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Electrical Flashcards

1
Q

How many sources of AC Power?

A

Five (2 Engine Integrated Driven Generators (IDGs), 1 APU Generator, 1 Hydraulic Motor driven Generator (HMG), 1 External power)

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2
Q

DC power normally comes from 2 Transformer Rectifiers Units (TRUs) which are powered by their respective MAIN AC busses. If AC power is not available to operate the TRUs, then either the HMG or the MAIN BAT provides DC power (APU battery only provides power for the APU).

A

True

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3
Q

To what bus is the Utility Bus connected, when the Utility Bus switch is ON?

A

Arms the automatic operation of the AC And DC Bus Tie system

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4
Q

When does the Utility Bus OFF light illuminate

A

Whenever the bus is unpowered

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5
Q

With the Bus Tie switch in AUTO, what causes the AC Bus ISLN light to

A

Bus fault has occurred

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6
Q

What does the generator Control OFF light indicate ?

A

Generator Breaker open

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7
Q

Pushing a Generator Control switch off opens both the field and generator breakers.

A

True

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8
Q

Pushing the Generator Control Switch off opens the generator field.

A

True

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9
Q

Pushing the Generator Control switch off resets fault trip circuitry

A

True

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10
Q

Pushing the Generator Control switch off causes the Generator Control OFF and Generator DRIVE lights illuminated

A

False

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11
Q

What causes the Standby Power Bus OFF light to illuminate ?

A

Loss of power on either the Standby AC or DC Bus

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12
Q

The OFF position of the Standby Power Selector de-energizes the battery bus, standby AC Bus & Standby DC Bus.

A

False

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13
Q

What causes the Standby Power Bus OFF light to illuminate?

A

Loss of power on either the standby AC or DC bus

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14
Q

The OFF position of the Standby Power Selector de-energizes the battery bus, Standby AC bus & Standby DC bus.

A

False

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15
Q

Which of the following will cause the Generator DRIVE to illuminate

A

High oil temperature

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16
Q

You are preparing for the first flight of the day. You have just positioned BAT switch to ON. Why are the DRIVE lights ON?

A

Low oil pressure in both drives - normal until drives are operational

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17
Q

A generator Drive light can indicate a high or low drive output RPM

A

False

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18
Q

A generator Drive light can indicate low oil pressure

A

True

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19
Q

What can power a Utility Bus?

A

Respective Main AC Bus only

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20
Q

The Bus tie system parallels engine generators but prevents any other sources from being paralleled.

A

False

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21
Q

The APU can be used to power the LEFT Main AC Bus while the RIGHT engine generator is powering the RIGHT Main AC Bus.

A

True

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22
Q

The APU can be used to power the LEFT Main AC Bus while external power is powering the RIGHT Main AC Bus.

A

False

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23
Q

Which bus is powered automatically when external power is plugged in and available?

A

Ground Handling Bus

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24
Q

Source order for powering LEFT and RIGHT Main busses?

A

Respective IDG then APU Generator then Opposite IDG

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25
The Ground Handling Bus powers the battery chargers.
False
26
The Ground Service Bus powers the cargo doors and cargo handling equipment.
False
27
What is the highest automatic priority on the LEFT Main AC Bus?
Left engine driven generator
28
The LEFT Main AC Bus can power the battery switch off
True
29
The standby buses can be powered from the LEFT Main AC and DC even with the Standby Selector OFF
False
30
With the APU supplying electrical power, what happens when the first engine is started?
The engine powers its respective buses only
31
What bus powers the fire extinguishers?
Hot battery bus
32
What bus powers most of the airplane fire detection systems?
Battery bus
33
What is closed by pushing the Generator Control switch ON before engine start?
Generator field only
34
Which has priority in supplying the ground handling bus, the APU or external power?
External power
35
Which of the following inhibits the APU Generator Control OFF light?
External power contactor being closed
36
Where is the external power receptacle?
Aft of the nose wheel well
37
When can the Ground Handling Bus be powered?
Only on the ground
38
What can power the Ground Service Bus?
APU, external power or an engine generator
39
What can power the Ground Handling Bus?
Only external power or the APU
40
When will the Utility Buses be shed during an engine start?
Only when the APU is supplying electrical and pneumatic power.
41
With the APU supplying both electrical and pneumatic power, what happens as the second engine is started?
Only the Utility Bus for the engine being started trips off
42
Three autopilots are armed for a triple channel approach. At 1200 ft RA, the LEFT generator is lost. As a result, the LEFT Main AC Bus is lost.
False
43
During a triple channel approach, the LEFT generator is lost at 140 ft RA. As a result the LEFT Main AC bus is lost.
True
44
What is required to enable the captain's flight instrument transfer bus to transfer with the loss of the LEFT Main AC?
Only the LEFT Bus tie switch must be in AUTO
45
Which of the following arms the load shed system to trip off both Utility Buses with the loss of a Generator?
Both engine Generator Drive lights extinguished
46
Which of the following arms the load shed system to trip off Utility Buses when a generator is lost?
Both thrust levers in the takeoff range
47
In flight the LEFT engine is shut down. What electrical buses are lost?
Only the two Utility Buses
48
During a triple channel approach, the RIGHT generator trips off at 140 feet RA. As a result, the F/O's primary flight instruments are lost.
False
49
What is required to enable the F/O's instrument transfer bus to transfer with the loss of RIGHT Main AC?
Only the Right Bus Tie switch must be in AUTO
50
When electric power fails, what happens to the cockpit door lock?
It unlocks automatically
51
When APU GEN switch is positioned to OFF, APU GEN OFF light comes on. What condition might be indicated by the presence of both the ON flow bar & the APU GEN OFF light
The APB is open as a result of a fault
52
Right DRIVE light comes on. EICAS advisory message appears. What is the cause of these indications?
Either the RIGHT Generator Drive oil pressure is too low or the oil temperature is too high
53
Airplane is in flight. Electrical system is in normal flight configuration. STBY POWER OFF light comes on. EICAS advisory message appears. Which position of the STBY POWER selector will provide an alternate power source to the standby buses?
BAT
54
When is the Ground Service Bus powered?
Whenever the RIGHT Main AC Bus is powered
55
Concerning 'Loadshedding' during engine start.
Utility and galleys trip with engine start selector to GND (both for N°1, affected for N°2)
56
What buses can be powered by the HDG if the Main AC buses fail?
Standby AC, Standby DC, both battery buses and both instrument transfer buses
57
What signals the HDG to operate?
If primary power is lost on both Left and Right AC Main Buses, the HDG operates automatically
58
You are in flight. If the RIGHT engine Generator is lost + RIGHT Bus isolated on the EICAS. What will happen to the electrical system?
Right AC Bus will have no back-up power source
59
What does the STBY POWER OFF light indicate?
Either or both Standby Buses are unpowered
60
Which statement is true of the Ground Service Bus?
It can be powered from the Ground Handling Bus by using a switch on Flight Attendant's panel
61
LEFT Main AC power is lost. What is the status of the STANDBY Buses?
RIGHT DC Bus powers LEFT DC Bus, STANDBY DC Bus and STANDBY AC Bus via static inverter
62
Which statement is true?
DC power normally comes from 2 Transformer Rectifiers Units (TRUs) which are powered by their respective MAIN AC busses. If AC power is not available to operate the TRUs, then either the HMG or the MAIN BAT provides DC power (APU battery only provides power for the APU)
63
What is the normal source of power for the STANDBY AC Bus?
LEFT Transfer Bus
64
The Ground Service Bus powers:
2 Battery chargers (MAIN + APU), Equipment cooling fan, LEFT forward pump, Main entry door & Passengers lights
65
Prior to establishing electrical power, the Main Battery powers the Hot Battery Bus and After establishing electrical power, Main Battery Charger powers the Hot Battery Bus.
True
66
The HDG produces power to:
Battery Bus and Hot Battery Bus, LEFT and RIGHT AC Transfer busses, Captain's Instrument Transfer bus & Standby AC & DC busses
67
The HDG is operating while the gear is retracting.
False
68
BUS OFF light is illuminated. What does it mean?
Bus Tie Breaker is locked open because switch is OFF or Fault occurred

Systems 2 (11 decks)

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