# US 7,745,950 B2 · Generator-starter system for a multi-shaft engine

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- Number: US 7,745,950 B2
- Document ID: US7745950B2
- Status: Granted
- Kind: B2
- Application number: 11/896,507
- Filed: 2007-09-04
- Published: 2008-03-06
- Granted: 2010-06-29
- Earliest claimed: 2006-09-01
- Assignees: Rolls-Royce Deutschland Ltd & Co KG
- Inventors: Rudolf Lueck
- Web page: https://patentgrep.com/patent/US7745950B2

## CPC

- F01D 17/16: by means of nozzle vanes
- F01D 5/026: {Shaft to shaft connections}
- F01D 15/10: Adaptations for driving, or combinations with, electric generators
- F02C 7/268: Starting drives for the rotor {, acting directly on the rotor of the gas turbine to be started}
- 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)
- F05D 2260/4023: through a friction clutch
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

In order to provide a high electric power for an aircraft via a generator driven by the engine, an additional free turbine is included in the hot-gas flow of the engine, which—equipped with generator-starter magnets (9) and surrounded by annularly arranged generator-starter coils (12)—forms a generator-starter turbine (5) and is connected to the high-pressure shaft (1) via an overrunning clutch (15), and hence, is also used for starting the engine.

## Claims

### Claim 1

A generator-starter system for a multi-shaft engine, comprising:
a generator-starter coupled to a high-pressure shaft of a high-pressure turbine of the engine for generating electric power and for starting the engine, the generator-starter comprising:
a free generator-starter turbine arranged in a hot-gas duct of the engine downstream of the high-pressure turbine, the free generator-starter turbine including a plurality of generator-starter magnets positioned around a periphery thereof to form a generator-starter rotor;
a generator-starter stator positioned adjacent the generator-starter magnets;
an overrunning clutch axially connecting the free generator-starter turbine to the high-pressure shaft;
at least one of variable guide vanes positioned upstream of the generator-starter turbine and variable turbine blades positioned on the free generator-starter turbine, the at least one of variable guide vanes and variable turbine blades constructed and arranged to control a rotational speed of the free generator-starter turbine to control electrical output from the generator-starter.

### Claim 2 (depends on 1)

A generator-starter system in accordance with claim 1, wherein the generator-starter magnets and the generator-starter stator are positioned in a bypass duct of the engine, separated from a hot-gas duct of the engine, and flown by cooling air.

### Claim 3 (depends on 2)

A generator-starter system in accordance with claim 2, wherein the generator-starter magnets are attached to tips of the variable turbine blades and the generator-starter stator includes a plurality of generator-starter coils positioned around a circumference of the generator-starter stator.

### Claim 4 (depends on 3)

A generator-starter system in accordance with claim 3, and further comprising both variable guide vanes positioned upstream of the generator-starter turbine and variable turbine blades positioned on the free generator-starter turbine.

### Claim 5 (depends on 4)

A generator-starter system in accordance with claim 4, and further comprising:
an annular chamber in which the generator-starter magnets are positioned and rotate; and
a thermal seal separating the annular chamber from a hot-gas flow in the hot-gas duct.

### Claim 6 (depends on 5)

A generator-starter system in accordance with claim 5, and further comprising cooling fins provided on the annular chamber.

### Claim 7 (depends on 6)

A generator-starter system in accordance with claim 6, wherein the generator-starter magnets are permanent magnets.

### Claim 8 (depends on 6)

A generator-starter system in accordance with claim 6, wherein the generator-starter magnets are electromagnets.

### Claim 9 (depends on 1)

A generator-starter system in accordance with claim 1, and further comprising:
an annular chamber in which the generator-starter magnets are positioned and rotate; and
a thermal seal separating the annular chamber from a hot-gas flow in the hot-gas duct.

### Claim 10 (depends on 9)

A generator-starter system in accordance with claim 9, and further comprising cooling fins provided on the annular chamber.

### Claim 11 (depends on 10)

A generator-starter system in accordance with claim 10, wherein the generator-starter magnets are permanent magnets.

### Claim 12 (depends on 10)

A generator-starter system in accordance with claim 10, wherein the generator-starter magnets are electromagnets.

### Claim 13 (depends on 1)

A generator-starter system in accordance with claim 1, wherein the generator-starter magnets are attached to tips of the variable turbine blades and the generator-starter stator includes a plurality of generator-starter coils positioned around a circumference of the generator-starter stator.

### Claim 14 (depends on 13)

A generator-starter system in accordance with claim 13, and further comprising both variable guide vanes positioned upstream of the generator-starter turbine and variable turbine blades positioned on the free generator-starter turbine.

### Claim 15 (depends on 1)

A generator-starter system in accordance with claim 1, and further comprising both variable guide vanes positioned upstream of the generator-starter turbine and variable turbine blades positioned on the free generator-starter turbine.

### Claim 16 (depends on 1)

A generator-starter system in accordance with claim 1, wherein the generator-starter magnets are permanent magnets.

### Claim 17 (depends on 1)

A generator-starter system in accordance with claim 1, wherein the generator-starter magnets are electromagnets.