Patent US4904945A successfully refreshed from Google Patents.
US4904945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and process for detecting direct current magnetic flux deflections in an electrical transformer employing Fourier analysis
Assignee: Mitsubishi Electric Corp
•
Filing: 1988-09-20
•
Granted: 1990-02-27
•
Expires: 2008-09-20
Abstract
Abstract An apparatus for detecting direct current magnetic flux deflection of an electrical transformer comprising a magnetic detector for generating an output voltage waveform and Fourier series developer connected to the magnetic detector for developing the output voltage waveform from the magnetic detector into a Fourier series. An even number harmonic detector is connected to the Fourier series developer for detecting an even number harmonic in the Fourier series, thereby determining the presence of a direct current magnetic flux deflection. A process for detecting direct current magnetic flux deflection is also disclosed.
Inventors
- 👤 Toyokazu Kouan
- 👤 Katsumi Shiono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:56
CPC Classifications
G; G01; G01R; G01R15/00; G01R15/14; G01R15/20; G01R15/207; G01R19/00; G01R19/145; G01R19/15
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
107 words
An apparatus for detecting direct current magnetic flux deflection in an electrical transformer having a magnetic core comprising: a transformer; a magnetic detector disposed within said transformer for detecting the magnetic flux in the transformer and for generating an output voltage waveform in response to the magnetic flux; Fourier series developing means connected to said magnetic detector for developing the output voltage waveform from said magnetic detector into a Fourier series; and an even number harmonic detector connected to said Fourier series developing means for detecting the presence of an even number harmonic in the Fourier series, thereby indicating the presence of direct current magnetic flux deflection.
Claim 2
Independent Claim
107 words
An apparatus for detecting direct current magnetic flux deflection in an electrical transformer having a magnetic core comprising: a transformer; a magnetic detector disposed within said transformer for detecting the magnetic flux in the transformer and for generating an output voltage waveform in response to the magnetic flux; Fourier series developing means connected to said magnetic detector for developing the output voltage waveform from said magnetic detector into a Fourier series; and an even number harmonic detector connected to said Fourier series developing means for detecting the presence of an even number harmonic in the Fourier series, thereby indicating the presence of direct current magnetic flux deflection.
Claim 3
Dependent Claim
43 words
An apparatus for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 1 further comprising an integrator connected between said magnetic detector and said Fourier series developing means for integrating the output voltage waveform from said magnetic detector.
Claim 4
Dependent Claim
26 words
An apparatus for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 1 wherein said magnetic detector comprises a search coil.
Claim 5
Dependent Claim
26 words
An apparatus for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 2 wherein said magnetic detector comprises a search coil.
Claim 6
Dependent Claim
26 words
An apparatus for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 1 wherein said magnetic detector comprises a Hall element.
Claim 7
Dependent Claim
26 words
An apparatus for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 2 wherein said magnetic detector comprises a Hall element.
Claim 8
Dependent Claim
80 words
A process for detecting direct current magnetic flux deflection in an electrical transformer comprising disposing a magnetic detector within an electrical transformer having a magnetic core for producing an output voltage waveform in response to magnetic flux generated in the transformer, developing the waveform of the output voltage of said magnetic flux detector into a Fourier series, and detecting direct current magnetic flux deflection in the transformer by detecting the presence in the Fourier series of an even number harmonic.
Claim 9
Dependent Claim
80 words
A process for detecting direct current magnetic flux deflection in an electrical transformer comprising disposing a magnetic detector within an electrical transformer having a magnetic core for producing an output voltage waveform in response to magnetic flux generated in the transformer, developing the waveform of the output voltage of said magnetic flux detector into a Fourier series, and detecting direct current magnetic flux deflection in the transformer by detecting the presence in the Fourier series of an even number harmonic.
Claim 10
Dependent Claim
37 words
A process for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 7 wherein said waveform of the output voltage from said magnetic detector is integrated before developing into a Fourier series.
Claim 11
Dependent Claim
25 words
A process for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 7 wherein said transformer is a shell-type transformer.
Claim 12
Dependent Claim
25 words
A process for detecting direct current magnetic flux deflection of an electrical transformer as claimed in claim 7 wherein said transformer is a core-type transformer.
References Cited (Backward Citations)
US3863109A
Cited
US4027239A
Cited
US4723220A
Cited
US4658213A
Cited
EP0278193A1
Cited
JPH06228353A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-26 | 1993-08-28 | 1994-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-26 | 1997-08-28 | 1998-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-26 | 2001-08-28 | 2002-02-27 | $7700.00 | Window Closed / Lapsed |