Electrical System Flashcards
PMG On/Off N2%
On - 50%
Off - 20%
PMG Output
3 x 28VDC
Battery Life (inflight)
5-10 min
Battery Voltage/Amps
24.5 V
15 Amp
Normal Battery Voltage
24V
Bad Battery Voltage Indication
18 V
Battery On Limit on Deck
2 min
AC Generators
Powered by AMAD Power Transmission Shaft
Either generator capable of powering entire aircraft load
PMG (Permanent Magnetic Generator)
Works independently from Generator
3x28VDC power windings
- 2 provide power to their respective FCC Channel
- 1 routed to back up the DC Ess Bus
Prior to Start Battery Powers
Maintenance Bus and APU
Gen Tie Logic
Isolates a Bus or Gen that is not performing properly
Allows one reset and if fault still exists, logic will isolate the problem
Requirements for Gen Tie Logic to work
Battery Switch On
Parking Brake Set
Gen Tie Switch not in Reset
Get Tie Light
On Ground
- Parking Brake Handle not set after first engine start
In Flight
- 115 AC Busses isolated for either bus or gen fault
T/Rs (Transformer/Rectifiers)
2 T/R’s convert 115 VAC from busses into 28VDC
Capable of entire load
Single T/R Failure
No cockpit indications
Dual T/R Failure
Loss of HUD
Bleed Air - to include cockpit pressure and OBOGS
FCC Electrical Redundancy
1) PMG
2) Ess Buss
a) R T/R
b) L T/R
c) R PMG
d) L PMG
e) Battery
Circuit Breakers
Left
- FCC 1
- FCC 2
- Launch Bar
Right
- FCC 3
- FCC 4
- Hook
- Landing Gear
Dual Gen Failure
Loss of all displays Bleed Air Radalt Nav Instruments Select Jett Hyd Press Indicator Cabin Press OBOGS Normal Gear Ext Anti Skid
EFD Shows RPM and EGT only
Comm 1 Maintains last Freq
Batt Gauge shows 28V with no Batt SW Caution
DUAL GEN & PMG Failure
Same indications as Dual Gen but Batt Gauge reads = 24V
Batt Voltage where FCC’s Lose Power
18V
GEN On/Off N2%
On - 60%
Off - 52%
