US3812428A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for the measuring of direct current
Assignee: Licentia Patent Verwaltungs GmbH
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Filing: 1972-03-14
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Granted: 1974-05-21
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Expires: 1992-03-14
Abstract
Abstract An apparatus for the potential free measuring of direct current with direct time coding includes a magnetizable core. A premagnetization winding, a measuring winding and an induction winding are wound about the core. The direct current to be measured is fed to the measuring winding. The core can be placed in its saturated state at least partially by the periodically varying current flow in the premagnetization winding. An output voltage is developed by the induction winding as a result of the changing flux density in the core. A differentiating circuit is coupled to the induction winding for differentiating the output voltage thereof to produce a differentiated voltage. An interval determining circuit, operatively arranged to receive the differentiated voltage, determines the time intervals between the zero passages of the differentiated voltage as a measure of the magnitude and direction of the direct current. A method of measuring direct current is also described.
Inventors
- 👤 G Trenkler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:46
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/18; G01R19/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
In an apparatus for the potential free measuring of direct current with direct time coding, the apparatus including a magnetizable core, a premagnetization winding wound about said core which may be placed in its saturation state at least partially by periodically varying current in said premagnetization winding, a measuring winding wound about said core for carrying the direct current to be measured and an induction winding wound about said core for developing an output voltage in response to the changing flux density in said core, the improvement comprising differentiating means coupled to said induction winding and responsive to its output voltage for producing a differentiated voltage therefrom, and interval determining means coupled to said differentiating means and responsive to its differentiated voltage for determining the time intervals of the zero passages of the differentiated voltage as a measure of the magnitude and direction of the direct current to be measured.
Claim 2
Dependent Claim
150 words
In an apparatus for the potential free measuring of direct current with direct time coding, the apparatus including a magnetizable core, a premagnetization winding wound about said core which may be placed in its saturation state at least partially by periodically varying current in said premagnetization winding, a measuring winding wound about said core for carrying the direct current to be measured and an induction winding wound about said core for developing an output voltage in response to the changing flux density in said core, the improvement comprising differentiating means coupled to said induction winding and responsive to its output voltage for producing a differentiated voltage therefrom, and interval determining means coupled to said differentiating means and responsive to its differentiated voltage for determining the time intervals of the zero passages of the differentiated voltage as a measure of the magnitude and direction of the direct current to be measured.
Claim 3
Dependent Claim
70 words
An arrangement as defined in claim 1 wherein said interval determining means responsive to the differentiated voltage includes a square wave producing circuit for producing an output voltage wave which changes from a first value to a second value during zero passages of the differentiated voltage in one direction and from the second value back to the first value during zero passages of the differentiated voltage in the opposite direction.
Claim 4
Dependent Claim
34 words
An arrangement as defined in claim 1 wherein said magnetizable core has a portion along its length of reduced cross section and said induction winding is disposed about said portion of reduced cross section.
Claim 5
Dependent Claim
83 words
An arrangement as defined in claim 1 wherein said interval determining means responsive to the differentiated voltage includes a square wave producing circuit for producing an output voltage wave which changes from a first polarity and given magnitude to the opposite polarity and the same magnitude during zero passages of the differentiated voltage in one direction and from the opposite polarity and given magnitude back to the first polarity and same magnitude during zero passages of the differentiated voltage in the opposite direction.
Claim 6
Dependent Claim
135 words
An arrangement as defined in claim 1 further comprising a second magnetizable core; a second premagnetization winding, said second premagnetization winding being positioned about said second premagnetization core, said first and second premagnetization windings being connected in series with each other in phase opposition; a second measuring winding positioned about said second core, said first and second measuring windings being connected in series with each other; a second inductioN winding, said second induction winding being positioned about said second core; a second differentiating means coupled to said second induction winding and responsive to its output voltage for producing a second differentiated voltage; second interval determining means coupled to said second differentiating means and responsive to its differentiated voltage; and means for connecting the outputs of both said interval determining means in series with each other.
Claim 7
Dependent Claim
20 words
An arrangement as defined in claim 1 further comprising a source of sinusoidal alternating current coupled across said premagnetization winding.
Claim 8
Dependent Claim
20 words
An arrangement as defined in claim 1 further comprising a source of triangular alternating current coupled across said premagnetization winding.
Claim 9
Dependent Claim
22 words
An arrangement as defined in claim 5 further comprising a source of sinusoidal alternating current coupled across said series connected premagnetization windings.
Claim 10
Dependent Claim
22 words
An arrangement as defined in claim 5 further comprising a source of triangular alternating current coupled across said series connected premagnetization windings.
Claim 11
Independent Claim
98 words
A method of determining direct current comprising: supplying a periodically varying current to a premagnetization winding wound about a magnetizable core, feeding the direct current to be measured to a measuring winding wound about the core, inducing a voltage in an induction winding wound about the core as a result of the changing flux density in the core, differentiating the output voltage from the induction coil, and determining the time intervals of the zero passages of the differentiated voltage produced by the preceding step as a measure of the magnitude and direction of the direct current being measured.
Claim 12
Independent Claim
98 words
A method of determining direct current comprising: supplying a periodically varying current to a premagnetization winding wound about a magnetizable core, feeding the direct current to be measured to a measuring winding wound about the core, inducing a voltage in an induction winding wound about the core as a result of the changing flux density in the core, differentiating the output voltage from the induction coil, and determining the time intervals of the zero passages of the differentiated voltage produced by the preceding step as a measure of the magnitude and direction of the direct current being measured.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |