friday test

✈ DC Alternator Systems – Final Practice Test (MC Only)

📝 Multiple Choice

1. The primary advantage of a DC alternator system is that full output is available regardless of:
A. Battery condition
B. Electrical load
C. Engine RPM
D. Ambient temperature

2. An alternator differs from a DC generator because it does NOT use a:
A. Rotor
B. Stator
C. Commutator
D. Field

3. The brushes in an alternator contact:
A. Commutator bars
B. Armature windings
C. Copper slip rings
D. Diodes

4. The rotor in a DC alternator functions as the:
A. Output winding
B. Armature
C. Field
D. Rectifier

5. The stator in a DC alternator is responsible for:
A. Providing excitation current
B. Rotating the magnetic field
C. Receiving induced current
D. Regulating voltage

6. Alternators have reduced wear compared to generators primarily because they have:
A. Higher voltage
B. Lower resistance
C. Less friction in field windings
D. More brushes

7. In a DC alternator system, AC is converted to DC by:
A. Slip rings
B. Commutator
C. Diodes
D. Brushes

8. Diodes used in alternators are best described as:
A. Mechanical switches
B. Solid-state devices with high reliability
C. Rotating electrical contacts
D. Current storage units

9. Which of the following can damage diodes?
A. Low voltage
B. High voltage and reverse current
C. Low current
D. Constant RPM

10. A reverse current relay is NOT required in alternator systems because:
A. The battery prevents reverse flow
B. The rotor controls current direction
C. Diodes block reverse current
D. The stator regulates voltage

11. Alternators typically do NOT require a current regulator because:
A. The voltage regulator replaces it
B. The windings limit maximum current
C. The battery controls output
D. The rotor is stationary

12. A voltage regulator controls alternator output by adjusting:
A. Stator resistance
B. Armature speed
C. Field circuit resistance
D. Diode polarity

13. The purpose of a voltage regulator is to maintain:
A. Constant current
B. Constant voltage
C. Constant RPM
D. Constant resistance

14. The latching circuit helps keep the master solenoid closed when:
A. Voltage is high
B. Engine is off
C. Battery voltage is low during starting
D. Alternator is offline

15. The latching circuit ensures the starter can:
A. Reduce voltage
B. Operate properly
C. Increase RPM
D. Limit current

16. Reverse current protection between the battery and alternator is provided by a:
A. Relay
B. Fuse
C. Diode
D. Switch

17. Which circuit breaker will shut down the alternator system if tripped?
A. MAIN BUS
B. BATTERY
C. ALT FIELD
D. AVIONICS

18. Continuous tripping of a breaker usually indicates a short in the:
A. Stator
B. Rotor
C. Battery
D. Voltage regulator

19. The ammeter indicates:
A. Voltage output
B. Engine speed
C. Electrical load in amperes
D. Frequency

20. The amount of charging current required depends primarily on:
A. Engine RPM
B. Battery state of charge
C. Alternator size
D. Wire length

21. In most alternator systems, the ammeter is red-lined at 100% output:
A. Always
B. Never
C. Only at idle
D. Only during startup

22. A common method to check alternator output is to:
A. Reduce RPM
B. Turn on landing lights and observe amperage
C. Disconnect the battery
D. Check frequency

23. If the ammeter reads below aircraft load plus battery demand, you should:
A. Increase RPM
B. Replace alternator
C. Reduce electrical load
D. Turn off regulator

24. Which of the following will show a noticeable increase on the ammeter?
A. Landing lights
B. Radio
C. Pitot heat
D. All of the above

25. Which system can be easily checked using only the ammeter?
A. Pitot heat
B. Starter motor
C. Landing gear
D. All of the above

✅ Answer Key

🔥 Last-Minute “Don’t Miss These” (High Probability)

These WILL show up in some form:

Commutator → NOT in alternator
Diodes → block reverse current
ALT FIELD breaker → shuts system down
Rotor = field
Stator = output
Voltage regulator → controls FIELD resistance
6 diodes
Battery charge = controls current demand