Electrics Flashcards

1
Q

When the Battery Master is selected on, what bus(es) will be powered?

A

L/R ESS buses + AC inverters

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2
Q

how many temp sensors are there per battery?

A

2

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3
Q

MAIN BATT HOT

A

Main battery internal temp over 65deg. Turn the charging to this battery off and monitor temp.
If it continues to rise then land immediately

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4
Q

What is the fixed AC system primarily used for?

A

Avionics and flight instruments

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5
Q

How many inverters need to be operational to power the system?

A

1

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6
Q

What selections are available for the aux inverter and where is the aux inverter connected to the system?

A

Primary, off, Secondary.

L MAIN bus

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7
Q

What lights are powered directly by the battery bus?

A

Dome lights and boarding lights

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8
Q

How many batteries does the aircraft have?

A

2 24v Nicad batteries in the nose

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9
Q

What buses will have power with the Batt master on and the main battery on and main tie connected?

A

L/R ESS and L/R MAIN buses

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10
Q

how do we get power to the L MAIN bus on the ground (no engines)?

A

Main bus tie

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11
Q

What voltage should we see on tthe DC monitor when external power is connected?

A

28V

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12
Q

Which buses will be powered with DC external power plugged in?

A

All DC buses

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13
Q

Will external power charge the batteries?

A

Yes if GPU voltage higher than battery voltage

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14
Q

Will the APU charge the batteries?

A

Yes if GPU voltage higher than battery voltage

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15
Q

Min voltage for engine start on batteries?

A

22V

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16
Q

At what voltage does over voltage protection lock out external power?

A

31.5V

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17
Q

Can external power and the engine DC gens be on line at the same time?

A

No, External power is sensed by the GCU which automatically turns off the DC gens

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18
Q

If a DC gen fails, will the opposite main bus be powered?

A

Yes through the main bus tie (bus tie logic)

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19
Q

How are DC gens cooled?

A

Air cooled

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20
Q

What are the DC gen load limits on the ground and in the air?

A
  1. 7 on the Ground

1. 0 in the air

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21
Q

If the Main buses are powered, are the essential buses automatically powered?

A

Yes, through diodes

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22
Q

Will the AC gens be online wil the props in feather?

A

No

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23
Q

What do the AC gens provide power to?

A

The L/R 115VAC buses

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24
Q

If an AC gen failed in flight, would the opposite AC bus be powered?

A

Yes through the bottom bus tie

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25
Q

Which buses power the TRU’s?

A

115VAC buses

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26
Q

What buses are directly powered by the TRU’s?

A

L/R secondary buses

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27
Q

What is the input and output of the TRUs?

A

In: 3 phase (87Amp per phase) 115V VAC
Out: 28V DC, 200Amp max each, (25-29.5V dependant on load)

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28
Q

How can a TRU be turned off?

A

Pull the CB

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29
Q

If one TRU fails, will both secondary buses be powered?

A

Yes through the secondary horizontal bus tie

30
Q

If both TRU’s fail, will the SEC buses be powered?

A

Yes through both main buses (vertical ties)

31
Q

What is DC logic?

A

The unit that controls closing of bus ties automatically following a set of perameters (Roger the mouse)

32
Q

What is the priority for DC logic?

A

Horizontal ties

33
Q

DC BUS

A

More than 400Amp draw detected on one of the main buses.
All Central ties inhibited from closing. If this caution persists for 7 seconds, appropriate battery and gen are also disconnected automatically

34
Q

What is the function of the DC bus reset switch?

A

To reset the DC BUS fault to check if the fault remains

35
Q

Loss of both DC generators procedure requires turning off all battery switches. why? what is supplying the power for the DC system? What if one fails?

A

To prevent over heating the batteies as the TRU’s arent regulated
The TRU’s supply all the DC power,
If one fails, all cockpit power is lost (horizontal tie priority)

36
Q

What are the TRU load limits?

A

1.0 in flight and on ground

37
Q

AC gen limits?

A

0.33 on Ground (above 10deg) otherwise 1.0

38
Q

At what voltage are the batteries considered flat?

A

20V

39
Q

What is the amp/hr rating of the batteries? how long will we have battery power for in a complete electrical failure?

A

40A/hr. 30mins guarenteed (51mins really)

40
Q

How many amps are being drawn from a DC gen at a load rating of 0.7?

A

210Amps

41
Q

What are the 2 battery heat sensors connected to?

A

One to temp gauge, other to BATT HOT warning. both to master warning

42
Q

What is connected to the Battery bus?

A
ENG +APU fire ext. activation circuits
Fuel and hydraulic shutoff valves
Refuel/Defuel shut off valves + refuel panel
Dome lights and Boarding lights
PA emergency power
43
Q

What bus does the external power and APU power feed into?

A

R MAIN (GPU is also L MAIN)

44
Q

What is the danger of turning on the GPU without the batteries on?

A

Power spike and damage to equipment

45
Q

What will happen is the GPU is left plugged in but switched off?

A

The external power circuit stays connected, green light stays on but massive discharge from batteries (~1.2)

46
Q

If you have a blown external power CB will starting be available?

A

Not on external power, the other CB will blow

47
Q

In the cockpit what instruments are powered by the ESS bus?

A

CAPT instruments and screens,
Engine instruments,
LDG gear and Flap
NAV1/COM1 (note no FMS)

48
Q

Where does power for F/O’s instruments come from?

A

R MAIN (also COM2/NAV2, Antiskid and an FMS)

49
Q

What temp do the BATT HOT warnings come on at?

A

65deg

50
Q

Where is the DC gen on the engine?

A

Accessory gbox

51
Q

What does a flashing +ve sign mean on a DC gen readout?

A

That gen is producing more than 300Amps

52
Q

What are the functions of the Generator control unit

A

Controls the start sequence to 63% NH
Regulates voltage to 28V
Fault sensing

53
Q

1/2 DC GEN

A

DC gen not connected

54
Q

1/2 DC GEN HOT

A

Gen overheat - QRH

55
Q

What freq do the VAC and FAC buses operate at?

A

400hz FAC, 200-400 VAC

56
Q

What inverter powers the CAPT nav gear?

A

Primary (L ESS)

57
Q

PRI/SEC/AUX INV

A

Inverter failure

58
Q

L/R 26VAC

A

Bus unpowered

59
Q

Max amps from GPU?

A

1500

60
Q

If the external power is a lower voltage than the batteries what will happen?

A

The batteries will discharge

61
Q

What cools the AC gens?

A

Oil cooled

62
Q

What are the 115VAC buses primarily used for?

A

heaters and pumps

63
Q

1/2 AC GEN HOT

A

AC gen overheat - QRH

No auto disconnect

64
Q

1/2 AC GEN

A

AC gen not producing power

65
Q

Where are the TRU’s and CB’s located in the AC?

A

Nose

66
Q

L/R TRU

A

TRU failure/not operating

67
Q

L/R TRU HOT

A

overheating TRU, manual disconnect

68
Q

How many ties can the mouse close at once?

A

2 (horizontal or vertical)

69
Q

Is it possible to run the entire AC on one AC gen?

A

yes if both TRU’s operational

70
Q

BBPU?

A

bus bar protection unit (disconnects main batt, dc gen and opens ties when DC BUS)