Where does emergency power come from?
A generator driven by the APU
What do the generators do?
Convert mech energy to elec
Where does DC power come from?
2 Converters
What voltage do the converters ouput?
28 Volts
Where does converter output go?
1 and #2 DC primary buses
What provides secondary or emergency power
2 slab batteries
where does power from the slabs go?
battery utility bus (bub), battery bus, DC essential bus
How many phases do the gen’s have?
3
How many priorities of power?
what are they?
3
main gen’s, apu gen, external power receptacle
how are main gen’s cooled?
how is apu gen cooled?
oil
air
how many gen’s are req’d for blade de-ice?
2
Main gen specs
-operates when rotor is turning.
-supplies power when NR above 85% in flight/97% ground
-1main gen can power entire aircraft with the exception of deice
must be replaced w/in 10hrs after bearing fail.
APU Gen specs
- APU must be running for generator to work.
- Aux/backup power for backup
- will not power windshield anti-ice while backup pump is running
- 2gens
GCU specs
- Voltage reg - 115/200
- Under voltage 85-89% NR
- Current Limiting (excessive demands disconnect gen.
- under frequency- 93-95%NR (ground only disables by WOW)
- feeder fault- when current transformers sense a short circuit in the feeder lines between the gen’s and the jnct boxes, the gen is disabled and disconnected from the system.
converter takes _ phase __ VAC and makes _ VDC
115VAC
28VDC
_ gen’s for blade deice
2
does backup pump have priority over anti-ice when APU GEN is sole source of power
yes
