Patent US4612500A successfully refreshed from Google Patents.
US4612500A
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US
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Temperature stabilized Faraday rotator current sensor by thermal mechanical means
Assignee: ABB Inc USA
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Filing: 1984-09-04
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Granted: 1986-09-16
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Expires: 2004-09-04
Abstract
Abstract Apparatus for measuring current in a conductor characterized by a magneto-optical current sensor employing the Faraday effect to measure current in a high voltage transmission line. Polarized light having a predetermined plane of polarization is directed into the sensor which plane of polarization is rotated by magnetic field lines generated by the current in the conductor. A bimetal coil rotates the sensor to achieve temperature stability of the current signal in the temperature range of -40° C. to 140° C.
Inventors
- 👤 Cheng-Lin Chen
- 👤 Juris A. Asars
- 👤 Eugene G. Vaerewyck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:12
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/145; G01R19/15; G01R15/00; G01R15/14; G01R15/24; G01R15/245; G01R15/246
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
A device for measuring the current flowing through an electric conductor, comprising: (a) a body of magnetic-optical material disposed within the magnetic field lines of a current-carrying conductor; (b) thermal-mechanical rotator means on the body for rotating the body within the magnetic field lines in response to variations in temperature; (c) polarizing means for directing a beam of polarized light having a predetermined plane of polarization into the body to produce a reflected polarized light beam having a rotated plane of polarization; and (d) analyzer means for detecting the rotated plane of polarization and generating an output signal in response thereto; and (e) electronic circuit means responsive to the output signal of the analyzer means for producing an electronic signal proportional to the current and temperature in the conductor.
Claim 2
Independent Claim
129 words
A device for measuring the current flowing through an electric conductor, comprising: (a) a body of magnetic-optical material disposed within the magnetic field lines of a current-carrying conductor; (b) thermal-mechanical rotator means on the body for rotating the body within the magnetic field lines in response to variations in temperature; (c) polarizing means for directing a beam of polarized light having a predetermined plane of polarization into the body to produce a reflected polarized light beam having a rotated plane of polarization; and (d) analyzer means for detecting the rotated plane of polarization and generating an output signal in response thereto; and (e) electronic circuit means responsive to the output signal of the analyzer means for producing an electronic signal proportional to the current and temperature in the conductor.
Claim 3
Dependent Claim
29 words
The device of claim 1 in which the thermal-mechanical rotation means includes a base and a rotatable member rotatably mounted on the base in response to ambient temperature variations.
Claim 4
Dependent Claim
15 words
The device of claim 2 in which the body is located within the rotatable member.
Claim 5
Dependent Claim
25 words
The device of claim 3 in which the body is comprised of a material selected from the group consisting of Hoya FR5 glasses and quartz.
Claim 6
Dependent Claim
15 words
The device of claim 4 in which the body is comprised of Hoya FR5 glass.
Claim 7
Dependent Claim
15 words
The device of claim 3 in which the thermal-mechanical rotation means includes a bimetallic coil.
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) | 1989-09-15 | 1990-03-17 | 1990-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-15 | 1994-03-17 | 1994-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-15 | 1998-03-17 | 1998-09-16 | $7700.00 | Window Closed / Lapsed |