Electrical Power Flashcards

1
Q

What do we check before turning the Aircraft Power Supply off?

A

ADIRUs, Emergency Light S/W etc. must be turned off

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2
Q

What is the purpose of Static Inverter (SI)?

A

Converts DC to AC

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3
Q

What is the purpose of Transformer Rectifier Unit (TRU)?

A

Converts AC to DC

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4
Q

What is the purpose of the HOT BAT BUS?

A

It is directly connected to the battery and all the users connected will always have
power available

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5
Q

Who supplies the AC ESS BUS?

A

AC BUS 1

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6
Q

When the AC BUS 1 is broken, who supplies the AC ESS BUS?

A

AC BUS 2 through the AC
ESSENTIAL FEED

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7
Q

When our GEN 1 is broken who supplies our AC ESS BUS?

A

It still the AC BUS 1 but the source comes from GEN 2 by passing through AC BUS TIE

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8
Q

When does the Emergency Generator operates?

A

When no other generators (normal power source) is available during flight

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9
Q

Who operates the Emergency Generator?

A

Ram Air Turbine (RAT)

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10
Q

When only the EMER GEN power source is
available, what buses is the only ones left
operating?

A

AC and DC ESS BUS

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11
Q

How do we charge the batteries of the Aircraft?

A

Is only possible when power is supplied by the generators and the battery S/W is turned on

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12
Q

What are the GCU functions?

A

Regulation, Protection, Switching

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13
Q

What are the parameters does the GCU regulates?

A

Frequency and Voltage

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14
Q

How do we increase the voltage by GCU?

A

Exciter Current

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15
Q

What does it mean when the AVAIL light is
on in the cockpit?

A

The EPU is connected to the aircraft
and it is ready to use.

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16
Q

What does it mean when the NOT IN USE light is on in the control panel below the
aircraft?

A

The EPU is connected but the EXT PWR P/B S/W is not pressed by the pilot

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17
Q

What is the meaning of IDG at its purpose?

A

Integrated Drive Generator and it is a combination of Constant Speed Drive (CSD)
+ Generator

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18
Q

Four types of AC Consumers?

A

FIRST – Single Phase (115V) Consumer with
low power demand.

SECOND – Single Phase Consumers that needs a different voltage (28V or 26V) by
using Step down Transformers

THIRD – Three Phase Consumers such as 3 phase motors and TRU and all needs to operate at the same time

FOURTH – Large load that need about 50% of the total electrical load

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19
Q

What do we do to the Large Loads consumers when there’s a power outage?

A

Shed

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20
Q

Shed is done by?

A

Automatically or Manually

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21
Q

How do we do the Manual Shedding?

A

By pressing the Gally P/B S/W (Airbus) or L/R Utility P/B S/W (Boeing)

22
Q

How do we protect the Wiring System?

A

By using Fuse or Circuit Breakers

23
Q

What is the advantage of CBs over Fuse?

A

The CBs trip when there’s a short circuit/fault in the system and can be reset when the repair of the wiring system is done while the Fuse wiring system trips but after
tripping, we need to replace it.

24
Q

If Battery Source is the only source left, what BUSES is the BAT 1 and BAT 2 dedicated?

A

In EMER Situations: BAT 1 for AC ESS BUS and BAT 2 for DC ESS BUS

In Normal Situations: BAT 1 for Main Users and BAT 2 for APU Starter Motor

25
Q

What are the Loads Shed able?

A

Galley (Airbus) and Utility (Boeing)

26
Q

What is the power supply for GCU?

A

Permanent Magnet Generator (PMG)

27
Q

What are the influences to modify Frequency?

A

By the Rotational Speed of the Rotor and By the number of rotating pole pairs

28
Q

The frequency of the VFG is not constant, so how do we meet the required Frequency?

A

It depends on the speed of the related engine

29
Q

If there’s a over voltage or over current, what does the pilot do?

A

Pressing the IDG 1/IDG 2 P/B S/W on the overhead panel

30
Q

If we press the IDG 1 P/B S/W, what will happen?

A

The GEN 1 will disconnect from the Engine Gearbox

31
Q

How do we reconnect the GEN 1 to the Engine Gearbox?

A

By pulling the Reset Ring below the section of the engine and inside the fan cowls.

32
Q

A kind of Power Relay wherein it operates for as long as the current flows?

A

Contactor

33
Q

Where is the Maintenance Bus S/W is located?

A

In the Cabin Ceiling Panel, before entering the Cockpit

34
Q

What illuminates when the External Power
Unit GPU is connected?

A

“Connected” and “Not in Use”

35
Q

What do we do to make sure the batteries will not discharge?

A

At least 1 Source that can Charge the battery and the Batt S/W is turned on

36
Q

WHAT IS THE DIFFERENCE BETWEEN A VARIABLE GENERATOR AND AN IDG?

A

VARIABLE GENERATOR - VARYING FREQUENCY OR SPEED IS NOT CONSTANT

IDG - CONSTANT FREQUENCY DUE TO CONSTANT SPEED DRIVE?

37
Q

WHAT BUS DOES POWERED BY EMERGENCY GENERATOR?

A

EMERGENCY BUS

38
Q

THE IDG 1 FAILED? WHAT WOULD BE THE POSSIBLE SCENARIOS?

A

MANUALLY OPEN THE BUS TIE SWITCH FOR THE IDG 2 TO SHARE POWER

39
Q

IS THE BTB THE EQUIPMENT THAT WILL POWER AC BUS 1?

A

BTB IS USED TO ISOLATE BUS 1 AND BUS 2 FOR INDEPENDENT PARALLEL OPERATIONS… PERO PAG FAIL.YUN 1 MAG TAKE.OVER.YUN ISA VIA BTB…

40
Q

WHEN GEN 1 FAILS, WHAT BUS POWERS AC ESSENTIAL.BUS?

A

STILL AC BUS 1 BUT POWER COMES FROM GEN 2 THRU BUS TIE

41
Q

When does the RAT or ram air turbine deploys?

A

Total loss of power supply

42
Q

What is the purpose of Static Inverter (SI)?

A

Converts DC to AC

43
Q

What is the purpose of Transformer Rectifier Unit (TRU)?

A

Converts AC to DC

44
Q

What does it mean when the AVAIL light is on in the cockpit?

A

The EPU is connected to the aircraft and it is ready to use.

45
Q

What does it mean when the NOT IN USE light is on in the control panel below the aircraft?

A

The EPU is connected but the EXT PWR P/B S/W is not pressed by the pilot

46
Q

What do we do to the Large Loads consumers when there’s a power outage?

A

Shed

47
Q

Shed is done by?

A

Automatically or Manually

48
Q

What illuminates when the External Power Unit GPU is connected?

A

Connected” and “Not in Use

49
Q

Why is there a small pin in the receptacle?

A

For correct installation and to prevent arching

50
Q

What is the meaning of IDG at its purpose?

A

Integrated Drive Generator and it is a combination of Constant Speed Drive (CSD) + Generator in one housing

51
Q

When does the Emergency Generator operates?

A

When no other generators (normal power source) is available during flight

52
Q

What are the parameters does the GCU regulates?

A

Frequency and Voltage