Electrical Flashcards
(43 cards)
When should an open circuit breaker be reset?
If the affected component is required for safe flight and landing
What is indicated if the R GEN switch displays an amber OFF light?
The GCU has tripped
When does the ARM position of the emergency power system switches allow the emergency power system to activate?
When the ESS DC bus voltage drops below 20 volts, or after 2.5 G impact
What buses will be powered with inoperative generators and APU, if HMG is selected on?
Both standby AC buses,
both ESS DC buses, and
the ESS AC bus
What is the rating of the hydraulic Motor Generator (HMG)?
10 kva
How is the HMG powered?
Left hydraulic system pressure or PTU (provided fluid is in the left system)
Selecting the L Bus tie switch to ISLN position will?
Isolate the L main AC bus from all power except the left IDG
The battery voltage which will cause the E BATTS to come on is?
< 20 volts DC
The minimum main battery voltage is?
22 Volts
What 3 items will illuminate the battery switch capsule lights?
When L & R batteries are powering the L-R ESSENTIAL DC BUS
whatever the aux hydraulic pump is on
During APU start
Which battery is used to close the main door from the outside door switch?
Only the right battery, which is wired to the main door switch
What is an IDG and how does it work?
Integrated Drive Generator - it operates much like a constant speed transmission. As the engine speed changes, the CSD maintains the generator at a constant speed
The function of the L-R Main TRU switch is?
The on side MAIN AC BUS powers each main TRU.
In the unlikely event that the on side MAIN AC BUS should fail, the L-R TRU can be selected to the opposite side MAIN AC BUS to restore the TRU and its respective MAIN DC BUS
In what situation can a TRU power more than one bus, and which buses can it power?
When the HMG and left ESS/ right ESS switches are IN/ON,
the AUX TRU can power both ESS DC BUSES
If the right main TRU fails, what should automatically power the right main DC bus?
AUX TRU
If ground service bus switch is selected ON, what will power that bus?
DC external power or the battery if external power is not available
Which batteries are activated when the external battery switch is turned on?
Both main batteries
What item will be lost with only one AC power source operating in flight?
Galley power
What type of Main DC Batteries are installed in the 550?
NICAD batteries
24volt, 53 amps
A no brake power transfer can occur between the APU and what other electrical component?
An engine driven generator (IDG)
How are Bus Tie isolation contactor relays controlled?
By isolation switches on the cockpit overhead panel,
the Generator Control Unit (GCU), or
the Bus Power Control Unit (BPCU)
What is indicated by an AMBER OFF light in either engine generator switch?
The IDG has been isolated by the GCU and the BPCU
How is the left main TRU powered when the L MAIN TRU switch on the overhead panel is selected to R AC
In this configuration, the L MAIN TRU receives power from the R MAIN AC bus
What is the indication associated with a batterie charger failure?
An amber BATT CHGR FAILL CAS message will illuminate
