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Unread 16-02-2015, 16:35
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dtengineering dtengineering is offline
Teaching Teachers to Teach Tech
AKA: Jason Brett
no team (British Columbia FRC teams)
Team Role: Mentor
 
Join Date: Jan 2005
Rookie Year: 2004
Location: Vancouver, BC
Posts: 1,828
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Re: pic: 5742: Capstan and String

Thanks! We actually got pretty lucky. The motor has enough torque to lift two totes and a bin (plus the rather hefty lift mechanism itself) but not quite enough torque to pull the lift mechanism apart. Okay... it wasn't luck that we had enough torque to lift the stack... that was a bit of physics and the Taigene motor power data. It was what would happen when we hit the top and the bottom of the lift that worried me. We had originally planned to add limit switches top and bottom (and if the team has time, I expect they will) but they are not required.

On the other hand, the taigene backdrives easier than I remember, so they actually have to use a bit of current to hold it in position. So long as they only use a little bit of current it seems to work okay. Cramming it full power on and stalled at the very top of the lift will trip the breakers and the lift and load will slowly descend. My faith in worm gear lifts remains solid!

It would have been nice to add a few more features... as I said to the team, "You're in really good shape for week four of build season!" But they are also in pretty good shape for week six of their rookie build season. They have a machine that moves reliably and can contribute to their alliance.

Jason

Last edited by dtengineering : 16-02-2015 at 18:29.
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