Electrical SV Flashcards
The minimum battery voltage for APU start is
23 Volts
What happens to the original electrical source when a new source of power is connected to a bus system
It automatically disconnects the existing source
What does the GRD POWER AVAILABLE light indicate?
Ground power is available, connected to the aircraft, and meets the quality standards
If the BUS TRANS switch is in the AUTO position and the source powering the transfer bus is discounted or fails, what does the source powering the opposite transfer bus through the BTBs do?
it automatically picks up the unpowered transfer bus.
What do the three transformer rectifier (TR) do?
Convert 115-volt AC current to 28 volt DC current
In flight when does an amber TR UNIT light illuminate?
when TR1 or TR2 and TR3 has failed
How long does a fully charged battery have sufficient capacity to provide electrical power for? (single battery configuration)
A minimum of 30 Minutes
When does an amber BAT DISCHARGE light illuminate?
When an excessive battery discharge is detected.
What is the indication of the STANDBY POWER light on the panel indicate?
The AC Standby bus, the DC Standby bus, or the Battery Bus is not powered.
In flight or on the ground, with the STANDBY POWER switch in auto (guarded position) with a loss of all AC power what is powering what buses?
The AC Standby Bus, the DC Standby Bus and the DC Standby bus are all powered by the Battery.
The Light on the overhead panel that illuminates if the APU is running and not supplying power to a bus is the
APU GEN OFF BUS
What buses can the APU supply power to?
Both transfer buses
In single generator operations what happens if the demand is to high?
the system is designed to shed load incrementally. It starts with Galley bus two, then galley on bus one, followed by the main bus two then one and finally IFE bus.
What causes the DRIVE caution light to be illuminated?
Low oil pressure or high oil temperature in the IDG.
What two ways are the IDG disconnected?
Manually through the generator drive DISCONNECT switch for low oil pressure,
Automatically high oil temperature
