Patent ID: 7481062

Claim:
A multi-spool gas turbine engine, comprising: a gas turbine engine including at least a high pressure turbine and a low pressure turbine, each turbine adapted to receive a flow of combusted gas and operable, upon receipt thereof, to generate rotational energy; a high pressure starter-generator coupled to the high pressure turbine and configured to selectively operate in either (i) a generator mode, in which at least a portion of the rotational energy generated by the high pressure turbine is converted to electrical energy or (ii) a motor mode, in which electrical energy is converted to rotational energy and supplied to the high pressure turbine; a first clutch assembly movable between an engaged position and a disengaged position; a multi-speed gear assembly coupled to the low pressure turbine and to the first clutch assembly, the multi-speed gear assembly operable, upon receipt of the rotational energy and in dependence on the position of the first clutch assembly, to supply a rotational drive force at a rotational speed that varies over one of a plurality of rotational speed ranges; a low pressure starter-generator coupled to the multi-speed gear assembly and configured to selectively operate in either (i) a generator mode, in which the rotational drive force supplied from the multi-speed gear assembly is converted to electrical energy or (ii) a motor mode, in which electrical energy is converted to rotational energy; and a second clutch assembly movable between (i) an engaged position, in which the low pressure starter-generator is coupled to the high pressure turbine, and (ii) a disengaged position, in which the low pressure starter-generator is decoupled from the high pressure turbine.