Motor issues- help!!

Hi All. So yesterday I was out riding at night and went down a steep hill. Shortly after this, one of my motors started cogging badly. I limped home and luckily was just around the corner.

I turned the motor by hand and didn’t notice any resistance, grinding etc…

This morning I ran detection again and unfortunately, more problems have persisted. First, I got a “Flux linkage” error.

I attempted motor detection again after reading a few threads as I wasn’t sure if any of the common problems applied in my case (e.g. cuttoff voltage setting incorrect) maybe with the exception that there could be an overcurrent fault.

After detection the second time around, this is what the VESC tool came up with.

The motor in question did not turn at all during detection either time. I know it’s possible that there is a phase short and also that I may have bricked one side of my controller by riding hm even a short distance and very slowly.

Would love some insight into how to approach troubleshooting this problem.

I would start with a hand test

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Have you tried opening up the motor and looking inside it at all? If the issue is with the motor itself and not the controller then taking a look inside might make the issue obvious. Given that the impact was on the motor itself a magnet could have gotten knocked loose or you might have a chunk of it chipped off. Might also be another issue, but you’d at least be able to rule out one potential issue

Also I would definitely do the BLDC tests before opening the motor up since it can be a pain in the ass to unscrew some motors and open them up.

No I haven’t gotten even close to that far yet. I’m going to try and avoid opening the motor until that’s my only option. They’re a royal PITA to open up.

What’s the BLDC test if I may ask?

It’s a a quick way to see if anything might be wrong if you’re buying used or troubleshooting.

Aka the hand test that you linked above? (Thx for that btw)

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Yes, that. There is another more in-depth test linked in that thread, but the hand test is usually sufficient IMHO to know whether the motor needs to be opened or not.

Also pay attention to where the bolts go into the motor and whether the bolts are going far enough in to contact anything they shouldn’t be contacting.


Ya I read that article and there’s some good stuff in there. Re the bolts, I was careful to select bolts that weren’t too long but I’ll def inspect the windings etc… if/when I open the motor.

really? i was surprised i was able to open the flipsky motors by hand

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IMHO putting them back together is more difficult than opening them. But I haven’t taken apart every kind of motor.

You need a circlip tool in most cases, or don’t even attempt it until you get the tool.

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I agree with b264 check all the phases wires for a short , the tiny sensors wires etc, he mentionned also the screws to the motor can touch the stator and causing weird things

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you can also try to plug the motor to the other vesc side to be sure its the motor not vesc hardware


It depends on the motor and the state it is in. For my hub motors, they were assembled with a type of screw that stripped ridiculously easily so they took several hours to get open initially, and then I went and used a replacement screw that also ended up stripping easily on accident.

If there is any build up of rust or road gunk that can also make opening the motor difficult due to the extra friction between the strator and rotor.

Depends on the motor and how far apart you need to get it. For my hub motors there are circlips holding the bearings from being pushed too far in. The bearings then just sit on top of the circlip. Neither needed to be removed to clean or repair the motor or to even replace the bearings.

Another hub motor I’ve take apart was either the same or just didn’t have any circlips at all.

I’ve not taken apart any inside-wheel motors, so that makes sense.

Yeah, they’re definitely built a bit differently. There is a chance that the bolt running through the strator can be removed if you take of the circlips, but there was no reason or need to try removing it. I’ve got a shitty hub motor I could try taking apart further for science if I ever buy a circlip tool to remove the clips.

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I have a circlip tool so not to worry there. I’m going to check all the wires and connections today and try motor detection with the phase wires swapped to the opposite motors to eliminate the controller as being the culprit.

@vegr0 I dunno why but these motors gave me a very hard time when I opened them before construction. One of them was damaged when it arrived although it was new so I’ve already opened them both once before installing.

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So I switched the phase wires and sensors on the vesc and ran detection again. This time the results were identical but for opposite motors. First, I got a flux linkage error. The second attempt lead the questionable motor to spin up fine and nothing happened on the other side which was previously spinning up fine.

So I’m assuming from these results that one side of the Xenith has been damaged and is no longer functional.