My motor setup is vibrating too much for my intended project.

Here are my assembled parts :

  • ClearPath® - Integrated Servo System motor, p/n CPM-MCVC-2310S-RQN
  • two Actobotics 15 Tooth, Flanged XL timing pulley, p/n 615432
  • one Actobotics 3/8” wide, 10" long, 1/5 pitch XL timing belt, p/n B375-100XL

The motor is running under the velocity controlled option and is spinning 0-4000 rpms depending on a knob setting.

A few ideas: I was reading that with timing belts a larger pinion diameter could lessen vibrations. Should I search for something larger? The current pinions are around 1" pitch. Also maybe my tension on the belt is not right? I'm not sure how to measure this or what tension I'm looking for. The assembly has slots, so I can move by hand to make the belt tighter or looser.

I'm far from an expert and this is my first project. Any advice would be much appreciated.

  • 1
    $\begingroup$ is the set screw on the pulley protruding by chance? $\endgroup$
    – jsotola
    Jan 24, 2018 at 7:04
  • $\begingroup$ I ran some isolation tests as you suggested and the mount is fine. It seems all the vibration is coming from the belt and shaft setup. This belt is very rigid and seems tight enough, so probably not flapping. I can't put an idler in due to lack of space. Maybe a less rigid belt and larger pinions would help? I should probably figure out how to measure the tension too and make sure it is installed correctly. Or maybe a different style of belt would be better for this application? I just guessed at the XL style timing belt. I'm spinning 0-4000 rpm with speed changes throughout this range. The ce $\endgroup$
    – caleb
    Jan 28, 2018 at 23:28
  • $\begingroup$ You should probably edit that into your question. $\endgroup$ Jan 29, 2018 at 0:38

1 Answer 1


A diagram would really help improve the answers you get on this. However, since it appears you are using 2 pulleys of the same size, I would guess that the belt may be flapping up and down, which might be causing some harmonic resonance throughout the entire assembly. I would try adding another pulley - an "idler" pulley, with a spring loaded attachment to dampen the fluctuations that are inevitable. One of Actobotics' Aluminum Robotic Shocks ( https://www.servocity.com/aluminum-robot-shocks ) might be just what you need to do that.

Also, a larger pulley size on the other end (not attached to the servo) might reduce some vibration.

First thing to try, before everything mentioned above, is to see what kind of vibration there is with the belt removed. It may be that the motor mount or some other components or architecture is causing the vibration. If you find the vibration is still there with the belt removed, then it could be that the way you are driving the motor (electronically) is what is really causing the vibration, and so you would need to fine tune that before moving on.


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