🔍 Key Concepts

• Relationship between field excitation and generator output voltage • Effect of prime mover speed on frequency vs. voltage in a synchronous AC generator • How load changes affect terminal voltage compared to the built‑in voltage control method

💭 Think About

• Ask yourself: in a 60 Hz, 440 V ship’s alternator running at constant speed, which quantity is normally adjusted by the voltage regulator? • Consider what determines frequency (Hz) versus what determines terminal voltage in a synchronous AC generator. • Think about which option would be practical to vary continuously in normal operation without changing the machine’s physical construction.

✅ Before You Answer

• Verify which factor the automatic voltage regulator (AVR) actually senses and adjusts to maintain constant voltage. • Confirm that frequency is tied to prime mover speed and number of poles, not the normal method of voltage control once the machine is built. • Check which option can be changed electrically and smoothly during operation, rather than being fixed mechanically by design.