US3568045A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alternating current devices for obtaining a 90 degree phase shift
Assignee: J J LLOYD INSTRUMENTS Ltd
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Filing: 1969-01-17
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Granted: 1971-03-02
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Expires: 1989-01-17
Abstract
Abstract An alternating current device for establishing adjustable currents having a 90* phase shift by which the in phase and quadrature components of an applied AC voltage may be measured. The device includes a variable mutual inductor having an in phase resistor in series with the primary winding of the variable mutual inductor and a quadrature resistor in series with the secondary thereof. The in phase and quadrature components of the applied voltage are measured across these resistors. Precise calibration to compensate for phase error and errors due to fluctuations in frequency are obviated by providing a capacitor in parallel with the in phase resistor. In addition, a shunt resistor may be connected across the in phase resistor to reduce the value of mutual inductance required to induce a given current in the quadrature resistor.
Inventors
- 👤 Robert Yorke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:32
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/18
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
113 words
An alternating current device for establishing adjustable currents having a 90* phase difference in two resistors comprising an ''''in-phase'''' resistor connected in series with a first inductor, a ''''quadrature'''' resistor connected in series with a second inductor, and a capacitor shunted across the ''''inphase'''' resistor, the first inductor forming the primary winding and the second inductor forming the secondary winding of a variable mutual inductor, and the capacitance of the capacitor being selected to correct the phase defect caused in the ''''quadrature'''' resistor by that component of the voltage drop in the second inductor due to the inductance thereof when an alternating current is supplied to the ''''in-phase'''' resistor and the first inductor.
Claim 2
Dependent Claim
113 words
An alternating current device for establishing adjustable currents having a 90* phase difference in two resistors comprising an ''''in-phase'''' resistor connected in series with a first inductor, a ''''quadrature'''' resistor connected in series with a second inductor, and a capacitor shunted across the ''''inphase'''' resistor, the first inductor forming the primary winding and the second inductor forming the secondary winding of a variable mutual inductor, and the capacitance of the capacitor being selected to correct the phase defect caused in the ''''quadrature'''' resistor by that component of the voltage drop in the second inductor due to the inductance thereof when an alternating current is supplied to the ''''in-phase'''' resistor and the first inductor.
Claim 3
Dependent Claim
49 words
A device according to claim 1 wherein the capacitance of the capacitor is + or - 10 percent where L2 is the inductance of the second inductor, R3 the resistance of the ''''in-phase'''' resistor, R2 the resistance of the second inductor, and R4 the resistance of the ''''quadrature'''' resistor.
Claim 4
Dependent Claim
48 words
A device according to claim 2 including an additional resistor shunter across the ''''in-phase'''' resistor thereby reducing the mutual inductance required to induce current in the ''''quadrature'''' resistor, (R3) being considered to be the resistance of the parallel combination of the additional resistor (Rp) and the ''''in-phase'''' resistor.
Claim 5
Dependent Claim
15 words
A device according to claim 3 wherein the inductance of the second inductor is constant.
Claim 6
Dependent Claim
100 words
An alternating potentiometer including an ''''in-phase'''' resistor connected in series with a first inductor, a ''''quadrature'''' resistor connected in series with a second inductor, and a capacitor shunted across the ''''in-phase'''' resistor, the first inductor forming the primary winding and the second inductor forming the secondary winding of a variable mutual inductor, and the capacitance of the capacitor being selected to correct the phase defect caused in the ''''quadrature'''' resistor by that component of the voltage drop in the second inductor due to the inductance thereof when an alternating current is supplied to the ''''in-phase'''' resistor and the first inductor.
Claim 7
Dependent Claim
100 words
An alternating potentiometer including an ''''in-phase'''' resistor connected in series with a first inductor, a ''''quadrature'''' resistor connected in series with a second inductor, and a capacitor shunted across the ''''in-phase'''' resistor, the first inductor forming the primary winding and the second inductor forming the secondary winding of a variable mutual inductor, and the capacitance of the capacitor being selected to correct the phase defect caused in the ''''quadrature'''' resistor by that component of the voltage drop in the second inductor due to the inductance thereof when an alternating current is supplied to the ''''in-phase'''' resistor and the first inductor.
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |