Magnet saturation at magnetization

[Clyde38]

I'm working with a supplier to magnetize a full rotor (multiple magnets, Neodymium). They state that they can only get an average of 95% saturation for each magnet (simulation). What are the risks to not fully saturating the material?

Clyde Hancock
Design & analysis of electric motors and generators

http://www.motorconsultants.com

 

[EdStainless]

It depends.
What does your grade of Neo look like when undercharged?
In some materials you may get 95% of B but only 50% of H, so not good.
But some grades are not like that.
And is it uniform?
How hard are you going to be working it, and how hot will it get?

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P.E. Metallurgy, consulting work welcomed

 

[MagBen]

this is a general question. the general answer is you donot use materials full potential. a bit more specific, you are working on a minor magnetization curve. if you design to the max BH, both you Bd and Hd can be sacrificed. If the operating point falls below "knee" point, you will have a risk of irreversible de-mag. the risk cold increase as the temperature increase with motor operating.

why cannot be fully saturated? i guess you use a fixture to magnetize the whole assemble? any way to magnetize
each Noe magnets separately?

 

[Clyde38]

I am magnetizing as an assembly.
In some materials you may get 95% of B but only 50% of H, so not good.

How can you have this situation?

Clyde Hancock
Design & analysis of electric motors and generators

http://www.motorconsultants.com

 

[EdStainless]

If you start drawing minor magnetization curves you will see that the behavior varies a lot depending on the grade of material.
In general the higher the saturation Hci the lower the fraction that you will get with sub-saturation.

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P.E. Metallurgy, consulting work welcomed

 

[MagBen]

For very high Hci material, you "waste" a large H for some magnetic circuit (assembly) or in a (BH)max; for a very low Hci material, you waste "B".

 

[Clyde38]

Thanks everyone!

Clyde Hancock
Design & analysis of electric motors and generators

http://www.motorconsultants.com