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Unread 06-10-2013, 14:06
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Re: WCD CAD Practice

Quote:
Originally Posted by Chris is me View Post
Gates's documentation on belts is very useful, and something that should be read by anyone designing a belt drive, but at times the guide's advice and specs are quite conservative. The Gates manual recommends never using an exact-center belt drive, but for FRC drivetrain purposes (at *most* a few hundred hours run time on a well used practice robot) the factors they cite that suggest a tensioning system don't really apply.
From what I remember from the documentation isn't that they say you should never do it, but rather if you do it you should recognize you must apply a strength derating to the belt to compensate for you not having perfect tension. In reality for all FRC applications this derating should exist as even with tensioners teams aren't able to measure tension to the levels required to determine it's proper.

I only make the point for teams that are looking at a pulley setup that is right at the ragged edge. Doing exact c-c in that case will be more likely to fail than a tensioner (if the tensioner is used to really dial in tension right).

I'd rather move away from the ragged edge and just skip the tensioner, less stuff to work on.

Separately, you do raise the correct point that most of their documentation is tailored for continuous operation in factories, etc. and as such is a fair bit conservative.

Last edited by AdamHeard : 06-10-2013 at 14:09.