One motor quits on me

[frogstarb]

Hello all,

So I didn't have time to properly debug this, which means I'm posting in hope that someone will point me to the right direction and save me a little time.

I have an hexa (flyduino spider) that has 1130kv motors running at 3s through 12A escs. I don't know the makes and models off the top of my head (I bought it assembled 2nd hand) but the motors are rated for 15A which always left me a little uncomfortable. Anyway, it flies and I'm using it in a *very* sedated way, only doing simple circuits and such. I've had some issues making it stable but it is stable enough, flies well and only on a hover does it have its twitches.

It happened some time ago that I had one motor stop in flight (almost glued to the ground, so no harm done) and then I had to disarm and arm again to get it to move again. As the pack was running low I discounted that as lack of battery. I have been careful and it didn't happen again, until today.

I flew a pack, nothing to report, was doing hovers and quick accelerations to further tune the PIDs and then stopped for a while (to see a friend to crazy 3D on his chopter ). An hour later I connected the other pack which was balanced and full, started the hexa and it dropped the front. A little touch to the landing gear and I was trying again when I noticed it was the motor again. If I accelerate a bit it stops, I disarm, rearm it runs perfect on low rpms but as soon as I put some load it stops.

So, what do you think? ESC or Motor? Since it is always the same one, I'll switch motors and that will tell me which is the culprit, assuming it doesn't start working fine again for a while, but since that's not a straight forward task, as I'll need to take a lot of stuff apart to access the esc and the motor is soldered to it I'd like to know what would be the more obvious cause.

Thank you!

[mgros]

Probably the connections (cable) between ESC an Motor, review and resolder

[NikTheGreek]

i was facing similar problem and the problem was my ESC.
Somehow and without reason the aluminium plate made contact with the componets of the ESC and created a short cirquit.

[vpb]

So, what do you think? ESC or Motor?

- Some wrong esc with bad FET(s) inside will shut the motor on a little high throttle, or just randomly. I've had some cases before.
- Motor with wire(s) (maybe inside, maybe one of the three wires), is going to break, sometimes it starts normally, sometimes it's like stuck at low throttle and spins at higher throttle, you have to check the the wire and solder it if it's break.

So, it's hard to tell the exact wrong point, you should check them all. If you have spare esc(s)/motors, it'll be easy to identify. Or you just can check the single motor with another good esc (whatever brand), if it's good, then check the esc with one another good motor.

[frogstarb]

I have no extras, and I've been planning on buying a set of ESCs that are rated with a little margin (18A+) and are flashable instead of buying spares for what I have. Still, once I disassemble things I'll check if I can reflash the ones I have now (and maybe move them to a smaller machine). I think I have these -> http://www.giantshark.co.uk/black-manti ... 02903.html

So ok, as soon as I have the time I'll resolder the esc/motor connections and we'll see where that leaves me. Failing that I'll move escs around and if I do have one that is failing I'll probably replace the whole set.

[wilco1967]

did you set all of them to NiMH ?

might want to try that particular ESC again..... I had one loose its setting once, and go back to LiPo all by itself.

[tovrin]

I havent understood this about setting your ESC to NIMH even though using li-po, whats the point?

[doughboy]

I havent understood this about setting your ESC to NIMH even though using li-po, whats the point?

I always wondered about that as well, until I read this thread
http://www.rcgroups.com/forums/showthread.php?t=1610229

the first thing they tell you to do is reprogram the esc to nimh from lipo.
lipo will cause esc to shut down the motor at a certain votage point, while nimh will not. since the title of the thread is motor quitting, hence the mention of setting esc to nimh.

[frogstarb]

The NIMH tip is great, but I seriously doubt that's the case as last time it quit I was running on a full pack which should not trigger the shut down for either bat type. Still I started disassembling things and it turns out my ESCs are HK 12Amp BlueSeries which don't have pads but should be flashable still. I ordered this: http://www.hobbyking.com/hobbyking/stor ... duct=27195 and will try to move all of them to one of the alternative firmwares.

Any advice on the firmware? simonk, ziss_dm, other?

Oh, and the solder points from esc to motor seem perfect so while I will redo them later today, I also ordered another ESC just in case...

[tovrin]

ok, i understand, i tried to read that thread, but RCgroups is so full of trolls it hurts my brain.

[doughboy]

lol. I think programming to nimh for that micro quad makes more sense since it uses 2s battery and I think users experienced one motor shutting down due to this hence they advise to change to nimh. I doubt it is the case for this thread, since OP uses 3s battery. simonk, if I am not mistaken, omitted this lipo voltage shutdown feature, so it works like nimh.

[frogstarb]

Well, I resoldered what appeared to be perfect solder joints and in fact the motor doesn't stop now, although I have the ESC held differently than before so I'm hoping it's not a bad connection that just happens to be right now.

Still, I should be getting some gear to allow me to reflash these ESCs and maybe then I can get rid of the stupid hover vibration, and in the mean time I'll also be getting a spare ESC, just in case.