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Re: Velocity Control - Battery Compensation Term
Quote:
Originally Posted by Ether
Consider the following thought experiment:
Take a CIM whose free speed is 5310 rpm at 12 volts and connect it to a good quality properly assembled and lubed 2:1 gearbox whose output shaft is connected to nothing (no load).
Using the same computation you did above, the CIM's speed would now be 5310*0.8 = 4248 rpm.
Now go to the motor curves for CIM and you'll see that CIM is drawing 29 amps.
Do you believe that? If not, where is the error?
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An unloaded, well lubed, 2:1 gearbox has a much higher efficiency factor and thus I would expect a higher CIM speed and lower current. If you lube the gearbox with toothpaste you might create enough friction to draw 29 amps at 4248 RPM.
The 0.8-0.9 factor approximates typical losses seen in FRC for gearboxes + belt/chain + bearing friction + wheel/roller windage.
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2016 Curie Quarter-Finalist (5803, 3310, 2168, 5940), Lubbock Regional Winner (3310, 4063, 4301), Arkansas Regional Winner (16, 3310, 6055)
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2013 Archimedes Semi-Finalist (126, 3310, 1756), Texas Robot Roundup Winner (3310, 624, 2848), Dallas Regional Winner (148, 3310, 4610)
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