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Compound wound generator output

Aviation Mechanic Powerplant (AMP) practice question 8 of 13 on Engine Electrical Systems. ACS element AM.III.F.K5 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONWhat is characteristic of the output of a compound wound DC generator as the electrical load changes?

  1. AIt rises sharply as the load increases.
  2. BIt remains relatively constant.
  3. CIt drops off in direct proportion.
Show the answer and explanation

Correct answer: B. It remains relatively constant.

  • A — incorrect Output rising with load is the series wound generator's behavior, and that poor regulation is why the series machine is not used on airplanes.
  • B — correct The handbook states that the compound wound generator, which has one field winding in series and another in parallel with the load, produces a relatively constant output even with changes in load.
  • C — incorrect Output falling as load is added is the shunt generator's behavior, which the added series winding of the compound machine is there to offset.

BACKGROUND

A compound wound generator employs two field windings, one in series with the load and one in parallel with it. This arrangement takes advantage of both the series and the parallel characteristics at the same time. The series field tends to raise output as load current increases, while the shunt field alone would let output sag. The combination gives an output that is relatively constant even as the load changes. Aircraft generators use field windings connected either in shunt or in compound form.

STUDY TIP

Picture the two windings pulling in opposite directions as load changes, and the constant output follows naturally.

KEY POINTS

  • Compound wound means one series plus one parallel field winding.
  • The two characteristics offset each other as load changes.
  • Output stays relatively constant with changing load.

SOURCES

  • amp-powerplant/ch04.txt "Compound Wound DC Generators"
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-32B Aviation Maintenance Technician Handbook – Powerplant, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.