Operation Manual Part 2

Aerosoft – Digital Aviation
CRJ-70 & CRJ-900
AOM PART 2
Systems Description
VOL
5
5-1-32
26-Jul-2017
DIRECT CURRENT, DC SYSTEM
Direct power is supplied by four transformer rectifier units, TRUs and two batteries.
The following table shows normal power distribution from the AC to the DC system:
INPUT BUS
TRU
OUTPUT BUS
AC BUS 1
TRU 1
DC BUS 1
AC BUS 2
TRU 2
DC BUS 2 / DC UTILITY BUS
ESSENTIAL TRU 2
DC BATTERY BUS
AC ESSENTIAL BUS
ESSENTIAL TRU 1
DC ESSENTIAL
ESS TRU 2 is normally supplied AC power from AC BUS 2. If AC BUS 2 is not available, ESS TRU 2 will be
automatically supplied from the AC ESS BUS, via the ESS TRU 2 XFR switch.
Battery
location
Output voltage
Capacity
APU
Aft equipment
compartment
24V DC
43 Ah (ampere hours)
MAIN
Nose avionics compartment
24V DC
17 Ah (ampere hours)
1. TRU VOLTAGE / TRU LOAD
2. FLOW LINES: Green indicates bus energized, white
indicates bus not energized
3. SERVICE CONFIGURATION: Indicates DC service is
selected ON
4. BATTERY VOLTAGE / BATTERY LOAD
EICAS DIGITAL READOUT
GREEN
WHITE
AMBER DASHES
XX V (TRU)
Between 22 and 29
volts
Less than 22 volts or
more than 29 volts
Invalid data
XX V (BAT)
Between 18 and 32
volts
Less than 18 volts or
more than 32 volts
Invalid data
XX A (TRU)
Between 3.7 and
120.7 amps
Less than 3.7 amps or
more than 120.7 amps
Invalid data
XX A (BAT)
Between 1.7 or not
less than 12 volts
Less than 1.7 amps and
less than 12 volts
Invalid data