Electrical System

Question 1

3 main components of power supply system?

Answer 1

starter/generator (2)

battery

external power unit

Question 2

E power consumers divide into what 3 buses?

Answer 2

essential equipment

non-essential equipment

shed bus equipment

Question 3

Generator engages at N1 >

Answer 3

40% / 50% (when no EPU)

Question 4

3 times generator disconnects from system:

Answer 4

1. gen voltage > .3 VDC of main bus
2. gen voltage < adjuting point of gen contol unit
3. N1 < 50%

Question 5

6 functions of GCU (gen control unit)

Answer 5

1. voltage regulation
2. parallel ops
3. reverse current protection
4. over voltage protection
5. over excitation protection
6. short circuit protection

Question 6

A separate power module (battery) supplies ___ VDC as emergency power for ___ and ___.

Answer 6

24
standby horizon
emergency lights

Question 7

How many volts is the battery?

Answer 7

24 VDC

Question 8

Purpose of the EPU:

Answer 8

spare power during ground ops, and

reduce strain during starts

Question 9

Purpose of bus tie switch?

Answer 9

connect and disconnect Main Bus 1 and Main Bus 2 to/from Battery Bus

Question 10

Emergency Shed Bus switch - ON does:

Answer 10

Energize Shed Bus with Bat Power if both generators lost

Question 11

Starter limits for:
Battery:
EPU:

Answer 11

30 sec for batt

20 sec for EPU

Question 12

Starter disconnects from N1 automaically from ambient temp through:

Answer 12

Temperature Start Control Relay