    Sentence 1: What is, it called, when  steam propels a turbo generator with  electric motor propulsion?    Sentence 2: Nuclear-powered. ships and  submarines either, use a steam turbine  directly, for main. propulsion, | with  generators, providing auxiliary, power,  or, else. employ, turbo-electric  transmission, where the steam drives a  turbo, generator set with. propulsion  provided by electric motors.