Patent US5576942A successfully refreshed from Google Patents.
US5576942A
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Method and apparatus for reducing the harmonic currents in alternating-current distribution networks
Assignee: Fermi Research Alliance
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Filing: 1994-09-30
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Granted: 1996-11-19
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Expires: 2014-09-30
Abstract
Abstract An improved apparatus and method reduce the harmonic content of AC line and neutral line currents in polyphase AC source distribution networks. The apparatus and method employ a polyphase Zig-Zag transformer connected between the AC source distribution network and a load. The apparatus and method also employs a mechanism for increasing the source neutral impedance of the AC source distribution network. This mechanism can consist of a choke installed in the neutral line between the AC source and the Zig-Zag transformer.
Inventors
- 👤 Leon H. Beverly
- 👤 Richard D. Hance
- 👤 Alexandr L. Kristalinski
- 👤 Age T. Visser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:06
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/01; Y; Y02; Y02E; Y02E40/00; Y02E40/40
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
94 words
An apparatus for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network, said apparatus comprising: a polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line, said input current lines and input neutral line being connected to said AC source distribution network, said output current lines and output neutral line being connected to said load; and a choke connected within said input neutral line between said AC source distribution network and said Zig-Zag autotransformer.
Claim 2
Independent Claim
94 words
An apparatus for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network, said apparatus comprising: a polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line, said input current lines and input neutral line being connected to said AC source distribution network, said output current lines and output neutral line being connected to said load; and a choke connected within said input neutral line between said AC source distribution network and said Zig-Zag autotransformer.
Claim 3
Independent Claim
106 words
An apparatus for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network, said apparatus comprising: a polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line, said input current lines and input neutral line being connected to said AC source distribution network, said output current lines and output neutral line being connected to said load; and means for increasing the source neutral impedance on said input neutral line experienced by said AC source distribution network relative to said Zig-Zag autotransformer connected in parallel with said load.
Claim 4
Independent Claim
106 words
An apparatus for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network, said apparatus comprising: a polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line, said input current lines and input neutral line being connected to said AC source distribution network, said output current lines and output neutral line being connected to said load; and means for increasing the source neutral impedance on said input neutral line experienced by said AC source distribution network relative to said Zig-Zag autotransformer connected in parallel with said load.
Claim 5
Independent Claim
93 words
A method for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network comprising the steps of: providing polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line; connecting said input current lines and input neutral line to said AC source distribution network; connecting said output current lines and output neutral line to said load; and connecting a choke within said input neutral line between said AC source distribution network and said Zig-Zag autotransformer.
Claim 6
Independent Claim
93 words
A method for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network comprising the steps of: providing polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line; connecting said input current lines and input neutral line to said AC source distribution network; connecting said output current lines and output neutral line to said load; and connecting a choke within said input neutral line between said AC source distribution network and said Zig-Zag autotransformer.
Claim 7
Independent Claim
104 words
A method for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network comprising the steps of: providing a polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line; connecting said input current lines and input neutral line to said AC source distribution network; connecting said output current lines and output neutral line to said load; and increasing the source neutral impedance on said input neutral line experienced by said AC source distribution network relative to said Zig-Zag autotransformer connected in parallel with said load.
Claim 8
Independent Claim
104 words
A method for reducing the harmonic content of AC phase and neutral line currents between a load and a polyphase AC source distribution network comprising the steps of: providing a polyphase Zig-Zag autotransformer having input and output current lines, an input neutral line and an output neutral line; connecting said input current lines and input neutral line to said AC source distribution network; connecting said output current lines and output neutral line to said load; and increasing the source neutral impedance on said input neutral line experienced by said AC source distribution network relative to said Zig-Zag autotransformer connected in parallel with said load.
References Cited (Backward Citations)
US3128438A
Cited
US4209757A
Cited
US4355241A
Cited
US4525764A
Cited
US4493016A
Cited
US4531085A
Cited
US4622474A
Cited
US4684875A
Cited
US4870557A
Cited
US4847745A
Cited
US5235503A
Cited
US5446643A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-19 | 2000-05-20 | 2000-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-19 | 2004-05-20 | 2004-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-19 | 2008-05-20 | 2008-11-19 | $7700.00 | Window Closed / Lapsed |