Electrical

Question 1

What Display Units normally display when Batteries are set to “On” and “Auto”?

Answer 1

• Display Units 2 and 3 (CA’s MFD / EICAS)

Question 2

What provides AC power to the aircraft?

Answer 2

• 2 Integrated Drive Generators (IDG)
• Auxiliary Power Unit (APU)
• AC Inverter
• Ram Air Turbine (RAT)
• AC GPU

Question 3

What provides DC power to the aircraft?

Answer 3

• 2 NiCad batteries
• 3 Transformer Rectifier Units (TRU)
• DC GPU

Question 4

The IDG(s) are monitored and controlled by what?

Answer 4

• Dedicated Generator Control Unit (GCU)

Question 5

The amber IDG light(s) will illuminate for?

Answer 5

• High oil temperature

- Low oil pressure

Question 6

The priority for AC power on the aircraft is?

Answer 6

• Onside (IDG)
• Inside (APU)
• Outside (GPU)
• Cross-Side (other IDG)

Question 7

How are the aircraft batteries charged?

Answer 7

• An AC power source providing power to the TRU(s)

Question 8

The batteries should last for how many minutes without being recharged?

Answer 8

• 10 minutes

Question 9

What is the purpose of the inverter?

Answer 9

• Converts 28 VDC from the batteries to 115 VAC to power the AC
  STANDBY BUS when an AC source is not available.

Question 10

What is powered via the AC STANDBY BUS?

Answer 10

• Engine Exciters 1A and 2A

Question 11

When will the RAT deploy?

Answer 11

• Main AC BUSSES loss power

- Manually via the RAT Deployment Handle

Question 12

How long after deployment before the RAT will supply power?

Answer 12

8 seconds

Question 13

Is there a total loss of power during the 8 second RAT deployment?

Answer 13

• NO, because the Batteries supply power to the DC ESS BUSSES and AC
  STANDBY BUS.

Question 14

What does the RAT directly power?

Answer 14

• AC ESS BUS

Question 15

What is minimum airspeed that the RAT is capable of providing AC Power?

Answer 15

• 130 kts (load shedding occurs below this speed)

Question 16

The Integrated Drive Generators (IDG’s) and APU Generator are electrically
rated at ___?

Answer 16

• 115 VAC
• 40 KVA
• 400 Hz

Question 17

What is the RAT rated at?

Answer 17

• 115 VAC
• 15 KVA
• 400 Hz

Question 18

Describe how BATT 2 is configured during an APU start?

Answer 18

• BATT 2 is isolated from the system and tied directly to the APU START
  BUS to power the APU Starter

Question 19

What is min BATT VDC to start the APU without following a Recharge
Procedure?

Answer 19

• 22.5 VDC

Question 20

What type of batteries do we have?

Answer 20

• Two NiCad 22.8 VDC, 27 Amp batteries