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Unread 22-01-2017, 16:58
Donut Donut is offline
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Re: What is your drivetrain's top speed?

Quote:
Originally Posted by Billfred View Post
As for Iron Kings, we'll be around 15 theoretical or about 13 in practice. 5.95:1 gearing, 4" HiGrip wheels.
We're running the same setup with wheels from 2015's kit since we used 6" wheels that year.

Quote:
Originally Posted by Billfred View Post
If you use two CIMs or one, your top speed will not increase--simply how fast you get to it (and how much current a motor will draw). To go faster, you would have to change the gearing or start integrating motors with a higher free speed (like a Mini CIM, whose free speed is about 500 RPM faster).
I understand the theoretical max speed won't increase with additional CIMs since they all have the same free speed, but won't the effective speed you can reach change because of the additional torque available at the same point on the motor torque/speed curve? If the kitbot is rated at 75% of free speed due to friction losses on one CIM per side, then I would think the additional CIM per side would add enough extra power to run at a higher percentage of free speed before friction becomes the limiting factor again. Is there a significant amount of friction added from the extra gear for the second CIM?
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