/diy/ - Do It Yourself

>>2406260
>A: it probably doesn't matter for balance purposes
k
>B: those look like really tiny channels for cooling
drill lots of them around its circumference.
>compared to the axial fans of even small motors
impellor blades are on the rotating shaft.
can't waste axial-face on fans, nor get its rotation to the device's outside.
>C: are you familiar with the biot-savart law?
left to right field will look like pic
the shaft inside the bearings (magnets) rotates, not the coil.

Magnets & coil are as butt-end view on pic here >>2404526, except surrounding coil with the rotating arc-magnets without using brushes.
This way the magnet field is converging instead of diverging.