Motor Frictional Loss: Torque Required at Any Freq?

[Physicist3]

Is the same torque required at any freq in order to overcome these losses?

 

[Crazymechanic]

you should tell more about what your talking exactly , well from the section you posted this I assume your talking about electric motors, which in most cases have only two bearings , all other parts ar non friction ones , except for the commutator in dc or AC synchronous motors, which for friction loss is extremely small.
Every motor needs to exert most torque at the beginning of operation , the higher the rotor goes in rpm the less force is needed to achieve even higher ones and overcome the same friction , because of back EMF and also because of inertia.

 

[Baluncore]

As the speed of an electric motor rises the bearing friction will rise in proportion to the speed.
As the speed of an electric motor rises the windage drag will rise in proportion to the square of the speed.