AMT Aircraft Electrical Systems 4

Question 1

What is the primary advantage of a brushless AC generator over a brush-type generator in aircraft applications?

Accepted Answer

Reduced maintenance and elimination of brush wear and arcing

Answer

Brushless generators use rotating rectifiers instead of slip rings and brushes, eliminating a major maintenance item and source of radio interference.

Question 2

An aircraft static inverter is used to:

Accepted Answer

Convert DC power to AC power for AC-dependent avionics

Answer

A static inverter converts DC (typically 28V) from the battery or DC bus into AC power (usually 115V, 400Hz) needed for certain avionics and instruments.

Question 3

When connecting a ground power unit (GPU) to an aircraft, which precaution is most critical?

Accepted Answer

Verify GPU output voltage and polarity match the aircraft system before connecting

Answer

Connecting a GPU with incorrect voltage or reversed polarity can instantly damage avionics, batteries, and control systems — voltage and polarity verification is mandatory.

Question 4

A diode used in an aircraft rectifier circuit allows current to flow:

Accepted Answer

Only in one direction, from anode to cathode

Answer

A diode is a one-way electrical valve that permits current to pass from anode to cathode and blocks reverse flow, enabling AC-to-DC rectification.

Question 5

Aluminum wiring used in aircraft requires special terminal lugs because:

Accepted Answer

Aluminum oxide forms on the surface and increases contact resistance

Answer

Aluminum rapidly forms an insulating oxide layer at connection points; special inhibitor-filled lugs are required to displace the oxide and maintain good electrical contact.

(AMT) Aviation Maintenance Technician Practice Test

(AMT) Aviation Maintenance Technician Practice Test

AMT Aircraft Electrical Systems 4