ELECTRICAL_STANDBY

Question 1

DRIVE Light

What does the amber drive light mean? (1sp)

Answer 1

[1sp - HOTLOP (hi oil temp, low oil press), eng is off, idg auto disconnect, or manually disconnect the drive]

Illuminated (amber):

• IDG low oil PRESSURE caused by:
  
  • IDG failure
  • eng shutdown
  • IDG auto disconnect due to high oil temp
  • IDG manually disconnected
• controlled by the GCU
• maint must reset a disconnected IDG

Question 2

GENERATOR DRIVE DISCONNECT Switch

What happens when we position the IDG Disconnect switch to the disconnect position? (1sp)

How do you know when you have disconnected the IDG? (1sp)

Answer 2

[1sp - we are disconnecting the IDG by removing it from the accessory drive.

(b) lift the cover, hold for 3-5 seconds, and verify by checking the voltage and frequency

• • disconnects the IDG if:
    
    • electrical power available AND
    • engine START LEVER is in IDLE
• Guarded and safety wired

Question 3

STANDBY PWR OFF Light

What does this light mean? (1sp)

Answer 3

[1sp - means the AC standby bus, dc standby bus or battery bus is not powered]

Illuminated (Amber): - one or more of the following busses are unpowered.

• AC Standby
• DC Standby
• Battery Bus

Question 4

STANDBY POWER Switch

• 3 position -

BAT

OFF

AUTO

How does standby power switch work in the AUTO position? (1sp)

How will it work in the BAT position (1sp)

Answer 4

[1sp - if we lose both generators (need to say this first!), (because if we lose only one gen - you will go to the bus transfer switch) - through the battery..we will power the DC standby bus and we will power the AC standby bus through the inverter.

(b) you are connecting the battery manually (forcing the battery) to power the standby buses]

Notes.

• gives manual control to override the auto control of the standby busees from AC Bus to Batt/Inverter power or to disable the standby busses

BAT: (unguarded position)

• AC Stby bus powered by Battery via the inverter
• DC Stby bus and Batt Bus are powered directly from the Battery

OFF:

• illuminates [STANDBY PWR OFF] light
• deactivates the STBY power system (AC, DC and Inverter) i.e. they are not powered

AUTO: (guarded)

• arms auto switching of the standby power system
• works on ground AND in the air
• if AC xfer busses powered:
  
  • AC Stby powered from AC xfer 1
  • DC Stby powered from TR 1, 2 & 3
• Loss of ALL AC power:
  
  • AC Stby bus - powered by the BATT (via the inverter)
  • DC Stby bus and Batt Bus - powered by the Battery