I've run some tests on rv160s motor. On this graph horisontal - rpm, vertical - power consumption...
as you can see when motor runs 4k+ RPM, power rises above 1kW!! I have find out that main problem of such losses is a big bearing, it is heats up instantly when motor spinning 4k.
Here is explanation vid: https://youtu.be/qTRJ4jqASRA it is in russian, but easy to understand where is problems
So i replaced this original NSK 6814 bearing to NTN 6814, cover now spins much longer!!
And finally some photo of RV160s
magnet width 25mm... winding NOT 6 parallel wire, but 5. im quite dissapointed with this motor