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DAL 737 S-LOD > Electrical > Flashcards

Electrical Flashcards

1
Q

Describe the function of the GROUND SERVICE switch on the Forward F/A panel

A

Provides manual control of ground service busses. Enables servicing of airplane using external power without activating AC transfer busses

ON - connects external power to ground service bus

OFF - disconnects external power from ground service bus

VOL 2 / 6.1.5

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2
Q

Explain the meaning of the blue GRD POWER AVAILABLE light

A

Illuminated blue - ground power is connected and meets airplane power quality standards

Note: doesn’t follow dim blue/bright blue logic. If it’s on - it’s available

VOL 2 / 6.1.4

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3
Q

Explain the meaning of the blue APU GEN OFF BUS light

A

Illuminated blue - APU is running and not powering a bus (it’s available for use)

VOL 2 / 6.1.4

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4
Q

Explain the meaning of the GEN OFF BUS

A

Illuminated blue - IDG is not supplying power to the related transfer bus

VOL 2 / 6.1.4

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5
Q

Recall where to read voltage, frequency and amps

A

AC and DC metering panel on the forward overhead panel

VOL 2 / 6.1.2

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6
Q

Explain the meaning of the amber DRIVE light

A

Illuminated (amber) - integrated drive generator (IDG) low oil pressure

VOL 2 / 6.1.3

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7
Q

Explain the meaning of the amber TRANSFER BUS OFF light

A

Illuminated (amber) - Related transfer bus is NOT powered

Extinguished - Related transfer bus IS powered

VOL 2 / 6.1.4

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8
Q

Explain the meaning of the amber SOURCE OFF light

A

Illuminated (amber) - No source has been manually selected to power the related transfer bus, or the manually selected course has been disconnected

Note: SOURCE OFF light triggers ELEC light and Master Caution to alert crew of change to source of power to associated Transfer Bus

VOL 2 / 6.1.4

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9
Q

Explain the meaning of the amber BAT DISCHARGE light

A

Illuminated (amber) - with BAT switch ON, excessive battery discharge detected

VOL 2 / 6.1.2

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10
Q

Explain the meaning of the amber TR UNIT light

A

Illuminated (amber) - TR failure

TR = Transformer Rectifier

VOL 2 / 6.1.2

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11
Q

Explain the meaning of the amber ELEC light

A

Illuminated (amber) - fault exists in DC power system or standby power system

Note: operates only with airplane on the ground

VOL 2 / 6.1.2

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12
Q

Explain the meaning of the amber STANDBY PWR OFF light

A

Illuminated (amber) - one or more of the following busses are unpowered:
- AC standby bus
- DC standby bus
- Battery bus

VOL 2 / 6.1.3

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13
Q

Recall the number of minutes available on standby power with two fully charged batteries

A

60 minutes
VOL 2 / 6.2.5.2.2

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14
Q

Recall the function of the Ground Power (GRD PWR) switch

A

Three position switch, spring loaded to neutral

OFF - disconnects ground power from AC transfer busses

ON - if momentarily moved to ON position and ground power is available:
- removes previously connected power from AC transfer busses
- connects ground power to AC transfer busses when power quality is correct

VOL 2 / 6.1.4

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15
Q

Recall that it is not possible to use APU power and GRD power at the same time.

A

There are two basic principles of operation for the 737 electrical system:

  • No paralleling of AC sources of power
  • The source of power being connected to a transfer bus automatically disconnects the existing source

VOL 2 / 6.2.1.2

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16
Q

Recall the function of positioning the APU Generator (GEN) switches to ON

A

Three position switch, spring loaded to neutral.

Neither AC transfer by powered by an IDG:
Moving an APU GEN switch to ON:
- Powers both AC transfer busses from the APU generator
- Disconnects external power, if connected
- Opposite SOURCE OFF light illuminates until the APU GEN switch is moved ON

Both AC transfer busses powered by IDGs:
Moving an APU GEN switch to ON:
- Powers the related AC transfer bus from the APU generator
- Other AC transfer bus continues to receive power from the IDG

VOL 2 / 6.1.4

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17
Q

Recall the components powered by the ground service bus

A
  • Utility outlets
  • Cabin lighting
  • Battery chargers

Memory Aid:

CUB

VOL 2 / 6.2.2.4

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18
Q

Recall the location of the GROUND SERVICE switch

A

The forward flight attendant control panel

VOL 2 / 6.1.5

19
Q

Recall the function of the Generator (GEN) switches

A

Three position switch spring loaded to neutral

OFF - disconnects IDG from related AC transfer bus by opening generator circuit breaker

ON - Connects IDG to related AC transfer bus by disconnecting precious power source and closing generator circuit breaker

VOL 2 / 6.1.4

20
Q

Recall the function of the BUS TRANSFER switch

A

AUTO (guarded position) - bus tie breakers operate automatically to maintain power to AC transfer busses from any operating generator or external power

OFF - isolates AC transfer bus 1 from AC transfer bus 2

VOL 2 / 6.1.4

21
Q

Recall the function of the Generator Drive Disconnect (DISCONNECT) Switches (guarded)

A

Disconnects IDG if electrical power is available and engine start lever is in IDLE. IDG cannot be reconnected in the air

Note: It’s mechanically disconnected and has to be fixed by maintenance on the ground

VOL 2 / 6.1.3

22
Q

Explain the function of the BAT (battery) switch

A

ON:
- provides battery power
- provides automatic switching of standby electrical system to battery power with loss of normal power

OFF:
- removes battery power

VOL 2 / 6.1.2

23
Q

An illuminated SOURCE OFF light indicates:

A

Both A and B

  • No source has been manually selected to power the related transfer bus
  • the manually selected source has been disconnected

ESV-VA: ELECTRICAL

24
Q

An illuminated STANDBY PWR OFF light indicates:

A

One or more of the above

  • An unpowered AC STBY BUS
  • An unpowered DC STBY BUS
  • An unpowered Battery Bus

ESV-VA: ELECTRICAL

25
Q

True or False:
An illuminated TRANSFER BUS OFF light indicates that the related transfer bus is not powered

A

TRUE

ESV-VA: ELECTRICAL

26
Q

True or False:
If an IDG has been disconnected while airborne, it cannot be reconnected while airborne.

A

TRUE

ESV-VA: ELECTRICAL

27
Q

With the BAT switch on, which light indicates an excessive battery discharge is detected?

A

BAT DISCHARGE

ESV-VA: ELECTRICAL

28
Q

Is it possible to use APU power and GRD power at the same time?

A

FALSE

ESV-VA: ELECTRICAL

29
Q

To isolate AC transfer bus 1 from AC transfer bus 2, the BUS transfer switch must be in what position?

A

OFF - it isolates AC Bus 1 from AC Bus 2

ESV-VA: ELECTRICAL

30
Q

The GROUND SERVICE switch is located on what panel?

A

the FORWARD flight attendant panel

ESV-VA: ELECTRICAL

31
Q

Selecting the battery switch to the OFF position provides automatic switching of standby electrical power to battery power with loss of normal power.

A

FALSE

That only happens if the battery is ON

ESV-VA: ELECTRICAL

32
Q

The connection and quality of ground power can be verified by observing which light?

A

GRD POWER AVAILABLE light

ESV-VA: ELECTRICAL

33
Q

Select component(s) NOT powered by the ground service bus

A

AC transfer busses

The components powered by the Ground Service Bus are CUB:

  • C: Cabin lighting
  • U: Utility outlets
  • B: Battery chargers

ESV-VA: ELECTRICAL

34
Q

What is the indication that the IDG is not supplying power to the related transfer bus?

A

the BLUE GEN OFF BUS light is ILLUMINATED

The light does not flash.
The light is not amber.
The light is not extinguished.

ESV-VA: ELECTRICAL

35
Q

When an engine driven generator (GEN) switch is selected OFF, it…?

A

disconnects the IDG from related AC transfer bus.

ESV-VA: ELECTRICAL

36
Q

A generator (DRIVE) light illuminates (amber) for low oil pressure in the integrated drive generator (IDG) caused by which of the following conditions:

A

All of the above (because they all could cause low oil pressure):

  • IDG failure
  • Engine shutdown
  • IDG automatic disconnect due to high oil temperature
  • IDG disconnected through generator drive DISCONNECT switch
  • Low generator frequency condition (engine running)

ESV-VA: ELECTRICAL

37
Q

What is the function of the GROUND SERVICE switch?

select all that apply

A
  • manual control of ground service busses
  • enables servicing airplane using external power without activating AC transfer busses

ESV-VA: ELECTRICAL

38
Q

What light indicates an excessive battery discharge is detected?

A

BAT DISCHARGE

ESV-VA: ELECTRICAL

39
Q

With both AC transfer busses powered by the IDGs, moving an APU GEN switch on:

select all that apply

A
  • Powers the related AC transfer bus from the APU generator
  • Allows the opposite AC transfer bus to remain powered by the respective IDG

ESV-VA: ELECTRICAL

40
Q

On aircraft equipped with two batteries, two fully charged batteries have sufficient capacity to provide standby power for a minimum of 60 minutes.

A

TRUE

ESV-VA: ELECTRICAL

41
Q

What switch is used to connect external power to the AC transfer busses?

A

GRD PWR Switch

Not the GROUND SERVICE SWITCH

ESV-VA: ELECTRICAL

42
Q

Illumination of an APU generator off (GEN OFF) light indicates that the APU…

A

is running and not powering a bus

ESV-VA: ELECTRICAL

DAL 737 S-LOD (15 decks)

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