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DB's SY 737 Electrical Flashcards

0
Q

TR UNIT light - ON

  1. Ground
  2. Flight
A
  1. Any TR has failed

2. TR1 OR TR2 and TR3 have failed

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1
Q

BAT DISCHARGE light - ON

A

Excessive battery discharge (with BAT switch on)

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2
Q

ELEC light - ON

A

A fault exists in DC or STBY power system.

Ground only

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3
Q

BAT Switch - OFF with normal power sources (with AC power)

A

Removes power from BAT and Switched Hot Bat buses

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4
Q

BAT Switch: OFF when only BAT power (without AC power)

A

Removes power from:

  1. BAT bus
  2. Switched Hot Bat bus
  3. DC Standby bus
  4. Static inverter
  5. AC Standby bus
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5
Q

BAT Switch - ON

A
  1. Powers Switched Hot Bat bus

2. Energizes relays for automatic switching of STBY system to Bat power with loss of normal power

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6
Q

What components are powered by the CAB/UTIL Switch?

A
  1. All 115V AC galley buses
  2. Recirc fan(s)
  3. Fwd and aft door area heaters
  4. Drain mast heaters
  5. Lav water heaters
  6. Logo lights
  7. Potable water compressor
  8. 115V AC shaver outlets
  9. LED Cabin lighting
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7
Q

What components are powered by the IFE/PASS Switch?

A
  1. 115V AC audio entertainment equipment
  2. 115V AC video entertainment equipment
  3. 28V DC video equipment and passenger seat electronic outlets
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8
Q

Generator DRIVE light - ON

A

IDG low oil pressure caused by:

  1. IDG failure
  2. Engine shutdown
  3. IDG auto disconnect due to high oil temp
  4. IDG DISCONNECT Switch
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9
Q

When is IDG DISCONNECT switch available?

A

If electrical power is a available and engine start lever is in IDLE.

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10
Q

STANDBY PWR OFF light - ON

A

One or more buses are unpowered:

  1. AC STBY
  2. DC STBY
  3. Bat bus
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11
Q

STANDBY POWER Switch - AUTO with AC transfer buses powered.
What powers:
1. AC STBY bus
2. DC STBY bus

A
  1. AC transfer bus 1

2. TR1, TR2 and TR3

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12
Q 
STANDBY POWER Switch - AUTO with loss of all AC power. 
What powers:
1. AC STBY bus
2. DC STBY bus
3. Bat bus
A
  1. Bat via static inverter
  2. Bat
  3. Bat
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13
Q

STANDBY POWER Switch - OFF

A

Removes power from:

  1. AC STBY bus
  2. Static inverter
  3. DC STBY bus
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14
Q

STANDBY POWER Switch - BAT

A
  • AC STBY bus powered by Bat via Static inverter

* DC STBY bus and BAT bus powered by Battery.

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15
Q

GRD POWER AVAILABLE light - ON

A

Ground power is connect and meets airplane power quality standards (good freqs and volts)

16
Q

GRD PWR switch - OFF

A

Disconnects ground power from AC transfer busses

17
Q

GRD PWR switch - ON (with GROUND PWR AVAILABLE light ON)

A

Removes previous power from AC transfer busses and then connects ground power.

18
Q

TRANSFER BUS OFF Light - ON

A

Related transfer bus is not powered

19
Q

SOURCE OFF light - ON

A
  1. No source has been manually selected to power transfer bus
    Or
  2. The manually selected source has been disconnected
20
Q

GEN OFF BUS light - ON

A

IDG is not supplying power to related transfer bus

21
Q

GEN switch - OFF

A

Disconnects IDG from related AC transfer bus (by opening generator CB)

22
Q

GEN switch - ON

A

Connects IDG to related AC transfer bus (by disconnecting previous source and closing gen CB)

23
Q

BUS TRANSFER Switch - AUTO

A
  1. BTBs operate automatically to maintain power to AC transfer busses
  2. DC cross tie relay automatically provides normal or isolated operation as required
24
Q

BUS TRANSFER Switch - OFF

A
  1. Isolates AC transfer bus 1 from AC transfer bus 2 (if one IDG is supplying power to both AC transfer busses)
  2. DC cross tie relay opens (to isolate DC bus 1 from DC bus 2)
25
Q

APU GEN OFF BUS light - ON

A

APU is running and not powering a bus

26
Q

What is the automatic gen online feature?

A

If the airplane takes off with the APU powering both AC transfer busses and the APU is the shut down or fails, the engine gens are automatically connect to their related busses. (Max once per flight)

27
Q

When will the cross bus tie relay open automatically?

A
  1. At glide slope capture

2. Bus transfer switch - OFF

28
Q

How long will two fully charged batteries provide STBY power?

29
Q

What buses are powered with only Batteries online?

A
  1. Bat
  2. DC STBY
  3. Hot Bat
  4. switched Hot Bat
  5. AC STBY (via static inverter)
30
Q

On STBY power only, what flight instruments are powered?

A
  1. CA’s inboard and outboard displays
  2. Clocks
  3. Left EFIS control panel
  4. STBY instruments (RMI, airspeed, altimeter, attitude, and mag compass)
31
Q

What does the GROUND SERVICE Switch (Flight Attendant Panel) provide?

A

Manual control of ground service busses enabling servicing airplane using external power without activating AC transfer busses

32
Q

What are the two basic principles of operation for the 737 electrical system?

A
  1. There is no paralleling of the AC sources of power

2. The source of power being connected to a transfer bus automatically disconnects an existing source

SCA (15 decks)

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