My pulleys are going to be rotated with a 1000-2000 RPM motor, with a constant RPM controlled by a hall effect sensor, there is going to be almost no torque as one of the pulleys just has a 100 gram optical element attached to it and all the pulleys are on bearings.

Any suggestions on choosing v belt or circular belt? Price is pretty similar and v seems to reduce risk of slipping and has better grip. Cant find a disadvantage of v belts.

I just assume slippage might become in issue with round belts at these RPMs if there isn't enough grip, no other reason to not choose them over v belts, really.

I'd imagine tooted belts wouldn't provide much advantage here besides any backlash or slippage when the system begins rotating but I don't see how it would be more precise after the speed is reached and the speed and load remain constant during operation.

  • $\begingroup$ Almost forgot, a round belt may be better if your shaft is hollow as it does not need nearly as much depth. $\endgroup$ – joojaa Mar 21 '18 at 10:17
  • $\begingroup$ Not sure if I understand, the shaft of the pulley? $\endgroup$ – Mark Legault Mar 21 '18 at 10:19
  • $\begingroup$ The groove needed for a round belt is potentially very shallow so i have sometimes just made it directly on the shaft itself, this is especially useful if the shaft itself is something like 50-120 mm tubing with only few mm of wall thickness. $\endgroup$ – joojaa Mar 21 '18 at 10:25

Depends on many things. For example I have sometimes used round belts for these applications simply because i happened to have suitably sized O- rings which i could use as belts and didnt have V- belts around. This means i could have a working version today, instead of in a day or two. *

The groove for a round belt may be minimally easier to manufacture with a manual lathe. Also the round belt is slightly easier to install if you do not use a tensioner mechanism as its possible to roll it into place.

Remember that your feedback should come from the final axis thisway it hardly matters if your belt slips. Slippage may be minimal anyway, but if you are really concerned use a toothed belt instead.

* dont underestimate this, as you may end up doing some higher priority work in future. But then if you do not need to concern yourself with assembly and manufacturing choose what you think is best.

  • $\begingroup$ What about the tendency to "take a set" and introduce vibration? I know this can be problematic with automotive-scale V-belts. Would it also be a consideration for something more "instrument-scale"? $\endgroup$ – scanny Mar 21 '18 at 17:16

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