I have a question regarding inertia and friction between gears. I have a gear which is connected to the rod at one end and an electric motor which is connected to the other end. I know the torque of the rod and I want to calculate the torque of the motor I need. I have been told that I can't lay on transmission ration only and I also have to include the calculations of the inertia and friction between gears.
Can please someone explain me how should I do it (every example will appreciated).
To turn your gear from rest, you'll need to overcome the inertia of your entire system (rod and gear).
Torque = inertia x angular acceleration. You'll need to figure out what angular (rotational) acceleration you need/can get from your motor. You can approximate inertia with I = (1/2) x mass x radius^2.
You can approximate gears being 95% efficient if you're using spur gears (straight teeth). This means 5% of the energy put in is being lost as friction. So your required motor torque = (operating torque + acceleration torque)/ 0.95 efficiency [friction].
