Electrical

Question 1

What are the 4 potential AC power sources?

Answer 1

1.Two IDGs (Integrated Drive Generators)
2. APU
3. ADG (Air driven Generator)
4. External Power

Question 2

What does a constant speed drive (CSD) do?

Answer 2

Allows IDG to spin at constant RPM which is better for electric as opposed to variable engine output.

Question 3

How are the CSDs depicted on the Synoptic page?

Answer 3

IDG 1 / IDG 2

Question 4

Can IDGs be reconnected inflight if failed?

Answer 4

No

Question 5

Do pilots have control over DC ties?

Answer 5

No they are completely automatic

Question 6

Which AC buses must have power for APU and Main battery charges to charge batteries?

Answer 6

Main battery must have AC Bus 1

APU must have AC service bus

Question 6

What does the AVAIL switchlight mean on AC electrical panel?

Answer 6

AC EXT power is connected and compatible with the aircraft.

Question 7

What is the difference between selecting AC external power on the electrical services panel and selecting it on the EXTERNAL services panel.

Answer 7

External panel only powers the service bus.

Inside all buses are powered.

Question 8

What are the Volts and amp hours for the main battery? APU?

Answer 8

Main = 24V 17AMP DC Bat
APU = 24V 43 AMP DC Bat

Question 9

What is the limitation regarding DC power only use on the ground? Why?

Answer 9

5 minutes. CRT screen cooling fans are AC power and they will overheat without them.

Question 10

You walk into the cabin after the secure check and you notice that the emergency lights are on, what should you do?

Answer 10

Turn off then back to arm to reset the logic.

Question 11

In flight how is the DC battery bus powered?

Answer 11

AC Bus 2 powers the ESS TRU 2.

Question 12

What happens when you bring the battery master switch ON?

Answer 12

Connects BATT BUS to MAIN BATT DIR BUS and APU BAT DIR BUS.

(SYS 6-30)

Question 13

What occurs when you select the DC service switch to on and from where will the DC service bus receive power?

Answer 13

Connects DC service bus directly to battery powered APU BATT DIR BUS

Receives power from TRU 2

(SYS 6-31)

Question 14

What are the approximate voltage, phase and frequency of the AC power?

Answer 14

115V
3 Phase
400HZ

Question 15

What is the GCU (Generator Control Unit) priority for AC BUS 1?

Answer 15

GEN1, APU GEN, GEN 2, External

Question 15

AC ESS XFER switchlight has illuminated. What does this mean?

Answer 15

AC ESS BUS switched to getting power from BUS 1 to BUS 2.

Question 16

What could cause the IDG to automatically disconnect?

Answer 16

Overtemp or overtorque

Question 17

What would you see on the electrical panel as a result of TRU 1 Failure?

Answer 17

Main tie closes and utility bus disconnected

Question 18

When would the DC EMER BUS appear on the DC electrical synoptic page?

Answer 18

1. One of two sources failed OR
2. Bus is faulted and both sources of power are removed

Question 19

What would you lose if the DC EMER BUS failed?

Answer 19

Fire protection

Question 20

Where would the ESS TRU 2 Transfer Contactor be visible and what would cause it to close?

Answer 20

Between ESS TRU 1 and ESS TRU 2 on top right of synoptic page.

“Multiple malfunctions”

Question 21

What would cause the ADG to auto deploy?

Answer 21

ADCU (auto deploy control unit) deploys when:
1. AC Bus 1 and 2 unpowered
2. No weight on wheels
3. Generator was last power source in use

Question 22

Which buses will power with ADG deployed and no other power source?

Answer 22

ADG Bus which powers AC ESSENTIAL / DC ESSENTIAL via the ESS TRU. DC Battery bus is also powered through the ESS tie.

Question 23

What does the ADG PWR TXFR OVERRIDE switch do?

Answer 23

Switches back to normal power source if one is able to be recovered after ADG is deployed.

Question 24

When will emergency lights illuminate?

Answer 24

When power is lost to either AC or DC ESS Buses.