24 Electrical Power Generation Flashcards
What are the two classifications of the electrical power system
power generation
power distribution
What ATA chapter is Electrical Power
ATA 24
what is a typical dc voltage
14V or 28V. 28 for pax main
which is lighter for power generation, ac or dc, low or high voltage
ac, higher voltage
what is a generator
a device that turns mechanical energy into electrical energy via inducing a changing magnetic field (faraday’s law of electromagnetic induction) and producing emf.
what type of energy do generators produce?
ac
what is an alternator?
converts mechanical energy into electrical energy. (technically a generator is an alternator) but it uses a rotating magnetic field. Typically driven by an IC engine. or in power plants putting most power onto the grid.
what determines if an aircraft will use a dc alternator or an ac alternator? (alternator = generator)
electrical load -> size
small-> dc
large -> ac
which type of generator do large commercial aircraft and many military aircraft use?
ac generator
How do lighter aircraft produce dc power?
full-wave rectifier is built into the generator
describe the construction of alternators for aircraft
stationary armature with a rotating magnetic field
what is the purpose of slip rings in generators ?
to transfer the power from rotating to non-rotating components
what determines the output frequency of the ac generator?
the drive speed (6000rpm)
what determines the voltage of an ac generator
magnetic flux and number of coils
what is the task of a constant speed drive?
ensure the output of a generator is always the same frequency
what is a IDG
integrated drive generator. contains csd and generator in one unit
what are advantages of ac high voltage system?
- weight savings
- voltage transformation possibility
- lower current for less power loss in lines
what is an inverter
dc to ac at a given frequency
what is a TR
transformer rectifier. converts ac to dc
what is VSCF?
variable-speed constant frequency is a type of generator that takes the engine drive at its variable speeds without a CSD (constant speed drive) and uses the GCU (generator control unit) to produce a constant frequency.
what type of aircraft uses a VSCF generator
B737
what does a GCU do? (generator control unit)
voltage regulation, current limiting, and frequency control.
