🔍 Key Concepts

• AC generator excitation system and how field current affects output voltage • difference between prime mover speed control and voltage regulation • role of the armature versus the field windings in setting terminal voltage

💭 Think About

• Which part of the generator directly creates the magnetic field that cuts the armature conductors? How can we control that magnetic field strength? • Do changes in mechanical input (prime mover) mainly affect frequency, voltage, or both in a governed alternator? • What would shorting parts of the armature or changing the air-gap reluctance actually do in practice—are these precise control methods or more like design/abnormal conditions?

✅ Before You Answer

• Identify which option deals with controlling the DC field current to the rotor/field windings • Eliminate any options that would normally be fixed at design time (like air-gap dimensions) rather than adjusted during operation • Eliminate options that would cause fault or damage instead of fine voltage regulation (e.g., intentional short circuits in the armature)