There is a video here that explains the concept: https://www.mahle.com/en/news-and-press/press-releases/mahle-develops-highly-efficient-magnet-free-electric-mot

There is a video here that explains the concept: https://www.mahle.com/en/news-and-press/press-releases/mahle-develops-highly-efficient-magnet-free-electric-motor--82368 https://www.mahle.com/en/news-and-press/press-releases/mahle... If you're like me, and thought this was basically a squirrel-cage motor, then they key point is that this is a synchronous motor which replaces the typical permanent magnets with electromagnets. But I wonder whether the poles in the rotor (which would ordinarily be permanent magnets) are DC or alternating field. If DC, then perhaps the rotor has a built-in rectifier? If alternating, then the stator coils must be doing some interesting compensation.