Originally Posted by
DamianW
hprt that is excellent information great explanation thank you.
BobW thanks for posting the drawing I will have to try one.
A further note on the dyno and consistency.
When running in brushed mode the consistency is very high but in brushless mode the consistency varies depending on the ESC used.
The best ESC I have used with the dyno is the LRP sphere. With this ESC I was able to make small adjustments to timing and rotor position and see the change in power output.
With the x car ESC the output varied a lot from run to run which whilst it was a cheap ESC I did not find the ESC helpful in tuning the motor. (perhaps the x car ESC with HW software loaded will work better?)
By finding the timing sweat spot and optimizing the rotor and sensor position I managed to gain 5% more power with several motors which has been noticeable on the track.
I have noticed that not all ESC's behave the same on this dyno.
To the point that in certain circumstances, I was getting what appeared to be current limiting going on but what I believe to be the ESC taking 200ms to reach full output. This gives weird results when plotted, as the peak torque doesn't arrive until 8 or 9000 rpm, which I know is wrong. These are also sensorless motor/ESC combos, and I have tested several of the same motor/ESC type with the same result - so it is inherent to the combination.
you can see this in the two attachments - one is a 17.5 D4 with a Novak Edge ESC, the second is an Orca Spark ESC and 2200kv sensorless combo (we use for Mini). Note the delay in peak current draw with the Orca - almost 250ms after the run starts, where as the Edge ESC is at full output in under 40ms.
What does this mean? Not sure yet. All I do know is that if you are comparing motors, definitely use the same ESC.