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Unread 20-01-2017, 01:13
Oblarg Oblarg is offline
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AKA: Eli Barnett
FRC #0449 (The Blair Robot Project)
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Re: Team 449 Climber

Quote:
Originally Posted by jojoguy10 View Post
I'd be very interested to know how it performs at about 150lbs (maximum robot weight is 154lbs)
The gearing was selected very conservatively to ensure that we're on the rising side of the power output curve.

The current gearbox is 50:1. Mini-CIM output torque is listed at 1.4 N*m. Our winch drum is 1.25'' diameter, so .625'' radius.

Neglecting friction, we have:

(150 lbs * .625'')/(1.4 N*m * 50) = ~15% of stall torque.

Now, I have really no idea how big the frictional losses actually are in this system, but I don't think there's any way they'll take us from 15% motor loading to over 50% (which is peak power, i.e. the loading for which this gearing provides optimal climb rate).

Fully-loaded climb rate (using the frictionless numbers) is somewhere around 6'' per second.

Upon reflection, we could probably gear it a bit faster (we had done the math for the gearbox when we were considering a larger-diameter winch).
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Member, FRC Team 449: 2007-2010
Drive Mechanics Lead, FRC Team 449: 2009-2010
Alumnus/Technical Mentor, FRC Team 449: 2010-Present
Lead Technical Mentor, FRC Team 4464: 2012-2015
Technical Mentor, FRC Team 5830: 2015-2016

Last edited by Oblarg : 20-01-2017 at 01:15.
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