US3848178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combined power and instrument potential transformer
Assignee: General Electric Co
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Filing: 1971-12-09
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Granted: 1974-11-12
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Expires: 1991-12-09
Abstract
Abstract A potential transformer having a low voltage metering winding and an auxiliary low voltage power winding on a single core with a common primary winding is provided with a current transformer in the auxiliary low voltage power winding that, in turn, develops a voltage across a compensating impedance located in the circuit associated with the low voltage metering winding that is proportional to the current in the auxiliary low voltage power winding for the purpose of compensating the metering winding for load current drop in the primary winding.
Inventors
- 👤 L Marks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:28
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/24; G05F1/32
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
167 words
A combined power and instrument potential transformer comprising a magnetizable core, a single high voltage primary winding on said core having a pair of input terminals, an instrument secondary winding on said core adapted to supply across a pair of output terminals a low voltage proporitonal in magnitude and similar in phase to voltage applied to said input terminals, a power secondary winding on said core having opposite ends connected to a pair of load terminals, a current transformer having a primary winding connected in series circuit relation with said power secondary winding across said load terminals and including a secondary compensating winding, a compensating impedance connected across said secondary compensating winding, and means connecting said conpensating impedance in series circuit relation with said instrument secondary winding between said output terminals, said compensating impedance being so connected that voltage drop thereacross resulting from current in said secondary compensating winding is in aiding voltage relation with voltage induced in said instrument secondary winding by flux in said core.
Claim 2
Dependent Claim
167 words
A combined power and instrument potential transformer comprising a magnetizable core, a single high voltage primary winding on said core having a pair of input terminals, an instrument secondary winding on said core adapted to supply across a pair of output terminals a low voltage proporitonal in magnitude and similar in phase to voltage applied to said input terminals, a power secondary winding on said core having opposite ends connected to a pair of load terminals, a current transformer having a primary winding connected in series circuit relation with said power secondary winding across said load terminals and including a secondary compensating winding, a compensating impedance connected across said secondary compensating winding, and means connecting said conpensating impedance in series circuit relation with said instrument secondary winding between said output terminals, said compensating impedance being so connected that voltage drop thereacross resulting from current in said secondary compensating winding is in aiding voltage relation with voltage induced in said instrument secondary winding by flux in said core.
Claim 3
Dependent Claim
37 words
A transformer according to claim 1 wherein said compensating impedance comprises inductance and resistance connected in series circuit relation and having an impedance ratio substantially the same as the like ratio of primary winding inductance and resistance.
Claim 4
Dependent Claim
60 words
A transformer according to claim 1 wherein said compensating impedance comprises inductance and resistance in series circuit relation and of such magnitude and ratio that the vectorial Sum of voltage induced in said instrument secondary winding and compensating current voltage drop across said impedance is substantially equal in magnitude and opposite in phase to voltage applied to said input terminals.
Claim 5
Dependent Claim
81 words
A transformer according to claim 1 wherein said power secondary winding has an intermediate point connected to a common load terminal, said common load terminal being adapted to supply load current to separate load circuits between said common terminals and each of said pair of load terminals, and wherein said current transformer has two primary windings disposed in aiding magnetic relation and connected respectively between end points of said power secondary winding and one terminal of said pair of load terminals.
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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |