Electrical Flashcards

1
Q

Recall the power sources for the AC Buses during normal operating conditions.

A

o AC Buses 1 & 2:
▪ Respective Engine Generator (IDG 1 or 2).
▪ External power
▪ APU generator
o AC ESS Bus:
▪ Normally by AC Bus 1
▪ AC Bus 2 manually, when AC ESS FEED pb is selected to ALTN
▪ AC Bus 2 automatically, via the auto switching logic

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2
Q

Describe the electrical system’s power priority.

A

Same side
External power
APU
Opposite side

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3
Q

BUS TIE pb.

AUTO (light out)

OFF

A

AUTO (light out) – Power priority order logic is active.

OFF – Power priority order logic is deactivated.

  • AC Bus 1 and 2 can only be powered by their respective engine generator.
  • External or APU generator power cannot be applied to the aircraft.
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4
Q

AC ESS FEED pb.

A

The AC ESS FEED pb is used to manually command AC Bus 2 to power the AC ESS Bus.

When in the “light out” configuration:
▪ AC Bus 1 powers AC ESS Bus. This the normal configuration.
▪ Should AC Bus 1 fail, AC Bus 2 automatically powers AC ESS BUS.
When selected to ALTN:
▪ AC Bus 2 is commanded to power AC ESS Bus regardless of the status of AC Bus 1.
▪ ALTN appears only when the pb is selected.

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5
Q

Recall the display on the ECAM ELEC page of an unpowered AC or DC ESS SHED Bus.

A

The word SHED (amber) appears under AC ESS or DC ESS buses only when the respective SHED Bus has automatically shed.
(Shed meaning unpowered).

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6
Q

GALLEY SHED display on the ECAM ELEC page.

A

o In-flight – When on single generator power, GALLEY SHED indicates that the galley’s main bus
has been automatically depowered. However, its secondary bus remains powered.
o On the Ground – With either external or APU generator power in use, both main and secondary galley buses
remain powered.
o When the GALLEY pb is selected OFF, GALLEY SHED indicates that the galley’s main and secondary buses are depowered.

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7
Q

Recall the cautions associated with selecting the guarded IDG 1 and IDG 2 pbs.

To avoid damage to the IDG disconnect mechanism DO NOT:

A

▪ Disconnect unless the engine is operating or is wind-milling.
▪ Hold the pb(s) for more than three (3) seconds.

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8
Q

Explain the color coding convention of the circuit breakers.

Green

Black

Yellow

Red

A

Green: Monitored by FWC’s, ECAM message when CB is open for more than 1 minute

Black: Not monitored by FWC’s, but system which the SB supports may be monitored by FWC’s

Yellow: Pulled when flying on batteries

Red: Red cap prevents CB from being reset. Wing tip brake CB’s

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9
Q

GEN 1 LINE pb is selected OFF.

A

o Opens generator 1’s line contactor, in affect isolating it from the remainder
of the aircraft’s electrical system.
o Generator 1 is limited to only powering one fuel pump in each wing tank.

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10
Q

Two methods of activating the emergency generator.

A

o Automatically:
▪ Loss of power to AC Bus 1 and 2 in flight will automatically deploy the Ram Air Turbine (RAT) and activate the
emergency generator.
o Manually:
▪ Selecting the red guarded MAN ON pb on the EMER ELEC PWR panel will manually deploy the Ram Air Turbine
(RAT) and activate the emergency generator.
NOTE: Selecting the RAT MAN ON pb on the HYD panel will deploy the RAT but
will not activate the emergency generator.

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11
Q

Emergency Electrical Configuration

A

AC 1 and AC 2 unpowered

Emergency generator is powering:

AC ESS BUS
DC ESS BUS
AC and DC ESS SHED buses through their ESS buses

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12
Q

what occurs to the emergency generator when the landing gear is lowered.

A

aircraft batteries become the sole source of electrical power.

NOTE: A red FAULT light illuminates on the EMER ELEC PWR panel when AC Buses 1 and 2 are unpowered and the RAT is deployed but the emergency generator is not supplying power

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13
Q

Recall the location and use of the MAINT BUS switch

A

▪ Located on the electrical panel on the ceiling of the forward galley.
▪ When selected ON, allows external power for ground servicing without energizing the entire aircraft’s electrical
system.
▪ Only requires external power to be connected and have good Volts and Freqs

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14
Q

The APU AVAIL light indicates:

The ON light indicates:

A

That the APU is “On Speed”

External power has been selected

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15
Q

Recall the power source when:

  • both engines are shut down
  • the APU START pb indicates AVAIL (green)
  • the EXT PWR pb indicates AVAIL (green)
A

APU generator

avail light on ext pwr only indicates good volts and freqs connected

ext pwr must always be manually selected to be used

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