You have a gearbox rotating an axle at constant speed. What external forces do you have resisting the rotation? What about the bearings? What happens to torque when axle rotation has to be accelerated?
Ok,I have to give a lot more details for my question.
There is a solid cylinder in picture. Max Surface speed is 1m/s on the cylinder. I want to calculate how much torque of gearbox for turnnig the cylinder with 1m/s? I will use motor and gearbox for turnning the cyclinder.
So I need to torque value on the axle or output of the gearbox. When I calculate it,and then I can choose gearbox model.
I'm assuming this is a project for school. Have you taken any basic physics courses yet?
There's a torque required to overcome forces resisting the rotation of the cylinder. There's also a torque required to increase the rotational velocity of the cylinder. There is no torque required above and beyond these two. You haven't mentioned any external forces acting on the cylinder, so I'll have to assume there are none. In that case, you only need torque to accelerate the cylinder so it's rotating at the speed you want, and then the only torque required is that needed to overcome any bearing resistance or possibly some very minor wind resistances, though from the looks of it you won't have any significant aerodynamic loading on this cylinder.
If you need to accelerate the mass at a certain rate, you need to consider how much torque is required to do that. Check one of these web pages:
http://theoryx5.uwinnipeg.ca/physics/rot/node5.html [Broken] http://hyperphysics.phy-astr.gsu.edu/Hbase/n2r.html
""If you need to accelerate the mass at a certain rate, you need to consider how much torque is required to do that""
I agree the points you said But i have one querey
TOrque=I * Alpha
While designing if we consider induction motors it will behave differently.
how to consider acceleration timings alpha to get required torque?