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Unread 27-01-2011, 22:58
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More Torque!
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Re: What values of free speed RPM, stall torque, and current to use?

This might help you:

http://www.chiefdelphi.com/media/papers/2059

It's JVNs's very useful mechanical design calculator. The "Linear Mechanism" tab would probably be of greatest use to you.


Just some quick math:
100" of travel (random number approximately in the ballpark)
4 550's
30lbs (just to be safe)
1.5" pulley radius
16:1 ratio
70% efficiency
<punches numbers into calculator>
129lbs stall
0.69 sec lift time
12.13 ft/sec
14.5 amps per motor loaded

So, if you had 4 550 motors it would be really, really, really fast and come nowhere close to stalling the motors

<does more math with only 2 550 motors>
25:1 reduction (next up that Banebots makes)
1.17 sec lift time
101 lb stall
18 amps
7.11 ft/sec
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