US3857096A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical current leakage detector
Assignee: Individual
•
Filing: 1973-04-05
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Granted: 1974-12-24
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Expires: 1993-04-05
Abstract
Abstract The disclosure describes apparatus for detecting the flow of electrical current in a conductor comprising a primary coil and a secondary coil that are magnetically coupled by a core preferably having a hysteresis coefficient of about 0.138 and a resistivity coefficient of about 1.915 ohms per centimeter. A differential amplifier is connected to the secondary coil in order to detect the flow of current, and means are connected to the differential amplifier output for visually or audibly indicating the detected flow of electrical current.
Inventors
- 👤 L Gregory
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:42
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/145; G01R19/15
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
235 words
A method of detecting the flow of electrical current having a predetermined frequency in a conductor by means of a primary coil, a secondary coil, core means, and a test coil, said method comprising the steps of: placing the test coil around the core means; passing an AC current having substantially the predetermined frequency through the test coil; measuring the flux density and magnetizing force resulting from the passage of the AC current through the test coil to form a hysteresis loop; determining the core loss resulting from the passage of the AC current through the test coil; recording the maximum flux density, Bm, of the hysteresis loop; calculatng the resistivity coefficient, Kr, of the core means by the equation Kr CBm2f2/core loss, where C equals a constant; calculating the permeability, uo, of the core means by dividing Bm by the corresponding magnetizing force indicated by the hysteresis loop; calculating the hysteresis coefficient, KQ, of the core means by the equation KQ (uoCfKr)2/(uoCf)2+Kr2, where C equals a constant; altering the core means until KQ/Kr is 0.03 or greater; connecting the primary coil in series with the conductor; magnetically coupling the secondary coil to the primary coil with the core means; detecting the secondary voltage induced across at least a portion of the secondary coil due to the flow of current in the conductor; and providing an indication when the secondary voltage exceeds a predetermined value.
Claim 2
Independent Claim
235 words
A method of detecting the flow of electrical current having a predetermined frequency in a conductor by means of a primary coil, a secondary coil, core means, and a test coil, said method comprising the steps of: placing the test coil around the core means; passing an AC current having substantially the predetermined frequency through the test coil; measuring the flux density and magnetizing force resulting from the passage of the AC current through the test coil to form a hysteresis loop; determining the core loss resulting from the passage of the AC current through the test coil; recording the maximum flux density, Bm, of the hysteresis loop; calculatng the resistivity coefficient, Kr, of the core means by the equation Kr CBm2f2/core loss, where C equals a constant; calculating the permeability, uo, of the core means by dividing Bm by the corresponding magnetizing force indicated by the hysteresis loop; calculating the hysteresis coefficient, KQ, of the core means by the equation KQ (uoCfKr)2/(uoCf)2+Kr2, where C equals a constant; altering the core means until KQ/Kr is 0.03 or greater; connecting the primary coil in series with the conductor; magnetically coupling the secondary coil to the primary coil with the core means; detecting the secondary voltage induced across at least a portion of the secondary coil due to the flow of current in the conductor; and providing an indication when the secondary voltage exceeds a predetermined value.
Claim 3
Dependent Claim
40 words
A method, as claimed in claim 1, wherein the step of altering the core means comprises the step of altering the core means until the hysteresis coefficient is about 0.138 and the resistivity coefficient is about 1.915 ohms per centimeter.
Claim 4
Dependent Claim
17 words
A method, as claimed in claim 1, wherein the predetermined frequency is about 60 cycles per second.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |