Chapter 22 - The Electrical System Flashcards
For what kind of things would an aircraft need an electrical system for?
Lights, motors, flaps, radios, gear, instrumentation, etc.
Does a typical light aircraft have a DC or an AC electrical system?
DC (direct current)
What is a bus bar?
A distribution centre for the electrical system
What type of battery is normally fitted to a light aircraft?
Lead-acid
What is the typical voltage of a light aircraft battery?
12 or 24 volts
What does a light aircraft battery typically supply power for?
Engine start and emergency situations
If you connect two 12V 60AMP-hour batteries IN SERIES, what is the resultant voltage and amp hours?
24 Volts, 60 AMP-hours
If you connect two 12V 60AMP-hour batteries IN PARALLEL, what is the resultant voltage and amp hours?
12 Volts, 120 AMP-hours
What supplies electrical power to the aircraft during normal flight?
The alternator
How is the alternator driven?
Belt-driven by the engine
What is a generator?
A self sufficient, electricity-generating device with it’s own permanent electrical field
Does a generator supply DC or AC power?
AC power
Does an alternator supply DC or AC power?
AC power
What device converts AC power into DC power?
A rectifier (transfer rectifier unit-TRU-)
What are the advantages of using an alternator over a generator?
- Lighter
- Produce a more constant voltage
- Easier and cheaper to maintain
What is the main disadvantage of an alternator?
An alternator requieres an initial ‘excitement’ to function, it can’t start itself. We use the battery to provide this initial excitement
What does the ammeter tell the pilot?
If electricity is flowing TO or FROM the charging unit (positive means battery is gaining energy-being charged-negative means the battery is losing energy)
What is the typical reading of the ammeter when the master is ON but the engine is not running?
A negative indication (battery being depleated
What is the typical reading of the ammeter after the engine has been started and the alternator has been connected?
A positive indication (battery charging)
What does the master switch do?
Basically, switches the battery on
What is the difference between a fuse and a circuit breaker?
If a fuse burns out, it has to be replaced. A circuit breaker can be reset (pushed back in)
