US3815012A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current transformer with active load termination for providing, inter alia, phase angle alteration
Assignee: General Electric Co
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Filing: 1973-03-30
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Granted: 1974-06-04
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Expires: 1993-03-30
Abstract
Abstract The secondary winding of a current transformer is terminated in a virtual or near short circuit condition by an operational amplifier which has connected therewith. Circuit means, such as passive circuit elements, are provided for shifting the phase angle between current in the primary, or the secondary, winding of the current transformer and an output voltage produced by said amplifier in response to current in the secondary winding. The output voltage produced by the amplifier is proportional to the primary, or the secondary, current in the current transformer.
Inventors
- 👤 M Milkovic
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:38
CPC Classifications
G; G01; G01R; G01R15/00; G01R15/14; G01R15/18; G01R15/183
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
113 words
In combination: a current transformer having primary and secondary windings; an operational amplifier having inverting and non-inverting input terminals and an output terminal, said secondary winding being connected between said inverting and noninverting terminals; first and second resistance elements connected in series and forming a first series circuit connected between said inverting terminal and said output terminal; a third resistance element and a capacitance element connected in series and forming a second series circuit, said second series circuit having one end thereof connected between said first and second resistance elements and an opposite end thereof connected to said non-inverting input terminal, said inverting and non-inverting input terminals being at substantially the same potential.
Claim 2
Dependent Claim
113 words
In combination: a current transformer having primary and secondary windings; an operational amplifier having inverting and non-inverting input terminals and an output terminal, said secondary winding being connected between said inverting and noninverting terminals; first and second resistance elements connected in series and forming a first series circuit connected between said inverting terminal and said output terminal; a third resistance element and a capacitance element connected in series and forming a second series circuit, said second series circuit having one end thereof connected between said first and second resistance elements and an opposite end thereof connected to said non-inverting input terminal, said inverting and non-inverting input terminals being at substantially the same potential.
Claim 3
Dependent Claim
30 words
The combination set forth in claim 1 wherein said one and opposite ends of said second series circuit are terminations of said third resistance element and said capacitance element, respectively.
Claim 4
Dependent Claim
81 words
In combination: a current transformer having primary and secondary windings; an operational amplifier having inverting and non-inverting input terminals and an output terminal, said secondary winding being connected between said inverting and non-inverting terminals; first and second resistance elements connected in series and forming a first series circuit connected between said inverting terminal and said output terminal; and, a capacitance element connected in parallel with said second resistance element, said inverting and non-inverting input terminals being at substantially the same potential.
Claim 5
Dependent Claim
81 words
In combination: a current transformer having primary and secondary windings; an operational amplifier having inverting and non-inverting input terminals and an output terminal, said secondary winding being connected between said inverting and non-inverting terminals; first and second resistance elements connected in series and forming a first series circuit connected between said inverting terminal and said output terminal; and, a capacitance element connected in parallel with said second resistance element, said inverting and non-inverting input terminals being at substantially the same potential.
Claim 6
Dependent Claim
32 words
The combination set forth in claim 3 wherein one end of said second resistance element and one end of said capacitance element is connected to said output terminal of said operational amplifier.
Claim 7
Dependent Claim
125 words
In combination: a current transformer having primary and secondary windings; an operational amplifier having inverting and non-inverting input terminals and an output terminal; a first resistance element connected in series between one end of said secondary winding and said inverting input terminal, the opposite end of said secondary winding being connected to said Non-inverting input terminal; a second resistance element having one end thereof connected to said one end of said secondary winding and an opposite end thereof connected to said output terminal; and, a capacitance element having one end thereof connected to said inverting input terminal and the opposite end thereof connected to said output terminal; said one end of said secondary winding being at substantially the same potential as said non-inverting input terminal.
Claim 8
Dependent Claim
125 words
In combination: a current transformer having primary and secondary windings; an operational amplifier having inverting and non-inverting input terminals and an output terminal; a first resistance element connected in series between one end of said secondary winding and said inverting input terminal, the opposite end of said secondary winding being connected to said Non-inverting input terminal; a second resistance element having one end thereof connected to said one end of said secondary winding and an opposite end thereof connected to said output terminal; and, a capacitance element having one end thereof connected to said inverting input terminal and the opposite end thereof connected to said output terminal; said one end of said secondary winding being at substantially the same potential as said non-inverting input terminal.
Claim 9
Dependent Claim
19 words
The combination set forth in claim 5 wherein said first resistance element has a relatively low ohmic resistance value.
Claim 10
Dependent Claim
134 words
In combination: a current transformer having primary and secondary windings adapted for conducting primary and secondary current, respectively; an operational amplifier having inverting and non-inverting input terminals and an output terminal; a resistance element having a relatively low ohmic resistance connected in series between said inverting input terminal and one end of said secondary winding, the other end of said secondary winding being connected to said non-inverting input terminal; and, at least one electrical impedance means coupled between said inverting input terminal and said output terminal so that an output voltage produced by said amplifier between said output terminal said non-inverting terminal thereof is displaced at a phase angle relative to current in said secondary winding, said non-inverting input terminal being at substantially the same potential as said one end of said secondary winding.
Claim 11
Dependent Claim
134 words
In combination: a current transformer having primary and secondary windings adapted for conducting primary and secondary current, respectively; an operational amplifier having inverting and non-inverting input terminals and an output terminal; a resistance element having a relatively low ohmic resistance connected in series between said inverting input terminal and one end of said secondary winding, the other end of said secondary winding being connected to said non-inverting input terminal; and, at least one electrical impedance means coupled between said inverting input terminal and said output terminal so that an output voltage produced by said amplifier between said output terminal said non-inverting terminal thereof is displaced at a phase angle relative to current in said secondary winding, said non-inverting input terminal being at substantially the same potential as said one end of said secondary winding.
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) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |