🔍 Key Concepts

• Difference between AC output and DC field excitation in an AC generator • Role of the field winding and how its magnetic field strength affects output voltage • How a voltage regulator controls generator voltage indirectly

💭 Think About

• Ask yourself: In a typical ship’s AC generator, is the rotating field usually supplied with AC or DC? • Consider which quantity, when changed, directly changes the strength of the magnetic field in the rotor and therefore the induced voltage in the stator. • Think about whether changing speed is the normal method of voltage control on an alternator that must stay at a constant frequency (60 Hz).

✅ Before You Answer

• Identify which choice correctly refers to field excitation as being DC, not AC, in a standard shipboard AC generator. • Verify which option describes changing the magnitude of the excitation current rather than changing speed or the regulator’s own supply. • Confirm that the method you pick would allow voltage control without changing frequency (which is tied to RPM).