What is an exciter stator in an AC alternator?

The exciter stator 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 stator 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 stator work?

The exciter stator generates a current in the exciter rotor as it spins on the alternators main shaft. Power fed to the exciter stator by the AVR, which is monitoring the voltage from the main stator at the generator terminals. If the voltage decreases below the preset level, the AVR boots the power to the exciter rotor which is in turn passed through the rest of the excitation system and results in an increase in voltage. If the voltage at the terminals increases above the preset level the AVR reduces the power, having the opposite effect.