Efficient Rare Earth Free Electric Motor

Q-reeus said:
Freedom from rare earth magnet motors looms:
https://techxplore.com/news/2021-05-mahle-magnet-free-electric-motor-require.html
Might pay to check how that share-market holding in rare earth miner stock(s) is trending.
Replacing lithium in storage batteries the next hurdle to get over.
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What this article does not explain is why rare earth metal magnets are used in motors at all. Using them is relatively new development. Motors in the past never used them. I can't see, from the description of this new motor, how it differs from the standard induction motor.

I had understood that these neodymium etc magnets are a way of using powerful permanent magnets to save space, or improve efficiency, relative to these older standard motors, none of which required permanent magnets. Can anyone explain the design of these rare earth motors and the advantage they provide? I think we need to know that before we can appreciate the significance of this new design that apparently does away with permanent magnets again.
 
exchemist said:
What this article does not explain is why rare earth metal magnets are used in motors at all. Using them is relatively new development. Motors in the past never used them. I can't see, from the description of this new motor, how it differs from the standard induction motor.

I had understood that these neodymium etc magnets are a way of using powerful permanent magnets to save space, or improve efficiency, relative to these older standard motors, none of which required permanent magnets. Can anyone explain the design of these rare earth motors and the advantage they provide? I think we need to know that before we can appreciate the significance of this new design that apparently does away with permanent magnets again.
Click to expand...
Rare earth aka neo magnets have the advantage of both high magnetization strength, and the ability to retain against demagnetizing (high coercivity) from motor winding back-reaction, over other relatively inexpensive types like alnico or hard ferrite. The term used is 'energy product'. For more technical details Wikipedia will be a good source. That high energy product has allowed neo magnet based electric motors to compete in power density with the internal combustion engine. Also used in those prolific litterers of the landscape/seascape - wind turbine 'farms'. I can't quite see the cost-benefits advantage for the latter, and heavy reliance there must be a significant driver of upward raw material costs. A weakness of neo magnets is the relatively low Curie temperature but careful cooling strategies help with that issue.

Here is their website page with video blurb promoting the new design:
https://www.mahle.com/en/news-and-p...y-efficient-magnet-free-electric-motor--82368
Probably needs looping a few times to try and get the basic idea. A patent search would throw up much more info no doubt. I note there is mention of it being a high voltage design, which similar to with HT power lines, allows much reduced resistive losses for a given amount of conductor. The design best I can tell is essentially 'coreless' i.e. no iron used - at least none in the rotor anyway.
 
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