🔍 Key Concepts

• Shaft generator speed vs electrical frequency – what happens to output frequency when main engine/shaft speed changes? • Difference between rectifying AC to DC and inverting DC to AC, and how these can be combined to change frequency. • Why the diagram labels one group as frequency sensitive loads and shows the frequency converter feeding those loads.

💭 Think About

• Look at the symbol inside the frequency converter box. Does it show AC becoming DC first, or DC becoming AC first, or both? • Ask yourself: is the shaft generator’s raw output frequency constant or does it vary with propeller/engine speed in this installation? How does that affect what the bus needs? • Which choice describes a process that would take the shaft generator’s type of AC and turn it into the kind of AC that frequency sensitive loads require?

✅ Before You Answer

• Verify whether the shaft generator, driven by the main engine, will normally produce variable frequency AC as shaft speed changes. • Confirm which process name is correct: rectification is AC → DC, and inversion is DC → AC. • Match the final output required at the bus: should it be constant frequency AC or variable frequency AC for the frequency sensitive loads shown?