Thinner laminations=less torque?

1boris

100 W
Joined
Dec 6, 2013
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214
Hi
I just ordered a Mac 10 which I will be running at 36v 20-25 a or 48v 20-25 a as a pedelec.I dont understand to much technical about the motor,but from what I have read here,the thinner laminations the better.So I ordered a new design Mac 10 casette motor with 0,27 mm laminations.Then I read on another post here that thinner laminations gave better effeiency but less torque.Is this correct and does it matter in my case.should I change the order while I still can to the 0.35 mm laminations?
 
Thinner lams means lower iron fill.
See it like this: there are "airgaps" between those sheets, and the more thinner sheets you have (for the same total stator width), the more "airgaps" there will be, which means less room for iron.

thinner lams mean less "magnetic friction" which means the kV will be higher. If the kV is higher, the kT will be lower so you need more amps for the same torque.

I once have seen a tuned RC motor where they used 0,1mm!!!! lams instead of the stock 0,2mm ones, and the motor was still performing a bit better overall.

If you ask me: keep that motor, because in 90% of your usage it will stay cooler.
 
Thinner lams does mean lower iron fill, but realistically modern metal oxide based lamination insulation materials are so thin relative to the lamination thickness, the iron fill difference becomes <1%, so the realized benefits in reduced core losses more than make up for it in dynamic situations with the rotor spinning.

Stalled rotor to stalled rotor, the thicker lam motor would do a tiny bit more torque before saturation, but you would be hard pressed to measure it beyond the range of measurement error.
 
1boris said:
Thanks for answering.
Will the torque difference be significant?
I almost bought the Mac 12 because I want maximal torque,but it is a little to slow for what I wanted.

Significant depends on your needs, but sub <1% torque loss either way.
 
hope it is ok to ask another question since Luke, one of the smartest ES members is represent here :)

is it normal to measure almost zero Ohm between the outer laminations (or becoming a "beep" when using a continuity tester)?
and doesn't the stator support anyway not make a "short circuit" among them all?
 
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