Chapter 6 Electrics

Question 1

Apart from traditional systems what else is electrically powered on the B787 ?

Answer 1

Start. Stabiliser Trim.Pressurisation, Braking system. Airframe Anti icing.

Question 2

What are the main sources of power for the flight control electronics ?

Answer 2

Three engine driven Permanent Magnet Generators (PMG) are the primary source of power for the flight control electronics. These power sources are independent from the main airplane electrical system, and are also independent from each other.

Question 3

Name the three types of voltage utilised

Answer 3

235 Vac
28v DC
115vAC

Question 4

List the large motor loads that the motor controllers convert power for

Answer 4

Hydraulic Pumps
Cabin Air Compressors
Ram Fans
Engine/ APU start
Centre Tank Fuel pumps
Nitrogen Generation System

Question 5

Name the Seven modes of Electrical Operation

Answer 5

Towing Power Mode
On ground Battery Only Mode
Ground Handling Mode
Ground Service Mode
External Power on Mode
In Air RAT Only Mode (Standby Power)
In Air Battery Only Mode (Standby Power)