Engine Electrical System

Question 1

Name the component of basic magnetic circuit

Answer 1

Permanent rotating magnetic , soft iron core , pole shoes

Question 2

How would seat a newly installed generator brushes to the commutator

Answer 2

Use fine grain sandpaper place around the commutator with he sanding surface facing outward . Turn the armature in normal direction of rotation until the face of the brushes is properly contour. Remove the sandpaper and blow out any residue with compress air

1. Remove cover
2. Remove bushes.
3. Install sandpaper
4. Install new brushes
5. Rotate generator
   6.remove bushes
6. Remove sand paper
   8.blow out generator
7. Install new brushes
8. Install cover

Question 3

When is it necessary to replace the brushes in a starter ?

Answer 3

When is half of their original length

Question 4

Where is the generator racing and performance data located

Answer 4

On the data plate attached to the generator

Question 5

What unite makes up a dc generator three unit regulator

Answer 5

Voltage regulator, current limiter and reverse current cutout

Question 6

What method is used to control the voltage of an aircraft generator

Answer 6

Voltage regulator

Question 7

What determines the frequency of the voltage of alternotor

Answer 7

Depends on the speed of rotation of the rotor and and the number of poles

Question 8

How is alternator frequency maintained

Answer 8

Using constant speed drive unit between the engine and the alternator

Question 9

What are the three basic type of dc motor

Answer 9

Series , shunt , and compound motor

Question 10

Name of the parts of dc motor

Answer 10

Armature , brushes commutator and field frame ( ABC-F)

Question 11

Why is a starter generator system, used on many turbine engines

Answer 11

Save space and weight . Operates as a starter motor during engine starting. When engine reach it self accelerating speed it become a generator which supplies ac power for aircraft system

Question 12

Why should stranded wire be used in powerplant application

Answer 12

Less likely to fatigue and break from vibration

Question 13

What is American wire gauge system of designating electrical wire size

Answer 13

Number is assign to wire according to it cross- sectional area . The smaller the gauge number the larger the wire

Question 14

What is open wiring

Answer 14

Any wire , wire group, wire bundle that’s not enclosed in conduits

Question 15

What methods are used to control the voltage output of a DC aircraft generator?

Answer 15

Vibrating type voltage regulator, three unit, and Carbon pile

Question 16

What aircraft electrical system normally doesn’t have a fuse or circuit breaker

Answer 16

Starter circuit

Question 17

What are the causes of excessive arcing at the generator brushes

Answer 17

Commutator is dirty, rough or out around , worn or binding of brushes and low spring tension

Question 18

Why are protective cover place on some electrical switches?

Answer 18

To prevent switch from accidentally being actuated

Question 19

When install a single wire wire bundle, whole bunch like it’s normally allowed between the suppor

Answer 19

Should normally not exceed .5”

Question 20

What precaution should be take when running wires close to heating duct or exhaust stack

Answer 20

Insulated with high temperature resistant material

Question 21

What is the indication on the amp meter when the engine is running and the AC generator is producing power

Answer 21

The power is being produced

Question 22

Why are multi generator systems paralleled

Answer 22

To ensure generator shares the load

Question 23

What DC alternator component Prevents battery reverse current flow into the Armature

Answer 23

The rectifier

Question 24

How many phases are using most aircraft AC alternator systems

Answer 24

Three phase

Question 25

Name some of the methods that are used to maintain 400 Hz alternator output frequency on a large turbojet/turbofan engine

Answer 25

CSD, IDG, and variable speed constant frequency power system

Question 26

What are the components of direct cranking electric starter system

Answer 26

Electrical, motor, reduction gear, and automatic engaging and disengaging mechanism

Question 27

What type of DC motor is commonly used for an aircraft engine starter

Answer 27

Series wound motor

Question 28

Why is series wound motor commonly used as on aircraft engine starter

Answer 28

It has high starting torque under heavy load condition