CRJ-200 Electrical System Flashcards
CRJ-200 Electrical System Question and Answers... (37 cards)
What voltage does the DC system provide?
28 v
What voltage does the AC system provide?
115 v
What two components make up the engine driven generators?
IDG (integrated drive generator) and GCU (generator control unit)
What provides DC power?
The TRU’s recitfy AC power into DC power. The aircraft also has two batteries, APU battery and main battery.
When can the pilot reset a circuit breaker in flight?
Under the direction of a QRH procedure or when in the judgement of the PIC it is necessary for the safe completion of the flight.
What two components compromise the IDG?
CSD (constant speed drive) and a generator
How does the CSD work?
It utilizes an internal oil system to hydr-mechanically to change variable input speed from the engine accessory gearbox to a constant speed output for the generator of 12,000 RPM.
To what altitude do the engine driven generators provide maximum output, what do they do above that?
30 KVA to 35,000’, 25 KVA above 35,000’
What voltage does the APU output to 37,000’?
30KVA
What causes an automatic shutdown of an IDG?
High oil temperature (132C) or low oil pressure (130 PSI)
What indications will the pilot recieve when the IDG shutdowns?
A caution message will be displayed on the EICAS and a fault message will be displayed on the cooresponding IDG switch on the electrical services panel.
What causes an automatic disconnect of the IDG?
A severe overtemp (168C) situation or overtorque (3,300 in/lbs) will causes an automatic disconnect of the IDG.
Can a disconnected IDG be reconnected inflight?
No, a disconnected IDG must be reconnected by maintenance personal on the ground.
What are the six AC buses?
UTIL BUS 1, UTIL BUS 2, BUS 1, BUS 2, ESS BUS, SERV BUS
What is the power priority for each of the main AC buses?
On side, Inside, Off side, Outsides (BUS 1 - Gen 1, APU, Gen 2, External AC)
Which AC bus normally provides power the ESS BUS? What causes an automatic transfer and can this be done manually?
The AC BUS 1 normally provides power to the ESS BUS. It will automatically transfer to the AC BUS 2 if the GCU determines there is a fault with AC BUS 1. It can also be manually transferred by pressing the AC ESS XFER button on the Electrical Power Services Panel.
How will the pilot know if the AC ESS BUS has been transferred to the AC BUS 2?
No matter how the transfer occurs the pilot will notice the AC ESS XFER switchlight is illuminated.
What is load shedding?
Load shedding is the removal of the AC UTIL buses from the AC system when only one generator is online. (Galleys, BATT Chargers, Pax reading lights)
What causes load shedding in the air?
One engine generator is unable to provide enough power to power the entire system, when only one generator is available in flight the UTIL buses will be load shed.
What causes load shedding on the ground?
The main cabin door and service doors must be closed with flaps greater than zero and only one generator available.
What causes an AC AUTOXFER caution message? What will occur as a result?
If a bus shorts the GCU will prevent the autotransfer of the bus to prevent losing all electrical power sources as they try to power a faulty bus. It can not be undone in flight.
Is it possible to manually isolate a BUS?
Yes, utilizing the QRH for smoke removal or other procedures will isolate an individual BUS. This will result in a AC AUTOXFER OFF status message.
In the SERVICE CONFIGURATION what buses are powered?
SERV BUS, UTIL BUS 1, UTIL BUS 2
How does the ADG operate?
The wet ADG utilizes an oil governor while the dry ADG utilizes springs and flyweights to adjust blade angles to maintain the required frequency.
