Electrical System Flashcards
Batteries (#, volts, amps)
3, 24vDC, 40amps
Engine Driven DC Starter-Generators (#, volts, amps)
2, 28vDC, 400amps
APU Generator #,volts, amps
1, 28v DC, 400amps
TRUs #, voltage, amps
2, 28v DC, 300amps
DC GPU
1, 28v DC
Batteries (names)
3, Main, Auxiliary & Standby
Battery Location
- Main & Auxiliary batteries are located on the left side nose of the aircraft (lower panel)
- Main Battery is also located forward of the Auxiliary battery in the lower panel
- Standby battery is located on the left side nose of the aircraft (upper panel)
Which battery(s) are able to assist with engine starts (when performing external power starts or battery starts)
Main & Auxiliary batteries
Which battery(s) supply DC power to the “HOT battery bus” for the operation of various emergency system operations
Standby Battery
Which battery(s) supply emergency backup power to the airplane’s “Essential DC buses” and for how long
All 3, (approx.45 minutes)
Which battery(s) for a second engine start MUST show a _ or less on the MFD- Electrical Systems Page
All 3 batteries for a second engine start MUST show a .4 or less on the MFD- Electrical Systems Page
Battery Master Switch closes…
o Closes 3 contactors directly connecting all 3 batteries to the “Essential DC buses”
Main Battery Switch connects…
o Directly connects the Main battery to the “RIGHT Main DC bus” allowing a two-way power flow
Auxiliary Battery Switch connects…
o Directly connects the Aux battery to the “LEFT Main DC bus” allowing a two-way power flow
Standby Battery Switch connects…
o Directly connects the Standby battery to the “LEFT Main DC bus”, allowing a “one-way” power flow (battery charging ONLY)
BATTERY TEMPERATURES
• WHITE
• AMBER
• RED
normal range
when 50° C to 65° C
temperature greater than 65° C
How many Engine Driven Starter-Generators
2
Engine Driven Starter-Generators
•Driven by the___ of each engine and are___cooled
engine accessory gearbox, air
Engine Driven Starter-Generators
• Each DC Starter-generator is monitored and controlled by its respective___
Generator Control Unit (GCU)
Engine Driven Starter-Generators
• After engine start and NH of___, the GCU converts the starter-generator from a starter mode of operation to a generating mode
50%
Engine Driven Starter-Generators
• GCU also ensures that the generator maintains a constant supply of (volts and amps) to its associated…
28.5v DC, 400 amps, “Main DC bus”
Engine Driven Starter-Generators
• Electrical Emergency occurs when a failure on___“DC Generators” AND___
. The EPCU automatically disconnects the batteries from the “Main buses” leaving them only able to supply power to the___ for approximately___
BOTH, a third AC power source failure (i.e. AC TRU) total 3 items. “Essential buses” (approximately 45 minutes).
DC GPU (Ground Power Unit) • Receptacle located on\_\_\_
the left side of the nose of the aircraft
DC GPU (Ground Power Unit) • Power is directly received by the \_\_\_
“LEFT Main DC bus”
DC GPU (Ground Power Unit) • “Auto Bus Tie” Closure enables \_\_\_
ALL 6 DC Buses to be powered
DC GPU (Ground Power Unit) • Engine DC generators and the APU generator are inhibited from coming online while in \_\_\_ configuration
Auto Bus Tie
DC GPU (Ground Power Unit) • EPCU will automatically disconnect if the external DC voltage drops below \_\_\_ or exceeds \_\_\_
22 volts, 31 volts
Main Bus Fault
• Electronic Power Control Unit (EPCU) confirms an actual “Main Bus Fault” and will automatically take offline all ___ components associated with the faulty bus (___) leaving the fault bus unpowered and isolated
• Abnormal Checklist will instruct the crew to cycle the “Bus Fault Reset” switch in an attempt to reset the EPCU’s bus fault protection logic
DC, (i.e. DC starter-generator & batteries)
How many TRUs
2
TRU’s
•Located in the___ section of the nose and are___-cooled
upper right, air
TRU’s
•Converts___
115vAC to 28vDC
• Each TRU then supplies___ power to its respective ___
28vDC, “Secondary DC Bus”
APU GENERATOR
• Supplies ___ power to the ___ during ground operations only
28vDC, “Essential, Main, and Secondary DC buses”
APU GENERATOR
• Provides ___power in parallel with the___
28vDC, Engine DC Starter-generators
How many AC Generators and voltage
2, 115vAC
AC GENERATORS
• Mounted on (driven by) the ___ and ___ cooled
propeller reduction gearbox and oil-cooled
AC GENERATORS
• Power is supplied to the___ busses
“Left and Right variable AC buses”
AC GENERATORS
• The following systems and components require 115 volt variable AC power: (5)
o De-Icing/Anti-Icing Heaters o Standby Hydraulic pump (#1 Hydraulic System) o Transformer Rectifier Units (TRUs) o #1 and #2 Auxiliary Fuel pumps o Galley loads
AC GENERATORS
• AC power will ___ provide support for engine start
Not
• AC External Power can power ___ via the ___
ALL “AC & DC Buses”, TRU’s
