Patent US4912618A successfully refreshed from Google Patents.
US4912618A
Expired / Lapsed
US
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Variable speed, constant frequency generating system with input transformer
Assignee: Sundstrand Corp
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Filing: 1988-11-04
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Granted: 1990-03-27
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Expires: 2008-11-04
Abstract
Abstract A variable speed, constant frequency generating system has a neutral forming autotransformer connected between a variable speed generator and an AC to AC converter. The converter includes a three-phase full wave-rectifier with positive and negative rails connecting the rectifiers with a DC to AC inverter. Each turn of the transformer windings has at least one surface exposed to air for cooling.
Inventors
- 👤 Alexander Krinickas, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:20
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/28; H01F27/30; H01F27/303; H01F30/00; H01F30/06; H01F30/12; H02; H02M; H02M5/00; H02M5/40; H02M5/42
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
122 words
In a variable speed, constant frequency electrical generating system having a variable speed prime mover, a variable frequency AC generator driven by said prime mover and having a three-phase output, a three-phase rectifier connected with the output of said generator and having a DC output and an inverter having an input connected with the output of the rectifier and having a constant frequency three-phase, wye connected output, the improvement comprising: a three-phase wye connected transformer connected between the output of the generator and the input of the rectifier to match the generator output to the rectifier input said transformer having three secondary windings interconnected at a common junction, the common junction providing a floating neutral point for the output of the inverter.
Claim 2
Dependent Claim
122 words
In a variable speed, constant frequency electrical generating system having a variable speed prime mover, a variable frequency AC generator driven by said prime mover and having a three-phase output, a three-phase rectifier connected with the output of said generator and having a DC output and an inverter having an input connected with the output of the rectifier and having a constant frequency three-phase, wye connected output, the improvement comprising: a three-phase wye connected transformer connected between the output of the generator and the input of the rectifier to match the generator output to the rectifier input said transformer having three secondary windings interconnected at a common junction, the common junction providing a floating neutral point for the output of the inverter.
Claim 3
Dependent Claim
27 words
The electrical generating system of claim 1 in which said generator has an output voltage greater than rectifier input voltage and said transformer is a stepdown transformer.
Claim 4
Dependent Claim
14 words
The electrical generating system of claim 2 in which said transformer is an autotransformer.
Claim 5
Dependent Claim
14 words
The electrical generating system of claim 1 in which said transformer is an autotransformer.
Claim 6
Dependent Claim
30 words
The electrical generating system of claim 1 in which said three-phase rectifier has positive and negative conductors connected thereto, the inverter input being connected to the positive and negative conductors.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-26 | 1993-09-25 | 1994-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-26 | 1997-09-25 | 1998-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-26 | 2001-09-25 | 2002-03-27 | $7700.00 | Window Closed / Lapsed |