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Flashcards in 6. Electrical Deck (25):
1

Recall ELEC SD symbology and color-coding

Power Buses

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Green – Bus has normal power

Amber OFF – Bus does not have power

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2

Recall ELEC SD symbology and color-coding

Battery

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Green - Battery discharging normally

Amber - Battery voltage is less than normal OR battery discharge is abnormal. Voltage digits will be boxed and amber

White - No load on the battery. Load numerics are white in all conditions

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3

Recall ELEC SD symbology and color-coding

Transformer Rectifiers

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White – Normal ops

Amber – TR is failed

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4

Recall ELEC SD symbology and color-coding

Generators

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Green – Generator is on with voltage and frequency w/in limits

Amber – Generator tripped off. Voltage, frequency, and load current digits are boxed amber if not w/in limits

White – Engine is not operating OR generator is turned off. Voltage and frequency digits are white if within limits or engine is not operating. Load current digits are white if w/in limits

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5

Recall ELEC SD symbology and color-coding

External Power

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White – External power is available. EXT switch in OFF or main external power relay tripped

Green – External power on and supplying power

Blank – External power not connected

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6

Recall ELEC SD symbology and color-coding

APU

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White – APU power is available. APU generator off due to APU GEN switch in OFF or APU power relay tripped

Green – APU power on and supplying power

Amber – APU available. APU generator tripped off

Blank – APU power not available

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7

Recall ELEC SD symbology and color-coding

Bus Tie Relay

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Green – Relay is closed. Normal conditions

Amber – Relay tripped open

White – Relay is opened. Normal condition

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8

Recall ELEC SD symbology and color-coding

Power Relays

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Green – Relay is closed. Normal condition

Amber – Relay tripped open

White – Relay is opened. Normal condition

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9

Recall ELEC SD symbology and color-coding

DC Tie Relay

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Green – Relay is closed. Normal condition

Amber – Relay tripped open

White – Relay is opened. Normal condition

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10

Recall ELEC SD symbology and color-coding

Schematic Flow Lines

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White – Normal powered condition

11

Recall the function of the battery switch

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OFF - connects to the battery direct bus only (battery charging not affected)

ON - Connects battery to the DC transfer bus and the battery direct bus

12

Recall the function of the EMER PWR Switch

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OFF - Emergency power is off. Resets the automatic emergency power system

ARM – Supplies emergency power automatically when power loss to the EMER AC or DC bus is detected

ON - Emergency power is on. The battery supplies power for AC EMER bus (through the static inverter) and DC EMER bus

**Note: Emergency power can only be tested on the ground with both engines shut down. It is automatically tested when the switch is moved from OFF to ARM. During the test, the ON light illuminates and an EMER PWR TEST alert is displayed. A successful test is indicated when the ON light is extinguished and the alert is no longer displayed.

13

Recall which buses are powered on EMER PWR and how long the battery can provide power

When activated, the emergency power system will provide power to the following buses for approximately 60 minutes:

 Battery direct bus

 DC transfer bus

 Emergency AC bus (through emergency inverter)

 Emergency DC bus

14

Explain the function of the L/R BUS TIE Switches

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Open – Respective generator cannot power the tie bus. Can also be used to reset a bus tie lockout on the ground

AUTO – Generator bus to tie bus connection is controlled automatically to meet aircraft power requirements

15

Recall the function of the DC BUS TIE Switch

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OPEN - Opens all three DC bus tie relays

AUTO - DC bus tie relays are automatically controlled to ensure all DC buses are powered

16

Recall the function of the L/R GEN Switches

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RESET – Resets the generator

OFF – Disconnects the generator from the respective bus

ON – Allows an operating generator to supply power to its respective bus

17

Recall the function of the APU Power Switch

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RESET – Resets the generator

OFF – Disconnects the APU generator from the tie bus

ON – Allows an operating APU generator to supply power to the tie bus

18

Recall the function of the EXT Power Switch

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OFF – Disconnects EXT PWR from the tie bus

ON – Connects EXT PWR to the tie bus

19

Recall the function of the GND SERVICE ELEC PWR Switch

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OFF - Neutral position for ground service power

ON - Connects external power to the AC ground service bus and powers the DC ground service bus. EXT power switch is OFF

20

Recall the function of the GALLEY PWR Switch

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OFF – Galley power is off

ON – Galley power is on

21

Recall features of the No Break Power Transfer (NBPT)

Normally, all electrical power source transfers will occur without power interruption

 Momentary breaks in power supply, however, may occur during the transfer of power from the APU to an external source OR if a supplying generator experiences an unexpected power loss (due to a flameout or unexpected shutdown, etc)

22

Recall the amber, green and blue lights displayed on the ELECTRICAL panel

EMER PWR

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ON – amber when EMER PWR is on

23

Recall the amber, green and blue lights displayed on the ELECTRICAL panel

APU PWR

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ON – APU powering tie bus

24

Recall the amber, green and blue lights displayed on the ELECTRICAL panel

APU, L/R GEN, EXT PWR Lights

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Blue – Indicate power source to associated bus

25

Recall the amber, green and blue lights displayed on the ELECTRICAL panel

EXT PWR

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AVAIL – EXT connected and w/in limits