US3727129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Logarithmic-response corona detector
Assignee: ABB Inc USA
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Filing: 1971-02-05
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Granted: 1973-04-10
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Expires: 1991-02-05
Abstract
Abstract Apparatus for detecting and measuring corona discharges. A sensing circuit is connected to the apparatus, material or sample which is being tested. The output of the sensing circuit is connected to a detector which converts the corona produced pulse signal from the sensing circuit into a voltage which can be observed. The response of the detector circuit is such that the output voltage thereof is approximately equal to the logarithm of the input voltage produced by the corona discharge. The amplitude of the pulse may be observed by an oscilloscope, a chart recorder, or a meter.
Inventors
- 👤 G Hummert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:59
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/12; G01R31/14; G01R31/50
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
192 words
A logarithmic-response corona pulse detector comprising a logarithmic-response amplifier, a buffer amplifier capacitively coupled to said logarithmic-response ampliFier, a peak detector connected to the output of said buffer amplifier, said peak detector producing an output proportional to the peak of the input to said peak detector, an amplifier driven by the output of said peak detector, the output of said amplifier being suitable for connection to indicating means, said logarithmic-response amplifier comprising a differential input operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, said non-inverting input terminal being grounded, a first diode connected between said inverting input terminal and said output terminal of said operational amplifier, a second diode connected between said inverting input terminal and said output terminal of said operational amplifier, said second diode having its forward conduction direction opposite that of said first diode, means providing a biasing current at said inverting input terminal of said operational amplifier, and a dampening impedance element with one end connected to said inverting input terminal of said operational amplifier and the other end connected to means applying an input signal voltage to said operational amplifier.
Claim 2
Dependent Claim
192 words
A logarithmic-response corona pulse detector comprising a logarithmic-response amplifier, a buffer amplifier capacitively coupled to said logarithmic-response ampliFier, a peak detector connected to the output of said buffer amplifier, said peak detector producing an output proportional to the peak of the input to said peak detector, an amplifier driven by the output of said peak detector, the output of said amplifier being suitable for connection to indicating means, said logarithmic-response amplifier comprising a differential input operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, said non-inverting input terminal being grounded, a first diode connected between said inverting input terminal and said output terminal of said operational amplifier, a second diode connected between said inverting input terminal and said output terminal of said operational amplifier, said second diode having its forward conduction direction opposite that of said first diode, means providing a biasing current at said inverting input terminal of said operational amplifier, and a dampening impedance element with one end connected to said inverting input terminal of said operational amplifier and the other end connected to means applying an input signal voltage to said operational amplifier.
Claim 3
Dependent Claim
63 words
the logarithmic-response corona pulse detector of claim 1 wherein the means providing a biasing current comprises a biasing resistance element and a source of adjustable negative polarity voltage, one end of said biasing resistance element being connected to the inverting terminal of the operational amplifier, and the other end of said biasing resistance element being connected to said adjustable negative polarity voltage source.
Claim 4
Dependent Claim
50 words
The logarithmic-response corona pulse detector of claim 1 wherein the input signal voltage is applied to the dampening impedance element of the logarithmic amplifier, said input signal voltage being developed across a parallel inductor-capacitor circuit connected serially with a high voltage source and a sample being measured for corona discharge.
Claim 5
Dependent Claim
86 words
A device for detecting corona discharge from an electrical inductive apparatus having a bushing, said device comprising the logarithmic-response corona pulse detector of claim 1, a parallel inductor-capacitor circuit having first and second terminals, a first terminal of said parallel inductor-capacitor circuit being connected to the dampening impedance of said detector and also to a point on a capacitive voltage divider circuit of said bushing on said electrical inductive apparatus, the second terminal of said parallel inductor-capacitor circuit being connected to a point at ground potential.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |