Electrical

Question 1

The minimum battery voltage for APU start is____.

Answer 1

• 23 volts

Question 2

When a source of power is connected to a bus system, _____ occurs.

Answer 2

• it automatically disconnects an existing source

Question 3

What does a GRD POWER AVAILABLE light do?

Answer 3

• provides flight deck indication that AC ground power is connected to the aircraft and meets aircraft power
  quality standards

Question 4

If the BUS TRANS switch is in the AUTO position and the source powering the transfer bus is disconnected or
fails, what does the source powering the opposite transfer bus through the BTBs do?

Answer 4

• automatically picks up the unpowered transfer bus

Question 5

What do the three transformer rectifier (TR) units do?

Answer 5

• convert 115-volt AC to 28-volt DC

Question 6

What do the three transformer rectifier (TR) units do?

Answer 6

• convert 115-volt AC to 28-volt DC

Question 7

Inflight, when does an amber TR UNIT light illuminate?

Answer 7

• TR1 or TR2 and TR3 has failed

Question 8

How long does a fully charged battery have sufficient capacity to provide electrical power for? (Single-
Battery configuration)

Answer 8

• A minimum of 30 minutes

Question 9

When does an amber BAT DISCHARGE light illuminate?

Answer 9

• excessive battery discharge is detected

Question 10

When does an amber BAT DISCHARGE light illuminate?

Answer 10

• excessive battery discharge is detected

Question 11

If one or more of the following buses are unpowered, __________, it is indicated by an illuminated STANDBY
Power (PWR) OFF Light

Answer 11

• all answers are correct

Question 12

In flight or on the ground, with the STANDBY POWER Switch in AUTO (guarded position) in with the loss of all
AC power, the AC standby bus is powered by __________________ and the DC standby bus is powered by

Answer 12

• The battery

Question 13

The light on the overhead panel that illuminates if the APU is running and not supplying power to a bus, is
the_____.

Answer 13

• APU GEN OFF BUS

Question 14

On the ground and inflight, the APU generator can supply power to ____________.

Answer 14

• both transfer busses

Question 15

The electrical system is designed to ___________ during single generator operation.

Answer 15

• shed electrical loads incrementally

Question 16

When ____ oil is sensed in the IDG, the amber DRIVE caution light is illuminated.

Answer 16

• low

Question 17

It _________ possible to reactivate the IDG in flight after the IDG disconnect switch is used to disconnect the
IDG from the engine.

Answer 17

• is not

Question 18

Which of the following can cause IDG low oil pressure?

Answer 18

• IDG automatic disconnect due to high oil temperature
• IDG disconnected through the generator drive DISCONNECT switch