What 2 factors determine the output frequency of an alternator?

1) Alternator speed: Output frequency is directly proportional to the speed at which the alternator rotates. At higher speed, the induced emf, and consequently, the output frequency increases.

2) Number of poles: The output frequency of an alternator is also influenced by the number of poles on its rotor. The higher the number of poles, the lower the output frequency will be at the same speed of rotation.