Aircraft Electrical Systems Flashcards
7 cards from real AMT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Aircraft Electrical Systems flashcards as text
What is the function of a voltage regulator in an aircraft generator system?
Answer: To maintain constant generator output voltage under varying loads
The voltage regulator controls generator field current to maintain a steady output voltage regardless of electrical load or engine speed changes.
When troubleshooting an open circuit, a voltmeter connected across the break will read:
Answer: Full system voltage
In an open circuit, the voltmeter reads full supply voltage across the break because no current flows and the entire EMF appears across the open point.
Aircraft wiring AWG (American Wire Gauge) sizing is selected primarily based on:
Answer: The current load and allowable voltage drop over the wire length
Wire gauge must handle the circuit's current without overheating and keep voltage drop within acceptable limits for the length of the run.
A reverse current cutout relay (or reverse current relay) in a DC generator system opens when:
Answer: Generator output falls below battery voltage causing reverse current flow
When generator voltage drops below battery voltage, current would flow backward from battery to generator; the relay opens to prevent this reverse flow and possible generator damage.
Which of the following best describes a 'phantom load' in an aircraft electrical system?
Answer: A continuous small current drain from devices left energized when the master switch is off
Phantom (or parasitic) loads are small but continuous drains from clocks, memory circuits, or improperly wired equipment that can discharge the battery over time.
The purpose of a current limiter (fuse link) between the battery and main bus is to:
Answer: Protect the heavy feeder cable from a catastrophic fault current
A current limiter is a high-amperage slow-blow protective device that guards the main feeder against fault currents that smaller circuit breakers cannot handle.
In an AC aircraft electrical system, frequency is expressed in hertz (Hz). What is the standard frequency used in most transport-category aircraft?
Answer: 400 Hz
Aircraft AC systems operate at 400 Hz, which allows smaller, lighter transformers and motors compared to the 60 Hz used in commercial ground power.