Study Guide: Electrical Flashcards
757/767: According to the graphic, the right utility bus OFF light is illuminated. What is the cause for its illumination?
a) The right DC bus tie breaker is closed
b) The center No. 2 electric hydraulic pump has shed
c) The right galley bus is unpowered
d) The right utility bus is unpowered
The right utility bus is unpowered
757/767: According to the graphic, the L GEN DRIVE DISC DRIVE light is illuminated. What is the cause for its illumination?
a) The associated generator drive has disconnected
b) The associated generator drive oil temperature is low or oil pressure is high
c) The associated generator drive oil pressure is high
d) The associated generator drive oil temperature is high or oil pressure is low
The associated generator drive oil temperature is high or oil pressure is low
757/767: According to the graphic, the standby power bus OFF light is illuminated. Which bus(ses) is/are not powered?
a) Left transfer bus, right transfer bus, or standby DC bus(ses) not powered
b) Battery, hot battery, or standby DC bus(ses) not powered
c) Standby AC, standby DC, or battery bus(ses) not powered
d) Standby AC, standby DC, or hot battery bus(ses) not powered
Standby AC, standby DC, or battery bus(ses) not powered
757/767: According to the graphic, what is providing power to the standby busses?
a) Left main AC and DC
b) Left main DC bus
c) Right main AC and DC
d) Right Transfer bus
Left main AC and DC
757/767: When external or APU electrical power is available on the ground, which bus is automatically powered?
a) Ground handling bus
b) Ground service bus
c) Standby AC bus
d) Standby DC bus
Ground handling bus
757/767: When the associated AC bus tie breaker is armed for automatic operation, the AC busses are powered according to the following system priorities:
a) Opposite IDG, associated IDG, APU generator
b) Respective IDG, APU generator, opposite IDG
c) APU generator, respective IDG, opposite IDG
d) AC priority is not set when the BUS TIE switches are in AUTO
Respective IDG, APU generator, opposite IDG
757/767: As the first engine is started with APU supplying electrical and pneumatic power, what load shed occurs?
a) Only the respective utility bus load sheds
b) Only the respective utility bus and all galley busses load shed
c) Both utility and all galley busses load shed
d) The utility busses remain powered but all the galley busses load shed
Both utility and all galley busses load shed
757/767: During flight, the hydraulic motor generator (HMG) automatically starts and supplies AC and DC power:
a) When the left hydraulic system pressure drops below a preset level
b) When the center and right hydraulic systems fail
c) When the HMG PWR switch is selected to ON
d) When primary AC power is lost on both main AC busses during flight
When primary AC power is lost on both main AC busses during flight
757/767: The center busses transfer from the left main busses directly to the static inverter and the hot battery bus when:
a) At least two generators are operating and three autopilots are armed for an autoland approach
b) The right main AC bus fails during a coupled approach
c) Any one generator is operating and any two autopilots armed for an autoland
approach
d) There is a failure of the left main AC bus when the airplane is above 200 feet RA
At least two generators are operating and three autopilots are armed for an
autoland approach
757/763: On a three autopilot approach with a LAND 3 indication, what will the ASA indicate if an engine-driven generator is lost below 200 feet AGL without the APU running?
LAND 3
757/767: Once commanded to operate, are there limitations associated with how long the hydraulic motor generator (HMG) can run?
No, there is no time limit for HMG operation
757/767: According to the graphic, what is providing power to the Ground Handling bus?
a) External electrical power
b) An IDG if operating on the ground
c) APU electrical power
d) The APU generator or an IDG if operating in flight
External electrical power
757/767: The main aircraft battery and the APU battery are connected to their own respective battery chargers. Both battery chargers are powered by the:
a) Right transfer bus
b) Ground service bus
c) Ground handling bus
d) Battery bus
Ground service bus
757/767: The integrated drive generator (IDG) oil is cooled by:
A fuel/oil heat exchanger
757/767: The main DC electrical system is powered:
a) From the battery when the battery charger is available and supplying power
b) From the associated DC generator
c) By a rectifier powered connected to the left and right utility busses
d) By the transformer-rectifier units (TRU’s) powered by the main AC busses
By the transformer-rectifier units (TRU’s) powered by the main AC busses