Abstract: Inefficiencies in electrical starter-generator systems for turbine engines are avoided in a construction including a dynamoelectric machine 16 operable as a motor or as a generator and having a rotor 26, a hydraulic torque converter 70 including an impeller 80 connected to the rotor 26 and a turbine 86. A system 94, 96 is provided for selectively providing hydraulic fluid to the torque converter 70 and a constant speed drive 112, 142, 144 is included. Overrunning clutches 108 and 158 interconnect the turbine 86 and an input for the constant speed drive for allowing the input to overrun the turbine 86 but not the reverse, and for interconnecting the rotor 26 and an output 130 of the constant speed drive for allowing the rotor 26 to overrun the output 130.