Patent ID: 8461704

Claim:
A method of operating a gas turbine engine that includes a core engine arranged in a casing that has a propulsor, a compressor and a first turbine arranged to drive said compressor, a power turbine positioned downstream of the first turbine and being arranged to drive the propulsor, an electrical machine configured upstream of the compressor having a stator and a rotor, a motor/generator, a first clutch to selectively connect the rotor of the electrical machine to the power turbine and a second clutch to selectively connect the rotor of the electrical machine to the compressor of the core engine, the method comprising the steps of: in a first mode of operation, disconnecting the rotor of the electrical machine from the power turbine using the first clutch, connecting the rotor of the electrical machine to the at least one compressor using the second clutch; and operating the electrical machine as an electrical motor such that the electrical machine starts the gas turbine engine, in a second mode of operation, disconnecting the rotor of the electrical machine from the at least one compressor using the second clutch, connecting the rotor of the electrical machine to the power turbine using the first clutch; and operating the electrical machine as an electrical generator such that the power turbine drives the rotor of the electrical machine to generate electricity; and in a third mode of operation, connecting the power turbine and the rotor of the electrical machine using the first clutch; connecting the rotor of the electrical machine and the at least one compressor using the second clutch such that the power turbine drives the at least one compressor.