Chalo said:
I doubt it's as easy as that. Otherwise, some better-funded industry would be making motors like that for another application. Are there any?
That's exactly what happened with the 9C motors when they switched to 0.35mm lams from 0.5.
Rolling resistance dropped dramatically.
Efficiency went up >5%. Continuous power went from 500w rated to 750w rated.
You can see this on dyno graphs of motors before and after.
Similar thing with the 35mm sized bike hubs. An early crystalyte 35xx used to cog like a bitch and only hit 83% peak efficiency. Continuous wattage around 1200w.
Leafmotor comes out.. same size.. tighter windings.. 0.35mm lams.. way less cogging ( you can now pedal it with minimal penalty ), 1900w continuous capable, and 91% peak efficiency.
Difference in cost for better laminations is on the order of $20 for the manufacturer, so it's not an expensive change.
Bigger DDs would probably benefit from 0.27mm, but beyond that, diminishing gains in efficiency, power, and rolling resistance.
DD motors do not spin fast nor have high power density, so smaller motors spinning quickly benefit from thin laminations more, because saving another 50 watts of heat production is critical when your motor is the size of a fist.