First of all, we need to make sure that the electricity generated by the generator has a practical value (50 HZ).
The lower the speed, the more windings need to be designed in the stator coil or the rotor coil. of the generator.
For example: The generator has only one set of stator coils and one set of rotor coils. Then, to get 50 HZ AC power, generator speed should be 50 × 60 = 3000 rpm.
If there are 2 sets of stators and 1 set of rotors or 2 sets of rotors and 1 set of stators, 50×60/1×2=1500 rpm is required.