ESC calibration motor "twitch"

Hey Folks,


I just built my ArduCopter kit from jDrones and all seems to be going well up until ESC calibration.  Looks like 3 out of the 4 ESCs work, but 1 makes the motor "twitch" sometimes--seems kind've random when it chooses to twitch or not (see vid).  I've tried the suspect ESC on another motor that didn't twitch and the suspect ESC makes it twitchy--so it looks like an ESC issue and not a motor.

 

Here's a video I made of the problem:

http://www.youtube.com/watch?v=Xc7Qfv-NFb8

 

Is my hardware broken? What should my next steps be? Buy a new ESC?  The bullet connections look solid.

 

Thanks,

Jeff

Tags: ESC, calibration

Views: 418

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Replies to This Discussion

Permalink Reply by Jeff Rousseau on September 19, 2011 at 7:30am

Just FYI if it's not immediately obvious from the video, I'm following the MANUAL instructions here:

http://code.google.com/p/arducopter/wiki/AC2_ESC

 

PS I just re-soldered the bullets on the ESC and no change...


DeveloperPermalink Reply by jasonshort on September 19, 2011 at 9:23am

Swap the motor with another one to see which failed: the motor or the ESC.

Do you really fly with your throttle inverted like that? Try reversing the throttle channel so neutral is low.

Jason

Permalink Reply by Jeff Rousseau on September 19, 2011 at 9:55am

It's definitely the ESC--I probably didn't explain it well in the first post, but I tried the bad esc on a good motor and it caused the good motor to twitch.  I also tried the first twitchy motor on another ESC and it no longer twitches.  

 

I just built this thing though, any ideas on what might have gone wrong?  I already ordered a spare ESC, but not sure why this thing died in the first place.

Permalink Reply by Michael Pursifull on September 19, 2011 at 2:14pm

It is possible that it did not die. This is the behavior you would get if one of the three connections is not good between the ESC and the motor. Maybe check the solder joints one more time? Or maybe the cable from the ESC got tugged and is not connected well?

 

Of course you can replace the ESC without checking, I only want to maybe save you the cost. 

 

Permalink Reply by Jeff Rousseau on September 20, 2011 at 11:26am

The cost has already been incurred, since I've ordered a new ESC...

 

I've resoldered the bullets again as well as the PDB power and ground connections--still twitchy.  Should I break open the yellow shrink casing and check the connections in there? It would probably void any hopes of warranty...but then again the replacement shipping cost would probably make returning it too expensive anyways (jDrones isn't exactly local to the US).

 

It seems like 1 out of every 3 to 10 tries is twitchy and the rest are fine... might it be flyable as-is? or is that just a disaster waiting to happen?

Permalink Reply by Jeff Rousseau on September 28, 2011 at 6:23am

UPDATE:  I ended up waiting for a new ESC--installed it and the problem went away--although I still have a 2-second interval "beep" sound and a corresponding "twitch" coming from the motors when the 4-pin PDB-ESC connector is not plugged into the APM.  Should I be concerned?


Regardless, I finished the setup process and had a successful maiden flight! Now to get the FPV to work...


DistributorPermalink Reply by Dany Thivierge on September 28, 2011 at 11:55am

where they 30 Amp ESC? 

I also got the exact same problem wiht mine... :) 

http://www.youtube.com/watch?v=FXutke7E7go

 

It was a problem with a brand new ESC... looks like there was a batch with some flaws... apparently it is "only" bad soldering on the components... talk to the support at jdrones as they might just send you a free one. They will not require you to send back the old one for the RMA. 

 

 

Permalink Reply by Kirill on September 28, 2011 at 1:17pm

You might have problems with wrong timing of ESC or motor. Try to reprogram timing settings according to your motor and other working ESCs.

Permalink Reply by Jeff Rousseau on September 28, 2011 at 1:43pm

how do I go about this? how is reprogramming different than calibrating?

Permalink Reply by Jeff Rousseau on September 29, 2011 at 6:49am

This one was also brand new--but mine was 20A (cross-model batch flaw?)

 

If it's just the solder I'll cut open the yellow shrink wrap and re-solder whatever looks fishy


DistributorPermalink Reply by Dany Thivierge on September 29, 2011 at 10:39am

I did open mine... this is small surface mount soldering that we have here... I am not up to the task to reflow all contact points! I wish but I can't! 

 

 

Permalink Reply by Michael Pursifull on September 28, 2011 at 6:32pm

look at the paperwork/instructions that come with the ESC. If it is a jDrones type ESC, then the two second beep means unusual throttle input. Which is what you can expect if you do not have them connected. 

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