DC Generation and DistributionAircraft & Engines — DGCA CPL practice questions
Question 1 of 5
In a DC generator, the device that converts the armature's AC into DC output is the:
All 5 questions — DC Generation and Distribution
Aircraft & Engines · DGCA CPL. The correct option is marked on each.
Q1. In a DC generator, the device that converts the armature's AC into DC output is the:
- A.Slip ring
- B.Commutator✓
- C.Rectifier diode
- D.Voltage regulator
Why: The commutator mechanically reverses the connections every half turn. Alternators instead rectify their AC output with solid-state diodes.
Q2. Compared with a DC generator, an alternator on a light aircraft:
- A.Is heavier and less efficient at low RPM
- B.Takes its high output current from stationary windings and works better at low RPM✓
- C.Needs no voltage regulation
- D.Produces DC directly
Why: The rotating-field/stationary-armature design avoids passing load current through brushes — lighter, more reliable, better at low RPM.
Q3. A voltage regulator holds generator output constant by:
- A.Varying engine RPM
- B.Adjusting the current through the field winding✓
- C.Switching loads off
- D.Changing the propeller pitch
Why: More field current = stronger magnetic field = higher output voltage; the regulator trims field current continuously.
Q4. In an earth-return electrical system:
- A.Two wires run to every component
- B.The airframe is used as the negative conductor✓
- C.The battery is isolated from the airframe
- D.Only AC can be distributed
Why: Grounding the negative side to the metal airframe halves the wiring — a major weight saving.
Q5. A zero reading on the alternator load meter in flight indicates:
- A.The battery is fully charged
- B.Alternator failure✓
- C.Normal cruise operation
- D.An open circuit breaker somewhere
Why: The load meter shows alternator output; zero in flight means the alternator has dropped offline.