What is a main stator in an AC alternator?

The main stator is the main component part an AC generator (or alternator). It is where the electrical energy is created to supply a load. The alternators excitation system attempts to control the voltage generated in the main stator to a pre-set point. The main stator is manufactured primarily from wound copper and electrical steel.

What does the main stator do?

The main stator has AC induced in it by the main rotor spinning on its shaft. The main stator has output cables connected from it to the generator terminals which are then in turn connected to an electrical load.

How does the main stator work?

The main stator works because the main rotor has a magnetic field, generated by the excitation system. As this field cuts through the copper windings of the main stator it induces a voltage. The voltage in the main stator is dependant on the electrical load connected and the amount of excitation provided by the excitation system. The output is connected to the terminals and voltage is monitored by the AVR, which can then adjust the excitation to increase or decrease the voltage to the pre-set level.

As current is passed around the main stator generates heat. A fan mounted on the alternators shaft draws cool ambient air through the whole alternator, cooling the main stator.