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Unread 04-02-2017, 23:14
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cbale2000 cbale2000 is offline
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AKA: Chris Bale
FRC #5712 (Gray Matter)
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Re: 2.5" CIM Motor stops when climbing

Quote:
Originally Posted by Ether View Post
He's not using a strap. He's using a 1.5 cm diameter cord:
Didn't see that response.
In that case would depend on how that specific cord wraps up.

The example I gave was based on my own testing and estimates, individual results may vary.


Quote:
Originally Posted by cbale2000 View Post
Based on the math I've done you need about a 9:1 ratio between the CIM motor and the spool (assuming a 1" diameter spool and a ratchet strap-style rope) to lift a fully loaded FRC robot with a decent margin of error (stalls at ~277lbs).

The biggest ratio you can get practically with sprockets (at least easily available ones) is about a 5:1. Now that said, at a 5:1 ratio, if you double the number of motors running it (like adding a second CIM to the opposite side of the system) that 5:1 ratio would work just fine.

Ideally though you would want a proper gearbox that will get you closer to that 9:1 ratio.
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