RS775 Gearboxes

[rahilm]

Originally Posted by Chris is me

4 is complete overkill. They're roughly 240W motors if I recall correctly - think the equivalent of a 2010 FP motor.

~390 if I did my math correctly; ~(voltage)*(stall current)/4 = (12)*(130)/4 = 390 (not factoring in motor inefficiency)

Also, the 2010 FPs had roughly 190w. This year's have 290w. (Both figures from the FIRST motor curves)

Originally Posted by noa_n_f

Thanks for the fast responses. If I go for two RS775, what typ of gear ratios should I be looking for? It will be a parallel lift with a diagonal surgical tubing assist. I'm looking to making the arm raise and lower as quickly as possible without worrying about the motors not being able to handle it.

The reduction we're going with is a 512:1 (256:1 with banebots gearbox, and then 2:1 with sprocket). This gives us ~576 lb-ft of torque if you go with 65% gearbox efficiency, which is more than enough to lift it, while we still have 25RPM, which is 150deg/s.