🔍 Key Concepts

• Relationship between prime mover speed and generator frequency when directly coupled • Difference between generator protection (electrical/magnetic/thermal) and prime mover protection (mechanical/lubrication/cooling) • Which conditions require an immediate automatic trip to prevent severe mechanical damage

💭 Think About

• Which of the listed conditions, if not corrected instantly, would most quickly and permanently damage the prime mover’s bearings or moving parts? • For a directly coupled set, does a change in frequency or power factor normally cause an automatic shutdown of the engine/turbine itself, or some other type of control action? • Which options are about electrical performance of the generator versus mechanical health of the driving machine?

✅ Before You Answer

• Identify which answer choices describe electrical characteristics of the generator (not usually cause for immediate prime mover shutdown). • Identify which choice directly relates to bearing protection and lubrication, which is critical for any rotating machinery. • Ask: Which condition would standard safety systems be designed to trip the prime mover on, rather than just alarm or reduce load?