Electrical System Flashcards
What is the extreme (red) voltage range
< 100V or > 124V
What is the abnormal (yellow) voltage range
100-107V or 118-124V
What is the normal (white) voltage range
108-117V
When is the ESS DC BUS OVERLOAD or MAIN DC BUS OVERLOAD ACAWS alert activated
If a TR load exceeds 110% for more than 5 seconds
What 3 sources can power AC buses
Four engine-driven generators, APU generator, and external power supply
Which AC buses are supplied power when external power is connected
All AC buses
Which AC buses are powered by the APU if it is the only power / if others are running
Essential and main buses / only essential if others are running
What saying describes how the engine generators power AC buses
Wing helps wing, symmetrical helps symmetrical
Which AC buses are supplied power when only one engine is running
Only the essential and main AC buses
Why must there be clearance between cargo and fwd bulkhead
To allow access to circuit breaker panels
Can MCBs be used as switches?
No
Where are the electrical system controls located / where are they duplicated
ELECTRICAL panel on overhead console / CNI-MU ELECTRICAL soft panel
Which switch is used to select power sources
External power/APU switch
What indicates correct phase AC power is connected
AC external power-on light illuminates
How do you reset an engine generator?
Switch to OFF/RESET to de-energize the generator, return switch to ON position to reset
What do you need to prepare for when the external power/APU switch will be moved through the OFF position?
A 10 second loss of the ICS (intercommunication system) will occur, prepare for alternate forms of communication
What are the 6 DC buses
Main, essential, isolated, avionics, utility battery, avionics battery
What powers the DC system
Four TR units that are powered by the main and essential AC buses
What are the two identical 24V 35 ampere hour batteries
Utility battery (powers utility battery bus); and Avionics battery (powers avionics battery bus)
What does the BTRY switch on the ELECTRICAL panel do
Connects the utility battery to the isolated DC bus; and the avionics battery to the avionics DC bus
What does the BTRY TEST switch do
Displays one of the following on the DC voltmeter: isolated DC bus voltage, avionics battery voltage, or utility battery voltage
When all 4 engine generators are running and APU is off how is power supplied to the AC buses
Each supplies power to one AC bus
Where are the UTILITY and AVIONIC BAT CONT circuit breakers located
Pilot side circuit breaker panel
