Aircraft Electrical Power System Maintenance

What is the role of the Permanent Magnet Generator (PMG) in the IDG system?

Supplying power to the aircraft electrical systems
Rectifying electrical output
Monitoring oil levels
Cooling the alternator (correct)

What happens if there is an in-flight oil loss or over temperature condition in the constant-speed drive unit?

The CSD re-engages automatically
Warning indicator illuminates on the flight deck (correct)
The aircraft loses power immediately
The cooling oil temperature increases

Why does the text mention that the term 'generator' is still used even though these items are brushless alternators?

To highlight their cooling features
To explain their power output in kVA
To discuss their speed of 12,000 rpm
To emphasize their function in the IDG system (correct)

What is the purpose of the quick attach/detach (QAS) adapter in the CSD and IDG systems?

To achieve easy connection/disconnection (C) Signup and view all the answers

Why is it important to monitor the oil level in most constant-speed drives?

To ensure proper cooling capacity (C) Signup and view all the answers

What is the significance of the electrically activated generator-drive disconnect mechanism in constant-speed drive units?

To disengage the CSD in specific situations (A) Signup and view all the answers

What manuals are referenced for performing maintenance on aircraft electrical systems?

Aircraft Maintenance Manual, The Wiring Diagrams Manual, Illustrated Parts Catalogue, and component vendor manuals (D) Signup and view all the answers

Which ATA chapters do transport aircraft maintenance manual systems comply with for electrical power?

Both ATA 20 Standard Practices and ATA 24 Electrical Power (C) Signup and view all the answers

How does a typical large aircraft electrical power system supply power?

Both AC and DC power (D) Signup and view all the answers

What type of system do aircraft almost without exception use for electrical grounding?

Negative-grounding system (B) Signup and view all the answers

What does connecting the negative terminal of the battery to the metallic portion of the aircraft structure achieve?

Places the structure at a negative potential (D) Signup and view all the answers

Which manual specifies the compliance with Air Transport Association (ATA) Specification Reference under chapters ATA 20 Standard Practices and ATA 24 Electrical Power?

Transport Aircraft Maintenance Manual (D) Signup and view all the answers

What is the purpose of the master switch in the transistorised voltage regulator system?

To supply initial excitation to the alternator field (C) Signup and view all the answers

How does the alternator rotor field gain earth in the transistorised voltage regulator system?

Via biased-on transistor T1 (B) Signup and view all the answers

What causes the charge indicator light to extinguish in the transistorised voltage regulator system?

Equal potential on each side of the light (C) Signup and view all the answers

Which component biases transistor T2 on in the transistorised voltage regulator system?

Zener Diode (ZD) (A) Signup and view all the answers

What happens when transistor T2 biases on in the transistorised voltage regulator system?

Causes a voltage drop across R4 (C) Signup and view all the answers

How does the alternator voltage drop occur in the transistorised voltage regulator system?

When resistors R1, R2, and R3 conduct current (C) Signup and view all the answers

What is the purpose of a rectifier circuit?

To convert alternating current into direct current (C) Signup and view all the answers

What does a tap represent in a transformer winding?

A wire connection made at some point on a winding (B) Signup and view all the answers

In a Transformer Rectifier Unit (TRU), what type of input does it typically operate on?

Three-phase AC input (B) Signup and view all the answers

How is the output voltage in a rectifier circuit compared to the input voltage?

Output voltage is always lower than the input voltage (C) Signup and view all the answers

What component is commonly used in rectifier circuits to allow current flow in only one direction?

Diodes (D) Signup and view all the answers

What is the frequency of the AC input typically used for Transformer Rectifier Units?

400 Hz (D) Signup and view all the answers

What maintains the breaker contacts in the closed position under normal current flow conditions in a Reverse Current Circuit Breaker system?

Magnetic field set up by the current flow through the RCCR (B) Signup and view all the answers

What happens to the reverse current circuit breaker when the generator output drops below the battery level?

Remains closed as current magnitude is low (A) Signup and view all the answers

Which component of the DC-generating system is supplied power through the auxiliary contacts of the RCCR?

Generator shunt field circuit (D) Signup and view all the answers

What is the function of the cut-out relay in a Reverse Current Circuit Breaker system?

De-energize the line contactor during reverse current flow (B) Signup and view all the answers

Which action causes the line contactor in a Reverse Current Circuit Breaker system to be de-energized?

Generator shutdown or output failure (B) Signup and view all the answers

What keeps the reverse current circuit breaker closed when reverse current flows through the system?

Current magnitude below trigger value (A) Signup and view all the answers