Electrical System Flashcards
How many AC busses are there and what are they?
AC system has 7 busses: Left, Main, Essential AC, Right, essential main avionics and 60 HZ AC.
How many generators does the aircraft have and their specifications? (Hz, Volts)
x4 engine driven oil cooled generators that output 115V 400Hz AC power to the AC system
Which bus(es) can be powered by any of the generators?
Essential Avionics and main bus, these can both be powered by the APU and can also be used as a source of DC power.
Which DC bus provides power to the essential avionics bus and vice versa?
The essential avionics AC bus is powered by the isolated DC bus through an inverter and vice versa
Which DC bus provides power to the main Avionics buss and vice versa?
Main avionics AC buss is powered by the avionics DC bus through an inverter and vice versa
What busses does the APU power with no engines running?
Main and essential avionics AC busses, if one of the engine driven generators are producing power the APU will only power the Essential AC bus
What controls the generators and protects against over voltage conditions?
Generator Control Unit (GCU)
When external AC power is connected to the aircraft which busses receive power?
All AC and DC busses
In ground power mode and APU mode is selected what must you do prior to switching to any other power mode
Completely power down
Why doesn’t the aircraft loose power when switching between EXTL power and APU power?
There is a holding relay which stores approx 2s worth of power.
Which AC busses prove power to the DC system, what power and how?
Essential AC and main AC through four transformer rectifier units to provide 28VDC power to the essential DC bus and the main DC bus.
How many DC Busses are there and what are they called?
6 DC Busses: Main DC, Essential DC, Isolated DC, Avionics DC, Utility battery bus, avionics battery bus
When you select the battery switch to on what happens?
The utility battery powers the isolated DC bus and the avionics bus powers the avionics DC bus
