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Unread 14-01-2016, 20:26
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RoboChair RoboChair is offline
He who fixes with hammers #tsimfd
AKA: Devin Castellucci
FRC #1678 (Citrus Circuits and 5458 Digital Minds)
Team Role: Mentor
 
Join Date: Jan 2007
Rookie Year: 2005
Location: Davis, CA
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Re: Is this a safe gearbox?

Quote:
Originally Posted by Kevin Sevcik View Post
That is a good gearbox, but you do NOT want your robot to go 20 ft/s. You really, really won't be happy with the results. 20 ft/s is far too fast to control easily. You'll find yourself constantly shifting into low gear to do pretty much anything. You should really aim for a top speed of no more than 14 ft/s.
I would like to point out that 20 fps is the geared speed, actual speed will be lower. I would guess about 17fps actual. Our 2014 robot was geared to 22fps and we got an actual top speed(on an open field) of about 18-19fps and our driver was more than able to handle it. It just required practice and coding to minimize the control challenges for the operator.

You want your robot to be fast, but you are unlikely to reach top speed on the field with that gearing. I'd aim for closer to 18fps theoretical top speed. You still have the brown out issue to deal with however.

EDIT: I have never seen a CIM motor straight up die. Lose max power by some percentage, yes, but never have I seen a team fry one(heard a couple stories though where egregious operator error was at fault). Also I only have good things to say about the 3 CIM ball shifter gearboxes.
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Last edited by RoboChair : 14-01-2016 at 20:37. Reason: added info