US4234846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods of eliminating conversion factor drift effects in a clip-on hall-effect ammeter
Assignee: Siemens AG
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Filing: 1978-07-27
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Granted: 1980-11-18
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Expires: 1998-07-27
Abstract
Abstract A clip-on ammeter includes a magnetic frame, which is designed as a clamp and accommodates a winding and a Hall element in an air gap, a reference current source and a commutating switch for connecting the current source to the winding. Methods of operating include taking measurements with reference current flowing in each of the two possible directions in the winding and secondly with reference current flowing to oppose the effect of the current under measurement and with no reference current flowing. The conversion factor is calculated for use in obtaining readings free of conversion factor drift.
Inventors
- 👤 Albert Maringer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:14
CPC Classifications
G; G01; G01R; G01R15/00; G01R15/14; G01R15/20; G01R15/202
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
166 words
A method of operating a clip-on ammeter which includes a magnetic frame in the form of a clamp for enclosing a conductor in which current is to be measured, an air gap in the frame in which a Hall element is disposed for developing a Hall voltage and a winding of w turns on said frame, comprising: (a) enclosing a conductor with said frame; (b) measuring the Hall voltage U H1 of the Hall element; (c) coupling a reference current source establishing a current I ref in said winding to said winding in a direction such as to weaken the magnetic induction caused by the current in said conductor; (d) measuring the Hall voltage U H2 with said reference current source coupled across said winding; (e) forming the difference of the two measurements; and (f) calculating a conversion factor K from said difference, said Hall voltage measurements said number of windings and said current I ref using the equation K=(U H1 -U H2 )/(I ref w).
Claim 2
Independent Claim
166 words
A method of operating a clip-on ammeter which includes a magnetic frame in the form of a clamp for enclosing a conductor in which current is to be measured, an air gap in the frame in which a Hall element is disposed for developing a Hall voltage and a winding of w turns on said frame, comprising: (a) enclosing a conductor with said frame; (b) measuring the Hall voltage U H1 of the Hall element; (c) coupling a reference current source establishing a current I ref in said winding to said winding in a direction such as to weaken the magnetic induction caused by the current in said conductor; (d) measuring the Hall voltage U H2 with said reference current source coupled across said winding; (e) forming the difference of the two measurements; and (f) calculating a conversion factor K from said difference, said Hall voltage measurements said number of windings and said current I ref using the equation K=(U H1 -U H2 )/(I ref w).
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said steps of forming and calculating are performed with a computer.
Claim 4
Independent Claim
168 words
A method of operating a clip-on ammeter which includes a magnetic frame in the form of a clamp for enclosing a conductor in which current is to be measured, an air gap in the frame in which a Hall element is disposed for developing a Hall voltage and a winding of w turns on said frame, comprising: (a) enclosing a conductor with said frame; (b) coupling a reference current source to said winding so as to result in a current I ref in one direction; (c) measuring the Hall voltage U H1 of said Hall element; (d) coupling said reference current source to said winding so as to result in a current I ref in the other direction; (e) measuring the Hall voltage U H2 of said Hall element; (f) forming the difference of said two measurements; and (g) calculating a conversion factor K from said difference, said measurements, said number of windings and said current I ref with the equation K=(U H1 -U H2 )/(2I ref w).
Claim 5
Independent Claim
168 words
A method of operating a clip-on ammeter which includes a magnetic frame in the form of a clamp for enclosing a conductor in which current is to be measured, an air gap in the frame in which a Hall element is disposed for developing a Hall voltage and a winding of w turns on said frame, comprising: (a) enclosing a conductor with said frame; (b) coupling a reference current source to said winding so as to result in a current I ref in one direction; (c) measuring the Hall voltage U H1 of said Hall element; (d) coupling said reference current source to said winding so as to result in a current I ref in the other direction; (e) measuring the Hall voltage U H2 of said Hall element; (f) forming the difference of said two measurements; and (g) calculating a conversion factor K from said difference, said measurements, said number of windings and said current I ref with the equation K=(U H1 -U H2 )/(2I ref w).
Claim 6
Dependent Claim
17 words
The method of claim 3 wherein said steps of forming and calculating are performed with a computer.
References Cited (Backward Citations)
US3050698A
Cited
US4059798A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-18 | 1984-05-19 | 1984-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-18 | 1988-05-19 | 1988-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-18 | 1992-05-19 | 1992-11-18 | $7700.00 | Window Closed / Lapsed |