CRJ Systems > Electrical > Flashcards

Electrical Flashcards

(94 cards)

Study These Flashcards
1
Q

What types of electrical power does the aircraft use?

A

115v AC and 28v
DC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the primary sources of AC electrical power?

A

The engine-driven
Integrated Drive GENERATORS (IDGs), and an APU generator.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the primary sources of DC electrical power?

A

Two 24 volt NiCADbatteries and four Transformer Rectifier Units, or TRUs, are the primary source of DC power for the aircraft.
DC power is distributed by two DC Power Centers or DCPCs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where are the DC Power Centers (DCPCs) located?

A

avionics compartment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the purpose of the Air-Driven Generator (ADG)?

A

Can supply AC
power in flight in the event that an emergency source of power is required. Shows on the AC page.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many circuit breaker panels are there, and where are they located?

A
  1. Two are located in the flight deck. the other panels are located in other
    locations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the AC Power Center (ACPC) do?

A

Distributes AC power to
appropriate electrical busses . Also, it supplies secondary power distribution to the hydraulic pumps, flaps, slats, and pitch trim system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the function of the electrical power control panel on the flight deck
overhead?

A

Contains the controls for system operation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the five AC buses in the system?

A

The AC system consists of the following five buses:
* AC bus 1 and 2,
* AC essential bus,
* AC service bus,
* and ADG bus.
These buses are depicted on the AC ELECTRICAL synoptic page

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the primary sources of AC electrical power? and how does it get to the AC BUSes

A

Two Integrated Drive Generators, or IDGs are the primary source of AC electrical power on the aircraft.
The AC Power Center, or ACPC distributes AC power from the IDGs to all the AC buses during normal operations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

10.What components make up an IDG (the generators)?

A

The IDGs consist of two parts: a 40 kVA generator, and a constant speed drive.
Both of these components are displayed on the AC ELECTRICAL synoptic page.

It is important to note that the portion of the synoptic that is labeled IDG is actually the constant speed drive

Together, these two sub-components provide 115 volt, 400 hertz, three-phase electrical power to four AC buses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the purpose of the constant speed drive (CSD)?

A

The AC generator needs to turn at a constant RPM in order to produce a constant 400 hz frequency output.

The job of the Constant Speed Drive, or CSD, is to convert variable engine accessory gearbox speeds to a constant output RPM for the AC generator.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

CSD Oil system

A

The constant speed drive uses an internal oil system.
The oil is cooled by an air-to-oil heat exchanger that utilizes air from the engine N1 fan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

12.What happens if a CSD has high oil temperature or low oil pressure?

A

If a CSD has high oil temperature or low oil pressure, the associated FAULT light will illuminate on the overhead control panel, and an associated IDG caution message will be displayed on the EICAS primary page

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can you do if there is an IDG Fault

A

In the event of an IDG fault or other malfunction, an IDG can be disconnected from its engine accessory gearbox by pressing the associated IDG DISC switchlight on the overhead control panel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

13.Can an IDG be reconnected in flight after disconnection?

A

No. Can only be
reconnected on the ground with the engine shut down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does the IDG disconnect

A

An electric solenoid is energized that causes the gear to retract from the engine accessory gearbox

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Automatic IDG Disconnect

A

If the electrical disconnect switch should fail, the IDG will automatically disconnect if its CSD oil temperature reaches an unacceptable level.

Also, an input shaft will shear and disconnect the IDG from the gearbox in the event of an overtorque condition.

In either case, the white DISC light will illuminate in the associated IDG switchlight, and an associated IDG status message will be displayed on the EICAS status page.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a GCU

A

Generator Control Unit. controls and monitors the related AC GEN and IDG and provides protection and voltage regulation for its engine generator. They are in conjunction with the ACPC provide bus priority and protection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When will an engine generator be tripped offline

A
  • over or under voltage,
  • over or under frequency,
  • generator or bus overcurrent,
  • or generator phase sequence problem.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

AC BUS 1 and 2

A

Main AC busses. Bus 1 located on CB1 and Bus 2 on CB2. Receive power from any operating generator or external power.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What powers the AC ESS BUS

A

AC BUS 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What powers AC SERV BUS

A

AC BUS 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

IF a generator goes offline what system makes sure we get the power we need at the places we need

A

ACPC and its priority Bus Logic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
AC BUS 1 priority
GEN 1 Onside APU GEN GEN 2 Offside External Power
26
AC BUS 2 Priority
Gen 2 Onside APU GEN Gen 1 Offside External power
27
What happens and what should we do if a generator trips offline
The flight crew will be informed of the malfunction by the master caution system, and an associated GEN OFF caution message on the EICAS. The abnormal procedure directs the flight crew to reset the tripped GCU.
28
What happens if a Gen can be restored?
Bus priority logic will take over and go to how it was before failure.
29
16.What is the purpose of the AC essential bus?
Supplies power to the equipment that is essential for flight, It powers ESS TRU 1 which produces power for the DC ESS BUS. AND SOMETIMES power ESS TRU 2
30
What powers the AC ESS Bus
AC BUS 1 unless it goes offline, then AC BUS 2. The ADG also powers the ESS if it is being used . Could also do this change manually via AC ESS XFER button on electric overhead panel.
31
Role of the APU GEN
Can be used to power the AC electrical system in the event of an IDG failure, both IDGs are selected off, or while the aircraft is on the ground with the engines off
32
APU GEN specs
Like the IDGs, the APU generator produces 115 volt, 400 hertz power. The APU generator is also rated at 40 kVA all the way up to 41,000 feet. There is no constant speed drive required for the APU generator because the APU runs at a constant RPM.
33
18.What is the function of the AC external power cart?
An alternate source of AC power during ground operation. If plugged in will show up on AC Synoptic page like another GEN.
34
Does external power supply power to all busses?
Depends.Will power all BUS if pressed on the flight deck. If pressed on the service panel only the SERV BUS is powered. (for servicing). If used from Service panel will get a green Service conguration EICAS message
35
Routing of power to Service bus from external power
Uses the service transfer contact for only powering of the SERV BUS
36
AUTO transfer feature disable
The bus priority logic can be inhibited by the automatic transfer switchlights located on the electrical power control panel. The bus priority logic is inhibited by depressing the desired automatic transfer switchlight
37
BUS Shorting
If the bus priority system senses a short on AC bus 1 or 2, it will automatically prevent the shorted bus from obtaining power from a source other than its onside engine generator
38
Whar happens when the ESS bus is being powered by AC BUS 2
When the AC essential bus is powered by AC bus 2, the white ALTN light in the AC essential transfer switchlight will be illuminated.
39
What normally powers the AC SERV BUS
AC bus two normally powers the AC service bus. The AC service bus supplies AC power to the service outlets located throughout the aircraft. The AC service bus can be powered by the external ground power cart.
40
What is the ADG min airspeed to power the AC ESS Bus
135 or greater
41
DC Electric system make up
The DC electrical system consists of four transformer rectifier units, two nicad batteries, and nine DC buses
42
What are all the DC Busses
* DC bus 1 and 2, * DC essential bus, * DC service bus, * DC utility bus, * DC battery bus, * DC emergency bus, * main battery direct bus, * and APU battery direct bus
43
Circuit breaker panels
DC electrical power is supplied to the buses by routing the power through the DC Power Centers and the circuit breaker panels located on the flight deck
44
The DCPC have 5 power contactors that are used to ensure that the DC BUSSES remain powered. What are they. The opening and closing of these contacts are automatic and are displayed on the synoptic page.
* main tie contactor, * essential tie contactor, * cross tie contactor, * essential TRU 2 transfer contactor, * and service bus contactor. These are all completely automatic no controls
45
21.What is the primary source of DC power? Where is the Original AC power source shown?
Majority of the power is produced by the 4 TRUs (they convert 115v AC power into 28v DC power, and they are rated at 120 amps) The AC power source for each of the TRUs is shown on the DC ELECTRICAL synoptic page.
46
Where are the Batteries located
The main battery and its associated charger is located in the forward equipment bay. The main battery can supply DC power to a limited number of the DC busses. The APU battery and its associated battery charger are located in the aft equipment bay.
47
22.What is the capacity of the main battery?
24v 17amp (can supply DC power to a limited number of the DC buses)
48
23.What is the capacity of the APU battery?
24v 43amp
49
24.What powers the main battery charger?
The main battery charger uses power from AC bus 1. The APU battery charger uses power from the AC service bus.
50
25.What powers the APU battery charger?
AC service bus
51
Primary purpose of the APU battery. Secondary purpose
The primary purpose of the APU battery is for starting the APU; it is also used as a secondary source of DC power
52
APU start
During APU start, the BATT BUS provides power to the APU's electronic control unit, and the APU BATT DIR BUS provides power for the APU starter.
53
Besides APU start what else are the batteries for
In addition to APU starting, the batteries provide power to the battery bus when the aircraft is on the ground, the BATTERY MASTER switch is selected to ON, and there is no other source of power available.
54
Minimum volts for APU start
A minimum of 22 volts is required on both batteries for an APU start
55
Battery Backup power
When the aircraft is airborne, weight-off-wheels logic allows the batteries to power the battery bus and the DC essential bus when the battery switch is ON and no other source of power is available. This allows the two battery direct buses to provide power to essential DC systems in the event of a total AC failure, or failure of both essential TRU 1 and 2
56
What charges the batteries
The batteries are charged by independent battery chargers installed next to each battery. The chargers operate whenever AC power is available from AC bus 1 for the main battery, and the AC service bus for the APU battery
57
What monitors the batteries
The battery chargers monitor the state of the battery at all times. A charger will shut down if a battery overheat, battery fault, or charger fault is detected.
58
EICAS messages
Battery and battery charger system messages will appear on the EICAS to inform the flight crew of any abnormalities.
59
MAIN BATT DIR BUS and APU BATT DIR BUS are connected to
The APU battery direct bus and main battery direct bus are connected directly to the respective batteries. THEY ARE ALWAYS POWERED, EVEN WHEN BATTERY MASTER IS OFF
60
Purpose of MAIN BATT DIR BUS and APU BATT DIR BUS
Supply DC power to consumers that need a constant source of power during generator switching, or when there is no power on the aircraft. The Refuel/Defuel panel and the clock memories are examples of equipment powered by these two buses
61
Circuit breakers for MAIN BATT DIR BUS and APU BATT DIR BUS
The circuit breakers for the APU and main battery direct buses are located on circuit breaker panel five(aft)and six.(nise)
62
27.What does the DC emergency bus power?
The DC emergency bus is always powered. It powers the engine and APU fire extinguishers (fire bottles), hydraulic shutoff valves, and fuel shutoff valves
63
How is the DC EMER BUS always powered
When the battery bus is powered, it provides power to the DC emergency bus. When the battery bus is not powered, the DC emergency bus receives power from the APU battery direct bus.
64
Is the DC EMER BUS displayed on the synoptic page
NO, unless there is a problem
65
Where is the Circuit breaker for DC EMER BUBS
bottom of CB 1
66
Purpose of DC ESS BUS
The DC essential bus provides power to the DC consumers that are essential for safe flight
67
What normally powers the DC ESS BUS
ESS TRU 1. In the event that essential TRU 1 fails, the DC essential bus will be automatically powered by ESS TRU 2
68
28.What happens if both essential TRUs fail?
the cross tie and essential tie contactors close automatically and TRU 2 will power the DC battery bus and DC essential bus
69
What controls the ESS TIE CONTSCTOR
DCPC 2
70
Complete TRU Failure
In the event that all the TRUs are inoperative, the main and APU battery direct buses will power the DC essential bus through the DC battery bus.
71
What normally powers the DC BATT BUS
Like the DC essential bus, the DC battery bus is normally powered by essential TRU 1. If essential TRU 1 fails, the DC battery bus will be powered by essential TRU 2. If both essential TRUs fail, the DC battery bus can be powered by TRU 2 through the cross tie contactor.
72
Besides TRUs how can the BATT BUS get powered
receiving power from the aircraft batteries by way of the APU battery direct bus and the main battery direct bus when the BATTERY MASTER switch is selected to ON, and there is no other source of DC power available.
73
WHat normally powers the DC service bus
The DC service bus is normally powered by TRU 2 through DC bus 2
74
What do we get from the DC Service BUS
Passenger cabin lighting and the exterior navigation lights are powered by the DC service bus.
75
DC SERVICE BUS Contactor
The DC service bus can be powered by the APU battery direct bus in the event that the flight crew or maintenance need lighting to prepare the aircraft for flight or to tow it around at night. The DC SERVICE switch on the overhead control panel accomplishes this by closing the DC service bus contactor between the two buses. The BATTERY MASTER switch does not need to be ON for this to occur. The DC service bus will also be powered when the aircraft is in the service configuration
76
DC Service switch on overhead panel
four DC buses powered when the DC SERVICE switch is selected ON. The buses are the APU battery direct bus, main battery direct bus, DC emergency bus, and DC service bus. The first three buses are always powered by the aircraft batteries. The DC service bus is powered by the APU battery direct bus when the DC SERVICE switch is ON.
77
What powers the DC BUS 1 and 2
TRU 1 and 2. Circuit breakers for these are in the flight deck
78
What powers the majority of the DC systems
DC bus 1 and 2 power the majority of the DC systems on the aircraft. If either TRU 1 or 2 fails, the DC bus on the failed side will automatically be powered by the opposite TRU through the DC main tie contactor
79
30.What happens when the DC utility bus is shed?
When either TRU 1 or TRU 2 fails, the DC main contactor closes to feed power to bus 1 or 2 (whichever one needs it). This sheds the utility bus in order to keep the remaining TRUs below the 120-amp load limit
80
What does the DC UTIL BUS supply.
The DC utility bus provides power to the overhead cabin reading lights on the right side of the aircraft.
81
What happens to the lights if the DC UTIL BUS is shed
These lights will be inoperative on that side of the cabin when the DC utility bus is shed. Load shedding is handled by the right DCPC
82
TRU 1 and TRU 2 Failure ESS TRU 1 and ESS TRU 2 failure
the cross tie contactor closes to ensure that both DC bus 1 and 2 remain powered. This will also cause the DC utility bus to shed. The cross tie contactor will also close in the event both essential TRUs fail
83
ESS TRU 2 Contactor
The essential TRU 2 transfer contactor provides the essential TRU 2 with an additional source of AC power. Normally, this contactor is not displayed on the DC ELECTRICAL synoptic page
84
When will the ESS TRU 2 contactor close?
The essential TRU 2 transfer contactor will close if the aircraft is on ADG power and essential TRU 1 fails. This allows the essential AC bus to power the essential TRU 2. ALSO The essential TRU 2 transfer contactor will also close if both AC bus 2 and TRU 1 fail. This powers the essential TRU 2 through the AC essential bus. In turn, the essential TRU 2 will power the DC battery bus and DC essential bus.
85
What is the ADG
The air driven generator (ADG) will deploy automatically in the event of a total electrical system failure. It is a 115v 400 hertz AC generator that is turned by a propeller which extends into the free airstream when the ADG is deployed
86
33.What does the ADG power when deployed?
It powers the two relays that route power to the AC essential bus, the AC 3B hydraulic pump (will power the hydraulic pump 3B regardless of the 3B switch position), and channel 2 of the flaps, slats, and pitch trim. In this scenario, you will see a red EMER POWER ONLY warning message on the EICAS.
87
ADG componets
The ADG consists of a generator and a constant speed propeller that is controlled by counterweights.
88
ADG AUTO Deploy
Deployment of the ADG is controlled by an auto deploy control unit and the ADG auto deploy control panel, which is located on the lower center pedestal. The deploy system monitors the two main AC buses for complete AC power failure.
89
If AC BUS 1 and AC BUS 2 are unpowered in flight what happens
If both AC buses are unpowered while in flight, the auto deploy control unit will deploy the ADG. The auto deployment system uses a spring-loaded hydraulic cylinder ejection actuator to release the uplock and deploy the ADG
90
How does the ADG power DC side
When the ADG is powering the AC essential bus, the DC essential bus and the DC battery bus will also be powered through essential TRU 1. In this case, the battery bus is powered through the essential tie contactor.(closed)
91
ADG manual deploy
The ADG can also be manually deployed in flight in the event the auto deploy function fails. This is accomplished by the ADG manual deploy handle that is located at the bottom of the center pedestal
92
Generator restore after ADG deployment
In the event that one or more of the aircraft's generators are restored after ADG deployment, the power transfer override switch can be used to transfer the AC essential bus back to the operating generator. This switch is not used when the ADG is manually deployed.
93
ADG stowage
Once the ADG has been deployed, it cannot be stowed until the aircraft is on the ground and power is removed from the aircraft
94
AC ESS BUS, what does it power
FIND in the QRH
CRJ Systems
flashcards
Decks in class (28)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions