US3863148A
Expired / Lapsed
US
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Method and apparatus for measuring the resistance, resistivity or the cross-sectional area of an electrical conductor such as a wire, cable or bar
Assignee: DES CABLES ELECTR SYSTEME BERT
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Filing: 1973-05-04
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Granted: 1975-01-28
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Expires: 1993-05-04
Abstract
Abstract To measure the resistance, resistivity or the cross-sectional area of a conducting cable or the like, a return conductor is connected to a length of the cable to form a loop, a low frequency alternating current of given value is induced in the loop, and the potential difference between two points on said length of cable set at a fixed distance from one another is measured.
Inventors
- 👤 Paul-Henri Fellrath
- 👤 Gerard Lavanchy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:30
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
132 words
A method of making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected section of an elongated electrical conductor comprising the steps of: forming a closed loop current path with a selected section of an elongated electrical conductor; externally inducing an alternating current having a predetermined value into said closed loop independent of a grounded, shortcircuited or floating condition in the remainder of the electrical conductor; said current being externally induced by a toroidal core for a limited period during which the heat produced by it in said elongate conductor cannot influence the precision of the results of the measurement, measuring the potential drop between two points spaced apart a given distance on said selected section; and deriving a selected physical parameter from the measured information.
Claim 2
Independent Claim
132 words
A method of making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected section of an elongated electrical conductor comprising the steps of: forming a closed loop current path with a selected section of an elongated electrical conductor; externally inducing an alternating current having a predetermined value into said closed loop independent of a grounded, shortcircuited or floating condition in the remainder of the electrical conductor; said current being externally induced by a toroidal core for a limited period during which the heat produced by it in said elongate conductor cannot influence the precision of the results of the measurement, measuring the potential drop between two points spaced apart a given distance on said selected section; and deriving a selected physical parameter from the measured information.
Claim 3
Dependent Claim
19 words
A method according to claim 1, in which the measuring cycle is repeated automatically until the results become stable.
Claim 4
Dependent Claim
22 words
A method according to claim 1, in which the current flowing in said elongated conductor is automatically regulated to a predetermined value.
Claim 5
Dependent Claim
41 words
A method according to claim 1, further comprising correcting the measured potential difference, by an electronic correcting device which is sensitive to the temperature of the conductor, to the value it would have at a reference temperature of said elongated conductor.
Claim 6
Dependent Claim
43 words
A method according to claim 1, in which said measured potential difference is compared to a second potential difference which said induced current would produce in a conductor in which the parameters which determine this potential difference are precisely fixed by a simulator.
Claim 7
Dependent Claim
17 words
A method according to claim 5, in which at least one of the potential differences is amplified.
Claim 8
Dependent Claim
44 words
A method according to claim 5, in which said potential differences are rectified by at least one synchronous rectifier, driven by a signal provided by an alternating current source which induces said induced current, to eliminate the influences of parisitic voltages and inductive impedances.
Claim 9
Dependent Claim
21 words
A method according to claim 5, in which said comparison of the two potential differences is made automatically by a ratiometer.
Claim 10
Dependent Claim
24 words
A method according to claim 8, in which the result of said comparison is expressed as a deviation with respect to a nominal value.
Claim 11
Dependent Claim
15 words
A method according to claim 9, in which said result is provided in numeric form.
Claim 12
Independent Claim
130 words
An apparatus for making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected section of an elongated electrical conductor comprising: means defining a closed loop current path with a selected section of an elongated electrical conductor; means for externally inducing an alternating current having a predetermined value into said closed loop independent of a grounded, short-circuited or floating condition in the remainder of the electrical conductor; means for inducing comprising a first toroidal core through which the conductor passes during use and a winding mounted on said toroidal core, means external of said closed loop for measuring the potential drop between two points spaced apart a given distance on said selected section; and means for deriving a selected physical parameter from the measured information.
Claim 13
Independent Claim
130 words
An apparatus for making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected section of an elongated electrical conductor comprising: means defining a closed loop current path with a selected section of an elongated electrical conductor; means for externally inducing an alternating current having a predetermined value into said closed loop independent of a grounded, short-circuited or floating condition in the remainder of the electrical conductor; means for inducing comprising a first toroidal core through which the conductor passes during use and a winding mounted on said toroidal core, means external of said closed loop for measuring the potential drop between two points spaced apart a given distance on said selected section; and means for deriving a selected physical parameter from the measured information.
Claim 14
Dependent Claim
42 words
An apparatus accoRding to claim 11, further comprising means for inducing a measuring voltage in the closed loop proportional to the current induced in the loop comprising a second winding and a second toroidal core surrounding said length of said elongated conductor.
Claim 15
Dependent Claim
13 words
An apparatus according to claim 12, in which each toroidal core is open.
Claim 16
Dependent Claim
20 words
An apparatus according to claim 13, in which each toroidal core is closed by at least one removable pole piece.
Claim 17
Dependent Claim
21 words
An apparatus according to claim 11, comprising means for automatically setting the current induced in said loop at a given value.
Claim 18
Dependent Claim
34 words
An apparatus according to claim 11, comprising electronic means for correcting the measured potential difference to the value it would have had if the temperature of the conductor was equal to a reference temperature.
Claim 19
Dependent Claim
52 words
An apparatus according to claim 16, in which said correcting means comprises a thermometric probe and an automatic thermometric bridge coacting therewith to provide a correction voltage which corrects the measured potential difference to the value it would have had if the temperature of the conductor was equal to a reference temperature.
Claim 20
Dependent Claim
42 words
An apparatus according to claim 11, comprising simulator means for providing a potential difference equal to that which the current induced in said elongate conductor would produce in a conductor in which the parameters which determine this potential difference are precisely fixed.
Claim 21
Dependent Claim
14 words
An apparatus according to claim 11, wherein said means for deriving comprises a ratiometer.
Claim 22
Independent Claim
160 words
A method making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected length of an elongated electrical conductor comprising the steps of: forming a closed loop current path with a selected length of an elongated electrical conductor; externally inducing an alternating current having a predetermined value into said closed loop; measuring the potential drop between two points spaced apart a given distance on said selected length forming a secondary circuit comprising a resistance and inducing an alternating current in this secondary circuit from the alternating current in the loop; measuring the potential drop on the resistance of the secondary loop; correcting at least one of said measured potential drops to a value that it would have if at least one of said physical parameters of the measured electrical conductor and its temperature had a determined value different from its real value; comparing the two potential drops measured and indicating the result of the comparison.
Claim 23
Independent Claim
160 words
A method making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected length of an elongated electrical conductor comprising the steps of: forming a closed loop current path with a selected length of an elongated electrical conductor; externally inducing an alternating current having a predetermined value into said closed loop; measuring the potential drop between two points spaced apart a given distance on said selected length forming a secondary circuit comprising a resistance and inducing an alternating current in this secondary circuit from the alternating current in the loop; measuring the potential drop on the resistance of the secondary loop; correcting at least one of said measured potential drops to a value that it would have if at least one of said physical parameters of the measured electrical conductor and its temperature had a determined value different from its real value; comparing the two potential drops measured and indicating the result of the comparison.
Claim 24
Independent Claim
141 words
An apparatus for making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected length of an elongated electrical conductor comprising: means defining a closed loop current path with a selected length of an elongated electrical conductor; means for externally inducing an alternating current having a predetermined value into said closed loop; means external of closed loop for measuring the potential drop between two points spaced apart a given distance on said selected length means defining a secondary circuit comprising a resistor; means for inducing an alternating current into said secondary circuit from said closed loop; means for introducing at least one correction to at least one of said potential drops; means for comparing the potential drop between said points and the potential drop on said resistor and means for indicating the result of the comparison.
Claim 25
Independent Claim
141 words
An apparatus for making on-line measurements of physical parameters such as resistance, resistivity and cross-sectional area on a selected length of an elongated electrical conductor comprising: means defining a closed loop current path with a selected length of an elongated electrical conductor; means for externally inducing an alternating current having a predetermined value into said closed loop; means external of closed loop for measuring the potential drop between two points spaced apart a given distance on said selected length means defining a secondary circuit comprising a resistor; means for inducing an alternating current into said secondary circuit from said closed loop; means for introducing at least one correction to at least one of said potential drops; means for comparing the potential drop between said points and the potential drop on said resistor and means for indicating the result of the comparison.
References Cited (Backward Citations)
US3417329A
Cited
US3665302A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-27 | 1978-07-29 | 1979-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-27 | 1982-07-29 | 1983-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-27 | 1986-07-29 | 1987-01-28 | $7700.00 | Window Closed / Lapsed |