US5036267A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aircraft turbine start from a low voltage battery
Assignee: Sundstrand Corp
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Filing: 1989-12-15
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Granted: 1991-07-30
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Expires: 2009-12-15
Abstract
Abstract A low voltage battery provides the power source for energizing an aircraft generator to operate it as a motor during a starting operation. The battery is coupled to an input to an inverter whose a.c. output is controlled by a pulse width modulator. By controlling the switching points of the output, the generator is so energized that it operates as a brushless d.c. motor. At a point where the available voltage to the generator is insufficient to further accelerate the turbine, even with field weakening and an increased commutation angle, an autotransformer is switched into the system to step up the output voltage from the invertor. Throughout the starting operation the commutation angle is controlled so that current drain on battery is such that the battery terminal voltage at one half its no load terminal voltage, thus providing maximum power transfer from the battery.
Inventors
- 👤 Albert L. Markunas
- 👤 Gregory I. Rozman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:26
CPC Classifications
F; F02; F02N; F02N11/00; F02N11/04; F05; F05B; F05B2220/00; F05B2220/50
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
132 words
A system for starting an aircraft turbine from a low voltage power supply by energizing a generator coupled to said turbine to operate as a motor during starting, comprising in combination: an inverter having a direct current input coupled to said low voltage battery and an alternating current output; an autotransformer having a starting mode input tap and a starting mode output tap, said autotransformer coupling a stepped up voltage between said input tap and output tap; means for coupling said output tap to said generator; control means for coupling said inverter output to said generator initially during starting and thereafter coupling said inverter output to said transformer input tap; and means for controlling the input current to said generator to maintain the battery terminal voltage during starting at a predetermined level.
Claim 2
Independent Claim
132 words
A system for starting an aircraft turbine from a low voltage power supply by energizing a generator coupled to said turbine to operate as a motor during starting, comprising in combination: an inverter having a direct current input coupled to said low voltage battery and an alternating current output; an autotransformer having a starting mode input tap and a starting mode output tap, said autotransformer coupling a stepped up voltage between said input tap and output tap; means for coupling said output tap to said generator; control means for coupling said inverter output to said generator initially during starting and thereafter coupling said inverter output to said transformer input tap; and means for controlling the input current to said generator to maintain the battery terminal voltage during starting at a predetermined level.
Claim 3
Dependent Claim
27 words
A system for starting an aircraft turbine as in claim 1, wherein said predetermined level is approximately equal to one half the no load battery terminal voltage.
Claim 4
Independent Claim
96 words
A system for starting an aircraft turbine by energizing a generator coupled to said turbine from a low voltage battery power supply to cause said generator to operate as a motor, comprising in combination: an inverter having a direct current input coupled to said low voltage battery and an alternating current output; control means for coupling said inverter output to said generator during starting; and means for controlling the input current to said generator during starting to maintain the battery terminal voltage at a level approximately equal to one half the no load battery terminal voltage.
Claim 5
Independent Claim
96 words
A system for starting an aircraft turbine by energizing a generator coupled to said turbine from a low voltage battery power supply to cause said generator to operate as a motor, comprising in combination: an inverter having a direct current input coupled to said low voltage battery and an alternating current output; control means for coupling said inverter output to said generator during starting; and means for controlling the input current to said generator during starting to maintain the battery terminal voltage at a level approximately equal to one half the no load battery terminal voltage.
Claim 6
Dependent Claim
28 words
A system for starting an aircraft turbine as in claim 3 wherein said means for controlling input current includes means for controlling the commutation angle of said generator.
Claim 7
Dependent Claim
18 words
A system for starting an aircraft turbine as in claim 3 wherein said coupling means includes an autotransformer.
Claim 8
Dependent Claim
18 words
A system for starting an aircraft turbine as in claim 4 wherein said coupling means includes an autotransformer.
Claim 9
Dependent Claim
20 words
A system for starting an aircraft turbine as in claim 1 wherein said generator operates as a brushless d.c. motor.
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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) | 1994-07-29 | 1995-01-28 | 1995-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-29 | 1999-01-28 | 1999-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-29 | 2003-01-28 | 2003-07-30 | $7700.00 | Window Closed / Lapsed |