M. Schrödl, S. Ojak:
"A novel design for an electrical stepless gear based on the DUOMOTOR® principle";
Poster: International Conference on Electrical Machines, Brugge, Belgien; 08-25-2002 - 08-28-2002; in: "Proceedings Conference Records", Tecnologisches Institut vzw,BE-2018 Antwerpen, (2002), 264.

A new field of use for a single stator double rotor machine
(DUOMOTOR®[1]) is presented in this paper.
This kind of machine consists of one conventional stator with a three
phase winding and two permanent magnet excited rotors. These two rotors are beared uniliterally and independent of each other. In this application the Duomotor works as a stepless gear. Energy from the input side is fed to the output side without mechnical components, but only by use of an electrical inverter.