🔍 Key Concepts

• Relationship between AC generator frequency and rotational speed • What a governor controls on a prime mover (engine or turbine) • Difference between controlling voltage (field rheostat) and controlling frequency

💭 Think About

• Ask yourself: Is AC frequency mainly determined by how strong the magnetic field is, or by how fast the generator is turning? • Which device in the options directly affects shaft speed of the generator set? • Which devices in the options are normally used to control voltage rather than frequency?

✅ Before You Answer

• Confirm the formula for AC frequency: f = (P × N) / 120 where P = poles, N = rpm • Identify which choice directly changes rpm under load • Eliminate any options that are primarily used for voltage regulation rather than speed control