B-737 Ng - Electrics

Front 1

When would the BAT DISCHARGE light illuminate?

Back 1

With the battery switch ON, indicates excessive battery discharge

Front 2

On the ground what is meant when the TR UNIT light is illuminated?

Back 2

Any TR unit has failed

Front 3

In flight what is meant when the TR UNIT light is illuminated?

Back 3

TR1 failed

OR

TR2 and TR3 failed

**Verify it on the Electrical panel

Front 4

Can the ELEC light illuminate in flight?

Back 4

No, only on the ground

Front 5

What does the ELEC light illuminated indicate?

Back 5

A fault exists in the DC OR standby system

Front 6

Does the IFE/PASS SEAT switch work?

Back 6

No, placarded inoperative

Front 7

When does the IDG automatically disconnect?

Back 7

High IDG oil temperature

Front 8

Can the IDG be reconnected in flight?

Back 8

No, on the ground, engine not running

Front 9

Does the APU have an IDG?

Back 9

No, it has it own generator

Front 10

When connecting one source of power to a transfer bus what happens to the previous source?

Back 10

The previous source automatically disconnects

Front 11

Where is the Ground Service switch?

Back 11

Forward Flight Attendants panel

Front 12

How many IDG's are there?

Back 12

2

Front 13

What AC busses do the Transfer busses power?

Back 13

2 Galley busses, Main bus and Ground Service bus

AC Transfer bus 1 also supplies power to AC Standby bus

Also power TRU's

Front 14

What does BTB stand for and what do they do?

Back 14

Bus Tie Breakers

If a power source supplying the Transfer bus fails the BTBs will allow the opposite transfer bus to be powered off that power source

Front 15

What is the automatic generator online feature?

Back 15

If the airplane takes off with the APU powering both transfer busses and the APU is either shutdown or fails the Engine generators are automatically connected to their related transfer bus.

This can only occur once per flight

Front 16

For single generator operation what is load shed and on what transfer bus does this occur first?

Back 16

Galley and Main bus on AC Transfer bus 2 are shed first followed by Galley and Main busses on Transfer bus 1 if more shedding is required.

Front 17

Is load shedding automatic?

Back 17

Yes

Front 18

Once dual generators are supplying power to their individual transfer busses after load shedding does the load restoration occur automatically?

Back 18

Yes

Front 19

In flight if the APU is the only source of electric power what gets load shed?

Back 19

All galley and main busses

Front 20

When does the DRIVE light illuminate?

Back 20

Engine shutdown

HOT (High IDG Oil Temp)

Engine shutdownHOT (High IDG Oil Temp)IDG FaultIDG manually disconnected

IDG Fault

IDG manually disconnected

Front 21

A single battery can provide standby power for how long?

Back 21

30 minutes

Front 22

Dual batteries can provide standby power for how long?

Back 22

60 minutes

Front 23

How many TR Units are there and how are they powered?

Back 23

3

Powered by the AC Transfer busses

Front 24

What is the difference between a Hot battery bus and a battery bus?

Back 24

Hot Battery bus items are directly linked to the battery and can drain it without the battery switch being turned ON.

A battery bus relies on the battery switch being ON to receive DC power. The same is true with the switched hot battery bus in the 737

Front 25

With the BUS TRANSFER switch in AUTO what happens during a FD or A/P ILS approach at glideslope capture?

Back 25

The cross tie repay opens which causes the DC system to isolate to prevent a single failure from affecting both sides of the DC power system and therefore both sides of the AP/FD Nav equipment

Front 26

Single and Dual batteries voltage?

Back 26

22-30 volts

Front 27

With a loss of all Engine and APU electrical power what is the standby source and what busses are powered?

Back 27

The battery is the Standby Power source. It powers;

DC standby bus

AC Standby bus using a static inverter

Battery Bus

Hot Battery Bus

Switched hot Battery bus

Front 28

Once the battery charger has finished charging the batteries does it do anything else?

Back 28

It reverts to TR mode and powers the Hot Battery bus and the switched hot battery bus

Front 29

What does the static inverter do?

Back 29

Converts DC from the battery to AC power during loss of normal electrical power to power the AC standby bus

Front 30

On standby power what displays will be working?

Back 30

Captain side DU, upper DU, Captain CDU

Captain nav radios (Nav, ADF)

RMI

Clock

Left IRS

Crossfeed valve

Front 31

How are emergency exit lights powered?

Back 31

A seperate battery which last 20 minutes. They charge when the switch is in the OFF position

Front 32

What does the APU GEN OFF BUS light indicate?

Back 32

The APU is running and not powering any AC transfer bus

Front 33

What does the GEN OFF BUS light indicate?

Back 33

IDG is not supplying power to the related transfer bus (breaker is open)

Front 34

What does the SOURCE OFF light indicate?

Back 34

No source has been MANUALLY selected to power the related transfer bus OR

The manually selected source has been disconnected

Front 35

How are the IDG's cooled?

Back 35

Engine fan air and fuel flow

Front 36

When the GROUND POWER AVAILABLE light is illuminated what does that mean?

Back 36

Ground power is connected and meets the power quality standards

Front 37

Using external power can the Ground Service busses be powered without applying power to the whole system?

Back 37

Yes, the forward flight attendant panel switch GROUND SERVICE can be pushed to directly apply power to ground service busses without powering the system using external power

Front 38

When will the GEN OFF BUS light extinguish after the IDG is running?

Back 38

When the GEN switch is turned on to power the associated AC TRANSFER bus

Front 39

When will the TRANSFER BUS OFF light illuminate?

Back 39

When the associated AC Transfer Bus is not being powered

Front 40

When will the STANDBY PWR OFF light illuminate?

Back 40

When there is no power supplied to the ONE OR MORE of the following busses;

DC Standby Bus

AC Standby Bus

Battery Bus

Front 41

What are some systems the CAB/UTIL switch provide power to?

Back 41

Galley busses

Logo lights

Front 42

What does the DC bus tie relay do on a A/P or F/D ILS approach?

Back 42

Opens to allow each AP to be powered by its own source (DC bus 1 and 2)

Front 43

What does moving the standby power switch to BAT do?

Back 43

Forces battery power to operate the Standby buses;

AC standby

DC Standby

Front 44

What is IDG power output?

Back 44

Three phase, 115 volt, 400hz AC

Front 45

What is the DC System voltage?

Back 45

28 volt