ESC restarts itself?

[ProxRB]

I recently finished my build and took it out for the first street-test. It ran fine for a couple minutes, and suddenly the ESC restarted itself. Now, even with no load, when I engage the throttle the motor will turn a revolution or two before the ESC restarts itself. The batteries are charged, the LVC has been disabled, my guess is the ESC is fried. Any idea what's going on?

120a ESC from diyelectricskateboards.com (I think its an FVT ESC)
1x 50mm, 200kv unsensored motor also from diyelectricskateboards
GT2b
2x Zippy 3s1p LiFePo
22T motor pulley
44T wheel pulley
83mm wheels
200lb rider

 

[torqueboards]

What is your settings on the ESC? Have you programmed it?

Motor Timing: Very Low, Low, Normal, High, Very High
Acceleration: Low, Medium, High, Very High
Running Mode: Forward/Brake, Forward/Reverse/Brake, Forward/Reverse
Brake Force: 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%
Drag Brake: 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%
Cut-Off Voltage: 2.6V/cell, 2.8v/cell, 3.0v/cell, 3.2v/cell, 3.4v/cell
Max Forward Force: 20%, 40%, 60%, 80%, 100%
Max Reverse Force: 20%, 40%, 60%, 80%, 100%
Motor Rotation: Normal, Reverse
Neutral Range: 3%, 5%, 7%, 9%
Battery Type: NiMh, LiPo

 

[bandaro]

The FVT can be tricky until set up right, check this thread and see if your issues fit any, and start by programming the esc to settings there? Each setup is different, but if the esc programs, then it's not toast.

http://endless-sphere.com/forums/viewtopic.php?f=35&t=70162&p=1058513#p1058513

 

[ProxRB]

I tried fiddling with motor timing, and within 30 seconds of plugging everything in the motor is already very warm, without actually ever turning (ESC restarted itself again). My guess is there's some sort of motor short that is drawing a lot of current which is heating up the motor and triggering some sort of protective protocol in the ESC causing it to restart. Any advice on how to test what the problem is?

 

[torqueboards]

@ProxRB - Can you show some photos of your current setup? Worse comes to worse. You can ship it back and I can replace that unit for you. Let me know.

 

[bandaro]

Yeah, does sound like you damages the motors somehow - did they burn out, hit anything or get a rock in them?

Do you have a different motor you can test the esc on? Or try switching the esc on without a motor connected, and see what the LED mounted between the wires on one end does. Always better to get it fixed without the delay of return shipping.

 

[ProxRB]

Pics and video below

I dont think they burned out, given that the test ride was so brief, but I'm not sure how to tell frankly. Didnt see any sparks or anything. Dont think I hit a rock and nothing got jammed at any point (or I would have been thrown off the board).

I dont have another motor unfortunately. The ESC with no motor seems to power up and light up fine.

[youtube]9-HpTrsdcGI[/youtube]

 

[torqueboards]

Has the ESC been programmed? ESC Signal wire is on Channel 2? Have you checked the trim on the GT2B possibly moved on accident?

 

[ProxRB]

Yeah, I've been fiddling with the programming, changed the timing, acceleration settings etc etc successfully. I've occasionally gotten the motor to turn a few degrees, but never as much as even a quarter turn. I've recalibrated the GT2b trigger throw as well. Yup, ESC definitely connected to channel 2 on the receiver.

 

[bandaro]

Ok, seems you have tried and corrected most problems... Here's a good motor test:

Option A

An easy way to find out if the motor is shorted is to poke about with a multi-meter (assuming you know where to poke and the readings you should get).

Option B

Disconnect the motor plugs, hold them apart and spin the motor a bit, take note of how difficult it is to spin and how long it will keep spinning (if at all) if you give the wheel a flick. Then do the same thing, but holding the motor plugs together so they are shorted out. Does this cause a distinct change to how freely the motor spins?


Buuuuuut.... The more I think about it, the more I think the motor is fine, it sounds healthy with those beeps, definitely healthy enough to start spinning. Tried removing the belt? Hate to say it but it could be time to get another esc sent out. I'm running two fvt's now and would be happy to help troubleshoot, but I doubt you are in Canberra...

On another note, the ESC is beeping for a 5s lipo, not 6s life, so make sure you don't run your batteries down too much by trusting the auto esc voltage cutoff.

 

[chaka]

If your transmitter is running low that can be an issue too.

 

[ProxRB]

Good ideas with the motor testing. My results:
Option A
Yeah, I have no idea what I'm doing... My multimeter says each of the three leads are all shorted together, but I dont know if thats normal. I can't really test the resistance since my multimeter basically says 0 resistance, I guess I'd need a milliohmeter?

Option B
I disconnected my motor from the ESC and spun the wheel (still connected to the belt/motor). It doesnt exactly freewheel, I can't spin it by flicking it with a finger there's too much friction for that, but neither is it difficult to spin. It turns roughly how I would expect a belt driven assembly to turn though. (Is that normal by the way? I recently got to play with a Boosted board, and there's definitely way less friction).
Then, with the motor still disconnected from the ESC, I touched the leads to one another and spun the wheel. Now there's definitely way more resistance, and it definitely feels like some EMF effect, it kind of has that characteristic non-linear feel where the resistance is very low for low rotational speed, but kind of "hits a wall" and when you try to spin it quickly.

So good news! It doesnt seem like the motor is totally shorted.

That said, I just plugged it in again, ran through the exact same testing sequence as in the video, and started to smell something "hot." And then I saw whisps of smoke coming out of the motor... So yeah, thats not good...

I then ran the motor through tests A and B again, its still behaving the same way. But clearly something's wrong hah!

Given the smoke, I'm pretty sure its not the transmitter batteries on this one

I didn't know the number of beeps the ESC makes corresponds to its perceived cellcount... that's kind of cool. Anyway, I disabled the ESC LVC cutoff right when I got it, so I'm pretty confident that's not a problem either. I've been keeping it plugged into a battery voltage alarm which has yet to dip below 3V.



So at this point, I'm really confused. I still think its likely a motor issue, given that the ESC starts up fine, shows no damage, doesnt smell funny when its plugged into the battery with no motor etc. Maybe one of the motor winding wires got pinched or something, so the internal resistance is super high? I'm totally out of ideas. I may try to bring it into a hobby shop and see what they think.