In this study, flow phenomena through the axial fan and the rotor dynamic performance analysis of a permanent magnet generator with three phases has been explored for a wide velocity range by using an Ansys-Fluent computational fluid dynamics package. In this respect, velocities of dependence angle for a flat blade have been analyzed, numerically. The self-sustained air cooling performance has been optimized in order to provide more efficient machine, namely the number of blades and blade angles have been considered as different input parameters in the simulations. As a result of simulations, the optimum flat angle of the blade is determined after having the highest velocity value from the outlet of the simulation. Besides, the rotor fan power is obtained from the pressure differences between the inlet and outlet. According to the results, the highest velocity has been predicted as 1.86 m/s and power has been calculated as 0.48 W at 65 degrees of blade. In addition, the optimum number of blade has been ascertained as 40 and the velocity for this blade geometry has been found as 1.39 m/s. Consequently, the optimum rotor blade angle and number have been determined as 65 degrees and 40, respectively.