To me, dynamo has always meant a generator, first and foremost. It's use to denote a person of extreme energy and drive I have aways regard as an analogy to the original meaning.
My prized possesion, as an eleven-year-old, was a bicycle whose lights were powered by a dynamo, rather than by batteries like thise of most of my contemporaries.
Most motor cars also had dynamos to re-charge their batteries, up until the '60s when they were replaced by the more efficient alternator.
I assume that the latest developments in clockwork radio sets use the mechanism to drive a dynamo which powers the receiver and speakers.