Part 1 - Chapter 1 - Electrical System

Question 1

Electrical System - main components

Answer 1

• 28V, 100 amp DC Generator feeding main busbar
• 3 x 115V AC Inverters (fed by main busbar)
• 2 x 24 Volt, 18amph batteries to energise main busbar
• 1 x 24 Volt, 7amoh battery for essential services

Question 2

Electrical Systems
AC power start

Answer 2

When generator delivers sufficient voltage, relay is closed to provide power to normal inverter (if cockpit selector switch is set to normal)

Question 3

Electrical System
Battery power supply to systems

Answer 3

• Batteries directly supply essential services
• Batteries linked to main busbar via isolation relay (can be operated from cockpit on/off)

Question 4

Emergency Battery - supplies which essential services?

Answer 4

• Cockpit light
• Attitude indicator and compass light
• Nose wheel landing light
• Standby radio

Question 5

What to do if circuit breaker pops?

Answer 5

Wait 30 secs for heating element to cool

Question 6

AC supply (3 inverters)

Answer 6

• One for cockpit light (operated by cockpit light on/off switch)
• One normal inverter (for fire detection system and gyro instruments)
• One standby

Question 7

Inverter indicator (normal)

Answer 7

Black

Question 8

AC Power before / during engine start

Answer 8

• Main busbar energises (batteries or external power)
• Standby inverter operates (white indicator)
• As generator comes online, normal inverter starts automatically

Question 9

Main battery switch

Answer 9

On / Off, connects main batteries to main busbar (automatically off if external power is connected or crash switches operate)

Question 10

Inverter switches

Answer 10

• Flight Instr. Start / Off - switches on standby inverter if main busbar is energised but engine not running
• Normal/ Standby - switches between normal and standby inverter
• Inverter test - if switched to Inverter test it supplies power to normal inverter even when engine not running to test normal inverter

Question 11

Inverter supply indication

Answer 11

Black - normal inverter running
White - standby inverter running or all inverters off
No AC power: gyro flags red

Question 12

Generator failure in flight

Answer 12

• Minimise load
• Land asap
• Standby inverter will come on

Question 13

Normal inverter failure but no generator failure

Answer 13

Can be brought back online with switch Normal / Standby to Standby and back to Normal

Question 14

Generator failure (bringing normal inverter back online)

Answer 14

• Generator failure causes switch from normal to standby inverter
• To bring normal inverter back, select “Normal”, then test to “test”, check for black indicator