US4677401A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise filter for three-phase four-wire system
Assignee: FDK Corp
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Filing: 1985-07-16
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Granted: 1987-06-30
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Expires: 2005-07-16
Abstract
Abstract A noise filter for an electric wire of star-connected three-phase four-wire system, in which a neutral conductor has a sectional area which is larger than a sectional area of each of voltage conductors. Three voltage conductors are wound on a magnetic core that constitutes a closed magnetic path. The neutral conductor is coupled to the three voltage conductors via three respective capacitors.
Inventors
- 👤 Masami Nonaka
- 👤 Noboru Kato
- 👤 Kazuhiro Hibi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:50
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/0115; H02; H02M; H02M1/00; H02M1/12
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
89 words
A noise filter for a star-connected three-phase four-wire system comprising: a common coil having a magnetic core which constitutes a closed magnetic path, wherein said common coil comprises: three voltage conductors wound on said magnetic core to provide R, S and T-phases, a neutral conductor for providing an N-phase, and three capacitors connected between said neutral conductor and each of said voltage conductors, and wherein said neutral conductor has a sectional area which is about three times as large as a sectional area of each of said voltage conductors.
Claim 2
Dependent Claim
89 words
A noise filter for a star-connected three-phase four-wire system comprising: a common coil having a magnetic core which constitutes a closed magnetic path, wherein said common coil comprises: three voltage conductors wound on said magnetic core to provide R, S and T-phases, a neutral conductor for providing an N-phase, and three capacitors connected between said neutral conductor and each of said voltage conductors, and wherein said neutral conductor has a sectional area which is about three times as large as a sectional area of each of said voltage conductors.
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) | 1990-06-29 | 1990-12-29 | 1991-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-29 | 1994-12-29 | 1995-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-29 | 1998-12-29 | 1999-06-30 | $7700.00 | Window Closed / Lapsed |