What is the primary function of the rotor shaft in an alternator?

The primary function of the rotor shaft in an alternator is to hold all rotating components together. This includes maintaining the structural integrity of the rotor assembly while allowing for the necessary rotational motion to generate electrical power. The rotor shaft connects the rotor to the prime mover, such as a turbine or an engine, enabling it to rotate and interact with the stator to produce electricity through electromagnetic induction.

The other functions mentioned in the available choices are important in the overall operation of an alternator, but they do not define the primary purpose of the rotor shaft itself. Generating electrical output, regulating voltage, and connecting the exciter are all tasks performed by other components in the alternator system. The rotor shaft’s main role is to provide the physical support for these components and facilitate the required motion for electricity production.