Hi

I just started to read whole website.

On page:

http://www.societyofrobots.com/mechanics_gears.shtml I think there is a mistake.

In section Compound Gears there is a formula for torque gear calculation:

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In this example, what minimum torque does the motor need to pull the weight up?

writing down the equations:

torque_motor * radius_gear1 = torque_gear2 * radius_gear2

torque_gear2 * radius_gear2 = torque_gear3 * radius_gear3

torque_gear3 * radius_gear3 = weight * radius_gear3

simplifying, we get:

torque_motor * radius_gear1 = weight * radius_gear3

so therefore the minimum required motor torque is

torque_motor = weight * radius_gear3 / radius_gear1

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BUT THE UNITS are not ok...? how can moment can be compare to load (mass)?....

can someone verify my opinion?