1968-03-14
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Granted: 1970-08-25
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Expires: 1988-03-14
Abstract
No abstract record available.
Inventors
- 👤 Frederick B Davis
- 👤 Charles W Ross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:03
CPC Classifications
H; H02; H02J; H02J3/00; G; G06; G06G; G06G7/00; G06G7/48; G06G7/62; G06G7/63; G06G7/635; H02J3/11; H02J13/00; H02J13/18; H02J13/181
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2688728A
Cited
US3419772A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-08-24 | 1974-02-23 | 1974-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-08-24 | 1978-02-23 | 1978-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-08-24 | 1982-02-23 | 1982-08-25 | $7700.00 | Window Closed / Lapsed |