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Re: Buggy BAG Motors
Our robot has three BAG motors: two that drive lead-screws that power our chin-up arms, through 20:1 VersaPlanetary gearboxes; and one that drives our scoop-store-shoot mechanism's tilt control, through a 100:1 VersaPlanetary gearbox and 3.6:1 VEX 20dp gearset, for 360:1 overall ratio. The tilt is back-driveable, and the leadscrews are not.
So far we have not seen any of the failures described in this thread. I have spoken and emailed with Paul a few times about the issue, and believe that his team is diligently pursuing a solution.
BTW, several other things on our robot have been stressed to failure already. The BAG motors have gotten very hot several times, even emitting smoke once or twice, but are still working well. After the drive team reported seeing smoke I took the motors off and measured free Amperes, still normal.
I like the BAG motor design for power and thermal robustness -- my personal theory is that the root cause of the failure mode reported here will ultimately be found to be an armature production process, either winding tension or commutator tang crimping, that is not properly controlled.
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Richard Wallace
Mentor since 2011 for FRC 3620 Average Joes (St. Joseph, Michigan)
Mentor 2002-10 for FRC 931 Perpetual Chaos (St. Louis, Missouri)
 since 2003
I believe in intuition and inspiration. Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution. It is, strictly speaking, a real factor in scientific research.
(Cosmic Religion : With Other Opinions and Aphorisms (1931) by Albert Einstein, p. 97)
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