Boeing 777 Electrics
1 / 15
What is the correct electrical panel configuration for normal flight?
2 / 15
Which condition(s) cause the ELEC GEN DRIVE L EICAS message to display?
3 / 15
During autoland, the busses isolate to allow three independent sources to power the three autopilot. In this case which one of the following is the power source for the right AC transfer bus, the right DC bus, and the first officer's flight instrument bus?
4 / 15
The standby inverter converts DC power to AC power. The inverter powers the AC standby bus if the right transfer bus is not powered.
The standby inverter converts DC power to AC power. The inverter powers the AC standby bus if the left transfer bus is not powered.
5 / 15
Primary power for the flight control DC electrical system comes from permanent magnet generators (PMGs) housed within each backup generator. Variable frequency PMG AC power is used by individual power supply assemblies (PSAs) to provide DC power to the three flight control DC busses. To ensure a high level of system reliability, each PSA also has multiple AC power sources.
To ensure a high level of system reliability, each PSA also has multiple DC power sources (No AC power!). If primary PMG AC power is not available, secondary power for the left and right PSAs is provided by the related main DC bus. Secondary power for the center PSA is provided by the captain’s flight instrument bus. The hot battery bus provides additional backup power for the left and center PSAs only. Each PSA also uses a dedicated battery to prevent power interruptions to the related flight control DC bus. The batteries have limited capacity and are incorporated to supply power for brief periods during PSA power source transfers.
6 / 15
Backup power is provided by one variable speed, variable frequency generator mounted on each engine. A frequency converter converts the generator frequency to a constant 400 Hz. Only one backup generator can power the converter at a time.
7 / 15
What is the electrical configuration during autoland?
8 / 15
When does the right transfer bus isolate from the right main bus?
9 / 15
Bus tie relays, controlled by BUS TIE switches, isolate or parallel the right and left main busses. When both BUS TIE switches are set to AUTO, the bus tie system operates automatically to maintain power to both main busses.
10 / 15
What provides DC power on the B777?
11 / 15
Which one of the following is not true about the Primary External Power?
12 / 15
Which one of the following is not true about the Secondary External Power?
13 / 15
How are the busses powered if the right engine is started with the APU powering the left bus system and external power powering the right bus system?
14 / 15
The Electrical Load Management System (ELMS), manages load shed priority (galley first, utility bus second, then selected AC components).
15 / 15
Will the IDG disconnect automatically for high temperature?
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