A330 Electrical

Question 1

If APU and EXT A and B are connected which system has priority over which?

Answer 1

• APU GEN will have priority over EXT B to power AC1

- EXT A will power AC2

Question 2

How much power can each EXT PWR supply?

Answer 2

90kVA max

Question 3

How long does NBPT take?

Answer 3

• Milliseconds

- APU can take up to 15sec

Question 4

Once the IDG’s are disconnected, can they be re-connected?

Answer 4

Only on ground by maintenance

Question 5

If the EMER GEN is powered by the RAT only, what can occur?

Answer 5

• If slats are extended, EMER GEN deactivates

- Can be re-activated when slats are retracted and MAN ON pb is pressed.

Question 6

Which has a higher priority? GEN 1/2, APU GEN, EXT A/B

Answer 6

1. GEN 1/2
2. APU GEN
3. EXT A/B

Question 7

How many generators are there?

Answer 7

• 2 engine generators
• 1 APU generator
• 1 emergency generator

Question 8

Where are the circuit breakers located?

Answer 8

Electronic Equipment Bay (Avionics Bay)

Question 9

How much power can each GEN supply?

Answer 9

115kVA of three phase 115/200V 400Hz

Question 10

What does NBPT stand for?
What does this system do?
When is it active?

Answer 10

• No Break Power Transfer
• Prevents busbar power interruption during supply source transfer
• On ground only

Question 11

How is the emergency generator driven?

Answer 11

• By the green hydraulic circuit via
• Engine 1 and or 2
• RAT

Question 12

How are GEN1 and GEN2 driven?

Answer 12

By engine 1 and 2 via an integrated drive

Question 13

What happens when both GEN1 and GEN2 are lost?

Answer 13

• The emergency gen kicks in

Question 14

What system controls the contactors?

Answer 14

Electrical Contactor Management Unit (ECMU)

Question 15

What happens if one generator is shut down due to over-current detection?

Answer 15

• The related AC BUS is lost

- No re-configuration

Question 16

If one generator is lost what happens?

Answer 16

• Re-configuration

- GEN1/2 powers complete system

Question 17

How does the ECMU control the NBPT?

Answer 17

It takes control of both busbars for a short period of time and synchronizes the frequencies.

Question 18

If AC1 fails, what happens?

Answer 18

• Re-configuration
• AC1 is lost completely
• AC2 powers AC ESS and ESS TR

Question 19

How much power can the APU GEN supply?

Answer 19

115kVA of three phase 115/200V 400Hz

Question 20

What happens when the ESS TR and TR 1 or 2 has failed?

Answer 20

• The DC ESS bus is lost

Question 21

What happens when one of the TR’s fail?

Answer 21

• Re-configuration

- The other TR replaces the faulty one

Question 22

Where can electrical power be supplied from?

Answer 22

• 2 Generators
• 1 Emergency Generator
• APU Generator
• 3 Batteries (1 for APU start only)
• 2 External Power Plugs

Question 23

How is the APU generator driven?

Answer 23

Directly by APU

Question 24

What system controls the NBPT?

Answer 24

ECMU

Question 25

How are the main generators controlled? What does it control?

Answer 25

• Generator Control Unit

- Frequency and Voltage

Question 26

What two types of electrical supply does the A330 have?

Answer 26

• 115/200V 400Hz AC

- 28V DC

Question 27

Your APU is inop and you’ve started one engine on the bay and you decide to start the second engine during pushback, what do you need to be aware of?

Answer 27

• There is no NBPT active between GEN1 and GEN2

- Power interruptions may occur in system (cabin systems)

Question 28

How much power can the emergency generator supply?

Answer 28

• 8kVA three-phase 115/200V 400 Hz

- when RAT supplies power and speed below 260kts then 3.5kVA