ZF makes magnet-free electric motor uniquely compact and competitive

Re:ZF makes magnet-free electric motor uniquely compact and ... by moffkalast on Sunday September 10, 2023 @04:24AM (#37453940)

I think it just dictates the number of poles the motor has? The fewer the poles the less torque it has, but higher RPM. Either way you have to gear it down for EV use, so I suppose it doesn't really matter much in the end, except if it makes the rotor less likely to explode.

I would've expected very high pole counts to be more practical though, since a lower RPM is more manageable in terms of bearings wearing out. On the other hand, steppers have a high pole count and their efficiency is crap so maybe they can get more power out with fewer poles.

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Re:ZF makes magnet-free electric motor uniquely compact and ... by Farmadupe on Sunday September 10, 2023 @04:33AM (#37453986)

Steppers are super optimized for being super precise and easy to controle while being (relatively) cheap to build.

They have weird "trick" geometry that means you can move the rotor to many different angles (tens, hundreds) with far fewer stator windings.

The cost of this is really low power and efficincy if you just want to spin them.

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Re:ZF makes magnet-free electric motor uniquely compact and ... by rawicki on Sunday September 10, 2023 @06:14AM (#37454459)

Unless you want to chase Tesla with marketing numbers trading off torque for something else is almost always a good tradeoff.

Modern electric motors are much stronger than most users need.

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