Electrical System Flashcards Preview

E Jet 175 Study Guide > Electrical System > Flashcards

Flashcards in Electrical System Deck (34):
1

What happens if a power generating source fails?

Bus ties automatically connect to provide no system degradation.

2

What components power the AC system?

2 IDG
APU
Inverter
RAT
AC GPU receptacle

3

What components power the DC system?

2 NiCad batteries
3 Transformer Rectifier Units (TRU)
DC GPU receptacle

4

How does the IDG maintain a stable power output?

A CSD (constant speed drive) attaches the IDG to the AGB (accessory gear box)

5

What monitors and controls the IDGs?

Generator Control Unit

6

Can one IDG supply the entire electrical system?

Yes

7

What will cause the Amber IDG light on the overhead panel to illuminate?

High oil temperature
Low oil pressure
HILOP

8

If an IDG is manually disconnected can it be reconnected by the flight crew?

No.
Maintenance

9

What is the primary purpose of the AC generators?

To power the AC buses and AC ESS Bus which...
Power three transformer rectifier units (TRU) 1, 2, and ESS

10

What is the purpose of the Transformer Rectifier Units?

To convert 115 VAC to 28 VDC

11

Can the APU replace a failed IDG

Yes

12

What is the AC electrical system's priority

Onside IDG
INSIDE APU
OUTSIDE GPU
CROSS-side IDG

13

How is it known that an AC GPU is hooked up to the airplane and ready to provide electricity?

GPU button displays AVAIL and the GPU icon is presented on the electrical synoptic page.

Once the GPU button is pushed in, the button will display IN USE provided another AC power source is not available

14

What does it mean if the AC GPU is plugged in and the outside GPU panel button displays IN USE?

Ground service bus is in use


Cockpit service button will display AVAIL even though the ground service bus is in use

15

If the airplane is using the AC GPU and the APU is started what should the pilot be sure to do?

Deselect the GPU button before the next GPU selection

16

What will charge the batteries?

Any AC power source

17

How long will the aircraft's batteries last with no recharging?

10 minutes

18

What is the purpose of the DC GPU receptacle ?

For APU start when batteries are less than 22.5 VDC, or

If battery temp is less than -20 degrees C


19

What is the minimum battery voltage to close the battery bus- ties?

18 Volts

20

What battery is used for the APU start ?

BATT 2 powers the APU start bus


BATT 1 powers the FADEC and EICAS for monitoring

21

What is the purpose of the inverter?

Converts 28 VDC from the batteries to 115 VAC to power the AC STANDBY BUS when an AC source is not available.

22

What is on the AC STANDBY BUS?

Engine exciters 1A and 2A

23

What powers the Ram Air Turbine RAT?

Airflow turns the RAT propeller which spins the turbine inside

24

When will the RAT deploy?

Automatically deploys if AC BUSSES are not powered

Manually by pilot

25

How long after deployment before the RAT will supply power?

8 seconds

26

Is there a total loss of power during the 8 second RAT deployment?

No. Batteries supply power to the DC ESSENTIAL BUSSES and AC STANDBY BUS

27

What does the RAT power ?

ESSENTIAL BUSSES

28

What is minimum airspeed for the RAT?

130 KIAS

Load shedding occurs below this speed

29

When is the RAT icon displayed on the electrical synoptic page?

When the RAT is deployed

30

What manages the electrical system?

4 Integrated Control Centers ICC

2 Secondary Power Distribution Assemblies ( SPDA)

31

What is an ICC?

An electrical control device, which provides power distribution and protection for electrical loads

32

What is an SPDA?

An electrical load management unit (powered be the ICC's) that distributes electrical loads to aircraft systems according to distribution logic

33

Can the flight crew reset the ICC and SPDA remote electronic CBs?

ICC CB's can only be reset by maintenance

SPDA CB's can be reset via the MCDU

34

# of networks and why

2
Redundancy
Fault isolation