11.6 Electrical Power Flashcards
How do you convert DC to AC?
static inverter
What is the voltage of a battery?
24v
What is a battery used for?
emergencies & APU start
What is the minimum time a battery can last for?
30 mins
What is thermal runaway?
when more heat is produced in a battery than the surroundings
What is the voltage of a battery cell?
1.2v
What is the voltage of a battery cell during charging?
1.5v
What is the voltage of a battery cell during discharge?
1v
How often must a battery get sent to the workshop for checks?
Every 2000 operating hours
What type of battery is prone to thermal runaway?
Nickel cadmium
What voltage must you not discharge a battery below?
22v
How do you convert AC to DC?
TRU’s
If a battery is in series what increases?
voltage
If a battery is in parallel what increases?
current
What are the 3 stages a lithium battery is charged in and what stage is not required if done before?
constant current, balance, voltage source - balance
What are the 2 methods of charging batteries & which method is used for each battery?
Constant voltage method - lead-acid batteries & Constant current method - Ni-cad batteries
What is labelled on a DC generator?
direction of rotation
What is the voltage between phases on AC?
200v
What is the frequency of a 3 phase AC system?
400Hz
What is the voltage from neutral in a 3 phase AC system
115/200v
What is the function of a GCU?
controls over/under drive & frequency
What is the function of an oil circuit & what happens if it goes into straight drive?
cooling - risks overheating
How many inductive pickup coils does a current transformer (CT) have and what is the function?
3 - current sensing
What is the function of circuit protection?
Prevent currents that are higher than the max allowed cross-section of the wire
What is used for circuit protection & what is the main difference?
fuses & circuit breakers - a CB can be reset
What is a fuse checker device known as?
multimeter
How many resets must you perform on a CB?
1
What indicates that a thermal CB has been tripped?
white band
How many pins does a DC ground connector have & which are + & -?
3, 2+ & 1-
How many pins does a AC ground connector have & which are neutral/phased & DC?
6, 4 neutral/phased & 2 DC
Why are the 2 DC pins on an AC ground connector smaller?
prevent arcing
What supplies DC power during flight?
EDG