As the rotor rotates within the stator windings, the DC current flowing through the windings creates a magnetic field. This magnetic field interacts with the magnetic field produced by the stator windings to induce an electromotive force (EMF) in the stator windings. The EMF causes an alternating current to flow in the stator windings, which is then converted to AC power by the alternator's rectifier.
The speed of rotation of the rotor determines the frequency of the AC power generated by the alternator. The higher the speed of rotation, the higher the frequency of the AC power.
In addition to the copper windings, the rotor of an AC alternator may also include a fan to provide cooling for the windings and a slip ring assembly to allow the DC current to be transferred to the rotor from the DC power source.
Overall, the rotor of an AC alternator plays a crucial role in generating the alternating current electrical power.
