In: Physics
Hey there!
By the given data since you have the rpm and the details of the shaft , let me assume that you have the values of Magnetic field "B", frequency "f" , which means the number of complete rotations per second.
The formula for this setup could be same as that of an AC generator. That is,
and
where, is the net emf , A is the cross sectional area , B is the magnetic field and t is the time taken for total number of rotations.
If this value of the emf has to be converted into current, then a load can be connected , which is of resistance R, and hence by Ohm's ;aw we could say that the current generated here would be
Hence
I hope the explanation helps... Cheers :)