Patent US3588689A successfully refreshed from Google Patents.
US3588689A
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US
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Variable impedance system for electrical cable fault locating and temperature monitoring
Assignee: Individual
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Filing: 1969-06-16
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Granted: 1971-06-28
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Expires: 1989-06-16
Abstract
Abstract AN APPARATUS IS DISCLOSED COMPRISING SENSORS MADE OF STRIP CONDUCTORS CONVERED WITH A NONCONDUCTING THERMOPLASTIC ENVELOPE WHICH ARE WRAPPED HELICALLY AROUND THE OUTSIDE METALLIC SHIELDING TAPE OF AN INSULATED CONDUCTOR OF A PIPE-TYPE CABLE SO AS TO PROVIDE, IN COOPERATION WITH SUCH APE, A UNIFORM CAPACITANCE PER UNIT LENGTH OF CABLE, AS WELL AS A UNIFORM RESISTANCE PER UNIT LENGTH. UPON OCCURRENCE OF A FAULT, A SENSOR IS EITHER OPEN CIRCUITED OR CAUSED TO CONTACT THE SHIELDING TAPE BY THE ENERGY DISSIPATED AT THE FAULT. A CALIBRATED BRIDGE MEASUREMENT OF THE EFFECTIVE CAPACITANCE OR RESISTANCE REVEALS THE DISTANCE TO AND LOCATION OF THE FAULT. D R A W I N G
Inventors
- 👤 Harry F Crawford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:34
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/16; G01M3/18; G01M3/181; G01R; G01R31/00; G01R31/08
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) | 1974-06-27 | 1974-12-27 | 1975-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-27 | 1978-12-27 | 1979-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-27 | 1982-12-27 | 1983-06-28 | $7700.00 | Window Closed / Lapsed |