Electrical

Question 0

What are the sources of dc power?

Answer 0

4 engine generators
1 APU generator 
2 nickel cadmium batteries
1 lead acid backup battery
External power cart

Question 1

What 2 electrical systems does the emb 145 have?

Answer 1

28v dc system

115v 400hz ac system

Question 2

Which generators are driven by the left and right engines?

Answer 2

Left engine are 1 and 3

Right engine are 2 and 4

Question 3

How many hours can an aircraft be operated with a generator bearing fail message?

Answer 3

20 hours.

Question 4

How are the engine generators cooled in the air and on the ground?

Answer 4

NACA air inlets in the air

Fan on the ground.

Question 5

What are the engine generator output limits?

Answer 5

400 amps
600 amps for 5 minutes
800 amps for 5 seconds

Question 6

What controls the contactors in the electrical system?

Answer 6

Electrical distribution logic

Question 7

When are all the dc buses powered on the ground?

Answer 7

3 generators are operating
1 generator and shed bus override
GPU

Question 8

When do the engine and APU generators come online?

Answer 8

Engines at 56.4% N2

APU 95% +7 seconds

Question 9

What are the APU generator output limits?

Answer 9

400 amps below 30,000’
300 amps above 30,000’
600 amps for 2 minutes
800 amps for 5 seconds

Question 10

What happens when you release the APU generator button?

Answer 10

The APU line contactor is commanded open and disconnects APU power.

Question 11

How is the APU powered when starting?

Answer 11

By the central bus through the APU starting contactor.

Question 12

What can power the APU for start?

Answer 12

External power
Battery 2
Battery 2 plus main generators

Question 13

Why isn’t there electrical interruption while starting the APU?

Answer 13

Battery 1 is isolated from the load busses.

Question 14

Describe the 2 main batteries and how long will they hold power for?

Answer 14

24 volt, 44 amp hour nickel cadmium batteries

40 minutes.

Question 15

How are the batteries cooled?

Answer 15

NACA inlets

Question 16

What busses are connected to battery 1 and 2?

Answer 16

Hot bus 1 and 2

Question 17

What do the hot busses power?

Answer 17

Elt, engine fire extinguishers, fuel pressure refueling, fuel shutoff valves, hydraulic shutoff valves, courtesy lights, main door, generator control units.

Question 18

Can the batteries be charged with the GPU? And why?

Answer 18

No, when the GPU is plugged in the battery contactors open and disconnect the batteries.

Question 19

What is the backup battery? And function?

Answer 19

1 24dcv 5 amp hour battery
Powers backup hotbus
Electrical distribution logic
Generator control unit

Question 20

What are the volts and amps for the GPU?

Answer 20

28.5 volts
1600 amps
Has priority over all batteries and generators.

Question 21

What busses does the GPU power?

Answer 21

The central bus.
Connects 
dc bus 1 and 2
Shed bus 1 and 2
Essential bus 1 and 2

Question 22

How is the electrical system protected from GPU malfunctions?

Answer 22

An over voltage circuit disconnects the GPU over 32 volts or under 23.5 volts

Question 23

How are the shed buses powered on the ground?

Answer 23

By placing the shed bus switch in the override position.

Question 24

What buses do you have in electrical emergency mode?

Answer 24

``` Batteries supply, Hot bus 1 and 2 Backup essential bus Backup hot bus Central bus Essential bus 1 and 3 ```

Question 25

How do you manually enter emergency mode?

Answer 25

By pressing the essential power button.

Question 26

What does the ground service bus power?

Answer 26

``` Cockpit dome lights Courtesy/stair lights Galley lights Cabin lights Lavatory lights Baggage service lights ```

Question 27

How is ac power produced?

Answer 27

By a 250 volt 400 hertz single phase static inverter. | 250vdc to 115vac

Question 28

What is on the ac system?

Answer 28

EGPWS Windshear FOQA

Question 29

Battery 1 controls what busses?

Answer 29

Hot bus 1 Backup essential bus Backup hot bus

Question 30

What is powered by the backup essential bus?

Answer 30

AHRS 1 DAU 1 and 2 EICAS

Question 31

What is powered by the backup battery?

Answer 31

Electrical Distribution Logic | Generator Control Unit

Question 32

Do the batteries charge with the GPU powering the airplane?

Answer 32

No, you have to take the batteries out to charge them. Minimum of 30 minutes.

Question 33

What electrical condition exists with 4 or 5 generators online?

Answer 33

Two systems all buses energized

Question 34

What electrical condition exists with 3 generators online?

Answer 34

One network all busses energized

Question 35

What electrical condition exists with 1 or 2 generators?

Answer 35

One system all buses energized in the air, lose shed buses on the ground

Question 36

What electrical condition exists with a loss of all generators?

Answer 36

Batteries supply essential buses in flight only.