pic: what is cooking

There are lots of different CAE / FEA type packages to do the testing. Of course, you could also do it old-school. Do it by hand. I don’t do this very often, but… I’d check the hub, the spokes, and the teeth in different calulations. Have to estimate the forces - remember that start and stop are very much higher than forces during drive.

I know there are people out here that would do a much better job of explaining this than I would, but rest assured, you can do a good job by hand calcs. One of those things you learn in school.

it is not the small CIM but the large CIM to be clear.

ah, well then…

free speed of around 2500 rpm down to 2.2…gear ratio of 1136…at your max current of 40 A, then that’s 1136*240 oz-in = 272700ish oz-in, and then considering dynamic loading you need to multiply that by at least a factor of 2 for safety one would think. 550000 oz-in is a pretty hefty requirement. Although, to be honest you will probably never ever ever see anything in FIRST that requires that sort of reduction to do something. Unless next year’s game is pick up an elephant and hang your robot on the bar carrying the elephant…which WOULD be pretty sweet to see aside from animal rights issues…

Also consider that every mesh you make decreases efficiency by a few percent.

Just things to keep in mind. :slight_smile: Keep up the good work.

the large gear reduction is for the speed that the arm gos up :slight_smile:

if it has that much strength than i need # 35 chain instead of # 25

So are you just trying to reduce the speed of the motor? IE, is maximizing torque the concern or do you just want it to move slower?

both