Electrical System Flashcards
What type of electrical power does the CRJ 550 use?
115 Volt AC and 28 Volt DC.
What are the primary sources of AC electrical power?
2 engine driven integrated drive generators (IDGs) and 1 APU driven generator.
What are the sources of DC electrical power?
2 batteries and 4 Transformer/Rectifier Units (TRUs).
How is DC power distributed to the aircraft?
2 DC Power Centers (DCPCs)
Where are the batteries and TRUs located?
The APU battery is in the aft equipment bay and the main battery and TRUs are in the forward equipment bay.
What kind of batteries does the CRJ 550 have and what are they rated to?
Both are 24 volts. APU is 43 amps the main is 17 amps.
Other than the generators, how can AC power be provided to the system?
On the ground, through a Ground Power Unit (GPU) and in flight for emergencies through an Air Driven Generator (ADG).
Where are the circuit breaker panels located?
Behind the Captain and First Officer’s seats, and in the forward and aft equipment bays.
What is the purpose of the AC Power Centre (ACPC)?
It distributes AC power to the aircraft systems. It also provides a secondary power supply to the hydraulic pumps, flaps and slats, and pitch trim system.
What does the constant speed drive do?
Converts the variable RPM on the accessory gearbox to a constant Rpm output for the AC generator.
How are the components of the IDG displayed on the EICAS?
Next to the associated engine, the AC generator is labelled GEN and the constnt speed drive is labelled IDG.
Describe the CSD internal oil system.
Oil is cooled by air to oil heat exchanger using air from N1.
What causes an IDG FAULT switchlight to illuminate?
HOTLOP on the affected IDG.
How can the IDG be disconnected from the engine in the event of a fault?
Push the DISC switchlight on the electrical panel.
Can the IDG be reconnected in flight?
No.
If the IDG DISC switchlight fails, under what conditions would the CSD disconnect automatically?
CSD oil temperature reaches an unacceptably high level, also an input shaft will disconnect the IDG from the gearbox in the event of an over torque condition.
What controls and monitors the IDGs and the APU generator?
Generator Control Units (GCUs) that, in conjuncion with the ACPC, the GPUs provide voltage regulation, fault protection and bus priority for the AC system.
When will a generator be tripped offline?
Over or under voltage, over or under frequency, generator or bus over current or a generator phase seuence problem.
What priority does the ACPC give to power the AC buses?
Onside generator, APU generator, offside generator, ground power.
Can a tripped generator be reset?
Yes by QRH.
Can the APU genertaor supply AC power on its own?
Yes.