Electrical System Flashcards Preview

Mesa EJET > Electrical System > Flashcards

Flashcards in Electrical System Deck (99):
1

IDG 1 and IDG 2 Selector Knob
-AUTO

This position allows the IDG contactor to close, connecting the IDG to the respective AC BUS automatically, according to system logic

2

IDG 1 and IDG 2 Selector Knob
-OFF

Opens the IDG contactor isolating the IDG from the respective AC BUS

3

IDG 1 and IDG 2 Selector Knob
-DISC

Must be held in this position for one second to mechanically disconnect the IDG

Can't be reconnected in flight

4

Normal AC Bus Priority

Onside IDG
AC BUS Tie
Offside IDG

5

Illumination of the Amber LED next to IDG DISC

Indicates to which pilot which IDG to disconnect

Will illuminate in association with the IDG 1(2) caution EICAS message & will extinguish when IDG is disconnected.

HOTLOP
-High oil temperature or Low oil pressure

6

AC BUS TIES Selector Knob
-1 OPEN

Opens the Bus Tie Contactor (BTC) 1, segregating AC BUS 1 from the AC BUS Tie

7

AC BUS TIES Selector Knob
-AUTO

This position allows automatic operation of the BTC's according to system logic

8

AC BUS TIES Selector Knob
-2 OPEN

Opens the Bus Tie Contactor (BTC) 2, segregating AC BUS 2 from the AC BUS TIE

9

AC BUS Tie Priority

APU
GPU
IDG

10

GPU Button
-PUSH IN

Connects the AC GPU to the AC BUS Tie, according to the source priority

11

GPU Button
-PUSH OUT

Isolates the AC GPU from the AC BUS Tie

12

GPU Button
-AVAIL Light

AVIL will illuminate with the button pushed in or out when the AC GPU is connected, but is not powering the AC BUS Tie. Also indicates GPU is set to correct power setting.

13

GPU Button
-IN USE Light

Will only illuminate when button is pushed in & the AC GPU is powering the AC BUS Tie

14

APU GEN Button
-PUSH IN

This position allows the APU generator to connect to the AC BUS Tie, automatically according to source priority

15

APU GEN Button
-Push OUT

Opens the APU generator contactor and isolates the APU generator from the AC BUS Tie. The APU is tripped off line and de-excited

16

TRU ESS Toggle Switch
-AUTO

This position allows automatic connection of the TRU ESS to the DC ESS BUS 3

17

TRU ESS Toggle Switch
-OFF

Isolates the TRU ESS from DC ESS BUS 3

18

TRU 1 and TRU 2 Toggle Switches
-AUTO

This position allows automatic connection of the TRU 1(2) to the respective DC BUS 1(2)

19

TRU 1 and TRU 2 Toggle Switch
-OFF

Isolates the TRU 1(2) from the respective DC BUS 1(2)

20

BATT 1 Selector Knob
-ON

The battery is connected to the DC ESS BUS 1

21

BATT 1 Selector Knob
-OFF

The battery supplies power to HOT BATT BUS 1 only

22

DC BUS TIES Toggle Switch
-AUTO

This position allows automatic operation of the DC Tie contactor's (1 DCTC / 1 & 2 ETC's) according to system logic

23

DC BUS TIES Toggle Switch
-OFF

Opens all DC Tie contactors

24

BATT 2 Selector Knob
-AUTO

This position connects BATT2 to either the DC ESS BUS 2 or the APU START BUS automatically, according to system logic

25

BATT 2 Selector Knob
-OFF

The battery supplies power to HOT BATT BUS 2 only

26

AC Power

2 IDG's (115 VAC, 400 Hz, 40 KVA)
1 APU (115 VAC, 400 Hz, 40 KVA)
1 AC GPU (115 VAC, 400 Hz, 40 KVA)
1 RAT (115 VAC, 400 Hz, 15 KVA)
1 Inverter (250 V)

27

1 IDG can power both AC Buses

On ground & In-flight

28

APU can power both AC Buses

On ground & In-flight up to FL330

29

GPU can power both AC Buses

On ground only

30

Primary source of AC power

IDG

31

IDG Selector Knob

AUTO- System logic controls contactor
OFF- Opens contactor
DISC- Mechanically disconnects the CSD from IDG

32

Can the flight crew reconnect an IDG

No, maintenance function only

33

Amber Light accompanied by an EICAS oil message indicates?

IDG disconnect is required

34

ICC

Integrated Control Center (4)
-Line replaceable

35

SPDA

Secondary power distribution assembly (2)
-An electric load management unit
-Receives power from ICC's
-Distributes power according to system logic

36

CSD

Constant speed drive

Converts variable engine speed into constant generator speed

37

IDG oil system is cooled how?

Air cooled

38

GCU

Generator control unit

39

Illumination of the amber LED next to IDG DISC indicates?

HOTLOP
-High oil temperature or low oil pressure

40

APU

Auxiliary Power Unit
-Secondary source of AC Power

41

Required for APU Start?

BATT 1 & 2 or BATT 1 & DC GPU

42

Which BATT is used to control APU's FADEC?

BATT 1

43

Why is BATT 2 isolated from the network during APU start?

To exclusively power the APU START BUS

44

Minimum VDC for APU Start?

22.5 VDC

45

Minimum VDC required to close batter contactor?

18.0 VDC

46

Minimum BATT 2 temperature for start?

-20 C

47

AC GPU

AC Ground Power Unit
-Secondary AC power source

48

GPU power can be turned on in 3 locations

-Cockpit Overhead Panel
-AC GPU Panel (only powers ground service bus)
-Opposite FWD Lav (only powers ground service bus)

49

Normal AC Electrical Priority

On-side IDG
APU
GPU
Cross-side IDG

50

Inverter

-Powers the AC STANDBY BUS when normal AC power source is not available
-Allows "A" igniters to always have power source

51

RAT

-Ram Air Turbine
-Emergency AC Power source
-No restriction for deployment
-Manual deployment available

52

RAT supplies power to which BUS

AC ESS BUS

53

Minimum airspeed for RAT

130 knots
-As airspeed decreases, load shedding occurs until AC ESS BUS is not longer powered

54

DC power provided by?

Transformer Rectifier Unit (TRU)
-28 VDC, 300 A

2 Batteries
-24 VDC, 27 AH

1 DC GPU
-28 VDC

55

Primary source of DC power?

TRU's

56

Function of TRU

Convert 115 VAC to 28 VDC

57

RAGO

AC System Priority

R- Respective IDG
A- APU
G- GPU
O- Opposite IDG

58

Electrical Emergency Situation
-Batteries Only

-Screen 2 (PFD)
-Screen 3 (EICAS)
-IESS
-Clock
-FO MCDU
-CA CCD
-2 Comm panels
-CA Display panel
-CA Reversionary panel
-Light for magnetic compass

59

DC HOT BATT BUS 1

-Engine 1A Fire Extinguisher
-Engine 2A Fire Extinguisher
-Engine Fuel SOV 1
-Hydraulic system SOV 1
-Engine 1 oil level indication
-Courtesy / Service lights
-DC ceiling lights

60

DC HOT BATT BUS 2

-Engine 1B Fire Extinguisher
-Engine 2 B Fire Extinguisher
-Engine Fuel SOV 2
-Hydraulic system SOV 2
-Engine 2 oil level indication
-CMC
-Panel refuel
-Water and waste system

61

EPC
BATT 1(2) Over temp

Associated Battery..............................OFF

Note-- Do not start the APU

62

Batteries

(2) NiCad Batteries
-Secondary source of DC power
-Back-up for DC ESS BUS
-Charged via any AC power source through TRU's
-18.0 volt min to close battery contactor
-Will provide 10 minutes of power during an electrical emergency

63

DC GPU

-Can replace BATT 2 during APU start
-Can only be turned on by a ground ramp button

64

Function of ICC's and SPDA's

ICC's collect and confirm the power is safe and then sends it to the SPDA's, which distributes it

65

How many networks make up the electrical system on the airplane? Why?

2 independent networks for redundancy and fault isolation

66

What happens if a power generating source fails?

Bus ties automatically connect to provide no system degradation

67

What components power the AC system?

1 IDG's
APU
Inverter
RAT
AC GPU

68

What components power the DC system?

2 NiCad batteries
2 TRU's
DC GPU

69

How does the IDG maintain a stable power output?

A constant speed drive (CSD) attaches the IDG to the AGB (accessory gear box)

70

What monitors and controls the IDG's?

Each has a generator control unit

71

Can one IDG power the entire electrical system?

Yes

72

What will cause the amber IDG light on the overhead panel to illuminate?

High oil temp
Low oil pressure

HOTLOP

73

If an IDG is manually disconnected can it be reconnected in flight?

No

74

What is the primary purpose of the AC generators?

To power the AC BUSSES and AC ESS BUS which power the 3 TRU's (1, 2 & ESS)

75

What is the purpose of the TRU's?

To convert 115 VAC to 28 VDC

76

Can an APU replace a failed IDG?

Yes

77

What is the AC electrical system's priority?

Onside (IDG)
Inside (APU)
Outside (GPU)
Cross-side (Other IDG)

78

How is it known that an AC GPU is hooked up to the airplane and ready to provide electricity?

GPU button displays AVAIL and the GPU icon is presented on the electrical synoptic page
-Once the GPU button is pushed in, the button will display IN USE provided another AC power source is not available

79

What does it mean if the AC GPU is plugged in and the outside GPU panel button displays IN USE?

-Ground service bus is in use
-Cockpit GPU button will display AVAIL even though the ground service bus is in use

80

If the airplane is using the AC GPU and the APU is started what should the pilot be sure to do?

Deselect the GPU button before the next GPU connection

81

What will charge the batteries?

Any AC power source

82

How long will the aircraft's batteries last with no recharging?

10 minutes

83

What is the purpose of the DC GPU receptacle?

For APU start when batteries

84

What is the minimum battery temp for APU start?

-20 C

85

What is the minimum voltage to close the battery bus ties?

18 volts

86

What battery is used for the APU start?

BATT 2 powers the APU Start Bus
BATT 1 powers the FADEC & EICAS for monitoring

87

What is the purpose of the inverter?

Converts 28 VDC from the batteries to 115 VAC to power the AC STANDBY BUS when an AC source is not available

88

What is on the AC STANDBY BUS?

Engine exciters 1A & 2A

89

What powers the RAT?

Airflow turns the RAT propeller which spins the turbine inside

90

When will the RAT deploy?

Automatically deploys if AC BUSSES are not powered or manually by pilot

91

How long after deployment before the RAT will supply power?

8 seconds

92

Is there a total loss of power during the 8 second RAT deployment?

No. Batteries supply power to the DC ESS BUSSES and AC STANDBY BUS

93

What does the RAT power?

ESS BUSSES

94

What is the minimum airspeed for the RAT?

130, load shedding occurs below this speed

95

When is the RAT icon is displayed on the electrical synoptic page?

When the RAT is deployed

96

What manages the electrical system?

4 Integrated Control Center's (ICC) &
2 Secondary Power Distribution Assemblies (SPDA)

97

What is an ICC?

An electrical control device which provides power distribution and protection for electrical loads

98

What is an SPDA?

An electrical load-management unit (powered by the ICC's) that distributes electrical loads to aircraft systems according to distribution logic

99

Can the flight crew reset the ICC and SPDA remote electronic CB's

-ICC CB's can only be reset by maintenance
-SPDA CB's can be reset via the MCDU