Electrical Flashcards
Power sources for the electrical system, volts etc,generator capacity, batteries
EPCU electrical power control unit
PCDU power control and distribution unit
IEPS integrated electrical power system
IDG integrated drive generators one for each engine
Power sources are the IDG’s , the APU generator,external power and batteries and battery charger
115 volt 400 hertz 3 phase 28 volt DC
IDG’s 35/40 KVA
APU 40/60 KVA
battery 3 nicad in series 60 min
Ground service Elec power panel and light
OFF - Neutral pos for ground service panel
ON- Connects external power to the AC ground service bus and powers DC ground service bus
EXT power switch is OFF
On light illuminates to indicate external power is powering the ground service bus
function of the emergency power switch and light
OFF e power is off , Resets the automatic emergency power system
ARM emergency power comes on when EPCU detects power loss to the Emergency AC or DC bus
ON emergency power is on battery supplies power
On light illuminates amber when the emergency power system is on
Emergency power test
Moving from OFF to ARM on ground starts the test
fuel switches must be off
During test the emergency power on light is illuminated and the EMER POWER TEST alert is displayed on the EAD
The ON light extinguishes and the alert is no longer displayed at the completion.
Normal and non normal battery system
Green Battery is discharging normally
Amber Battery voltage is less than normal or discharge is abnormal
Voltage digits will be boxed and amber
White no load load numerics are white in all conditions
NO break power transfer and break transfer
momentary paralleling oncoming off going power sources on the same bus. EPCU must be functioning for NBTP to occur .
Break power transfer when insufficient time to parallel power sources —unexpected loss of APU or IDG power flame-out or uncommanded shut down transfer aircraft power from APU to external power source may also cause
generator voltage and loads displayed
Green - Generator is on voltage and freq within limits
Amber- Gen is off due to relay protective trip, Voltage,frequency and load are boxed and amber if not within limits
white– engine not operation or gen turned off Voltage and freq are white if within limits or engine is not operating. Load current are white if within limits
what busses powered by e power and how long
Batt direct DC and AC emergency DC transfer
60 min
left and right Bus tie switches
OPEN generator cannot power the tie bus can also be used to reset the bus tie lockout
AUTO bus connection is controlled automatically to satisfy power requirements
function of the DC bus tie switch
OPEN opens all three bus tie relays used during smoke procedure
AUTO the DC bus tie relays are controlled by the PCDU and the EPCU to make sure all DC busses are powered
function of the BATT switch and main battery components
3 nicad in series 28 volt DC power to E power system
OFF battery connected to battery direct bus only Battery charging not affected
ON connects to DC transfer and battery direct
what power required for fueling the airplane
access to cockpit not required only battery power
what is epcu and pcdu and how many
1 electrical power control unit 3 power control and distribution units
what does the epcu provide
in the E and E compartment provides external power protection,automatic power transfer , emergency power automatic activation, galley power shedding
what does the pcdu provide
3 pcdu a different one controls each gen receives power from their respective IDG distributes to the main bus
