# Torque required to drive

Dear all,

I need clarification regarding torque requirement in the following arrangement.
Imagine a shaft 25mm diameter 600mm length simply supported and one end.
Gear is attached to drive the shaft.
Load is externally applied via lever arm and different material(polymer) same
diameter is in contact.
My query is what is the torque required to drive this shaft arrangement.
Load,shaft geometries,speed are the known values.

My approach is assumed that at static condition load is applied over shaft, finding

the reaction force at each bearing end and from this force multiplied by bearing

mean radius with co efficient of friction of bearing which is normally(0.0025max).

Is the approach is correct?

1)My suspect is when applying force to the bearing, friction coefficient will
increase how to change of friction is accommodated?
2)Rollers in contact with pressure, to overcome frictional resistance will be less
only i.e. shaft in contact assume that 100 N is acting,to overcome this force we
will multiply with friction coefficient of two materials say 0.3 and the calculation is
100 x 0.30=30N is enough to overcome the force of 100 N
3)To find reaction force at the ends can i use of 30N instead of 100N?
4)Suppose reaction force will changes in each end,say one end is 50 N and
another end is 35N can i take highier value?
5)Above is that running torque what will the empherically starting torque to select
induction motor or servo drive motor specification.can i take say 1.5 times
running torque for both? Can i use T=IxAlpha approach?
6)In this gear is going to drive the shaft gear PCD has any influences?bcoz gear
radius is used to drive the shaft torque?

(Since image is not uploading i am narrating the problem)