Electrical

Question 1

When does the DRIVE light illuminate on the IDG panel?

Answer 1

-IDG Failure
-engine shutdown
-IDG Automatic disconnect
-IDG disconnected with the DISCONNECT switch

Question 2

How much power is produced by the engine generators?

Answer 2

115v, 400 Hz

Question 3

What does it mean when the TRANSFER BUS OFF light is illuminated?

Answer 3

Indicates that the related transfer bus is not powered.

Question 4

What is a TRU?

Answer 4

Transformer rectifier unit

It converts AC power to DC power

Question 5

Under what conditions will the TR UNIT light illuminate?

Answer 5

On the ground for any TRU failure
Inflight, TR1 has failed or both TR2 & TR3 have failed

Question 6

The Cross Bus Tie Relay opens automatically:

Answer 6

1. At glideslope capture with the flight director or auto pilot selected to ILS approach
2. BUS TRANSFER switch selected to off

Question 7

What powers the AC STANDBY BUS?

Answer 7

Main power source is AC TRANSFER BUS 1
The secondary source is from the MAIN BATTERY through the STATIC INVERTER.

Question 8

Where does the DC STANDBY BUS receive power from?

Answer 8

TR1, TR2, & TR3

Question 9

What happens if power is not available from the TR’s in regards to the DC STANDBY BUS?

Answer 9

The DC STANDBY BUS can be powered directly by the battery

Question 10

What type of battery is there?

Answer 10

A single 24v DC nickel-cadmium battery

Question 11

What is the normal battery voltage range

Answer 11

22-30 volts

Question 12

The battery charger has two modes of operation:

Answer 12

A charge mode (when battery voltage drops below a predetermined limit
A transformer rectifier mode (completion of the charge cycle, it reverts to constant voltage TR mode. To keep the battery at full capacity

Question 13

The battery charger charges loads connected to which buses?

Answer 13

Hot battery Bus and Switched Hot Battery Bus

Question 14

If power is lost to AC TRANSFER BUS 1 or the source of power to DC BUS 1 what can power both the AC and DC STANDBY BUSES?

Answer 14

The battery charger

Question 15

How long can a fully charged battery supply standby power for?

Answer 15

A minimum of 30 minutes

Question 16

Which busses comprise the standby power system

Answer 16

HOT BATTERY BUS
SWITCHED HOT BATTERY BUS
BATTERY BUS
DC STANDBY BUS
AC STANDBY BUS

Question 17

All generators inop, equipment available: Airplane general

Answer 17

Standby compass light
White dome lights
Emergency instrument flood lights
Flight crew oxygen
Pax oxygen

Question 18

All generators inop, equipment available: Air systems

Answer 18

Air conditioning pack valves
BLEED TRIP OFF LIGHTS
Manual pressurization control
Altitude warning horn
PACK TRIP OFF lights

Question 19

All generators inop, equipment available: Anti-ice

Answer 19

Captains pitot probe heat

Question 20

All generators inop, equipment available: Communications

Answer 20

Flight interphone system
Service interphone system
Pax address system
VHF 1

Question 21

All generators inop, equipment available: ELECTRICAL

Answer 21

STANDBY POWER OFF light

Question 22

When does the STANDBY PWR OFF light illuminate?

Answer 22

Illuminates if the AC STANDBY BUS, DC STANDBY BUS, or BATTERY BUS is not powered.

Question 23

What does the blue GRD POWER AVAILABLE light indicate?

Answer 23

External power meets aircraft quality standards

Question 24

What does the blue APU GEN OFF BUS light indicate?

Answer 24

The APU is running and not powering any AC Transfer Bus.

Question 25

Which of the following causes the DRIVE light to illuminate?

Answer 25

IDG oil low oil pressure or under frequency condition

Question 26

What is the purpose of the Bus Tie Breakers?

Answer 26

Auto control AC power distribution

Question 27

What is the purpose of selecting the BUS TRANSFER switch OFF?

Answer 27

1. To inhibit Bus Tie Breaker auto switching 2. To open the cross bus tie relay

Question 28

An illuminated STANDBY PWR OFF light indicates a power loss to which bus?

Answer 28

DC STANDBY BUS BATTERY BUS AC STANDBY BUS

Question 29

The guarded STANDBY POWER switch powers what when in Auto ?

Answer 29

In flight or ground, and AC transfer busses powered: - AC standby bus is powered by AC transfer bus 1 - DC standby bus is powered by TR1,2,3 In flight or ground, loss of all AC power: - AC Standby bus is powered by Battery through static inverter - DC standby bus is powered by battery - Battery bus is powered by battery

Question 30

The guarded STANDBY POWER switch does what when in the Off position?

Answer 30

- STANDBY POWER OFF light illuminates - AC standby bus, static inverter, and DC standby bus are not powered

Question 31

The guarded STANDBY POWER switch powers what when in The BAT position?

Answer 31

- powers AC standby bus through static inverter - powers dc stand by bus and battery bus directly from the battery

Question 32

Generator drive and standby power panel: the generator drive “DRIVE” lights illuminate for what conditions?

Answer 32

DRIVE light is caused by a low pressure condition. The light illuminated when: - high oil temp (Auto disconnect) - IDG failure - Engine shutdown - IDG disconnected through generator drive DISCONNECT switch

Question 33

Generator drive and standby power panel: when will the STANDBY PWR OFF light illuminate?

Answer 33

One or more of the following buses are unpowered: - AC STANDBY BUS - DC STANDBY BUS - BATTERY BUS

Question 34

Generator drive and standby power panel: what do the generator drive DISCONNECT switches do?

Answer 34

- Manual disconnect if the associated IDG drive - Disconnects IDG if electrical power is available and engine start lever in idle

Question 35

AC/DC Metering Panel: what does the BAT DISCHARGE light when illuminated mean?

Answer 35

BAT switch is on and excessive battery discharge is detected.

Question 36

AC/DC Metering Panel: what does the TR UNIT light illuminated mean?

Answer 36

On ground: - Any TR failed In flight: - either TR1 failed or both TR 2&3 failed

Question 37

AC/DC Metering Panel: what does the electrical ELEC light illuminated mean?

Answer 37

Only illuminates on the ground: - A fault exists in the DC Standby power system or standby power system.

Question 38

AC/DC Metering Panel: what does the guarded BAT switch do? How many positions does it have?

Answer 38

Two positions ( Off and On) ON- turns the battery on, provides power to the : - Hot battery bus - Switched hot battery bus - Battery bus - AC/DC standby bus - Static inverter When in off position: - prevents automatic switching of standby bus to battery power when normal el creo also power is lost - Only hot bat bus will be powered

Question 39

AC/DC Metering Panel: what does the GALLEY or CAB/UTIL switch do in its two positions?

Answer 39

When in on position: - Supplies power to Galley 115v bus - Broadband satellite system - cabin recirc fans - Logo lights

Question 40

AC/DC Metering Panel: what does the IFE/PASS SEAT switch do?

Answer 40

When on supplies power to the broadband satellite system When off removes electrical power from broadband satellite system

Question 41

AC/DC Metering Panel: what checked limitations are there?

Answer 41

-On the ground limit one generator operation to a maximum 215amps -Don’t remove AC power from aircraft for at least 30 seconds after IRS shutdown - in flight reset of circuit should only be accomplished when directed QRH. Allow approx 2 mins before reset