Electrical System - NATOPS CH. 2.6 Flashcards
What are the sources of AC power?
Generators, APU, External power
How are the main generators driven?
Transmission
What battery do we have?
24V Nickel Cadmium battery
Two primary uses of the battery
Start the APU
Power the battery utility bus
Description of the Main Generators
Oil cooled, 30/45kVa, 115 Vac, 3 phase, 400 Hz power
Description of the APU Generator
Air cooled, 35kVA, 115 Vac, 3 phase, 400 Hz
Functions of the GCU
Connects generators to AC bus
Regulated generator output
Protects against over voltage, undervoltage, feeder faults, under frequency
With weight on wheels, at what percent Nr does the GCU remove the main generators from the ac power system?
94% Nr
In flight, under frequency protection is disabled and generators remain online until ______ Nr.
80% Nr
A minimum of _____ Nr is required for the GCU to reconnect the generators to the ac power system.
97% Nr
What is external power monitored for?
Phase rotation, over voltage, under voltage, over frequency, under frequency.
External power system includes a ___ amp circuit breaker that places a ___ amp draw.
4 amp, 2 amp
What are the five AC buses?
No. 1 AC Primary
No. 2 AC Primary
AC Secondary
AC Essential
AC Monitor
Three Pigs
- Backup Hyd Pump on No. 1 AC Primary
- Mission computer and TR De-Ice on AC Secondary
- Main Rotor De-Ice on AC Monitor
What does the RESET switch do on the generators?
Resets the GCU if it was disabled or disconnected
External power will automatically be ____________ when either a main or APU generator is brought online.
Disconnected
With only one generator and backup pump off, what is the only bus that gets dropped?
AC Monitor
With one generator and backup pump on, what are the two buses that get dropped?
AC Secondary, AC Monitor
What voltage is DC power?
28 Vdc
With an _____ charge, normal battery life is _____ minutes during the day, and _____ minutes at night.
80%, 11 minutes, 9 minutes
What are the functions of the battery analyzer/conditioner?
Monitor for fault conditions, battery charge, internal temperature, cell conditions, and provides battery charging capability.
Where does the charging circuit of the battery analyzer/conditioner get its power?
No. 2 AC Primary
Where does the battery analyzer/conditioner get its dc charging power from?
No. 2 DC Primary
What are the five buses in the DC power system?
No. 1 DC Primary
No. 2 DC Primary
DC Essential
Battery Bus
Battery Utility Bus
What powers the No. 1 DC Primary Bus, DC Essential, and Battery Bus?
No. 1 Converter
What powers the No. 2 DC Primary Bus?
No. 2 Converter
What powers the battery utility bus?
Battery
If both converters fail, what does the battery power?
Battery Utility Bus, Battery Bus, DC Essential bus
With no other source of DC power and the battery below a _____ charge, battery power may not be sufficient to activate the fire extinguished CADs.
30%
When do you get BATT CHARGE LOW?
Less than 40%
What bus do you lose with battery only, less than 35% charge?
DC Essential
______ _______ _________ will be inoperative when the ac essential bus is lost and _______ ______ capability will be lost when the dc essential bus is lost.
Stab auto programming
Manual slew
Warning: Without electrical power to the dc primary buses, the engine and inlet anti-ice valves are automatically opened. With an improperly operating engine inlet anti-ice system, a loss of up to _____ power available per engine is possible.
49%
