US3714545A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current transformer connection control
Assignee: Compteurs Schlumberger SA
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Filing: 1972-04-18
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Granted: 1973-01-30
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Expires: 1992-04-18
Abstract
Abstract An apparatus for detecting specific conditions in a current transformer during the establishment of a short circuit current and anticipating saturation to prevent the connection of the transformer output to a utilization device. The apparatus include a voltage divider connected to the secondary winding and an integrater connected to integrate a portion of the voltage developed across the divider. The result of the integration is monitored as to direction and magnitude and an output signal is generated which is indicative of both direction and whether or not the magnitude has exceeded a predetermined threshold. This value is used as being representative of the generation of flux in the magnetic circuit. Simultaneously, the sign of the derivative of the current is determined. The signals thus generated are coupled to a circuit which performs the logical decision S A.B + A.C. A signal resulting from this decision inhibits connection of the transformer to the utilization device.
Inventors
- 👤 A Chiffert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:57
CPC Classifications
H; H02; H02H; H02H1/00; H02H1/04; H02H1/046; H02H1/0007; H02H3/00; H02H3/02; H02H3/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
119 words
An apparatus for controlling the connection of a current transformer output to a utilization device comprising the combination of: a current transformer having a secondary winding; means coupled to said transformer secondary winding for producing a first signal representative of the sign of the derivative of the transformer secondary current; means for producing second and third signals representative of the direction and magnitude of flux generating forces in said transformer with regard to a predetermined magnitude threshold at saturation; and logic circuit means for accepting said signals and for producing an inhibiting signal to inhibit the connection of said transformer output to a utilization device whenever the combination of said signals is indicative of an interval of transformer saturation.
Claim 2
Independent Claim
119 words
An apparatus for controlling the connection of a current transformer output to a utilization device comprising the combination of: a current transformer having a secondary winding; means coupled to said transformer secondary winding for producing a first signal representative of the sign of the derivative of the transformer secondary current; means for producing second and third signals representative of the direction and magnitude of flux generating forces in said transformer with regard to a predetermined magnitude threshold at saturation; and logic circuit means for accepting said signals and for producing an inhibiting signal to inhibit the connection of said transformer output to a utilization device whenever the combination of said signals is indicative of an interval of transformer saturation.
Claim 3
Independent Claim
119 words
An apparatus for controlling the connection of a current transformer output to a utilization device comprising the combination of: a current transformer having a secondary winding; means coupled to said transformer secondary winding for producing a first signal representative of the sign of the derivative of the transformer secondary current; means for producing second and third signals representative of the direction and magnitude of flux generating forces in said transformer with regard to a predetermined magnitude threshold at saturation; and logic circuit means for accepting said signals and for producing an inhibiting signal to inhibit the connection of said transformer output to a utilization device whenever the combination of said signals is indicative of an interval of transformer saturation.
Claim 4
Independent Claim
119 words
An apparatus for controlling the connection of a current transformer output to a utilization device comprising the combination of: a current transformer having a secondary winding; means coupled to said transformer secondary winding for producing a first signal representative of the sign of the derivative of the transformer secondary current; means for producing second and third signals representative of the direction and magnitude of flux generating forces in said transformer with regard to a predetermined magnitude threshold at saturation; and logic circuit means for accepting said signals and for producing an inhibiting signal to inhibit the connection of said transformer output to a utilization device whenever the combination of said signals is indicative of an interval of transformer saturation.
Claim 5
Dependent Claim
50 words
An apparatus according to claim 1 wherein said first signal is identified as A, said second and third signal are identified as B and C, respectively, said inhibiting signal is identified as S and said logic circuit means performs the decision operation S A . B + A . C
Claim 6
Dependent Claim
36 words
An apparatus according to claim 1 and further comprising memory circuit means associated with said means for producing said second and third signals, said memory means being operative to retain values of the signals produce thereby.
Claim 7
Dependent Claim
66 words
An apparatus according to claim 3 wherein said memory comprises, in series circuit relationship, an OR circuit, an AND circuit, circuit means connecting the output of said AND circuit to one input of said OR circuit, and circuit means connecting the output of said OR circuit to an input of said AND circuit, said last mentioned means including at least one delay circuit and an inverter.
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) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |