In an AC generator, the field windings are energized by the _____.

In an AC generator, the field windings are energized by the exciter. The exciter provides the necessary DC power to the field windings, which is crucial for establishing the magnetic field needed for the generation of electricity. This magnetic field interacts with the armature windings in the rotor or stator of the generator, inducing an alternating current.

The role of the exciter is essential because it enables the generator to produce the required voltage output by controlling the strength of the magnetic field. By adjusting the excitation level, operators can regulate the output voltage of the generator to match the demands of the electrical load.

Alternators and power transformers have different functions within the electrical system. An alternator specifically refers to the machine itself that generates AC power, and while it's involved in the generation process, it does not provide the DC excitation to the field windings. A power transformer is used for voltage regulation and transferring electrical energy between circuits but also does not supply the excitation for the field windings in the generator.