Quote:
Originally Posted by Greg Woelki
Hell no, that is significantly overtensioned. If you take a closer look at that document you'll see that they aren't referring to pretensioning distances at all:
The table immediately below that you got the 0.02" and 0.03" numbers from refers to the minimum amount adjustability (think versablock) in c-c distances that they recommend so that the belt is easy to install and so that it can be tensioned as it stretches over time (as timing belts often do in industrial applications).
In FRC, however, fixed c-c distances work great because of the limited run-time of our robots, and are generally designed to be exact or a couple of thousandths large.
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The Nominal Center Distance is for very light loads, it is a zero belt tension condition. Also consider that belt lengths have tolerances (typically +/- 0.08 inches for short belts). With a Drive Train with two CIMs near stall torque; you will skip teeth if you don't have adequate tension. The only options are a tensioner or extra length in the Center Distance to insure a preload.
The belts are normally rated for 8000 hours, so run time isn't a FRC issue. Adequate Tension for the required load and speeds is a concern for reliability.
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13-10-2016, 01:42
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