Electrical Flashcards
Two basic principles of AC Electrical operation are? (select all that apply)
No Paralleling of AC power sources and A source of power connected to an AC Transfer Bus automatically disconnected the previous sources
What does the blue GRD POWER AVAILABLE light indicate?
External power meets aircraft quality standards.
What does the blue APU GEN OFF BUS light indicate?
The APU is running and not powering any AC Transfer Bus
Which of the following causes the DRIVE light to illuminate?
IDG oil low, oil pressure or under frequency condition.
The GEN OFF BUS light only illuminates when the engine generator is running and is not powering the related AC Transfer Bus?
False. The GEN OFF BUS light illuminates anytime the engine generator is not powering the related AC Transfer Bus.
What is the purpose of the Bus Tie Breakers?
Automatically control AC power distribution.
What is the purpose of selecting the BUS TRANSFER switch OFF?
1.To inhibit Bus Tie Breaker auto switching.
2. To open the cross bus tie relay.
What is the purpose of the automatic on-line feature?
To automatically transfer power to the engine generators in the event the APU is shut down or fails. If the aircraft takes off with the APU providing power to the AC Transfer Busses and the APU fails or is shutdown, the BTB’s transfer the electrical load to the engine generators. This feature operates in flight and only once per flight.
What does the TRANSFER BUS OFF light indicate?
The respective AC Transfer Bus is not Powered.
The Ground Service Busses provide power to?
The aircraft cabin and battery chargers.
What is the normal AC source of power for TR3?
AC Transfer Bus 2, with a backup from AC Transfer Bus 1.
A TR UNIT light in-flight indicates?
1.TR 1 has failed.
2.TR 2 and TR 3 have failed.
When will the DC cross bus tie relay open automatically?
Glide slope capture during a Flight Director or Autopilot approach.
What is the aircraft power source while operating on standby power?
The Aircraft Battery
An illuminated STANDBY PWR OFF light indicates a power loss to which bus?
DC Standby Bus, AC Standby Bus, Battery Bus
