Electrical

Question 1

What is the ram air turbine used for?

Answer 1

Emergency generator inflight when both AC Buses 1 and 2 are not powered

Question 2

What does the ram air turbine (RAT) supply power to?

Answer 2

The ESS Buses

Question 3

What speed is required for the RAT to supply power to the AC/DC Buses

Answer 3

130 kt

Question 4

Is there an altitude restriction on the RAT?

Answer 4

No altitude restriction

Question 5

What comprises the DC electrical system?

Answer 5

• 2 batteries

* 3 TRUs

Question 6

What supplies power to the APU START BUS during APU starts?

Answer 6

Battery #2

Question 7

Describe the batteries

Answer 7

Two NiCd 22.8 VDC 27A batteries

Question 8

Minimum battery temperature for starting the APU

Answer 8

-20°C

Question 9

How are the batteries charged?

Answer 9

Constantly charged by any AC source through the TRUs, including the AC GPU and RAT

Question 10

What are the IDG’s and APU rated at?

Answer 10

40 kVA, 115 VAC, 400 hz, three-phase

Question 11

What is the source priority for powering the plane?

Answer 11

• Respective IDG
• APU generator
• GPU on ground
• Opposite IDG

Question 12

What components are turned off via load shedding?

Answer 12

• Galleys

* Right windshield heating

Question 13

What causes the amber IDG light on the overhead panel to illuminate?

Answer 13

• High oil temperature

* Low oil pressure

Question 14

Can an IDG be reconnected if it was manually disconnected?

Answer 14

No

Question 15

What is the purpose of the TRU’s?

Answer 15

Converts 115 VAC to 28 VDC

Question 16

How long will the aircraft batteries last with no recharging?

Answer 16

10 minutes

Question 17

What compromises the AC electrical system?

Answer 17

• Two IDG’s
• One APU
• One inverter
• One RAT
• One AC external power unit

Question 18

How long after the RAT deploys will it take to power the AC ESS BUS?

Answer 18

After 8 seconds

Question 19

What are the TRU’s rated at?

Answer 19

300 A

Question 20

When will the BATT 1 (2) OVERTEMP EICAS message trigger?

Answer 20

Battery temperature reaches 70°C for at least 2 seconds

Question 21

Minimum battery voltage to close the battery bus ties

Answer 21

18 volts

Question 22

What is the RAT rated at?

Answer 22

15 kVA, 115 V AC, 400 hz, 3 phase

Question 23

Which ACMP does the RAT power?

Answer 23

ACMP 3A

Question 24

Which circuit breakers can only be reset by maintenance?

Answer 24

ICC remote thermal circuit breakers

Question 25

What items are on the hot battery buses?

Answer 25

• Engine fire extinguisher
• Engine fuel SOV
• Engine hydraulic SOV
• Engine oil level
• Refuel panel
• DC service lights

Question 26

What items are on the STBY AC BUS?

Answer 26

• Engine exciter 1A

* Engine exciter 2A

Question 27

When is the RAT icon displayed on the electrical synoptic page?

Answer 27

When the RAT is deployed

Question 28

What manages the electrical system?

Answer 28

• 4 integrated control centers (ICC)

* 2 secondary power distribution assemblies (SPDA)

Question 29

What is the purpose of the ICC?

Answer 29

• Electrical control device

* Provides power distribution and protection for electrical loads

Question 30

What is the purpose of SPDA?

Answer 30

•Distributes electrical loads to aircraft systems