Electrical Flashcards
When the battery master is selected ON, what happens within the electrical system?
Essential buses are powered; and if inverter switches are selected on, fixed AC buses are powered
What is the function of the TRUs?
Converts variable frequency AC to DC
What is the function of inverters?
Converts 28VDC to 115V fixed freq AC
How many inverters are required to power the fixed AC system?
One
What precautions must be taken if only one inverter is operational?
Monitor the load on the operating inverter
What is the function of the BBPU?
Protects the DC generators and batteries from faults in the main feeder buses
How many selections are available for the Aux inverter?
Three
If we get a battery overtemperature do we manually isolate the battery?
Yes
Which lights are directly powered by the battery power bus (hot battery bus)?
Boarding lights and dome light
How many batteries does the aircraft have?
Two
What type of batteries does the aircraft have?
NiCad
What voltage should we see on the DC monitor with external power on?
28 Volts
Which buses will be powered with DC external power?
Left and right; Essentials, mains and secondary, all fixed AC if the inverter switches are selected ON.
What is the minimum battery voltage required for a battery powered engine start?
22 Volts
At what voltage does the overvoltage protection lock out DC external power?
31.5 Volts
What is the input and output power of the TRU?
115 VAC to 28 VDC
How can the TRU be shutoff?
Pull the circuit breaker
If a TRU fails, will both secondary buses be powered?
Yes, from the opposite secondary bus through a horizontal tie
If both TRUs fail, will the secondary buses be powered?
Yes, both vertical ties from the main buses
Will external DC power charge the battery? External AC?
No, unless there is a mod equipped
Will the APU gen charge the battery?
Yes, with the main and auxiliary switches on
Which buses are powered with the battery master and main batt switched on?
Both essentials, right main (fixed AC with inverters on)
Which buses are powered with the battery master & main and aux battery switches on?
Both essentials, right main (fixed AC with inverters on)
How do we get the battery power to the left main buses?
Main bus tie
