Electrical System

Question 1

Batteries (#, volts, amps)

Answer 1

3, 24vDC, 40amps

Question 2

Engine Driven DC Starter-Generators (#, volts, amps)

Answer 2

2, 28vDC, 400amps

Question 3

APU Generator 
#,volts, amps

Answer 3

1, 28v DC, 400amps

Question 4

TRUs #, voltage, amps

Answer 4

2, 28v DC, 300amps

Question 5

DC GPU

Answer 5

1, 28v DC

Question 6

Batteries (names)

Answer 6

3, Main, Auxiliary & Standby

Question 7

Battery Location

Answer 7

• Main & Auxiliary batteries are located on the left side nose of the aircraft (lower panel)
• Main Battery is also located forward of the Auxiliary battery in the lower panel
• Standby battery is located on the left side nose of the aircraft (upper panel)

Question 8

Which battery(s) are able to assist with engine starts (when performing external power starts or battery starts)

Answer 8

Main & Auxiliary batteries

Question 9

Which battery(s) supply DC power to the “HOT battery bus” for the operation of various emergency system operations

Answer 9

Standby Battery

Question 10

Which battery(s) supply emergency backup power to the airplane’s “Essential DC buses” and for how long

Answer 10

All 3, (approx.45 minutes)

Question 11

Which battery(s) for a second engine start MUST show a _ or less on the MFD- Electrical Systems Page

Answer 11

All 3 batteries for a second engine start MUST show a .4 or less on the MFD- Electrical Systems Page

Question 12

Battery Master Switch closes…

Answer 12

o Closes 3 contactors directly connecting all 3 batteries to the “Essential DC buses”

Question 13

Main Battery Switch connects…

Answer 13

o Directly connects the Main battery to the “RIGHT Main DC bus” allowing a two-way power flow

Question 14

Auxiliary Battery Switch connects…

Answer 14

o Directly connects the Aux battery to the “LEFT Main DC bus” allowing a two-way power flow

Question 15

Standby Battery Switch connects…

Answer 15

o Directly connects the Standby battery to the “LEFT Main DC bus”, allowing a “one-way” power flow (battery charging ONLY)

Question 16

BATTERY TEMPERATURES
• WHITE
• AMBER
• RED

Answer 16

normal range
when 50° C to 65° C
temperature greater than 65° C

Question 17

How many Engine Driven Starter-Generators

Answer 17

2

Question 18

Engine Driven Starter-Generators

•Driven by the___ of each engine and are___cooled

Answer 18

engine accessory gearbox, air

Question 19

Engine Driven Starter-Generators

• Each DC Starter-generator is monitored and controlled by its respective___

Answer 19

Generator Control Unit (GCU)

Question 20

Engine Driven Starter-Generators
• After engine start and NH of___, the GCU converts the starter-generator from a starter mode of operation to a generating mode

Answer 20

50%

Question 21

Engine Driven Starter-Generators

• GCU also ensures that the generator maintains a constant supply of (volts and amps) to its associated…

Answer 21

28.5v DC, 400 amps, “Main DC bus”

Question 22

Engine Driven Starter-Generators
• Electrical Emergency occurs when a failure on___“DC Generators” AND___
. The EPCU automatically disconnects the batteries from the “Main buses” leaving them only able to supply power to the___ for approximately___

Answer 22

BOTH, a third AC power source failure (i.e. AC TRU) total 3 items. “Essential buses” (approximately 45 minutes).

Question 23

DC GPU (Ground Power Unit)
•	Receptacle located on\_\_\_

Answer 23

the left side of the nose of the aircraft

Question 24

DC GPU (Ground Power Unit)
•	Power is directly received by the \_\_\_

Answer 24

“LEFT Main DC bus”

Question 25

``` DC GPU (Ground Power Unit) • “Auto Bus Tie” Closure enables ___ ```

Answer 25

ALL 6 DC Buses to be powered

Question 26

``` DC GPU (Ground Power Unit) • Engine DC generators and the APU generator are inhibited from coming online while in ___ configuration ```

Answer 26

Auto Bus Tie

Question 27

``` DC GPU (Ground Power Unit) • EPCU will automatically disconnect if the external DC voltage drops below ___ or exceeds ___ ```

Answer 27

22 volts, 31 volts

Question 28

Main Bus Fault • Electronic Power Control Unit (EPCU) confirms an actual “Main Bus Fault” and will automatically take offline all ___ components associated with the faulty bus (___) leaving the fault bus unpowered and isolated • Abnormal Checklist will instruct the crew to cycle the “Bus Fault Reset” switch in an attempt to reset the EPCU’s bus fault protection logic

Answer 28

DC, (i.e. DC starter-generator & batteries)

Question 29

How many TRUs

Answer 29

2

Question 30

TRU's | •Located in the___ section of the nose and are___-cooled

Answer 30

upper right, air

Question 31

TRU's | •Converts___

Answer 31

115vAC to 28vDC

Question 32

• Each TRU then supplies___ power to its respective ___

Answer 32

28vDC, “Secondary DC Bus”

Question 33

APU GENERATOR | • Supplies ___ power to the ___ during ground operations only

Answer 33

28vDC, “Essential, Main, and Secondary DC buses”

Question 34

APU GENERATOR | • Provides ___power in parallel with the___

Answer 34

28vDC, Engine DC Starter-generators

Question 35

How many AC Generators and voltage

Answer 35

2, 115vAC

Question 36

AC GENERATORS | • Mounted on (driven by) the ___ and ___ cooled

Answer 36

propeller reduction gearbox and oil-cooled

Question 37

AC GENERATORS | • Power is supplied to the___ busses

Answer 37

“Left and Right variable AC buses”

Question 38

AC GENERATORS | • The following systems and components require 115 volt variable AC power: (5)

Answer 38

``` o De-Icing/Anti-Icing Heaters o Standby Hydraulic pump (#1 Hydraulic System) o Transformer Rectifier Units (TRUs) o #1 and #2 Auxiliary Fuel pumps o Galley loads ```

Question 39

AC GENERATORS | • AC power will ___ provide support for engine start

Answer 39

Not

Question 40

• AC External Power can power ___ via the ___

Answer 40

ALL “AC & DC Buses”, TRU’s