Ludwig Herbrand, Dipl.Ing.
Herbrand lived in Germany. He came in contact with a super efficient hydroelectric power generating turbine through his professor in engineering school, who had him calculate and compare the electrical generators at two different power generation sites.
In 1989, the German magazine raum&zeit published (in its number 38) an article by Herbrand entitled 'The Secret of Water Power' (in German "Das Geheimnis der Wasserkraft"). After an attack on Herbrand in a reader's letter written by an orthodox engineer, I analysed Herbrand's writings and published (in raum&zeit 62, 1993) my article on water power which refuted the attack and explained the Herbrand story with reference to the earlier work of Schauberger.
Herbrand has not invented any turbine (as he tried to imply in his writings), but he did seriously analyse the connected generation equipment from an electrical engineering point of view, and he "blew the whistle" on this buried and forgotten technology, getting it into public view after more than 50 years of having somehow been hidden away.