US4380045A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thyristor convertor failure detection device
Assignee: Mitsubishi Electric Corp
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Filing: 1981-08-06
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Granted: 1983-04-12
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Expires: 2001-08-06
Abstract
Abstract A failure detection device for a convertor which converts alternating current into a direct current through a plurality of rectifying thyristors. The waveform of the output direct current of the convertor is detected and is supplied to a band-pass filter which selectively passes the harmonic component which has a frequency corresponding to that of the AC voltage source for the convertor. The existence of the component of this frequency is characteristic of an occurrence of a failure within convertor. The amplitude of the component passing through the filter is then detected by a zener diode, and a failure signal is generated when the amplitude exceeds a predetermined level.
Inventors
- 👤 Toshiaki Ishii
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:30
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/10; H02H7/12; H02H7/125; H02H7/1255; H02M; H02M7/00; H02M7/02; H02M7/04; H02M7/12; H02M7/145; H02M7/155
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
164 words
A failure detection device for a convertor circuit which converts alternating current into an output direct current through a plurality of rectifying elements connected between an alternating current voltage source and a direct current load, said failure detection device comprising: waveform detector means for detecting the waveform of said output direct current of said convertor, and for producing a waveform signal corresponding to said waveform; harmonic component detector means connected to said waveform detector means and responsive to said waveform signal for detecting a harmonic component of said waveform, and for producing a harmonic component signal corresponding to said harmonic component, said harmonic component being a harmonic component having a frequency which is characteristic of an occurrence of a failure within said convertor; and amplitude detector means connected to said detector means and responsive to said harmonic component signal for detecting the amplitude of said harmonic component and for producing a failure signal when said amplitude of said harmonic component exceeds a predetermined level.
Claim 2
Dependent Claim
164 words
A failure detection device for a convertor circuit which converts alternating current into an output direct current through a plurality of rectifying elements connected between an alternating current voltage source and a direct current load, said failure detection device comprising: waveform detector means for detecting the waveform of said output direct current of said convertor, and for producing a waveform signal corresponding to said waveform; harmonic component detector means connected to said waveform detector means and responsive to said waveform signal for detecting a harmonic component of said waveform, and for producing a harmonic component signal corresponding to said harmonic component, said harmonic component being a harmonic component having a frequency which is characteristic of an occurrence of a failure within said convertor; and amplitude detector means connected to said detector means and responsive to said harmonic component signal for detecting the amplitude of said harmonic component and for producing a failure signal when said amplitude of said harmonic component exceeds a predetermined level.
Claim 3
Dependent Claim
28 words
A failure detection device as claimed in claim 1, wherein said harmonic component detector means comprises a band-pass filter for selectively passing the harmonic component having said frequency.
Claim 4
Dependent Claim
28 words
A failure detection device as claimed in claim 1 or 2, wherein said frequency of said harmonic component corresponds to the frequency of said alternating current voltage source.
Claim 5
Dependent Claim
41 words
A failure detection device as claimed in claim 1 or 2, wherein said waveform detector means comprises a current transformer coupled to said alternating current voltage source for detecting said alternating current flowing from said voltage source to said convertor circuit.
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) | 1986-04-11 | 1986-10-11 | 1987-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-11 | 1990-10-11 | 1991-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-11 | 1994-10-11 | 1995-04-12 | $7700.00 | Window Closed / Lapsed |