ELECTRICAL

Question 1

What happens to the APU and RAT when both transfer busses are lost in flight?

Answer 1

The APU automatically starts and the RAT automatically deploys

Question 2

What are the components of the standby electrical system?

Answer 2

The Main battery, Standby inverter, RAT generator, and the C1 and C2 TRUs

Question 3

What causes the IDG drive to automatically disconnect from the engine?

Answer 3

High generator drive temperature

Question 4

The engine airplane AC/DC electrical load is supplied by ______.

Answer 4

any two main AC power sources

Question 5

Secondary external power can power the ______.

Answer 5

left and right main busses

Question 6

What does the illumination of a generator DRIVE light indicate?

Answer 6

Low IDG oil pressure

Question 7

The primary external AVAIL light illuminates when the ______.

Answer 7

primary power source voltage and frequency are within limits

Question 8

The external AVAIL light means power is plugged in and ______.

Answer 8

voltage and frequencies are within limits but not yet selected/connected

Question 9

The BACKUP GEN OFF Light illuminated indicates _______.

Answer 9

a backup generator failure, a circuit fault, or the switch is off

Question 10

Pushing the IFE/PASS SEATS power switch to OFF removes power from what?

Answer 10

All inflight entertainment components

Question 11

Once one engine is started, with no other electrical source providing power and the BUS TIE switches
are in AUTO, the ______ powers both main busses.

Answer 11

IDG

Question 12

The primary power source for the flight control DC electrical system are the _______ backup generator
PMGs.

Answer 12

left and right

Question 13

If demand from the RAT exceeds capacity to provide hydraulic and electrical power, which has priority?

Answer 13

Hydraulic power - electrical load is shed until satisfactory hydraulic pressure can be
maintained

Question 14

What does the main DC electrical system use to produce DC power?

Answer 14

TRUs

Question 15

Several events can cause the backup AC electrical system to operate automatically, one of these events
is when _____.

Answer 15

power to one or both main AC busses is lost

Question 16

The ground service bus is normally powered by the right main bus. The ______ and ______ are alternate
sources of power.

Answer 16

APU generator, primary external power

Question 17

When the GEN CTRL switches are ON, the generator breaker is armed to close automatically when
generator power is ______.

Answer 17

available

Question 18

The main battery provides standby power to the ______.

Answer 18

hot battery bus, battery bus, and standby inverter

Question 19

When AC power is removed from the airplane with the BATTERY switch ON, the PA system remains
powered ______.

Answer 19

in flight or on the ground

Question 20

The backup generator system automatically powers the right transfer bus when _____.

Answer 20

approach mode (APP) is selected

Question 21

The main battery charger, when powered, will power the ______.

Answer 21

hot battery bus

Question 22

The ______ normally supply power to the flight control DC electrical system.

Answer 22

PMGs

Question 23

What is the maximum altitude for APU start?

Answer 23

43,100 feet

Question 24

Each engine-mounted backup generator contains _____ permanent magnet generator(s) (PMG).

Answer 24

2

Question 25

Inflight, when both BUS TIE switches are set to AUTO, the priority for powering the left and right main busses is the ______.

Answer 25

respective IDG, APU generator, opposite IDG

Question 26

The ______ powers the AC standby bus if the left transfer bus is not powered

Answer 26

standby inverter

Question 27

Several items are powered by the ground handling bus, item(s) include the _____.

Answer 27

forward and aft cargo doors

Question 28

During power source transfers (such as switching from the APU generator to an engine generator) operating sources are momentarily paralleled to prevent power interruption _____.

Answer 28

on the ground

Question 29

While on the ground, normally the IDG can be electrically disconnected from the main busses by selecting an external electrical power source or ______

Answer 29

by selecting the GEN CTRL switch to OFF

Question 30

On the ground, power transfers are made without interruption, except when ______.

Answer 30

switching between primary and secondary external power sources

Question 31

Pushing the CABIN/UTILITY power switch to OFF removes power from the ______.

Answer 31

ground service bus

Question 32

If primary external power is powering one or both main busses, and then the APU is started, the APU automatically connects to _______ after reaching operating speed.

Answer 32

the left main bus

Question 33

Which of the following is NOT powered by the ground service bus?

Answer 33

Refueling panel

Question 34

If the electrical loads exceed power available (airplane or external), ELMS ______.

Answer 34

automatically sheds nonessential systems

Question 35

Can you turn the battery off in flight?

Answer 35

No, the switch is inhibited

Question 36

How does the APU generator compare to the IDGs?

Answer 36

It is electrically identical to the IDGs

Question 37

What does the main DC electrical system use to produce DC power?

Answer 37

TRUs

Question 38

If an IDG is manually disconnected in flight with the DRIVE DISC switch, can the pilots reconnect it?

Answer 38

No, maintenance action is required on the ground