ELECTRICAL_MAIN PANEL Flashcards
METERING PANEL - LED DISPLAY
- powered WHEN BATT Switch is turned ON
- DC data on left - AMPS (top) VOLT (bottom)
- AC data on right - CPS FREQ (top) VOLTS (bottom right) AMPS (bottom center)
DC AMPS: (top left) - STBY PWR and BAT BUS positions will NOT show AMPS
BATT DISCHARGE Light
What does this light mean? (1sp)
Is it ever normal to see that light?
[1sp - excessive battery discharge.
(b) it could be if we started the APU on batt power because the battery charger is not working]
Illuminated (Amber):
- with BAT switch ON - it detects excessive battery discharge
Notes.
- could mean a failed battery charger
- will illuminate a MC & ELECT caution (except during an APU battery start)
- you will get this light during APU battery start (high discharge)
- will NOT get this light during APU AC start (#1 AC transfer bus powered)
- GROUND CREW CALL HORN - will sound a continuous sound 2 minutes after condition is detected
TR UNIT Light
What is the TR Unit light mean? (1sp)
[1sp - if on the ground, it means that any of the 3 TRs fail, if it comes on in flight it means that either TR 1 or TR2 & 3 have failed]
Illuminated (amber):
- Ground: ANY TR has failed.
- Air: TR 1 failed OR TR 2 AND TR 3 failed.
ELEC Light
What does the ELEC light illuminated mean? (1sp)
[1sp - means we have a DC system or the standby system electrical fault.]
Illuminated (Amber):
- fault exists in either - DC system OR Standby Power system
- works ONLY on GROUND
To see the BITE message - press the MAINT button
MAINT Button
Notes.
- works ONLY on the ground.
- connects to BITE for ELECT light fault analysis
- if a fault exists it will show on LED display
- if an āIā follows the fault message - that means it intermittant
This is a MAINT ONLY button.
DC METER Selector
Notes.
- each position EXCEPT TEST is related to a DC power source or bus
- BAT: shows volts/amps (load) of the battery (or battery charger) if operating
- BAT BUS or STBY PWR: only shows VOLTAGE (since these are not SOURCES of power)
- TR 1 & TR 2: indication is taken from the respective DC BUS and amps come from the respective TR which is different than TR 3 which shows BOTH volts AND amps from TR 3
- TEST - used by MAINT
- BAT (and Aux BAT): amps are normally 0 (means full battery - not charging)
BAT Switch
- 2 positions -
OFF
ON
How many batteries do we have installed? (1sp)
How many volts is the battery? (1sp)
DC system voltage?
TRU output voltage?
Min voltage for APU start?
[1sp - normally 1 with an option for 2
(b) 24 v
(c) 28 v
(d) also 28v - TRU output
(e) 23v
OFF:
- removes power from: (with NORMAL power sources available)
- BATT Bus AND
- SWITCHED Hot Bat Bus
- removes power from: (when BATT is ONLY source of power)
- BATT BUS
- SWITCHED HBB
- AC & DC STANDBY BUSES
- STATIC INVERTER
ON: (guarded)
- powers the SWITCHED HBB
- energizes relays to provide auto switch of standby system to BATT power with loss of normal power
AC METER Selector
Notes.
- 7 positions
- each position EXCEPT TEST is related to an AC power SOURCE or BUS
- shows AC Volts / Amps (load) / or output FREQ on display
- Will only show VOLTS and FREQ in these positions: STBY PWR, GRD PWR, INV (no AMPS)
- Normally 115 +/- 5 V and 400 cps +/- 10
- TEST position: used by maint
CAB UTIL Switch
- 2 positions -
OFF
ON
ON:
- powers galley and cabin equip systems
- all 115vac galley busses
- RECIRC fans
- door heaters & drain masts
- lav water heaters
- LOGO LIGHTS
- potable water compressor
OFF: removes power to the above
IFE/PASS SEAT Power Switch
ON:
- supplies power to componets of the pax seats and inflight entertainment (and other power systems)
- 115vac audio & video equipment
- cabin telphone equipment
- 28vdc video equipment and pax seat electronic outlets
- ACARS Printer
OFF: removes electrical power from the above items.
