US3378728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical protective relay employing phase angle comparators
Assignee: English Electric Co Ltd
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Filing: 1965-04-26
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Granted: 1968-04-16
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Expires: 1985-04-26
Abstract
No abstract record available.
Inventors
- 👤 William Derek Humpage
- 👤 Sudesh Parkash Sabberwal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:20
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/38; H02H3/382; H02H3/40; H02H7/00; H02H7/26; H02H7/30
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-04-16 | 1971-10-16 | 1972-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-04-16 | 1975-10-16 | 1976-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-04-16 | 1979-10-16 | 1980-04-16 | $7700.00 | Window Closed / Lapsed |