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Unread 27-09-2011, 21:13
James Tonthat James Tonthat is offline
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Re: pic: 2 Speed Switching Module

No need for physics majors.

I've got to refer to this guy. Just type in gear ratios, it spits out torque, speed, and current draw numbers. It'll also indicate where cut offs for traction limiting is when you play around with the numbers.

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

You did your numbers with CIM normal load value, this means that the CIM can do this loading all day. Realistically for an FRC application, you should use at minimum the max power numbers (171 oz-in, 2655 rpm, 67.9 amps). While there are other things constraining it (speed controllers, breakers, wiring, efficiencies, etc.), this will give you a better value. When I say FRC application, I mean short pushing matches, two minute matches, etc.

Let me just say, we used 4" x 2" roughtop wheels last year at a 10.75:1 ratio and they were still spinning up the wheels.

Do yourself a favor, use JVN's calculator.

I got to ask, how are you doing your center to center distances on gears?

Edit: Forgot to say, while I wrote about the max power numbers up there, the CIMs are capable of putting out 343.4 oz-in at stall current.
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Unread 27-09-2011, 21:45
crazyStone crazyStone is offline
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Re: pic: 2 Speed Switching Module

Quote:
Originally Posted by James Tonthat View Post
No need for physics majors.


Do yourself a favor, use JVN's calculator.

I got to ask, how are you doing your center to center distances on gears?

Edit: Forgot to say, while I wrote about the max power numbers up there, the CIMs are capable of putting out 343.4 oz-in at stall current.
Thanks for that link. I got all the stats from probably the same data sheet you did for the CIM's, the normal load was picked because it would prove to some more conservative members of our team it could maintain that torque. The gears are standard andymark shifting gears for the most part and in addition their charachteristics were placed with the gear portion of design accelerator on Autodesk Inventor. On top of hand calculations to ensure proper meshing. The modules are being lasercut to ensure the precision.
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