Revolt RV-series motor review and comparisons

ElectricGod said:
I can check RPM with my laser tacho at a 66 and 82 volts.
If you have a CA you could program it to show you the RPM in tenth instead of the speed.
You would need to set the wheel circumfernce to 1666 or something like that, but better check the manual or CA thread.
Just for clarity, what's no load current?

Measure the current it draws at WOT without any load at two differnt voltages like 10s and 20s battery.
Write down the exact voltage so you can calculate the Watts later with the Amps you measure.

I think the maximum no load consumption for this motor will be around 300W. This tells you max usable RPM.

btw: what controller are you using?

ElectricGod said:
Checked a few things.

Phase resistance: 57.6-57.7 mOhms.

Inductance: .2 to .21 uH

I doubt that a phase is wound incorrectly with that small of a difference.

Yes that can be called as consistent wound.
Whats the kV?
The sale version is 57kV (no other windings to choose), but this could have been different when you bought yours..
 
ElectricGod said:
How does the no load watts tell you the max usable RPM? Motor theory is not exactly my strong suite.

The higher the RPM, the higher the no-load Watts.
Above a given point the motor will just overheat without any load because it cannot shed the heat anymore which is coming from eaddy current and hysteresis losses.
You want to stay below that point (RPM).
 
Touching and conducting is not the same thing so the hubmonster and similar motors can still be good. The larger the low resistance current path, the more eddy losses so conduction between magnets is bad and conduction towards backiron is bad.

I think the optimum for efficiency is not touching but slightly less magnet coverage (=gaps). I guess this is due to less agressive flux change when magnets are spaced out.

Segmentation of magnets is done to lower eddy heating and losses in magnets. You could google "joule loss magnet segmentation" or "eddy loss magnets" - you'll find plenty of hits.
 
Interesting.. Are the magnets segmented in those motors? How many magnets for each pole?
It only takes insulating glue or a layer of varnish to sink the conduction.

Should be possible to measure the actual resistance and compare. I can try it on my rotor.

My Revolt motor gets hotter rotor than stator most of the time. Normally the largest losses are copper losses in an ok motor so something's wrong.

Same reported in this video for rv-160 pro:
https://youtu.be/6whYU1mLjlU

The rotor design is not good. If it's the magnets or backiron type or conduction.. It's hard to tell but for sure losses are where the temps are high.
 
If you repeat same test then take two metal plates, glue with thin layer of glue and measure between them. This is a normal joint so is more representative. I wouldn't use JB. Why take a chance?

But the most interesting test is if the motor works :)

What is no load A?
Will it function like it should?
 
Back
Top