Electrical

Question 1

What provides normal AC power?

Answer 1

IDGs

Question 2

What connects the Main AC buses ?

Answer 2

2 Synchronous buses

Question 3

What are the auxiliry sources of AC power?

Answer 3

2 APU generators
2 EXT power connections

Question 4

How is AC converted to DC?

Answer 4

Transformer Recifiers

Question 5

When on the ground, auxiliary AC power can be provided by ________.

Answer 5

2 APU generators or
2 EXT power connections

Question 6

T/F: Both AC and DC Power Flow are displayed on the Electrical Synoptic Display.

Answer 6

False

Question 7

What is the normal position of the Split System Breaker?

Answer 7

Closed and the AC buses are interconnected

Question 8

How is IDG oil cooled?

Answer 8

By Engine fuel flow and fan bypass air

Question 9

What do the IDG DRICE DISC switch fo?

Answer 9

Disconnect the IDG from the engine, must be reset on the ground

Question 10

When will the split system breaker be open?

Answer 10

When two aux sources on the ground are powering the system
A fault is detected

Question 11

When is uninterrupted power transfer availible?

Answer 11

On the ground only

Question 12

What does turning a IDG GEN CONT switch to OFF do?

Answer 12

Opens the associated Generator Control Breaker.

Question 13

When can IDG disconnect be preformed?

Answer 13

With the engine running above idle speed

Question 14

What does a IDG DRIVE light indicate?

Answer 14

IDG Oil Pressure
IDG Oil Temperature

Question 15

When will an automatic IDG disconnect occur?

Answer 15

With engine running and excessive oil temperature detected.

Question 16

What connects the auxiliary power to the main AC busses?

Answer 16

The synchronous bus

Question 17

What power Main Deck Cargo Handling Bus?

Answer 17

Number 2 Auxiliary Power Source

Question 18

There are ______ IDGs, _____ APU generator(s), and _____ external power source(s) that supply AC power to the B747-400.

Answer 18

4,2,2

Question 19

T/F: Disconnecting an IDG is an irrevocable action that can only be reset on the ground.

Answer 19

True

Question 20

External Power and an APU generator cannot both be connected to the same side of the synchronous bus simultaneously. What divides the synchronous bus and allows each side to be powered by two different auxiliary sources?

Answer 20

Split System Breaker (SSB)

Question 21

How many IDGs are required to power the electrical system?

Answer 21

1

Question 22

What is the purpose of the ground handling bus?

Answer 22

Power items without the need of flight deck activation.

Question 23

How is the ground handling bus powered?

Answer 23

When any auxiliary power is available

Question 24

How is the main deck cargo handling bus powered?

Answer 24

Any auxiliary power 2
APU 2 or EXT 2 only if they are NOT ON

Question 25

What powers the ground service bus?

Answer 25

AC bus 1

Question 26

If the ground handling bus is powered, how can the ground service bus be used?

Answer 26

By pressing the GND service switch by door L1

Question 27

What are the Captain/FO transfer bus power?

Answer 27

Critical flight equipment

Question 28

What is the ELCU?

Answer 28

Electrical Load Control Unit, protects electrical system from utility load faults and load management by auto load shedding.

Question 29

Each IDG normally powers its related AC bus through a _________.

Answer 29

Generator Control Breaker (GCB)

Question 30

T/F: The Ground Handling Bus is never available during flight.

Answer 30

True

Question 31

The Captain's Transfer Bus is normally powered by ________.

Answer 31

AC Bus 3

Question 32

If the Left Utility Power switch is ON, which utility busses are powered?

Answer 32

Utility Bus 1 and Utility Bus 2

Question 33

What is a DCIR?

Answer 33

DC Isolation Relay, provides an interconnection between all DC busses

Question 34

What powers the MAIN BATT BUS and APU BATT BUS?

Answer 34

DC BUS 3 or the respective HOT Battery BUS

Question 35

How can the battery busses receive power from the HOT battery busses?

Answer 35

Battery must be ON and AC Bus 3 unpowered

Question 36

Where is battery information displayed?

Answer 36

Status page

Question 37

What is on the MAIN Hot Battery Bus?

Answer 37

-APU Fuel SOV, Spar Valves all engines -APU and Lower cargo fire extinguishers -Engine fire extinguishers -Fire Switch Unlock

Question 38

What is on the APU Hot Battery Bus?

Answer 38

-IRU L, C, R DC Power -Left and Right Outflow Valve -APU Inlet Door, APU Controller

Question 39

What powers the Battery Chargers?

Answer 39

AC Bus 1

Question 40

How do the Battery Chargers function?

Answer 40

They act as TRU for the associated HOT Battery Bus and also charge the battery

Question 41

What is another sources that can power the Battery Chargers?

Answer 41

GND Service Switch

Question 42

When will the Standby Inverted be powered?

Answer 42

A loss of power on DC Bus 3

Question 43

The four main DC busses are connected through ____ to the DC tie bus.

Answer 43

DC Isolation Relays (DCIR)

Question 44

T/F: There are NO switches or relays to control power to the Hot Battery busses.

Answer 44

True

Question 45

Why are the busses isolated during an autoland?

Answer 45

To prevent faults to crossover onto other busses

Question 46

During an autoland, when are the busses isolated?

Answer 46

Descending below 1,500' RA

Question 47

During an autoland, what busses are isolated and why?

Answer 47

AC and DC 1,2, and 3 This separates the 3 autopilots

Question 48

During an autoland, what powers the synchronous bus?

Answer 48

AC bus 4

Question 49

What indication does the crew get when the busses are isolated for an autoland?

Answer 49

None

Question 50

What is displayed on the Electrical Synoptic Display during an autoland?

Answer 50

“ELECTRICAL SYNOPTIC INHIBITED FOR AUTOLAND”

Question 51

How is Autoland Isolation cancelled?

Answer 51

-Autoland is canceled -TO/GA is activated -Autopilot Disengaged -Loss of autoland redundancy

Question 52

Autoland Isolation occurs during what conditions?

Answer 52

Autoland approach, when descending below 1,500' RA

Question 53

T/F: The Electrical Synoptic is inhibited during autoland.

Answer 53

True

Question 54

What normally powers the captains transfer bus?

Answer 54

AC Bus 3

Question 55

What will power the captains transfer bus if AC Bus 3 fails?

Answer 55

AC Bus 1

Question 56

As it relates to the captains transfer bus, what will happen if both AC Bus 1 and 3 fail?

Answer 56

The APU Standby Bus will be powered by the APU Standby Inverter.

Question 57

When the APU battery charger is not powered, how long can the APU battery provide power and to what?

Answer 57

Minimum of 30 minutes to the APU standby inverter and the Standby Bus

Question 58

If AC Bus 3 is not powered, the Standby Bus will be automatically powered by the _____________.

Answer 58

Standby Inverter

Question 59

The Standby Power Selector is required to be in the _____ position for the automatic switching of the Standby Power System.

Answer 59

AUTO