Patent US3568057A successfully refreshed from Google Patents.
US3568057A
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Phase measurement apparatus incorporating square wave voltage difference compensation
Assignee: Doble Engineering Co
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Filing: 1968-10-24
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Granted: 1971-03-02
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Expires: 1988-10-24
Abstract
Abstract Apparatus for measuring the dielectric quality of electrical insulating oil includes a test cell for receiving the oil. The test cell includes two electrodes of a capacitor and a high value no loss capacitor is connected in series with the test cell, so that a sinusoidal voltage in quadrature with the current through the test cell is produced. A second sinusoidal voltage is provided across a zero phase angle standard resistor. Both sinusoidal voltages are converted to symmetrical square waves and a difference signal is produced by comparing the two square waves. The difference signal is integrated and applied to a meter to provide a direct indication of the loss characteristics of the oil being tested.
Inventors
- 👤 Edmund Povey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:05
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/26; G01R27/2617; G01R27/2623; G01R27/2629; G01R23/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
113 words
In apparatus for the measurement of small differences in phase between two square waves of nearly equal magnitude including subtractor means for generating a difference signal, means for aPplying two square waves to said subtractor means, an integrating circuit, and an indicating circuit connected to said integrating circuit for indicating the difference in phase between said two square waves, the improvements comprising a pair of reverse connected asymmetrically conductive devices connected in series between said subtractor means and said integrating circuit, the magnitude of the voltage required for forward conduction of each said asymmetrically conductive device being greater than the difference between and less than the magnitude of either of said square waves.
Claim 2
Dependent Claim
113 words
In apparatus for the measurement of small differences in phase between two square waves of nearly equal magnitude including subtractor means for generating a difference signal, means for aPplying two square waves to said subtractor means, an integrating circuit, and an indicating circuit connected to said integrating circuit for indicating the difference in phase between said two square waves, the improvements comprising a pair of reverse connected asymmetrically conductive devices connected in series between said subtractor means and said integrating circuit, the magnitude of the voltage required for forward conduction of each said asymmetrically conductive device being greater than the difference between and less than the magnitude of either of said square waves.
Claim 3
Dependent Claim
14 words
The improvement of claim 1 wherein each said asymmetrically conductive device is a diode.
Claim 4
Dependent Claim
27 words
The improvement of claim 1 wherein said subtractor means includes a resistance element and said two square waves are applied at opposite ends of said resistance element.
Claim 5
Dependent Claim
114 words
In apparatus for measuring a phase characteristic of an alternating electric signal, a clipping circuit including a pair of reverse connected asymmetrically conductive devices connected in parallel with one another, means for applying an input signal to said clipping circuit to place one of said asymmetrically conductive devices in forward conducting condition, and an impedance connected in series with said pair of asymmetrically conductive devices, the phase characteristic of said impedance being equal to the phase characteristic of each of said asymmetrically conductive devices when the asymmetrically conductive device is in forward conducting condition so that the output signal of said clipping circuit remains in phase with the input signal to said clipping circuit.
Claim 6
Dependent Claim
114 words
In apparatus for measuring a phase characteristic of an alternating electric signal, a clipping circuit including a pair of reverse connected asymmetrically conductive devices connected in parallel with one another, means for applying an input signal to said clipping circuit to place one of said asymmetrically conductive devices in forward conducting condition, and an impedance connected in series with said pair of asymmetrically conductive devices, the phase characteristic of said impedance being equal to the phase characteristic of each of said asymmetrically conductive devices when the asymmetrically conductive device is in forward conducting condition so that the output signal of said clipping circuit remains in phase with the input signal to said clipping circuit.
Claim 7
Dependent Claim
14 words
The apparatus of claim 4 wherein each said asymmetrically conductive device is a diode.
Claim 8
Dependent Claim
21 words
The apparatus of claim 4 wherein said impedance is a resistive capacitive network connected to the input of said clipping circuit.
References Cited (Backward Citations)
US2923884A
Cited
US3193771A
Cited
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 |