Electrical Flashcards
Location of Main Battery
Nose compartment
Location of the APU Battery
Aft equipment bay
Max Engine Generator load
40 KVA
Max APU Generator load
40 KVA
Max Transformer rectifier unit (TRU) load
120 amps
Max permissible time for ground operations with battery power only
5 minutes
Prevents ED1/ED2 from overheating, fans are AC powered
How many TRUs are installed in the CRJ 900
4
Where are the TRUs located
nose compartment
The Main Battery is rated to
17 ampere hour/24 volts
APU Battery is rated to
43 ampere hour/24 volts
How many generators are installed
4, 2 engine generators, 1 APU generator, 1 ADG
What is the function of the 4 TRUs
To convert 115 V AC to 28 V DC
How are the TRU’s cooled
Individual fans
Which buses are powered when the Battery Master switch is selected on
Main battery direct bus, APU battery direct bus, DC Battery bus
If the main buses are powered, are the essential buses automatically powered
Yes
Is there an on/off switch for the TRU’S
No, they are automatically powered when the AC busses are powered
What controls the DC tie contactors
The DC Power Centers (DCPC) automatically control DC tie operation
With the ADG deployed, what are the basic items that are powered
AC ESS Bus, Hydraulic pump 3B, flaps/slats, STAB trim CH 2
What is the ADG max load
15 KVA
ENG driven IDGs have an overload rating of
45KVA/5min
60KVA/5sec
Main Generators provide AC power to how many AC buses
4
Bus 1/2, ESS Bus, Service Bus
Power to the 28v DC Systems is supplied by
4 TRUs
Transformer Rectifier Units
TRU 1 Supplies PWR to
DC Bus 1
TRU 2 supplies PWR to
DC Bus 2
ESS TRU 1/ESS TRU 2 normally supplies
DC ESS Bus
The Main Battery is charged by
AC Bus 1
The APU Battery is charged by
AC Service bus
IDG provide a means of converting
variable engine speed to contact GEN speed of
12,000rpm
Fault protection is provided by
Generator Control Units (GCUs)
Priority for allowing power to AC Bus 1 is
Gen 1
APU
Gen 2
External AC
IDG 2 (Gen2) normally powers
AC Bus 2
Service Bus
Which DC Bus ties are automatic
Main Tie Cross Tie ESS Tie TRU Contactor Control ESS TRU Transfer
The ADG will auto deploy
With complete loss of A/C power AC Bus 1&2 falls below 50v WOW indicates Aircraft is airbourne Any GEN was online for 3.45 sec prior to power loss on AC Bus 1/2
Amber IDG Fault/Caution light indicates
Low IDG oil pressure / High oil Tempurture
AUTO XFER fail light on Electrical panel indicates
GEN overcurrent or Bus Fault
AC ESS XFER light (White) on ELEC panel indicates
AC Bus 1 is no longer powering AC ESS Bus
What happens when you switch on the DC SERVICE switch
- W/no AC PWR, SERV BUS is powered by APU BATT BUS via Service Bus contactor
- SERVICE CONFIGURATION message appears on DC Synoptic page
- Service Bus contactor not represented on DC Synoptic page
What happens when the Battery Master is
Switched on
Connects Main Battery to BATT BUS through MAIN BATT Direct Bus
APU Battery to BATT BUS through APU BATT
Direct Bus
How many DC busses are there
9
DC Bus 1,2 Service Bus Utility Bus ESS Bus BATT Bus APU Battery Direct Bus MAIN Battery Direct Bus DC EMER Bus
What happens when TRU 1 fails
Main Tie Contactor Closes
TRU 2 PWRs DC Bus 1
DC Utility Bus loads sheds
Status Message Appears:
-(TRU1 failed, Main Ties Closed)What happens when TRU 1 and 2 fail
DC Main and Cross Tie automatically closes
ESS TRU 2 PWRs:
-DC Bus 1/2, DC SEV Bus
DC Utility Bus is shed (OFF)
Status Message appears:
-Main&Cross Tie have closed
-TRU 1/2 failed
What happens when ESS TRU 1 fails
DC ESS Tie closes allowing ESS TRU 2 to power
DC ESS Bus
DC ESS Tied Closed Status Message appears
Which DC Bus Ties DON’T have automatic operations
Service Bus Contactor
It is activated by DC Service switch on the overhead panel when there is no AC power to airplane
