Motor making knocking & ticking sounds at low speed

Didn’t notice any major scratches on the magnets though, mostly dust being scratched off as you can see in the pictures and light marks. Seems like one more washer between bearing and circlip would have eliminated movement of the rotor. Bearings spinned freely.


Hmm that is strange. Do you feel any resistance or grinding when rotating by hand? What I am thinking now is that when the power cuts out for a moment i the noise might be the motor stopping and starting to rotate again. Same way as when you start the motor rapidly, that knock or whatever when it jumps from 0 to X rpm.

Can you connect the vesc to a computer and check the red current curve in real time data? if the motor is stopping the current should drop significantly or even to 0 and it should be in sync with the sound you hear. is that the case?

Both sounds are gone if I support the rotor while the motor in running at low speed, so it must be the rotor moving either from side to side, up and down or both, making the magnets becoming slighlty misaligned to the stator.

Another washer would hopefully take care of this issue, since it’s that gap that allows movement of the can/rotor. Is this something you could help out with @fottaz ?

Forgot you said that. Try to put one more or as many washers as you can to make the motor move less. Hope it helps

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Sorry, didn’t see this post. I’ll check this later! Thanks

Hey Sebastian!! That noise could happens when motor is not rotating 100% perfectly. It maybe hitted something? I had the same noise since a motor hitted the ground very bad

The circlip is not tight too, it seems.

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Hi Alberto! Motor has never hit anything, so that wouldn’t be the cause. No marks or dents suggesting any impact that I didn’t notice either.

Besides, there’s been a slight noise since the beginning that sounded as if something grinded against some part of the motor once every turn of the motor (before board was ridden), so maybe it’s that noise that has become worse.

Anyway, I’m pretty sure the noise is due to the slight movement of the rotor along the shaft (the gap between the 2 washers and bearing is too big) and it seems as eliminating the gap will make the motor run smoothly without noise.

Yes. First and only time circlip has been removed was now when I disassebled the motor, so the videos that you see here are before I even touched that circlip.

Just tell me as soon as possible if you have any issue, if that sound there was before don’t hesitate to contact me!

If you fixed it by yourself all right, but when you need help on my products write me as soon as you can ! Thanks :slight_smile:

Ok. I have sent you a pm. :slight_smile:

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Yes, I believe this is the case. Here is a printscreen from the realtime data. Each downward spike represents a “knock” in the motor.

The grinding noise is gone which was due to the shaft having moved in the direction towards the pulley. After shaft was put back into a better position (I can no longer move the rotor in and out) that noise disappeared and motor runs smoother than ever before upto a certain low rpm where this knocking starts taking place.

As before, if motor is supported from the bottom the knocking sound is gone as seen in this video.

The screeching noise is also still present at a certain higher rpm.

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@Martinsp any thoughts on what these current drops could be?

I am not really sure what could cause this problem. Has not happened to me yet. Maybe try changing the settings that caused this back and doing a motor detection again. Since this started happening since you changed settings. And see if there are any weak joints or failing cables just like with headphones where the cable is cutting the sound out sometimes before it fails completely.

Oh ok. Settings were set back to the previous settings before I even started analyzing this issue, so there’s nothing more to change back (unfortunately).

I’ll check connections again, although there are not many that could fail right? I have phase wires and sensor wires coming out of the motor going directly to pre-soldered focbox wires via bullet connectors. Also, motor detection gave the same result as when I had no issues.

And why these current cut-offs only when reaching a certain rpm?

Why are they gone when giving rotor bottoma slight push…?

Getting frustrated and don’t want to use the board as long as motor acts this way… HEEEELP! :joy: :fearful:

Now that you mention that it is sensored… sensores are used only until a certain RPM afterwards it is going sensorless because it is better. So sensors are for very low RPM performance only. Try turning the sensors off in the bldc tool. Check the cable precisely.

I think you can use the board without problems because it seems like under load the motor runs just fine and on a skateboard it is under load constantly…

That could be possible. Although I believe in FOC hybrid mode (?) sensors are only used until it reaches 2000 erpm and these knocks seems to appear above that at about 2700.

Will try switching sensored mode off though to see if it makes any difference.

You can set the “sensorless ERPM” in FOC motor config and the “general” part in the left corner.

I am pretty curious if that will make a difference. I think it will but who knows.

You have good current flowing so I must be a mechanical fault. See if the motor gets unduly hot as it could be chaffing from the moving parts.

Got some recent read on this thread, so it might be worth mentioning that the main problem with this motor was loose magnets.