Whar are stators and rotors

It is the active parts of an alternator. The rotor is the inside rotating part that is connected via slip ring to a DC voltage normally supplied by the exciter, that can be a DC generator on the same shaft as the rotor or it can be a diode bridge that is converting AC from the stator to DC and is regulated by the AVR(Automatic Voltage Regulator). The rotor serves is the rotating magnetic field that is induced in the stator where the output AC mains is generated