Drive system

An electric machine (16) comprises a stator (44) and rotor (60) with drive coupling. The coupling either drives, or is driven; in which latter case, electrical energy is recovered. The clutch (14) is connected to the coupling. It has input and output components (18, 82, 32) to turn an output shaft (12). The surrounding casing assembly (68, 56, 70 respectively) has an intermediate section (56) supporting the stator (44).