Electrical Flashcards
Name some important items on the main hot battery bus
APU shutoff valves
spar valves
APU and lower cargo extinguishers
Engine Fire extinguishers and fire switch unlock switches
(Dark Airplane) When I place the battery switch to on, what busses are powered?
- 2 hot battery busses- 2 battery busses
When I place the STBY PWR selector to AUTO, what busses are powered and how?
APU and Main STBY busses through inverters from the APU and Main Battery Busses
What Items are on the APU STBY bus?
NAME?
What items are on the MAIN STBY bus?
NAME?
What don’t we have when we lose all generators?
NAME?
During electrical emergency, when does the central IRS go offline?
5 minutes
What will cause an IDG to disconnect?
NAME?
Which bus charges the battery bus?
ground service bus
What is the primary power source for the ground service bus?
AC bus 1
After starting engines 1 or 2 do and the GCU close giving power to the sync bus, do you need to push the APU Gen 1 switch to disconnect it?
No, auto disc
Which has priority ext pwr or APU gen?
Ext pwr
What’s a good way to think about what the ground hacking bus powers?
Basically the right side of the plane: Lowe cargo doors and lights, fuelling and hyd elec aux pumps 1&4
What’s a good way to look at what the ground service bus powers?
Things to get started from a dark ship:)Lighting in the upper deck and cockpit (plus navs)Upper deck doorsAPU fuel pumps (2&3 aft)And Battery chargers for both batteries so you don’t drain them while you’re getting everything fired up.
What’s a good way to think about what the cargo handling bus powers?
Anything main deck related:To open and close doorsTo use the equipment to move palates around.
Will the main deck cargo handling bus be powered if neither ext 2 or APU pwr avail lights are illuminated?
No, the cargo handling bus only receives power when one or both if them shows available (Ext takes priority)
What systems do the D.C. busses powered?
Primarily various controllers for different systems:Cabin pressure and pack temp controlsWing and nacelle antiice controlHydraulic pump controlsFuel transfer and jettison valve control
What equipment does the APU HOT BATT BUS power?
Think of it this way: airplane is dark and you need to get power to it and get the IRS going.D.C. power for IRU’sL/R outflow valves APU inlet doorAPU primary controllerAPU fire warning horn
What systems does the Main Hot Batt bus power?
Think of it this way: you’re having a bad day and you need protection for all your engines and APU from fire. “It’s the MAIN thing keeping you from dying”Engine fuel spar valvesEngine fire extLower cargo fire extAPU fire extAPU fuel shutoff valve
How is the D.C. system structured?
Normally each D.C. bus is powered by its AC bus which powers it’s D.C. bat bus and the D.C. hot batt bus. However if the power fails to that D.C. bus, the battery can feed the hot bat bus which feeds in reverse to the bat bus.
Where can you see batt voltages?
Secondary EICAS STAT
When does bus isolation stop on an auto land app?
Disconnect apOr TOGA
ELEC BUS ISLN 1,2,3,4
Bus tie is open due to improper voltage, phase or frequency for the synchronous bus.
ELEC AC BUS 1,2,3,4ISLNOFF
The AC BUS is not powered.Objective: to reset the generator and then the bus tie. Also to reset the EEC’s if the bus is recovered.Be careful to avoid icing conditions if AC Bus 1 or 4 are not powered due to loss of ice protection of pitot static. You will also be level 3 automation with no AT.
ELEC DRIVE 1,2,3,4DRIVE
One of these occurs:IDG oil press lowIDG oil temp highObjective: to prevent damage to the IDGOnce the drive button is pushed, the GCU disc and you get:>DRIVE DISC 2ELEC GEN OFF 2
ELEC GEN 1,2,3,4
Gen control is openObjective: reset the gen
> ELEC SSB OPEN
Split system breaker is open
ELEC BUS ÚTIL BUS L,R
A utility bus is not poweredPower automatically removed by the ELCU to the utility bus due to faultObjective: reset power
> BAT DISCH APU
APU batt is discharging
> BAT MAIN DISCH
Main batt is discharging
> BATTERY OFF
Batt switch off
> DRIVE DISC 1,2,3,4
Gen drive is disconnected
> STBY BUS APU
APU stby bus not powered
> STBY BUS MAIN
Main stby bus not powered
