Electrical System (Ch. 2)

Question 1

Three major loads

Answer 1

• Backup HYD pump (No 1 AC primary) will always be powered if required
• Mission avionics system (AC secondary). Tail rotor deice pwr is also on this bus
• Main rotor deice system (AC Monitor). Lowest priority.

Question 2

5 AC Electrical buses

Answer 2

• No. 1 AC Primary (backup hyd pump)
• No. 2 AC Primary
• AC Essential
• AC Secondary (mission pwr/tr deice)
• AC Monitor (main rotor deice)

Question 3

How is primary AC power supplied?

Answer 3

• By two oil cooled 30/45 kVA, 115-volt ac, 3 phase, 400Hz generators.
• driven by transmission accessory modules.

Question 4

Secondary ac power is supplied by ____

Answer 4

• an air-cooled 35-kVa, 115-volt ac, 3 phase 400 Hz generator driven by the APU
  *

Question 5

What does the GCU do?

Answer 5

• Generator control unit
• connects each generator to the ac electrical bus system
• regulates generator output
• protects system composnents and circuitry against:
  
  • overvoltage
  • undervoltage
  • feeder fault
  • underfrequency

Question 6

When do you lose generators on ground?

in flight?

what percentage N_r is required for teh GCU to reconnect to the ac electrical distrib. system?

Answer 6

94% N_r

80% N_r

97% N_r

Question 7

What kind of battery is used?

Answer 7

24 volt dc Nickel Cadmium (NICAD) battery.

used to start APU and power Battery Utility Bus

Question 8

Two converters supply ____ ____ power.

what powers them?

Answer 8

• 28-volt dc
• powered by the No. 1 and No. 2 AC Primary buses.

Question 9

What does the battery analyzer/conditioner do?

Answer 9

• Monitors battery system for fault conditions, battery charge, internal temp, cell conditions, and charging.
• if a fault is sensed, it will automatically disconnect the dc loads from the battery, or the battery from the charging circuit.