United 737 Electrical

Question 1

Minimum voltage for APU start___

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 BTB’s do?

Answer 4

Automatically picks up the unpowered transfer bus

Question 5

What do the 3 TRs do?

Answer 5

Conver 115 volt AC to 28 volt DC

Question 6

Inflight, when does an amber TR UNIT light illuminate?

Answer 6

TR1 or TR2 AND TR3 has failed

Question 7

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

Answer 7

30 Minutes

Question 8

When does an amber BAT DISCHARGE light illuminate?

Answer 8

Excessive battery discharge is detected

Question 9

If one or more of the following buses are unpowered, _____ it is indicated by an illuminated STANDBY POWER PWR OFF light

Answer 9

All answers are correct

Question 10

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 10

the battery through static inverter; battery

Question 11

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

Answer 11

APU GEN OFF BUS

Question 12

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

Answer 12

both transfer busses

Question 13

The electrical system is designed to ____ during single generator operation

Answer 13

Shed electrical loads incrementally

Question 14

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

Answer 14

LOW

Question 15

Which of the following can cause IDG low oil Pressure?

Answer 15

IDG Auto Disconnect due to HIGH OIL TEMPERATURE

IDG Disconnected through Generator Drive Disconnect Switch

Question 16

An amber ___ light illuminates to indicate the DC system or standby system equipment has failed, while the aircraft is on the ground. The light is inhibited in flight.

Answer 16

ELEC

Question 17

Primary electrical power is provided by ___ engine driven IDGs

Answer 17

2

Question 18

During normal operation the guarded Standby Power Switch will be in ____ and the battery switch will be ___

Answer 18

AUTO; ON

Question 19

Which switch can be used to remove power from the left and right recirc fans, forward and aft door area heaters, lav water heaters, ECS fan, all 115V AC galley busses, 115V AC shaver outlets logo light and potable compressor?

Answer 19

CAB/UTIL SWITCH

Question 20

IFE/PASS SEAT SWITCH does what

Answer 20

removes power from 115V AC audio entertainment equip, video entertainment, airphone equipment, pax seat electronic unit

Question 21

Moving ground power switch to on does what?

Answer 21

ALL answers are correct

Question 22

What light on the overhead panel immuniates if the transfer bus is not being powered?

Answer 22

TRANSFER BUS OFF

Question 23

What light on the overhead panel illuminates if the transfer bus is not powered by the source selected by the related generator switch?

Answer 23

SOURCE OFF

Question 24

What light on the overhead illuminates if the IDG is not supplying power tot he related transfer bus?

Answer 24

GEN OFF BUS

Question 25

Moving the Generator switch to ON connects ____ by disconnecting the previous power source and closing the generator circuit breaker.

Answer 25

IDG to the AC Transfer Bus

Question 26

What light on the overhead panel illuminates if the APU is running and not supplying power to a BUS?

Answer 26

APU GEN OFF BUS

Question 27

Which switch provides manual control of ground service busses enabling servicing of the aircraft using external power without activating AC transfer busses?

Answer 27

GROUND SERVICE switch on the FWD attendant panel