Engine Electrical Systems

Question 1

Name the components of a basic magnetic circuit.

Answer 1

Permanent multi-pole rotating magnet, Soft Iron Core, Pole Shoes

Question 2

How would you seat newly installed generator brushes to the commutator?

Answer 2

Remove Cover, Remove Brushes, Install Sandpaper, Install new Brushes, Rotate Generator, Remove Brushes, Remove Sandpaper, Blow out Generator, Install new Brushes, Install Cover

Question 3

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

Answer 3

Once they reach half their original length

Question 4

Where is the generator rating and performance data located?

Answer 4

On the generator data plate

Question 5

What units make 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 alternator?

Answer 6

Voltage Regulator

Question 7

What determines the frequency of the voltage of an alternator?

Answer 7

Rotation speed of the rotor and number of poles

Question 8

How is alternator frequency maintained?

Answer 8

Installing a constant speed drive (CSD) unit between the engine and alternator

Question 9

What are the three basic types of DC motors?

Answer 9

Series, Shunt, Compound

Question 10

Name the parts of a DC motor.

Answer 10

Armature, Brushes, Commutator, Field Frame

Question 11

Why is the starter-generator system used on many turbine engines?

Answer 11

Save space and weight

Question 12

Why should stranded wire be used in powerplant applications?

Answer 12

Less likely to fatigue and break from vibrations

Question 13

What is the American Wire Gauge (AWG) system of designating electrical wire size?

Answer 13

A gauge number is assigned to the wire according to its cross-sectional area

Question 14

What is opening wiring? (not an open circuit)

Answer 14

Any wire, wire group, or wire bundle not enclosed in conduit

Question 15

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

Answer 15

Vibrating type voltage, three-unit, and carbon-pile regulators

Question 16

What aircraft electrical system normally does not have a fuse or circuit breaker?

Answer 16

Starter circuit

Question 17

Why are protective covers placed on some electrical switches?

Answer 17

To prevent the switch from accidentally being actuated

Question 18

What are the causes of excessive arcing at the generator brushes?

Answer 18

Dirty, rough or out of round commutator and brushes that are worn, binding or low tension

Question 19

When installing single wires or wire bundles, how much slack is normally allowed between supports?

Answer 19

Not to exceed 0.5 inches

Question 20

What precaution should be taken when running wires close to heating ducts or exhaust stacks?

Answer 20

Wires should be insulated with a high temperature resistant material

Question 21

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

Answer 21

That power is being produced

Question 22

Why are multiple generator systems paralleled?

Answer 22

To ensure that each generator shares the load

Question 23

What DC alternator component prevents battery reverse current flow into the armature?

Answer 23

Rectifier

Question 24

How many phases are used in most aircraft AC alternator systems?

Answer 24

Three

Question 25

Name some methods that are used to maintain 400 Hertz alternator output frequency on large turbo jet/turbo fan engines.

Answer 25

Constant speed drives, integrated drive generators, variable speed constant frequency power systems

Question 26

What are the components of a direct cranking electric starter system?

Answer 26

Electric Motor, Reduction Gears, Automatic engaging and disengaging mechanism

Question 27

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

Answer 27

A series wound motor

Question 28

Why is a series wound motor commonly used as an aircraft engine starter?

Answer 28

It has high starting torque under heavy load conditions