Electrical

Question 1

Electrical

Which AC buses are depicted on the Synoptic ?
115 VAC or 235 VAC ?

Answer 1

235 VAC

Question 2

Electrical

How are lower amperage loads distributed ?

Answer 2

By the RPDUs (remote Power Distribution Units)

Question 3

Electrical

What manages the circuit breakers ?

Answer 3

The CBIC (Circuit Breaker Indication and Control)

Question 4

Electrical

Which equipment are energized by the Towing Power mode ?

Answer 4

• Captain’s audio control panel
• Captain’s flight interphone
• flight deck dome lights
• Aisle stand flood lights
• Navigation lights
• Brakes
  NOTE : the radio communication systems are NOT energized.

Question 5

Electrical

3 Permanent Magnet Generators (PMGs) provide power to which system ?

Answer 5

The Flight Control Electronics.

The FCE also have 2 dedicated batteries in case of temporary loss of regular power.

Question 6

Electrical

Where is the Main 115 VAC system located ?

Answer 6

FWD E/E bay as well as the 28 VDC system

Question 7

Electrical

How are higher amperage loads distributed ?

Answer 7

By the main electrical busses

Question 8

Electrical

Where is the Main 235 VAC system located ?

Answer 8

AFT E/E bay

Question 9

Electrical

What is the purpose of the Power Electronics Cooling System (PECS) ?

Answer 9

To dissipate the heat generated by the high voltage motor controllers.

Question 10

Electrical

What do the motor controllers do ?

Answer 10

They regulate the frequency power sent to large motor loads.

Question 11

Electrical

2 Permanent Magnet Alternators (PMAs) provide power to which system ?

Answer 11

The Electronic Engine Control (EEC)

Question 12

Electrical

In addition to traditional electrically powered systems, which other systems does the 787 electrical system power ?

Answer 12

• Engine start
• Pressurization
• wing ice protection
• Stabilizer trim
• 2 pairs of spoilers
• wheel brake systems

Question 13

Electrical

Can ECBs (electronic circuit breakers) be controlled via the CBIC ?

Answer 13

YES they can.

Question 14

Electrical

How many electrical power sources are there ?

Answer 14

17 !

• 3 External Power receptacles (2 FWD, 1 AFT)
• 4 Engine starter/generators VFSGs (variable frequency)
• 2 APU starter/generators (variable frequency)
• 1 RAT
• 1 main battery
• 1 APU battery
• 3 PMGs (Permanent Magnet Generators) powering the FCEs
• 2 PMAs (Permanent Magnet Alternators) powering the EECs

Question 15

Electrical

Can TCBs (thermal circuit breakers) be controlled via the CBIC ?

Answer 15

NO, only an Indication can be given.

Question 16

Electrical

When is the PECS (Power Electronics Cooling System) energized ?

Answer 16

When:

• APU is running or,
• One or both engines is running or,
• A FWD external power is connected and selected ON

Question 17

Electrical

What powers the 28 VDC system ?

Answer 17

The 235 VAC system through power conversion devices.