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Originally Posted by DAN THE MAN

I am looking for atwood specs for this years atwood motors. i have seen alot from previous years and i need to know for sure that this years will be the exact same. as well i am unsure of what speed to use to do my calculations. i have found out that for out robot to go 5 feet /sec with a 6inch wheel i need to gear down the motor 28:1. can someone complete this calculation for me to make sure i am correct. thank you

dan the man

I dont currently have the specs but i will give you some aproximations

well under a regular load the CIM does just under 5000 (something lke 4960) rpms SO:

5000rpms /60 seconds is 83.33 rps which is 41.6 FPS with 6" circumferance whells without a tansmission.

so you equation would be 41.6fps * (gear ratio) = 5fps

that gear ration would be apx 1:8 giving you a speed of 5.2 fps under a normal load remember you need to consider load and amperage when designing a transmission theese atwoods have the potential to draw much much more than the 40amps you are allowed.

(The above is all using the 5000rpm aproximation)

For info on this i suggest you read through :
http://lancet.mit.edu/motors/

it is listed in the FRC manual on page 4 of the robot chapter.


Just as a side note i learned this lesson the hard way last year when we drew 90 amps in a stall and continually popped breakers. Its not fun at all.