[solved] VESC - Motor Detection Failed (No spinning)

cricrithezar · May 15, 2017, 1:22am

EDIT: Looks like the temperature reading was was off (113C when idle) and that was causing the vesc to not want to spin the motor. Bumping up the mofset max temp made it spin but this isn’t really a fix since i have no idea what the actual temperature of the chip is. It looks like a hardware defect with the VESC, shouldn’t be too hard to fix and they offered to replace it so I’ll probably go with one of those two options.

Hi!

Sorry if you see these all the time (I’m sure that’s the case given how many of these threads I’ve read and still couldn’t fix my issue). I have my VESC set at pretty standard settings. Just changed the battery cutoff start to 33V (which is way lower than my current voltage of 38V on my 10s4p battery). I tried running it with both the stock and Ackmaniac firmwares and had the same results (it’s the hw4.12 vesc from diyelectricskateboards). My motor is a 192kv 6374 turnigy sk3 if that makes any difference. Tried various minimum erpms. Not sure what’s wrong, when I run motor detection, the motor doesn’t even react, it just sits there and after a few seconds outputs a detection failed message.

I’m using this config and I can see the motor spinning in realtime data (when I spin it with my hand) so the connection is probably good enough for it to at least try to spin it up:

Is there anything I’m doing wrong? First time using a VESC

mmaner · May 13, 2017, 2:21am

On your current limits i would start with 60, -60, 60, -30 ams adjust from there after your running

Have you setup PPM yet? Go to app > general and select PPM and click write. The got to app > PPM and select watt/current no reverse with brake and click write.

That should get you running.

cricrithezar · May 13, 2017, 2:24am

I just set it to 60,-60,30,-30 (my motor is 80 though, but I guess that won’t hurt it in any case). PWM was set up, and I could see it change (can’t find a receiver, I’m still waiting for it to get here so I’m using an arduino instead, but the pwm reading was varying which means it should work). Still not spinning though. I’m not quite sure what’s wrong. Can’t see changes in pulsewidth anymore with the new firmware/software, but even with the motor detection nothing happens.

mmaner · May 13, 2017, 2:29am

Just because the PPM signal moves doesn’t mean that your Arduino is working. With my remote off and the RX unplugged it still bounces a little. Can you move the motor using the arrow keys? Look at the @Ackmaniac firmware, gives a lot more options and a ton of explanations. Double check the PPM is selected in app > general. Do a read when on that tab.

Edit: I see you are running the @Ackmaniac firmware, carry on.

cricrithezar · May 13, 2017, 2:30am

actually you were right I didn’t reboot but that’s still not fixing the issue. PWM signal is now showing but still no motor spinning

cricrithezar · May 13, 2017, 2:32am

Yes I have PPM set in general and I have now rebooted. The arduino changes the PWM signal from 0 to 0.98ms in the PPM tab. Still, no dice.

Blasto · May 13, 2017, 2:34am

Ah so you’re using an arduino, make sure your signal passes through the safe start (dead zone)

mmaner · May 13, 2017, 2:35am

Can you move the motor using the arrow keys? Make sure KB Ctrl is ticked on the motor > bldc tab.

cricrithezar · May 13, 2017, 2:39am

Just found a controller-receiver combo. I can make it vary from 1ms to 2ms which does display on the PPM tab. Can’t see keyboard controls anywhere on the BLDC tab.

Thanks for the help in any case. I’m slightly confused and getting limited feedback from both the software and the hardware doesn’t help.

EDIT: just found it, but it’s enabled already.

mmaner · May 13, 2017, 2:40am

KB Ctrl is on the bottom right, it’s ticked in your screen shot. Just use the arrow keys 1 at a time and see if the motor moves.

cricrithezar · May 13, 2017, 2:46am

No motor movement unfortunately.

EDIT: Oh this is wierd. Mofset temp is being read as 113C

EDIT2: Changed that and it worked. Really wierd my read mofset temps are so high. They’re not even hot to touch. Is this something I can fix in software? Maybe recalibrate it?

mmaner · May 13, 2017, 2:46am

What are you peering the VESC with?

cricrithezar · May 13, 2017, 2:52am

So it seems that the relative temps are being somewhat read (not sure how accurate they are). But the base temp is 113C.

I’m just using my finger to feel if it’s hot and there’s a thick layer of heat shrink on there but it’s definitely not 113C. Is this something that has to be calibrated?

mmaner · May 13, 2017, 2:55am

I really don’t know, never had that problem across a dozen VESCs. If your using a 3s or 4s battery to power the VESC that might cause weird shit, at least is has for some people in the past. I would see if you can contact diy support via the chat bubble on the website, or ask @torqueboards here.

cricrithezar · May 13, 2017, 3:02am

After a bit of research, it looks like it might hardware https://www.electric-skateboard.builders/t/solved-mosfets-over-temp/19461/6 Bought it around that time too.

@torqueboards is this something I have to return my VESC for or is there some conversion factor I can use to set my max temps (since I assume it was just the wrong kind of thermistor giving the software the wrong value?)

EDIT: Also @mmaner thank you for the help. Took a long time to notice that value especially since it’s half cut off on that page.

mmaner · May 13, 2017, 3:13am

No worries brother, wish we could’ve gotten you on the asphalt today.

torqueboards · January 19, 2019, 8:27am

@cricrithezar send us an email [email protected] We’ll replace your VESC if it’s related to the R1 temp issue.

cricrithezar · May 14, 2017, 7:32pm

@torqueboards I sent an email and a replacement would probably be the safest solution. Is there any way I could know what the issue with the R1 thermistor was and if it would be possible to simply change the max temp in software to take into account the different resistance of the thermistor? Or do you simply recommend not using this VESC at all? Everything else seemed to be working fine and I would be fine keeping this VESC if this is something I can fix on my end.

torqueboards · May 14, 2017, 9:35pm

You can replace the R1 located here and/or we’ll send you an RMA and we can send you a new one without the R1 issue.

I wouldn’t recommend using it with the R1 issue.

cricrithezar · May 14, 2017, 11:27pm

Thanks for the reply, I’ll probably RMA it but would you happen to know what NTC thermistor was used on that batch?

EDIT: After looking at the datasheet on mouser it looks like you used the 1kohm thermistors (assuming that was the only error, if you have the part number I’d love to know to make sure, as I said everything else seems ok and this can likely be fixed in software), which means I should be able to find the temperatures that the software will see for the temperatures I actually want. This also makes sense since the temperature seen by the software is higher than the actual temp and my values fall right about where they should. I’m working on a spreadsheet and will report back (not testing it, but I’m fairly confident this should work without replacing the resistor).

Ok calculator is done but the resistance value seems funny. If you can give me the exact part name I can find the temperature characteristics value B and that should give me the correct values. I’ll stay on the conservative side since it won’t be as accurate but it should work:

I can post this once I test it out but I don’t want to be the reason other people fry their vescs haha.

In any case I’ll set it to something low (maybe an actual limit of 70C), but also current limited since it’ll probably be fine temperature wise as long as I’m below 50A (my limit is set to 40A right now).