Generator assembly

• US 7,543,439 B2
• Filed: 06/28/2005
• Issued: 06/09/2009
• Est. Priority Date: 07/22/2004
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Butt, David C, Maguire, Alan R
• Primary Examiner(s): Casaregola; Louis J
• Application Number:
  US11/167,383
• Publication Number:
  US 20070017226A1
• Time in Patent Office: 1,442 Days
• Field of Search: 60/391.83, 607/85, 608/02, 290/4.C, 290/4.D
• US Class Current: 60/39.183
• CPC Class Codes: F02C 7/32 Arrangement, mounting, or driving, of auxiliaries
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: H02K 7/108 with friction clutches

Abstract

A generator assembly for a gas turbine engine. The assembly includes an electrical generator connected via a first sprag clutch to an accessory gearbox driven by the engine. The generator is also connected by a second sprag clutch to an air turbine connected to engine bleed valves which are selectively open when the engine speed falls below a predetermined level. The clutches are arranged such that the generator is driven at any time by the fastest rotating of the gearbox and turbine.

Claims

1. A generator assembly for a gas turbine engine, the assembly including an electrical generator, wherein the assembly also includes a first clutch arrangement which selectively connects the electrical generator to an accessory gearbox driven by the engine, an air turbine, a second clutch arrangement which selectively connects the electrical generator and the air turbine, the air turbine being connected to one or more engine bleed valves so as to be driven by air directed from the valve or valves, the first and second clutch arrangements being configured such that in use the electrical generator is connected to whichever of the accessory gearbox or air turbine is rotated fastest, and the electrical generator is disconnected from the other of the accessory gearbox and air turbine, wherein the one or more engine bleed valve is constructed and arranged to only be open when the engine speed is below a predetermined level.

3. An assembly according to claim 1, wherein a manifold is provided which connects a plurality of engine bleed valves, to collect air from the valves for delivery to the air turbine.

4. An assembly according to claim 1, wherein the first and/or second clutch arrangements are in the form of a sprag clutch.

5. An assembly according to claim 1, wherein the first and or second clutch arrangements comprise any of dry or wet friction plates, hydraulic torque converters, ratchet and pawl arrangements.

6. An assembly according to claim 1 wherein an inlet connection is provided to permit connection of the assembly to an external source of air to drive the air turbine.

7. An assembly according to claim 6, wherein a non return valve is provided in the inlet connection to prevent air passing out thereof.

8. An assembly according to claim 6 wherein a non return valve is provided between the inlet connection and the engine bleed valve or valves to prevent air passing from the connection to the valve or valves.

9. An assembly according to claim 6 further comprising an aircraft engine electronic controller for actively controlling the first clutch arrangement to enable the generator to drive the gear box.

17. An aircraft, wherein the aircraft includes a plurality of gas turbine engines according to claim 1.

18. An aircraft according to claim 17, wherein the aircraft also includes one or more electrically powered compressors for providing cabin pressurisation, the or each electrically powered compressor being electrically connected to one or more of the electrical generators of the engines.

2. A gas turbine engine assembly, the assembly including an electrical generator, an accessory gearbox, and one or more engine bleed valves, wherein the engine also includes a first clutch arrangement which selectively connects the electrical generator to the accessory gearbox, an air turbine connected to the engine bleed valve or valves so as to be driven by air directed from the valve or valves, a second clutch arrangement which selectively connects the electrical generator and the air turbine, the first and second clutch arrangements being configured such that in use the electrical generator is connected to whichever of the accessory gearbox or air turbine is rotated fastest, and the electrical generator is disconnected from the other of the accessory gearbox and air turbine, wherein the one or more engine bleed valves is constructed and arranged to only be open when the engine speed is below a predetermined level.

10. An aircraft, wherein the aircraft includes a plurality of gas turbine engines according to claim 2.

11. An aircraft according to claim 10, wherein the aircraft also includes one or more electrically powered compressors for providing cabin pressurisation, the or each electrically powered compressor being electrically connected to one or more of the electrical generators of the engines.

12. An assembly according to claim 2, wherein a manifold is provided which connects a plurality of engine bleed valves, to collect air from the valves for delivery to the air turbine.

13. An assembly according to claim 2, wherein an inlet connection is provided to permit connection of the assembly to an external source of air to drive the air turbine.

14. An assembly according to claim 13, wherein a non return valve is provided in the inlet connection to prevent air passing out thereof.

15. An assembly according to claim 13, wherein a non return valve is provided between the inlet connection and the engine bleed valve or valves to prevent air passing from the connection to the valve or valves.

16. An assembly according to claim 13, further comprising an aircraft engine electronic controller for actively controlling the first clutch arrangement to enable the generator to drive the gear box.