Electrical Flashcards
How many NiCad batteries are there on the aircraft?
3
How many engine-driven DC starter-generators are there on the aircraft?
2
How many Transformer Rectifier Units (TRUs) are there on the aircraft?
2
How many APU generators are there on the aircraft?
1
True or False: The electrical system comprises both a direct current (DC) system and an alternating current (AC) system.
True
True or False: DC power to the electrical system is supplied by two engine-driven DC generators only.
False
True or False: Circuit breaker panels can be found in the left and right main landing gear wheel wells.
True
How many circuit breaker panels are there in the flight compartment?
4
Which of the following are NOT electrical buses?
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The aircraft is equipped with which of the following batteries?
Main, Auxiliary, Standby
How long will the batteries power the aircraft if normal electrical power fails?
60 minutes
How many battery switches are there?
4
. True or False: If the battery master is in the OFF position, the other batteries can still be used to power the aircraft.
False
True or False: When the battery master is in the OFF position, all battery power is turned off no matter what position the other switches are in.
False
If the battery is being charged at a 100% rate of charge, how will it be depicted on the MFD Battery page?
1.00
How is negative discharge on a battery indicated on the MFD Battery page?
-.XX
When the battery temperature is within limits, what color does it display as on the MFD Electrical page?
White
When the battery temperature exceeds normal limits, what colors would display on the MFD Electrical page?
Yellow +50C to +65C,
Red Exceeds +65C
If any battery temperature is 50 degrees C to 60 degrees C, what color does the battery temperature display as on the MFD Battery page?
Amber
Where can the GPU be connected to the aircraft for DC power?
Left forward fuselage
When connected to external power on the ground, what is displayed on the MFD Electrical page?
DC External Power On
True or False: The EPCU protects the system from too high and too low DC power voltage form the external power source.
True
After engine start, how many volts does the DC generator provide?
28V DC Power
Where are the Transformer Rectifier Units (TRUs) located?
The nose compartment
TRUs change 3-phase 115v AC to what?
28V DC Output
During normal operation, which busses do the TRUs power?
Left or Right Secondary bus
A L TRU caution light will illuminate when what happens?
The respective Left or Right TRU is off or has failed
On the ground, what busses does the APU generator provide power for?
6 Buses
What does it mean when a plus sign (+) is displayed in front of a value on the MFD Electrical page?
An overload of the power source
The entire electrical system can still be powered when up to how many power sources have failed?
2
When does the EPCU send a signal to the generator to trip it offline during a Main DC bus fault?
5 Seconds or more
If the Right Main Bus has a bus fault, which battery is disconnected from the system?
Main battery
True or False: If a Secondary bus fault occurs, the increased current will trip the circuit breaker for the respective TRU.
True
In addition to an inoperative TRU, what is required for the EPCU to enter emergency mode?
Airplane in Air both DC Generators are not available
In addition to a dual DC Generator failure, what is required for the EPCU to enter emergency mode?
Airborne at least 1 TRU is not available
True or False: In emergency mode, the batteries are the main source of power.
True
When in emergency mode, which busses automatically disconnect from the batteries?
Main Bus
What is the voltage output of the AC generators?
115V
Where are the AC generators mounted on the aircraft?
Propeller reduction gear box
How many external AC power ports are there on the aircraft?
1 - INBD SIDE OF #2 NACEL
When the aircraft is powered by external DC power, which busses are powered?
6
L/R Essential
L/R Main
L/R Secondary
True or False: When a DC generator fails, the Main Bus Tie switch must be manually selected.
False
Which switch would pilots use to connect the main battery to the associated feeder bus?
Main Battery Switch
How many batteries is the aircraft equipped with?
3
True or False: When a minus sign (-) is shown before a number on the MFD Electrical page, it means the battery is discharging.
True
At what point will electrical bus load shedding begin?
If more than 2 DC Sources Fail
In emergency mode, the _____ are the main energy source for the airplane.
Batteries
The AC generators connect to the system when the engines are started, Gen 1 and 2 switches are selected ON, and _____.
Condition levers are in Min to Max range
Which of the following statements regarding the AC cross tie function is most accurate?
Works automatically to ensure both AC buses are powered
The DC electrical system is supplied by:
- (3) NiCad batteries (24v DC)
- (2) Engine driven DC Starter-generators (28v DC)
- (2) Transformer Rectifier Units (28v DC)
- (1) Auxiliary Power Unit generator (28v DC).
The AC electrical system is supplied by:
• (2) Engine driven AC generators that provide 115 volt, three phase, variable AC power.
Selecting the Standby Battery switch to STBY BATT (ON) directly connects
the Standby battery to the left Main DC bus, allowing a “one-way” power flow for battery charging ONLY.
Selecting the Auxiliary Battery switch to AUX BATT (ON) directly connects
the Auxiliary battery to the left Main DC bus allowing a two-way power flow
Selecting the Main Battery switch to MAIN BATT (ON) directly connects
the Main battery to the right Main DC bus allowing a two-way power flow.
Battery temperature values are displayed in WHITE
Normal Range
Battery temperature values are displayed in AMBER
Battery temp between 50-65°C
Battery temperature values are displayed in RED
BATT TEMP above 65°C
A Left Main Bus fault is indicated by the illumination of these caution lights:
- DC Bus
- Standby Battery
- AUX Battery
- # 1 GEN Annunciator
A Right Main Bus fault is indicated by the illumination of these caution lights:
- DC BUS
- Main BATTERY
- # 2 GEN Annunciator
Which batteries are used for engine starting when ground power is not available?
Main, Auxiliary
True or False: If the battery master is in the OFF position, the other batteries can still be used to power the aircraft.
False
True or False: When the battery master is in the OFF position, all battery power is turned off no matter what position the other switches are in.
True
