M11.6 Flashcards
What is electrical power used for?
- electrical heating
- lighting
- electronic devices
- produce mechanical power
How much electrical energy does a 2 engine aircraft need?
100Kw
How much electrical energy does a 4 engine aircraft need?
400Kw
What does a static inverter do?
It converts DC to AC
What voltage and frequency is AC power?
115 volt
400 hertz
What does a transformer rectifier unit do?
It transforms AC to DC
What voltage does the DC power work on?
28 volts
What are most batteries made from?
Nickel cadmium
How much voltage does a battery provide?
24 volts DC
What are batteries used for?
- engine starts
- APU starts
- emergency distribution
What are the four things that supply AC power to the aircraft?
- engine generator
- APU generator
- external power
- emergency generator
What supplies the aircraft with DC power?
Batteries
What is a ‘bus’ used for?
It connects the power source to the consumers
What does AC stand for?
Alternative current
What does DC stand for?
Direct current
What must be done when switching on/off power whilst on the ground?
Large loads must be switched off
How long can a battery last as emergency power?
30 minutes
What drives the air driven generator?
Ram air
What drives the constant speed motor generator?
A hydraulic motor
What is always powered?
Hot battery bus
What is the main task of fuse or circuit breaker?
To prevent overheat or fire due to a short circuit
What happens in a short circuit?
A current is larger than the maximum allowed cross section of the wire
How does a fuse work?
A smaller cross section of metal is placed before the terminal to absorb the short circuit
Why do most aircraft use circuit breakers over uses?
Because fuses are time consuming
What does location of the circuit breaker depend on?
The location of the consumer to minimise wire length
What is the basic fundamental of a generator?
A rotating magnets spins between a magnetic North and South Pole (pole pair)
If a generator takes one second to complete one cycle, how many hertz does it produce?
A frequency of 1hertz
How much voltage is produce in a ‘line to neutral’ (phase to ground)?
115v
How much voltage is produce in a ‘line to line’ (phase to phase)?
200v
During low speeds the constant speed drive will do what?
Speed up
During high speeds the constant speed drive will do what?
Slow down
What combines together to create the integrated drive generator?
Constant speed drive and a generator
How many TRUs are there?
1 for each main DC bus
What type of fluid is found in a battery?
Electrolyte fluid
How often should a battery be check for operation?
2,000 hours
What are the 6 pins on the external power plug for?
- 4 thick pins for phases A,B,C and neutral
- 2 thin pins to control connection
