ESC32 Q&A

[Astudillo]

Hi Jussi,

I used motor 2(unburned) and it's ESC to do the first part of the video, and used the "bad" ESC for the second part with the same motor.

I calibrated the ESC with the prop that was on it.
Here is a screenshot of the parameters.


After the firmware flash, i also tried to start the motor with the default settings, but i got the same result.

Cheers,

Ray

[Trnquill]

The arm was hot? This would indicate a short between the arm and some wires. Check the motor bolts!

I had similar issue once. Motor bolts were just a tad too long and rubbed against motor windings. They shorted via carbon fiber motor mount and resulted in smoke, odd motor behavior and smell of vaporizing carbon fiber...

[Astudillo]

Hi Trnquill,

Thanks for pointing that out. I just checked the motor plate, and i see a tiny spot of burned residue. But its on the spot of the circular air vents(probably leaked from the wiring). I use 6 mm bolts and they just barley stick through they engines bottom.

Cheers,

Ray

[Trnquill]

But you are sure the boom was hot? I would check all wires for cracks/holes in insulation next.

[JussiH]

The point about checking for shorts in distribution is very valid, if the boom got hot you either had a short in the distro or drew enough amps to make the wires heat up. I would take the whole thing apart and measure for shorts in the power supply.

In any case, you are allowing 25A overall current and that is "a lot". Have you checked how much these motors draw at full whack? I suspect its much lower.

Did you perform ESC calibration for this motor/prop combination?

In any case, the motor should not lock up and burn a motor phase, mechanisms in the firmware should prevent it if communtation is lost. I cant really give a plausible explanation for why it would happen, except for a dodgy ESC. Of course if there was a short in the power supply, it could create all sorts of ripple effects and possibly that could have caused the lockup.

But its guesswork...the most likely "smoking gun" here is short circuit in Power supply, clued by the arm getting hot - but of course if the ESC shorted out 2 phases, the effect would be pretty much the same as shorting the supply wires.

However, as I cant rule out ESC failure, I will in this case replace the ESC under warranty. You will need to send the other one back for examination.

[Astudillo]

Hi Trnquill and Jussi,

Thanks for your replies! I checked the cables from the motor and there was nog damage there or on the bullet connectors.

@Jussi Sorry for bothering you with the e-mail i send, i missed your commend here. Thanks for the service! Ill will send the ESC32 to you.
I did Calibrate the Motor/prop combo and reduced the default 30A to 25A and it ran both calibrations till the end.
The U3 Motors are rated at 25A(180sec). I Tested the motor with the prop on the bench, and at full throttle it was pulling 21A. Should i set the max at 21 amps? I thought i had to give a little head room for fast corrections. Or isn't that necessary?

Cheers,

Ray

[JussiH]

If it pulls 21 at full whack, 25A is not that much off. In reality, you probably could limit a bit lower, around 22-23A - you only need a little overhead (1-2A usually)

But it likely has nothing to do with this issue.

I am curiuos about the wire gauge and the arm that got hot...Whats the wire gauge and whats the C rating and size of the battery?

[Astudillo]

Hi Jussi,

The wires on the motor are awg18 and the wires from the esc to the bullet connectors are awg15. The battery that was connected is a 4s 8A 30c

Cheers,

Ray

[superwxm]

Hi,
I am studying the code of ESC32 which is downloaded from this web.
Now I have a question about how the code control the motor to start?
I knew there are some methods for this kind of BLDC to start witout sensor. But I didn't find out which method the code used?
Is there anyone know where the code about start is? I found some code in fet.c, but I was not sure if it is the correct place?
Thank you for everyone's help!
Best regards!

[bn999]

All of the start code is in fet.c