ELECTRICAL SYS Flashcards
AC GENERATORS (type and power)
APU GEN
2 oil-cooled, 30/45kVa, 115Vac, 3-phase, 400 HZ generators
APU - 35kVa, 115Vac, 3-phase, 400HZ
GCUs regulate/protect against what?
regulate generator output, protect against over voltage, undervoltage, feeder fault, and underfrequency
Underfrequency protection
WOW - GCUs remove main generators from the AC system if Nr < 94%
WoffW - protection disabled, generators remain online until Nr < 80%
Minimum of 97% Nr required for GCU to reconnect the generators
Electrical bus load shedding priority
- Backup hydraulic pump - major load on #1 AC PRI
- Mission power / T/R De-Ice- major load on AC SEC
- M/R De-Ice - only system one the AC Monitor
Which AC buses (primary, secondary, or monitor) can be powered if you only have one generator and the APU?
Only 2/3 of the buses.
Which AC buses (primary, secondary, or monitor) can be powered if you only have one generator?
Either the #1 AC primary or the AC secondary bus (backup pump or mission power). The monitor bus is dropped.
Which AC buses (primary, secondary, or monitor) can be powered if you only have the APU?
Only the #1 AC primary bus will be powered. (backup pump)
How many converters do we have and what do they supply?
two converters that supply 28Vdc by converting 115Vac from the #1 and #2 AC primary buses
What is the primary source of power
for APU starts?
the 24Vdc battery - used for APU starts, and is a secondary power source for the DC essential and battery buses
With ____% charge, the battery can run for how long during the day/night?
80% charge - 11 min day, 9 min night
The battery analyzer / conditioner monitors and provides what?
fault conditions, battery charge, internal temp., cell conditions, battery charging capability
Where does the battery analyzer / conditioner receive power from?
receives power from the #2 AC primary bus and DC charging power from the #2 DC primary bus
What is the difference between a single and a dual converter failure?
Single converter fail - the operating converter picks up the load dropped by the failed converter
Dual converter fail - battery becomes emergency power source to the utility bus, battery bus, and the DC essential bus (if charge > 35%).
Battery charge at ____% indicates [BATTERY LOW CHARGE]
40%
The DC essential bus will be dropped when battery charge is ____%. What will you no longer be able to do?
35%, slew the stab
If battery charge reaches ____% you will no longer be able to fire the CADs.
30%
External power system includes a ___-amp circuit breaker that places a ___-amp draw.
4-amp, 2-amp
External power is monitored for:
phase rotation, overvoltage, undervoltage, underfrequency, and over frequency
The #1 AC generator powers which buses?
AC secondary, #1 AC primary, AC essential
The #2 AC generator powers which buses?
2 AC primary, AC monitor
The #1 converter powers which buses?
1 DC primary, DC essential, battery bus
The #2 converter powers which buses?
2 DC primary bus
In a dual converter failure, what can you expect to lose?
DTU 1&2 (util mode)
AFCS computer and control
Jettison power
Aux fuel and fuel management
Backup pump operation
Pilot / copilot mission displays
Engine anti-ice/start-bleed valve open (18% torque)
Rast probe
#1 EGI (AFCS functionality)
If you lose all DC power or your DC ESNTL bus where the battery dies after 11 or 9 minutes, what can can you expect to lose?
SAS/Boost
Lights
#2 EGI
Stab man slew capability
What happens if you lost the BAT BUS?
APU fire detection capability
Fuel prime boost pump (no more APU)
Backup attitude indicator charge (lose after 9 min)
