US4305785A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensor for detecting changes in magnetic fields
Assignee: United States Department of Energy
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Filing: 1980-02-26
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Granted: 1981-12-15
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Expires: 2000-02-26
Abstract
Abstract A sensor for detecting changes in the magnetic field of the equilibrium-field coil of a Tokamak plasma device comprises a pair of bifilar wires disposed circumferentially, one inside and one outside the equilibrium-field coil. Each is shorted at one end. The difference between the voltages detected at the other ends of the bifilar wires provides a measure of changing flux in the equilibrium-field coil. This difference can be used to detect faults in the coil in time to take action to protect the coil.
Inventors
- 👤 Walter F. Praeg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:56
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/028
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
172 words
A sensor for detecting changes in magnetic flux in an equilibrium-field coil in a Tokamak plasma device comprising: a first bifilar wire disposed inside and parallel to a turn of the equilibrium-field coil in sensing proximity to the equilibrium-field coil; a short circuit applied at a first end of the first bifilar wire across the wires thereof; a second bifilar wire disposed outside and parallel to the turn of the equilibrium-field coil in sensing proximity to the equilibrium-field coil; a short circuit applied at a first end of the second bifilar wire across the wires thereof at a location corresponding to the short circuit at the first end of the first bifilar wire; and control means connected across the wires at a second end of the first bifilar wire and across the wires at a second end of the second bifilar wire to obtain a difference voltage of voltages generated in the first and second bifilar wires, which difference voltage is a measure of change in magnetic flux in the equilibrium-field coil.
Claim 2
Dependent Claim
172 words
A sensor for detecting changes in magnetic flux in an equilibrium-field coil in a Tokamak plasma device comprising: a first bifilar wire disposed inside and parallel to a turn of the equilibrium-field coil in sensing proximity to the equilibrium-field coil; a short circuit applied at a first end of the first bifilar wire across the wires thereof; a second bifilar wire disposed outside and parallel to the turn of the equilibrium-field coil in sensing proximity to the equilibrium-field coil; a short circuit applied at a first end of the second bifilar wire across the wires thereof at a location corresponding to the short circuit at the first end of the first bifilar wire; and control means connected across the wires at a second end of the first bifilar wire and across the wires at a second end of the second bifilar wire to obtain a difference voltage of voltages generated in the first and second bifilar wires, which difference voltage is a measure of change in magnetic flux in the equilibrium-field coil.
Claim 3
Dependent Claim
22 words
The apparatus of claim 1 wherein the first and second bifilar wire extend over substantially a full circumference of the equilibrium-field coil.
Claim 4
Dependent Claim
27 words
The apparatus of claim 1 wherein the first and second bifilar wires extend over a sector that spans less than the full circumference of the equilibrium-field coil.
Claim 5
Independent Claim
78 words
The apparatus of claims 1, 2, or 3 wherein the second end of the first bifilar wire is connected to the second end of the second bifilar wire to form a single sensor responsive to a difference in voltages generated in the two coils, and wherein the control means comprise a voltmeter connected to the sensor to measure the difference in voltages, which difference in voltages is a measure of the change in flux in the equilibrium-field coil.
References Cited (Backward Citations)
US3925724A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-14 | 1985-06-15 | 1985-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-14 | 1989-06-15 | 1989-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-14 | 1993-06-15 | 1993-12-15 | $7700.00 | Window Closed / Lapsed |