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
753/764: During hydraulic motor generator (HMG) operations, what is the status of the IRUs?
a) After 5 minutes, the left and center IRU’s are no longer powered
b) Only the right IRU remains powered
c) Captains RDMI switches to the left IRU
d) All three IRU’s remain powered
All three IRU’s remain powered
752/763: Hydraulic motor generator (HMG) operation automatically switches the Captain’s RDMI to:
a) The center IRU
b) The right IRU
c) The left IRU
d) Any available IRU
The center IRU
757/767: In the case of a generator overload, which busses automatically load shed?
a) Only galley busses
b) Only utility busses
c) Both utility and galley busses
d) Associated utility and galley busses
Associated utility and galley busses
757/767: The ground service bus is normally powered by the:
a) Hot battery bus
b) Right main AC bus
c) Left main AC bus
d) Right utility bus
Right main AC bus
767: The left recirculation fan is powered by the:
a) Right utility bus
b) Right main AC bus
c) Standby AC bus
d) Left utility bus
Left utility bus
757/767: The associated utility and galley busses have shed due to a generator overload. What is required to restore power to the bus?
a) The utility busses (and therefore galley busses) must be reset manually
b) The busses cannot be reset and will remain unpowered
c) The busses will automatically reset when another AC power source is selected on
d) The busses can be reset by moving the associated BUS TIE out of AUTO
The utility busses (and therefore galley busses) must be reset manually
757/763: If primary AC power is lost on both main AC busses during flight, the hydraulic motor generator (HMG) automatically starts and supplies AC power to the:
a) Standby busses only
b) Left and right AC transfer busses, standby AC bus via the left AC transfer bus, and Captain’s flight instrument transfer bus
c) Left and right main AC busses only
d) Standby flight instrument busses only
Left and right AC transfer busses, standby AC bus via the left AC transfer bus, and Captain’s flight instrument transfer bus
752/763: According to the graphic, which electrical busses are still being powered? (HMG not operating)
a) Hot battery bus, battery bus, standby DC bus
b) Hot battery bus, standby DC bus, standby AC bus
c) Hot battery bus, battery bus, standby DC bus, standby AC bus
d) Battery bus, standby DC bus, standby AC bus
Hot battery bus, battery bus, standby DC bus, standby AC bus
757/767: According to the graphic, the DISCH light is illuminated. The main aircraft battery:
Is discharging
757/767: According to the graphic, the BUS TIE ISLN light is illuminated. This occurs when:
a) The AC bus tie breaker is locked closed from a fault trip
b) The automatic DC bus tie system is inhibited
c) The AC bus tie breaker is locked open from a fault trip
d) The DC bus tie system is armed
The AC bus tie breaker is locked open from a fault trip
