US3713003A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fault or leak detector
Assignee: Hydrotech Chemical Corp
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Filing: 1971-02-16
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Granted: 1973-01-23
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Expires: 1991-02-16
Abstract
Abstract A FAULT DETECTOR FOR AN A.C. CIRCUIT INCLUDING AN OSCILLATOR INDUCTIVELY COUPLED TO THE A.C. LINES TO IMPRESS A SIGNAL VOLTAGE RELATIVELY HIGH IN FREQUENCY AND RELATIVELY MUCH LOWER IN VOLTAGE THEREON AND A SENSE CIRCUIT RESPONSIVE TO HIGH FREQUENCY CURRENT IN THE LINE. THIS CURRENT ONLY FLOWS WHEN A LEAK OR FAULT FROM THE LINE TO EARTH IS PRESENT. THE RESULTING SENSE CIRCUIT SIGNAL IS AMPLIFIED AND PASSED THROUGH A PHASE SENSING CIRCUIT TO ELIMINATE STRAY FAULT READINGS AND USED TO TRIP A CIRCUIT INTERRUPTER TO DISCONNECT THE LOAD FROM A.C. POWER.
Inventors
- 👤 R Benham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:58
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/33; H02H3/337; H02H3/16; H02H3/17
Claims Analysis
Total Claims: 0
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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) | 1976-01-23 | 1976-07-24 | 1977-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-23 | 1980-07-24 | 1981-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-23 | 1984-07-24 | 1985-01-23 | $7700.00 | Window Closed / Lapsed |