Timing pulleys - fixed centers - belt tension?

[wheelman122]

I have a 5mm pitch timing pulleys approx. 8" fixed center to center distance. Do I need a tensioning device, or can I run without?

 

[Ross0684]

A lot depends on:
Reason for using timing belts(accurate positioning ?)
Belt load/driving effort required
Quality of belt
Constant running or stop/start/variable load.
I run 8 mm belts (x 13 mm wide-specials!!) on conveyor rollers at different centres, but only up to about 150 mm centres, without any issues.
If it is only a one off installation, maybe play it safe and put in a tension device(spring loaded type?)just for peace of mind.
Remember that the final centre distance is a function of number of teeth on pulleys and belt length-
talk to belt manufacturer and check if any pretension is their recommendation.
Ross

 

[MikeHalloran]

I've done it, but I would fight harder not to do it again.

With fixed center distances, you get either a little slack, or tension that's controlled by the elasticity of the belt. In the latter case, you may notice some sensitivity to the construction/ brand of belt.



Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

Oh. I almost forgot an important reason to use a tensioner:

When you lose control of the belt tension, you also lose control of the bearing loads, and life.



Mike Halloran
Pembroke Pines, FL, USA