ZF makes magnet-free electric motor uniquely compact and competitive
Well, magnet-less separately exacted synchronous motors with the exact same architecture have existed since  ... <i>checks notes</i> ...  over 100 years, so it took me a while to digest the whole marketing fluff where they use an entire page to explain how an electric motor works, and see what's so special about this besides the claim that it's now "up to 90mm more compact axially".<p>It seems like the big innovation here is that it doesn't use slip rings and brushes anymore, and the power to the rotor is now transferred via induction coils:<p><i>"energy is transferred inductively, i.e. without mechanical contact, into the rotor, generating a magnetic field by means of coils. Thus, the I2SM does not require any brush elements or slip rings. Furthermore, there is no longer any need to keep this area dry by means of seals. As with permanently magnetized synchronous motor, the rotor is efficiently cooled by circulating oil."</i><p>The good part is there's no more brushes to wear out and no dry seal needed so the motor can now be oil cooled from the inside as well, but to me it raises the big question about the power losses incurred by the energy that's transferred to the rotor via induction versus the previous direct contact via brushes and slip rings.<p>Those coils seem to be quite far apart from one another, have a look at this moment in their video: <a href="https://press.zf.com/press/en/media/media_60352.html?kalturaStartTime=33" rel="nofollow noreferrer">https://press.zf.com/press/en/media/media_60352.html?kaltura...</a>