Quote:
Originally Posted by dradel
Having a problem trying to find out the force required to back drive a versa 2 stage box.
Plan would be bag motor driving a 2 stage box first and second stage at 10:1 giving an overall 100:1 with 1/2" hex output.
Also anyone know what the no load speed would be?
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This is the exact same setup that The GreenHorns have for our winch. We used the hex output shaft to drive a 1 1/2" pulley by press fitting a versa hub inside it. It would get us 21" off the ground before really struggling and eventually stalling. The pulley was about 3 inches wide so the pulley grew in diameter as it wound up. The JVN calculator said it should take about 5.5 seconds for it to winch us up to that 24" mark.
I'd recommend a smaller diameter pulley than 1.5" because that's pushing the limits. Another thing to note is that out robot weighed only 86 lbs with the battery and without bumpers. A single bag motor at 100:1 is pushing it I think. It would suck to have an underpowered winch.
Mixing and matching the motors/gearboxes/gear ratios to get that winch to lift the robot in under 10 seconds was fun. Like trying to solve a puzzle (however we didn't have all the pieces i.e. gearboxes at our disposal).
Edit: Also, we didn't experience any backdrive when our robot was in the air. Again, it was only 86 lbs.