Electrical Flashcards
The AC system is composed of:
- two integrated drive generators (IDGs)
- one auxiliary power unit generator (APU)
- one inverter
- one Ram Air Turbine (RAT)
- one AC external power unit
The DC system is composed of:
- two NiCad batteries
- three transformer rectifier units (TRUs)
- one DC external power input
IDG 1 or 2 Selector Knob AUTO
allows automatic operation of the electrical system; closes IDG contactor connecting IDG to the respective AC BUS
IDG 1 or 2 Selector Knob OFF
opens IDG contactor isolating the IDG from the respective AC BUS
IDG 1 or 2 Selector Knob DISC
must be held for one second to mechanically disconnect the IDG.
APU Generator Button PUSH IN/OUT
IN - allows auto operation by connecting APU generator to the AC BUS TIE according to source priority
OUT - opens the APU generator contact
AC BUS TIES Selector Knob 1 OPEN/AUTO/2 OPEN
1 OPEN - opens the Bus Tie Contactor 1, segregating AC BUS 1 from AC BUS 2
AUTO - allows auto operation according to system logic
2 OPEN - opens the Bus Tie Contactor 2, segregating AC BUS 2 from AC BUS 1
GROUND POWER UNIT Button PUSH IN/OUT
IN - connects the AC GPU to the AC BUS TIE according to source priority
OUT - isolates the AC GPU from the AC BUS TIE
TRU Toggle Switches AUTO/OFF
AUTO - allows auto operation by connecting the TRU to their respective DC Bus
OFF - isolates the TRU from their respective DC Bus
BATT 2 Selector Knob AUTO/OFF
AUTO - allows auto operation by connecting battery 2 to the DC ESS BUS 2
OFF - the battery supplies power only to the HOT BATT BUS 2
DC BUS TIE Toggle Switch AUTO/OFF
AUTO - allows auto operation by controlling the operation of the DC Tie Contactors according to system logic
OFF - opens all tie contactors
BATT 1 Selector Knob ON/OFF
ON - the battery is connected to the DC ESS BUS 1
OFF - the battery supplies power only to the HOT BATT BUS 1
IDG and APU gen rating
115 VAC, 40 KVA, 400 HZ, three-phase
Can you reconnect an IDG after manual disconnection
NO
Describe the inverter
the AC/DC inverter converts 28 volt DC power from batteries to 115 volt AC power to supply the STANDBY AC BUS when an AC power source is not available
Ram Air Turbine rating
115 V, 15 KVA, 400 Hz, three-phase AC
When is the RAT automatically deployed
when the AC ESS BUS loses power
What buses does the RAT power after deployment
AC ESS BUS; DC ESS BUSES are powered through the ESS TRU
What hydraulic system does the RAT power after deployment
AC motor driven hydraulic pump (ACMP 3A) from primary flight control tasks
Min speed for RAT to power AC/DC ESS BUSES
130 knots
What will a DC GPU provide power for
APU START BUS
TRUs are rated at
300 A; convert 115 VAC into 28 VDC
TRU 1 provides power to
- DC BUS 1
- DC ESS BUS 1
- DC GND SVC BUS
- HOTT BATT BUS 1
- Batt 1 charging
TRU 2 provides power to
- DC BUS 2
- DC ESS BUS 2
- HOT BATT BUS 2
- Batt 2 charging
