US6043569A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zero phase sequence current filter apparatus and method for connection to the load end of six or four-wire branch circuits
Assignee: Individual
•
Filing: 1998-03-02
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Granted: 2000-03-28
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Expires: 2018-03-02
Abstract
Abstract An apparatus and method for substantially reducing zero sequence harmonic currents at the load-end of branch circuits that supply single-phase, non-linear loads. The invention includes a three-phase, six-terminal, zig-zag autotransformer which functions as the zero sequence filter. The first winding, which is located on the first core leg, is connected in series with the sixth winding, which is located on the third core leg. The third winding, which is located on the second core leg, is connected in series with the second winding, which is located on the first core leg. The fifth winding, which is located on the third core leg, is connected in series with the forth winding, which is located on the second core leg. In this configuration, the first winding is magnetically coupled to the second winding, the third winding is magnetically coupled to the forth winding and the fifth winding is magnetically coupled to the sixth winding.
Inventors
- 👤 Gregory N. C. Ferguson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:37
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/01; Y; Y02; Y02E; Y02E40/00; Y02E40/40
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
73 words
An apparatus for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a six-wire branch circuit, and their three-phase, four-wire distribution system source, said apparatus comprising: a three-phase zig-zag autotransformer, having three pairs of phase and neutral terminals; and means for respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof.
Claim 2
Independent Claim
73 words
An apparatus for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a six-wire branch circuit, and their three-phase, four-wire distribution system source, said apparatus comprising: a three-phase zig-zag autotransformer, having three pairs of phase and neutral terminals; and means for respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof.
Claim 3
Dependent Claim
49 words
The apparatus as set forth in claim 1, wherein said autotransformer comprises six windings having an equal number of turns respectively installed in pairs on three core legs of a three-phase core, the paired terminal ends of said windings defining the three pairs of phase and neutral terminals, respectively.
Claim 4
Dependent Claim
45 words
The apparatus as set forth in claim 2, wherein said means for respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof comprises connecting the phase and neutral terminals within a junction box.
Claim 5
Dependent Claim
45 words
The apparatus as set forth in claim 2, wherein said means for respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof comprises connecting the phase and neutral terminals within a partition wireway.
Claim 6
Dependent Claim
45 words
The apparatus as set forth in claim 2, wherein said means for respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof comprises connecting the phase and neutral terminals via a connecting plug.
Claim 7
Independent Claim
91 words
An apparatus for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a four-wire, "shared neutral" branch circuit, and their three-phase, four-wire distribution system source, said apparatus comprising: a three-phase zig-zag autotransformer, having three pairs of phase and neutral terminals; means for connecting the three neutral terminals to the shared neutral of the branch circuit; and means for respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof.
Claim 8
Independent Claim
91 words
An apparatus for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a four-wire, "shared neutral" branch circuit, and their three-phase, four-wire distribution system source, said apparatus comprising: a three-phase zig-zag autotransformer, having three pairs of phase and neutral terminals; means for connecting the three neutral terminals to the shared neutral of the branch circuit; and means for respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof.
Claim 9
Dependent Claim
49 words
The apparatus as set forth in claim 6, wherein said autotransformer comprises six windings having an equal number of turns respectively installed in pairs on three core legs of a three-phase core, the paired terminal ends of said windings defining the three pairs of phase and neutral terminals, respectively.
Claim 10
Dependent Claim
44 words
The apparatus as set forth in claim 7, wherein said means for respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof comprises connecting the phase terminals within a junction box.
Claim 11
Dependent Claim
44 words
The apparatus as set forth in claim 7, wherein said means for respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof comprises connecting the phase terminals within a partition wireway.
Claim 12
Dependent Claim
44 words
The apparatus as set forth in claim 7, wherein said means for respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof comprises connecting the phase terminals via a connecting plug.
Claim 13
Independent Claim
61 words
A method for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a six-wire branch circuit, and their three-phase, four-wire distribution system source, said method comprising respectively connecting three pairs of phase and neutral terminals of a three-phase zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof.
Claim 14
Independent Claim
61 words
A method for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a six-wire branch circuit, and their three-phase, four-wire distribution system source, said method comprising respectively connecting three pairs of phase and neutral terminals of a three-phase zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof.
Claim 15
Dependent Claim
49 words
The method as set forth in claim 11, wherein said autotransformer comprises six windings having an equal number of turns respectively installed in pairs on three core legs of a three-phase core, the paired terminal ends of said windings defining the three pairs of phase and neutral terminals, respectively.
Claim 16
Dependent Claim
45 words
The method as set forth in claim 12, wherein the step of respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof comprises connecting the phase and neutral terminals within a junction box.
Claim 17
Dependent Claim
45 words
The method as set forth in claim 12, wherein the step of respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof comprises connecting the phase and neutral terminals within a partition wireway.
Claim 18
Dependent Claim
45 words
The method as set forth in claim 12, wherein the step of respectively connecting the phase and neutral terminals of the zig-zag autotransformer in parallel with the six-wire branch circuit at the load-end thereof comprises connecting the phase and neutral terminals via a connecting plug.
Claim 19
Independent Claim
83 words
A method for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a four-wire, "shared neutral" branch circuit, and their three-phase, four-wire distribution system source, said method comprising connecting three pairs of phase and neutral terminals of a three-phase zig-zag autotransformer to the shared neutral of the branch circuit and respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof.
Claim 20
Independent Claim
83 words
A method for reducing the non-linear load-generated zero sequence harmonic currents and voltages on three single-phase circuits, which are combined to form a four-wire, "shared neutral" branch circuit, and their three-phase, four-wire distribution system source, said method comprising connecting three pairs of phase and neutral terminals of a three-phase zig-zag autotransformer to the shared neutral of the branch circuit and respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof.
Claim 21
Dependent Claim
49 words
The method as set forth in claim 16, wherein said autotransformer comprises six windings having an equal number of turns respectively installed in pairs on three core legs of a three-phase core, the paired terminal ends of said windings defining the three pairs of phase and neutral terminals, respectively.
Claim 22
Dependent Claim
43 words
The method as set forth in claim 17, the step of respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof comprises connecting the phase terminals within a junction box.
Claim 23
Dependent Claim
44 words
The method as set forth in claim 17, wherein the step of respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof comprises connecting the phase terminals within a partition wireway.
Claim 24
Dependent Claim
44 words
The method as set forth in claim 17, wherein the step of respectively connecting the phase terminals of the zig-zag autotransformer in parallel with the three phases of the branch circuit at the load-end thereof comprises connecting the phase terminals via a connecting plug.
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) | 2003-03-28 | 2003-09-27 | 2004-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-03-28 | 2007-09-27 | 2008-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-03-28 | 2011-09-27 | 2012-03-28 | $7700.00 | Window Closed / Lapsed |