Electric

Question 1

During takeoff if the right engine generator fails what happens to the utility and galley power?

Answer 1

Both utility and galley buses will be shed

Question 2

Where is the ground service switch used to power the ground service bus located?

Answer 2

Forward cabin flight attendant panel

Question 3

In flight, the left engine is shut down. What electrically powered items are lost?

Answer 3

Both utility buses, the left center fuel boost pump, both recirc fans, and the C2 hydraulic
pump

Question 4

What is accomplished by pushing the AC Bus Tie Switch to AUTO?

Answer 4

Arms the automatic operation of the Bus Tie Breaker

Question 5

What causes the Standby Power Bus OFF light to illuminate?

Answer 5

Loss of the Standby AC or DC bus or STBY power switch is in the OFF position

Question 6

What normally powers the Battery Bus during cruise?

Answer 6

The left DC bus

Question 7

Inflight the left generator trips off. What electrical busses are lost?

Answer 7

The two UTILITY buses and the galley buses

Question 8

Which bus is powered automatically when external power is plugged in?

Answer 8

Ground handling bus

Question 9

What automatically has the highest priority on the left main AC bus?

Answer 9

Left engine driven generator

Question 10

With external power available and the APU supplying both electrical and pneumatic power, what
happens as the first engine is started?

Answer 10

Both utility buses trip off

Question 11

What electrical bus powers the discharge squibs for the fire extinguisher bottles?

Answer 11

Hot battery bus

Question 12

What bus powers most of the fire detection systems?

Answer 12

Battery bus

Question 13

What is an integrated drive generator (IDG)?

Answer 13

Generator and CSD(constant speed drive) in one casing using the same oil

Question 14

Which has priority in supplying the ground handling bus?

Answer 14

External power

Question 15

What is required to enable the Captain’s flight instrument transfer bus to transfer with the loss of the
left main AC?

Answer 15

Both the left and right Bus Tie Switches must be in AUTO

Question 16

When will the utility buses be shed during an engine start?

Answer 16

Only when the APU is supplying electrical and pneumatic power

Question 17

With the APU supplying both electrical and pneumatic power, what happens as the second engine is
started?

Answer 17

Only when the APU is supplying electrical and pneumatic power

Question 18

With the APU supplying both electrical and pneumatic power, what happens as the second engine is
started?

Answer 18

Only the utility bus for the engine being started trips off

Question 19

During triple channel approach, the left generator is lost at 140 feet radio altitude. As a result the left
main AC bus is lost.

Answer 19

T

Question 20

What action would cause the engine generators to trip off?

Answer 20

Pushing the External Power switch ON

Question 21

With the APU supplying electrical power, what happens when the first engine starts (reaches idle
RPM)

Answer 21

The engine driven generator powers its respective main AC bus only

Question 22

With the Generator Control switch ON, what automatically closes when the engine starts?

Answer 22

Generator breaker only

Question 23

When will the APU Generator Control OFF light illuminate?

Answer 23

When the APU Generator breaker opens due to a fault

Question 24

The left main DC bus can power the battery bus with the Battery switch off

Answer 24

T

Question 25

What normally powers the battery bus during cruise?

Answer 25

L main dc bus

Question 26

What is powering the standby buses?

Answer 26

Left main AC and left main DC

Question 27

The APU can be used to power the left main AC bus while the right engine generator is powering the right main AC bus.

Answer 27

True

Question 28

To what bus is the utility bus connected, when the Utility Bus switch is ON?

Answer 28

Respective main AC bus

Question 29

What is accomplished by pushing the AC Bus Tie switches to AUTO?

Answer 29

Arms the automatic operation of the AC and DC bus tie system

Question 30

With the Bus Tie switch in AUTO, what causes the AC Bus ISLN light to illuminate?

Answer 30

Bus fault has occurred

Question 31

Pushing a Generator Control switch off opens both the field and generator breakers.

Answer 31

T

Question 32

Pushing the Generator Control switch off and then on resets the fault trip circuitry

Answer 32

T

Question 33

What does the run light on the APU control panel indicate?

Answer 33

That the APU is at operating speed

Question 34

Will the Generator Control Breaker close automatically when the voltage and frequency of the respective IDG are within limits.

Answer 34

Yes

Question 35

What has occurred if during flight an off light illuminates and the “on” indicator is visible in the generator control switch?

Answer 35

A fault has occurred and the generator control circuit breaker has automatically opened

Question 36

What can cause the DRIVE light of the GEN DRIVE DISC switch to illuminate?

Answer 36

The generator drive disconnect switch is pressed, High oil temp, Low oil press

Question 37

How many electrical buses are there in the Standby Power System?

Answer 37

4

Question 38

How is the hot battery bus normally powered?

Answer 38

Right main AC bus through the ground service bus and the main battery

Question 39

The battery bus is normally powered by the?

Answer 39

L DC bus

Question 40

What is the backup source of power for the battery bus if the normal source is not available?

Answer 40

The main battery

Question 41

The left main DC bus can charge the battery bus with the battery switch in the off position.

Answer 41

True

Question 42

The standby AC bus is normally powered by the?

Answer 42

Left main AC bus

Question 43

The standby DC is normally powered by the?

Answer 43

Left main DC bus

Question 44

With a loss of main AC and DC power what provides electrical power to the standby AC and DC buses?

Answer 44

Main bat

Question 45

An amber standby bus off light illuminates and the EICAS message Standby Bus Off displays when?

Answer 45

Either standby AC or DC bus is unpowered

Question 46

What is the priority of power supply to the main AC buses?

Answer 46

Respective engine-driven generator, APU generator, opposite engine-driven generator

Question 47

What does an ISLN light mean in the bus tie switch?

Answer 47

The switch is off or a fault has occurred

Question 48

The AC bus tie switch must be on for the DC bus tie breaker to operate.

Answer 48

T

Question 49

The ground handling bus can only be powered on the ground by?

Answer 49

Apu external power

Question 50

When the utility bus switch is “on”, the utility bus is connected to the?

Answer 50

Respective main AC bus

Question 51

The HDG is supplied from which hydraulic system?

Answer 51

Center

Question 52

Which condition is not an example of load shedding?

Answer 52

Left or right AC bus load shedding

Question 53

When will the utility bus shed during an engine start?

Answer 53

Only when the APU is supplying electrical and pneumatic power

Question 54

With the Standby Power Selector in the BAT (Battery position) _______

Answer 54

The main battery and standby inverter powers the standby AC Bus

Question 55

Which electrical power sources can provide power for the Lower Cargo Doors, Main Cargo Door, and Fueling Panel?

Answer 55

External power (AVAIL or ON) or APU generator

Question 56

What happens when you push a Generator Drive Disconnect (DRIVE DISC) switch?

Answer 56

Disconnects IDG from engine when above idle speed and opens related Generator Control Breaker