What is an exciter rotor in an AC alternator? What does it do? How does it work?

What is an exciter rotor in an AC alternator?

The exciter rotor is a component part an AC generator (or alternator) and forms part of the alternators excitation system. It is manufactured primarily from wound copper and electrical steel.

What does the exciter rotor do?

The exciter rotor has AC current induced as it rotates on the main rotor shaft inside the exciter stator. The exciter rotor then passes this energy to the main rotor via the diodes.

How does an exciter rotor work?

The exciter rotor generates electrical energy as it spins because the magnetic field of the exciter stator cuts through the copper windings of the exciter rotor, inducing a voltage. The induced power in the exciter rotor varies depending on the power supplied to the exciter stator by the AVR, which monitors the voltage at the generator terminals and tries to correct it to a pre-set value.