Electrical Flashcards
Each IDG consists of
A constant speed drive and a generator
Power for starting the APU is provided by
APU battery
Amber IDG Fault light
HOTLOP
hi oil temperature
Low oil pressure
IDG automatically disconnects when
Severe oil temp
Over torque
What happens if we lose the number 2 IDG
Interruption of first officer flight data and disengage the autopilot if connected to the fo’s side
The ADG continues to operate and supply power to the ADG bus until what airspeed
Until the airspeed decreases below approximate 135 kts
Can the ADG deployed on the ground
Automatic deployment is inhibited on the ground by a wait on wheels switch
Priority control of AC power distribution during normal operation
IDG one powers AC bus one
IDG two Powers AC bus two
Does transfer occur during a generator failure
Yes for any reason other than a fault on its associated bus it will automatically transfer the load from the failed I DG to the remaining operative IDG
What is the priority logic for AC buses one and two
On side IDG
APU generator
Opposite Side IDG
External power
What power sources are available for the service configuration
Either external power or the APU generator
What buses are powered in the service configuration
AC service bus
The ADG is automatically deployed if
AC bus one and two are off-line
Both AC generators are off-line
APU gen is not available
The ADG bus supplies power to
The AC Essential bus
Hydpump 3b
Flaps and slats .. Half speed
Pitch trim channel 2
Where is the external DC receptacle located on the aircraft
The 900 is not equipped with an external DC power receptacle
6-64
Each TRU has on internal cooling fan, when does it operate
Whenever AC power is supplied to the TRU
Main battery amp and volt
17 amp hour /24 volt nickel cadmium battery
APU battery amp and volt
43 amp hour. 24 V nickel cadmium battery
If on EICAS:
AC bus two caution
Gen two caution
AUTOXFR FAIL caution
??
Go to AUTOXFR fail, we probably have a short in AC bus two
(The other checklists direct us to reset generator$
Main battery charged by bus
APU battery charged by bus
Main battery is charged by AC bus one
APU battery is charged by AC service business
What items are on the DC utility bus
Right side reading lights
Load shed bus
How many ACPC’s
How many DCPC’s
1 ACPC
2DCPC
The APU generator is driven by
Directly by the APU gearbox
IDG automatically disconnected when
OVER OVER
over torque Overtemp
What type is our ADG
Wet ADG … Fly weights no oil
115v AC
What happens when the DC main tie closes
Dc utility bus shed
right side reading lights
What fire suppression systems are available at all times on the DC emergency bus
APU and engine fire bottles
Fuel and hydraulic SOV’s
Where are the circuit breakers located for the main and AP you battery direct buses
CBP5 in the afternoon equipment bay
What powers the DC emergency bus
The DC battery bus and the APU batt direct bus
Continuously
What is the backup for failure of TRU one or two
Main tie will close and operative TRU willpower
Failure of one Essentil TRU?
ESS tie connector closes
What will occur if we lose both Essential TRU’s
Cross tie closes
Where are the two DCPCs located
In the avionics compartment
If both essential TRU’s fail, what happens
The cross tie automatically closes to allow TRU 2 power Tru essential battery an emergency bus
ESS TRU2 transfer contactor?
In the event of multiple malfunctions
If TRU one or TRU two fails?
The main tie will close to connect to the operating TRU
What happens when both essential TRU’s fail?
The cross tie closes
TRU two now becomes power source
If essential TRU one or two failure?
ESS TIE closes
If complete loss of AC power Will The essential tie close?
Yes… To connect the DC essential bus to the battery bus for emergency power
If the DC service which is selected on,
The DC service bus is powered from the APU battery direct bus
How many circuit breaker panels
8
CBP one and two are located in the flight deck
CBP5 is located in the aft equipment compartment
CBP6 is located in the forward equipment compartment
CBP on the Galley Control Panel
CBP on the AC PC
To CBP’s on the DC PC
EMER POWER ONLYmsg?
Indicates the ADG has deployed
AC bus 1/2 caution?
Associated bus is not powered
Where is the main battery located
In the nose avionics compartment
ACPC?
AC POWER CENTER
AC service bus is normally powered from AC bus two..
On the ground?
Powered from the APU or external power
If power is restored by pressing thePWR XFR OVERRIDE button..what happens?
Restored IDG willpower AC bus one and two
However the ADG will continue to power The critical flight controls and the ADG bus
DC power is supplied by
4 TRU’s and two batteries
2 DCPC’s Located
Avionics compartment
What’s feeds the DC emergency bus
Both the battery bus and the APU battery direct bus
What is on the emergency bus
Hydraulic SOV
Engine fuel SOv
APU fuel SOV
Firex
Test question
The APU fuel pump is off what bus
DC BATTERY BUS
Is there any AC shed logic?
No
Auto xfr switchlight?
Fail
Off
Fail… Auto ( yellow)
OFF.. manually selected .. (Checklist)
How many ACPC’s?
1
How many DCPC’s
2
ADG located?
Right side of the nose section
How many AC buses
4
How many DC buses
9
The APU. Generator is driven?
Directly by the APU gearbox
(At a constant speed)
(W/its own GCU)
Failure of an IDG Will automatically transfer the load from the failed IDG to the remaining operative IDG For any reason other than?
A fault on its associated
ALTN (white) indicates?
The essential bus is fed from AC BUS 2
Service config?
External AC power is available.. AVAIL switch light on the external AC Service panel has been selected
Only the AC service bus. Will be powered
Max TRU load in flight
120 Amps
Maximum time with DC power only for CRT displays
Five minutes
Where is circuit breaker panel five
Where is circuit breaker panel six
CBP 5 ….aft equipment bay
CBP 6….forward equipment compartment
How many total circuit breaker panels
8
What is the constant speed drive depicted as on the synoptic page?
IDG
How many AC buses?
4
AC bus one
A C bus two
SERV BUS
ESS BUS
Can the AC ESS bus transfer happen both automatically and manually?
Yes
What does the AC service bus provide power for
Passenger cabin and lavatory cleaning
How many DC buses
9
6/23 ch6 electrics
What is on the DC utility bus?
Right cabin reading lights
If the right cabin reading lights do not work what may have happened?
The problem with the DC utility bus
What might be the problem if we lose passenger cabin lighting and nav lights
A problem with the DC Service bus…provides electrical power for lighting passenger cabin and nav lights
If we see DC EMER BUS caution!
Means that the bus is faulted or one or more of its power sources are not powered
What would a repercussion be if we see the DC EMER BUS caution!
We have lost fire protection
When does the DC utility bus shed?
When the main Tie closes
When will the main Tie close?
With loss of either TRU one or two
The ADG maintains a constant RPM through
Flyweights
The cockpit domelight is on what bus?
The main battery direct bus
The APU generator is driven directly by
The APU gearbox
APU Constant or variables
Constant speed
APU GEN OFF caution?
APU GEN is off ready to load
EMER PWR ONLY
WARNING
ADG has deployed
Hydr pump 3 B?
Off what bus
ADG BUS
And
AC BUS 1
ADG Will continue to operate and supply power until
135 kts
Which circuit breaker’s are accessible during flight
1/2
Galley cbs
Gen priority?
Onside
Inside
Cross side
Outside
Where are the trus located?
Nose cone
If we have a EMER BUS ..caution..
What is a big concern
We have lost the bus therefore no fire extinguishing
Bus is not powered
When will the DC utility bus shed
If closure of Main tie Because of the loss of TRU 1 or 2
6-27 ch 6 Electrics 6/8/20
Also if the crosstie closes because this would happen if we lose both. TRU 1 and 2
6-28 ch 6 electrics
Is there an AC utility bus?
No
Does the 900 have a external DC power receptacle?
No
How many DCPCs
Where located
2 DCPC
located in the avionics compartment
When does the essential DC tie close
In the event of an ESS TRU 1 or 2 failure
6-28 ch6 Electrics
The IDGs supply ? V AC PWR to 4 AC buses?
115 V AC
IDG consists of?
CSD + gen
Generators cooled how?
Air/oil cooled
What are the main AC buses?
Bus 1/2
AC bus switchlt illuminates when?
Bus 2 supplying pwr to ac ess bus
How much time on emer pwr?
30 minutes
If lose emerg bus.. we have no?
Fire protection
HOW MUCH TIME ON ISI WITHBAT POWER ONLY
30 minutes
What type of electrical power
115 vac
28vdc
What is the lowest priority power source
External power
What are the main busses of the AC system
AC BUS1
AC BUS2
ADG deploys when?
Loss of both AC BUS 1 and 2
The ADG HTR Is controlled by
The nose landing light relay
ADG deployed and a gen restored? Power xfr override pressed…
What powers the critical flight controls at this point?
The critical flight controls in the ATG bus continue to be powered by the ADG
ISPS..What happens when passenger oxygen masks are deployed
The cabin pressure controller removes power
Or
When PAX OXY is selected on manually in flt deck
ISPS ELEC POWER
110 VAC 60 HZ
The CSD oil is cooled by?
An air/oil heat exchanger
Using N1 fan air
What are the main buses of the aircraft?
AC BUS 1/2
Bus protection is provided by the?
ACPC, GCU and other electrical relays
The ADG door is
Mechanically linked
And held in place by mechanical lock
ADG ..The heater is controlled by
The nose Landing light relay
Energized when the nose gear is down and locked
IDG 1 status?
IDG Has been disconnected either manually or automatically
How many dc buses?
9
TRUS do what?
115v to 28v dc
When does the DC emergency bus show up on the DC synoptic page?
With a bus fault or a failure of a source
AUTO XFR FAIL refers to!
Failure to xfr load to next gen
The constant speed drive is cooled by?
Air / oil heat exchanger
The ADG is heated inflt ?
Buy a relay controlled by the nose landing light!!
Once the ADG is deployed heating is no longer required
6-17 systems
What is the ADCU?
Auto deploy control unit..
For the ADG
In order for the ADG
AC bus1/2 .. unpowered
no WOW
A/C gen was last pwr source
The inside power supply system is removed when?
The oxygen masks are deployed automatically by the CPC
Or manually selected
AC 1/2 autoxfr caution
Means the auto transfer system is inhibited!!
T2 probe is heated?
Pneumatically
