🔍 Key Concepts

• Difference between droop and isochronous speed governing for alternators • How frequency (speed) changes as load (kW) increases on the curves for machines A and B • What an isochronous speed characteristic looks like on a frequency vs. load graph

💭 Think About

• Look at machine A’s curve in figure A: as alternator power increases, what happens to system frequency? Does this match droop or isochronous behavior? • Now compare machine B’s curve: does its frequency stay exactly constant with changing load, or does it also change with load? • On a frequency vs. kW graph, which governing mode would be represented by a perfectly horizontal line, and which by a sloping line?

✅ Before You Answer

• For a droop governor, verify that frequency decreases as load increases (a downward‑sloping line). • For an isochronous governor, verify that frequency remains constant with load (a horizontal line). • Confirm whether either machine’s curve is horizontal over the whole load range shown. This tells you which answers you can immediately eliminate.