US3973185A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for monitoring the inductance of an inductive load to indicate occurrence of a fault
Assignee: General Electric Co
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Filing: 1974-11-13
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Granted: 1976-08-03
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Expires: 1994-11-13
Abstract
Abstract A circuit for monitoring the inductance of an inductive load controlled by phase-operated thyristor devices or similar devices. One embodiment of the invention comprises a first current sensitive device to produce a signal proportional to the current flowing through the load, a voltage sensitive device to produce a signal proportional to the voltage across the load, an inductor driven by the voltage signal and a second current sensitive device for producing a signal proportional to the current flowing through the inductor. The first current signal is then rectified and fed to a voltage divider consisting of five series connected resistors. The second current signal is also rectified and fed to the same voltage divider. A comparator is connected to the aforementioned voltage divider and senses any voltage change on the voltage divider due to a change in the ratio of the second current signal to the first current signal (or the inverse ratio) and thus in effect, senses any change in the impedance of the load.
Inventors
- 👤 John H. Beak
- 👤 Gordon W. Speer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:17
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/10; H02H7/12; G; G01; G01R; G01R27/00; G01R27/02; G01R27/16; G01R31/00; G01R31/50
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
202 words
A circuit for sensing change in the inductance of an inductive load energized from controlled switching means which comprises: a. an inductor; b. first circuit means connected in circuit with the inductive load for generating a voltage proportional to the voltage applied across the inductive load and for applying said generated voltage across said inductor; c. a first current transformer responsive to current flowing through said inductor for generating a first signal proportional to the current flowing through said inductor; d. a second current transformer responsive to the current flowing through said inductive load for generating a second signal proportional to the current flowing through said inductive load; e. means for rectifying said first signal and applying unidirectional voltage proportional to said first signal across a first resistor; f. means for rectifying said second signal and applying unidirectional voltage proportional to said second signal across a second resistor, said first and second resistors being connected in series circuit relation; g. a voltage divider connected across said first and second resistors; and h. indicating means connected between a selected point on said voltage divider and the junction of said first and second resistors for detecting change in the inductance of said inductive load.
Claim 2
Dependent Claim
202 words
A circuit for sensing change in the inductance of an inductive load energized from controlled switching means which comprises: a. an inductor; b. first circuit means connected in circuit with the inductive load for generating a voltage proportional to the voltage applied across the inductive load and for applying said generated voltage across said inductor; c. a first current transformer responsive to current flowing through said inductor for generating a first signal proportional to the current flowing through said inductor; d. a second current transformer responsive to the current flowing through said inductive load for generating a second signal proportional to the current flowing through said inductive load; e. means for rectifying said first signal and applying unidirectional voltage proportional to said first signal across a first resistor; f. means for rectifying said second signal and applying unidirectional voltage proportional to said second signal across a second resistor, said first and second resistors being connected in series circuit relation; g. a voltage divider connected across said first and second resistors; and h. indicating means connected between a selected point on said voltage divider and the junction of said first and second resistors for detecting change in the inductance of said inductive load.
Claim 3
Dependent Claim
70 words
A circuit as recited in claim 1 wherein the first circuit means comprises: a. a first potential transformer having a primary winding connected across the power source; and b. a second potential transformer having a primary winding connected across the control switching means, the secondary windings of said first and second transformers being connected in voltage opposition to provide the voltage proportional to the voltage applied across said inductive load.
References Cited (Backward Citations)
US2808566A
Cited
US2879472A
Cited
US3202877A
Cited
US3281681A
Cited
US3340434A
Cited
US3284705A
Cited
US3519910A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |