B777F - FCOM - Systems > Ch 6 - Electrical > Flashcards

Ch 6 - Electrical Flashcards

(77 cards)

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1
Q

Generator DRIVE light - Amber

A

IDG oil pressure is low

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2
Q

Backup Generator OFF lights - Amber

A

Backup gen switch is off

Fault occured

Engine is shutdown

Eng Fire Switch is out

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3
Q

STANDBY POWER switch

A

Ground ops only

OFF -> AC STBY BUS not powered

AUTO (guarded)
-> STBY busses transfer to battery power if normal AC power is lost

BAT (momentary)
-> With AC power not available and BAT switch ON, powers the STBY AC Bus from the battery through the inverter

Initiates a DC/standby self-test in the inverter when AC power is available

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4
Q

Does the electrical flow bars on the electrical synoptic page represent actual operation?

A

No, actual flow is not displayed

Display is created from switch and contactor positions by the displayed status of the electrical equipment.

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5
Q

Are the display of switch, contactor, flow bar position and status included in the MEL/DDG?

A

No, and the are not required for crew normal or non-normal procedures

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6
Q

What colours on the synoptic page will indicate power is not flowing or a generator is off or Bus state unknown?

A

Thin white line and

White

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7
Q

What is the electrical system comprised of?

(5)

A

Main AC power

Backup Power

DC power

Standby power

Flight Controls power

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8
Q

What is ELMS?

A

Electrical Load Management System

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9
Q

What does ELMS do?

A

Manages loads and protects critical and essential equipment by ensuring power is available to it

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10
Q

What is the priority of the ELMS loadshedding?

A

Galleys

Utility busses

Individuel equip. on main AC busses

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11
Q

What does the ELMS also monitor during climb and cruise?

A

Fuel pumps

To alert crew of unintentional dry fuel pump ops when center tank is empty

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12
Q

Where can you see if ELMS is active?

A

LOAD SHED on electric synoptic page

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13
Q

Name the Main AC electrical power sources

A

Left and Right IDG’s

APU generator

Prim & Sec Ext. Pwr.

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14
Q

How many AC power sources are needed to supply the entire AC electrical load?

A

Any two main AC power sources

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15
Q

Does the power sources normally operate parallel or isolated from one another?

A

Isolated

Parallel during power transfers on the ground to prevent power interruption

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16
Q

What will cause the IDG to disconnect automatically?

A

High Oil Temperature

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17
Q

What will the APU power if the primary ext. source is powering both main busses?

A

APU will power the left main bus

(and primary ext. source the right main bus)

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18
Q

What will the APU power if primary ext powers the right main bus and

Secondary ext powers the left main bus?

A

APU will power the left main bus

(and primary ext. source powers the right main bus)

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19
Q

What will the APU power if the Secondary ext. source is powering both main busses?

A

APU will then power both main busses

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20
Q

Can the APU generator connect to the busses if APU GEN switch is ON and a fault is detected?

A

No

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21
Q

When will the APU start automatically?

A

In flight

Both transfer busses are unpowered

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22
Q

One IDG powers both busses and primary ext.pwr ON?

A

Prim.Ext Pwr’s both busses and removes IDG source

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23
Q

If both IDG’s powers both busses and Prim.Ext. Pwr ON and no APU or Sec. Ext. Pwr?

A

Prim. Ext. Pwr’s both busses and removes the IDG sources

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24
Q

Both IDG’s powers respective busses +
Sec Ext. Pwr available
pushing Prim.Ext. Pwr ON?

A

Connects Prim. Ext. Pwr to Right Main Bus

IDG powers Left Main Bus

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25
If APU is running what happens if you push the Prim. Ext. Pwr ON?
Prim Ext. Pwr connects to right main bus Previous source connected to left main bus
26
If Sec. Ext Pwr is powering both main busses and Prim. Ext. Pwr ON?
Prim EXT -> Right main bus Sec. EXT -> Left main bus
27
With no AC Power, what must be fulfilled before the Sec Ext Pwr can connect?
Battery must be ON, or Prim Ext. Pwr available
28
Is there a no-break transfer of power of Sec. EXT power to the right main bus when the right engine is shut down?
Yes
29
How is AC power distributed?
Through the left and right main busses, Handling bus Ground Service bus
30
What does the BUS TIE switches do?
Isolate or parallel the right and left main busses
31
Power transfer is normally made without interruption on the ground except when?
Switching between primary and secondary external power
32
What is the source order for the main busses in flight?
Respective IDG APU generator Opposite IDG
33
What individual equipment does the main busses power? (5)
Cooling vent fan Recirc. fans Lavatory/gallery fans IFE Elec Hydraulic pumps
34
What associated busses does the Main busses also power?
Transfer bus - DC transformer rectifiers + AC stby bus Utility bus Gallery bus
35
What normally powers the Ground Service bus?
Right Main bus
36
What are the alternate power sources for the Ground Service bus?
APU generator Primary EXT PWR.
37
What does the Ground Service bus power? (3)
Main Battery Charger APU Battery Charger Misc. cabin and system loads
38
What can power the Ground Handling bus?
APU generator Primary EXT. PWR *ground ops only
39
What does the Ground Handling bus power?
Cargo handling Fuelling Other equipment energized on ground only
40
During Autoland what does the left IDG power?
L AC transfer bus L main DC bus Capt FI bus
41
During Autoland what does the right IDG power?
Battery bus AC standby bus through main bat charger
42
During Autoland what does the backup system power?
R AC transfer bus R main DC bus F/O FI bus
43
What does the backup electrical system power?
One or both transfer busses
44
When does the backup system power the transfer busses?
Only 1 main AC Gen Power to one or both AC bus is lost APP mode Autoland
45
When is the backup electrical system tested?
Automatically after engine start and transfers power without interruption
46
What kind of generator is the backup generator and where is it located?
1 variable speed, variable frequency generator mounted on each engine. frequency converter 400 Hz
47
What are PMG's in relation to the backup generators?
Permanent magnet generators
48
What does each backun generator contain?
2 PMG's (power magnetic generators) Powers the flight control DC electrical system
49
Which systems are inoperative due to load shedding when the backup generators are running? (8)
TCAS SATCOM Right HF CTR Tank pumps (fuel unusable and no jettison) Pos lights. Ext lights non-essential cabin equip. SupN lighting Cabin Temp Control in degraded mode
50
What does the DC system consist of?
Main DC elec system Batteries Battery chargers Flight Control DC system
51
How many TRU's in the DC system?
4
52
What powers the TRU's?
AC transfer busses
53
What does the Left TRU power?
Left Main DC bus 2nd. Source for: Left flight control power supply assembly (PSA) Right Main DC bus
54
What does the right TRU power?
Right Main DC bus 2nd source for: Right flight control PSA Left Main DC bus
55
What does the C1 TRU power?
Capt. FI bus Battery bus Capt. FI bus 2nd source for: Center flight control PSA F/O FI bus
56
What does the C2 TRU power?
F/O FI bus -> 2nd source for Capt. FI bus
57
What does the main battery charger normally power?
Hot battery bus and keeps battery charged
58
What does the APU battery connect to?
APU battery bus and APU electric starter
59
What is the flight control DC electrical system?
Dedicated power source for the primary flight control systems
60
Where does the primary power for the flight control DC electrical system come from?
Via permanent magnet generators (PMG's) Housed within each backup generator
61
Where are the PMG's
In the backup generators
62
How does the PMG's operate?
Variable frequency PMG AC power is used by individual power supply assemblies (PSA's) to provide DC power to the 3 flight control DC busses
63
Secondary power for the left and right PSA?
Related main DC bus
64
Secondary power for Center PSA?
Capt. FI bus
65
Additional secondary power for the left and center PSA's only?
HOT BAT BUS
66
Which PSA's does the hot battery bus provide backup power to?
Left and center PSA's
67
What does the standby electrical system consist of?
Main battery Standby Inverter RAT C1 and C2 TRU's
68
Main battery powers?
Hot battery bus Battery bus Capt. FI bus Left and Center PSA's Standby inverter
69
How many minutes can the main battery power the standby system for?
Min 5 minutes
70
What powers the AC standby bus of the left transfer bus is not powered?
The inverter
71
What does the RAT supply power to?
C1 and C2 TRU's
72
What kind of power can the RAT supply?
Electrical and hydraulic power simultaneously
73
When does the RAT deploy?
If both AC transfer busses lose power in flight
74
What are the RAT's speed and operating altitudes?
RAT operates at all speeds and altitudes
75
What is the time limit for RAT ops?
No time limit for RAT ops
76
Which displays will remain unpowered when the RAT is providing power?
Lower display Right CDU
77
Where is electrical power outlets removed from when pushing the CARGO FIRE ARM switch to ARMED?
Main deck Lower FWD cargo Lower AFT cargo
B777F - FCOM - Systems
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