1.01 Flashcards
Main power source q400
DC system
3 x Nicad 24vDC 40 Ah
2 x starter/gen 28,5V 400amp
2 x TRU 28vDC 300 amp
1 x APU 28,5vDC 400 amp
AC System
2 x AC generators mounted on prop reduction gearbox, 115v 3ph AC
Electrical system supply
Entire system can be powered by AC generators
Standby battery
Provides protection to the EPCU by absorbing current spikes
Has a one way flow from left DC main bus for charging
Provides power to essential bus in emergency
Backup Power
3 40Ah batteries can supply 60 min power to Left and Right essential bus
Hot battery bus
APU Fire bottle
Battery master switch
Battery power fueling
Boarding lights
Clocks
Emergency power for PA
Fire bottles discharge squib
Fuel/Hyd shutoff valves
Right essential DC Bus
Main and Standby batteries
Left essential DC bus
Auxiliary battery
Battery Caution light Illumination
71 then goes out at 63
Electrical page Battery display
0-50= white
50-65= amber
Above 65=red
When connecting external power
GPU must be connected and ON before EXT power is selected on DC control panel
EPCU Electric Power Control Unit
Operates in emergency mode when
-The Airplane is in air
-both DC Gens are not available
-at least one TRU is not available
AC generators come online when
Cond Levers are out of Start/feather
If one AC generator fails, what systems are lost?
Only Galley power (galley buses)
DC generator cooling
Air cooled
AC generator cooling
Oil cooled
Power sources in flight?
2 x DC gens power Main Bus
2 x AC TRU power Secondary Bus
Single DC generator failure
Main Bus Tie is automatically closed by EPCU, remaining generator powers both Main buses
Single TRU failure
Secondary Bus Tie is automatically closed by EPCU
Remaining TRU powers both secondary buses
Both DC generators fail
EPCU closes both secondary-to-main bus Ties, TRU powers all DC buses
Both TRU and one DC generator fails
Main bus Tie closes, to allow remaining generator to power L and R main bus
EPCU prevents main to secondary bus from closing resulting in all services from secondary bus to be lost
Faulty BUS
If a fault persists after 5 seconds the EPCU isolates the affected bus by
Sending a trip signal which isolates the affected generator
Caution lights associated with Right Main bus fault
DC Bus
MAIN battery
#2 DC Gen
Secondary Bus Fault
Causes affected TRU CB to trip
7 secs after trip, secondary bus tie closes, allowing system to be powered by opposite TRU.
Excessive current causes a fuse to blow, effectively isolating the faulty bus, and services are lost.
AC power protection unit
Located in right landing gear well
AC system components
De/Anti-ice heaters
Sby Hyd Pump
2 x TRU
Fuel aux pump #1/#2
(Galley)
