Airframe Electrical Systems

Question 1

A clipping diode may be installed across the coil of the master relay to eliminate _________
that could damage sensitive electronic components.

Answer 1

Voltage spikes

Question 2

The term _______ is often used to define a heavy current solenoid, such as the one used to energize the starter.

Answer 2

Contractor

Question 3

An electrical schematic diagram shows the

________ of all the electrical components and associated wiring in a particular system.

Answer 3

Relationship

Question 4

In any generator, current will flow whenever there is ________ motion between the wire coil and themagnetic field.

Answer 4

Relative

Question 5

The strength of the induced current depends on the _______ of the magnetic field and the ______ at which the lines of flux are cut.

Answer 5

Strength , speed

Question 6

What does each of the three digits represent in the left-hand rule for generators?

A. First finger ____________
B. Middle finger __________
C. Thumb ________________

Answer 6

A. Direction of magnetic flux (north to south)
B. Direction of induced EMF ( voltage)
C. Direction conductor moves through the magnetic field

Question 7

The coil of wire in a generator where the current is enduced is called the _________.

Answer 7

Armature

Question 8

The device that converts the AC current produced in the armature into DC current is called the ___________.

Answer 8

Commutator

Question 9

Current is transferred from the rotating commutator to stationary __________.

Answer 9

Brushes

Question 10

The principle parts of a small aircraft DC generator are the:

A._____________
B._____________
C._____________
D._____________

Answer 10

A. Field frame
B. Armature
C. Commutator
D. Brushes assembly

Question 11

The field frame of a generator has two primary functions. They are to:

A. ___________
B. ___________

Answer 11

A. Complete the magnet circuit

B. Provide mechanical support for the other parts

Question 12

The magnetizing force inside a generator is produced by an electromagnet called a ________ coil and a core called the ________ ________ or ________.

Answer 12

Field, field posts, shoes

Question 13

Each brush is connected to the external circuit by a flexible braided-copper ________.

Answer 13

Pigtail

Question 14

Brushes are made of high-grade ________ to prevent undue wear on the _________ yet still have a reasonable service life.

Answer 14

Carbon , commutator

Question 15

Generators may be constructed in one of three ways. They may be:

A. _________ wound.
B. _________ wound.
C. _________ wound.

Answer 15

A. Series
B. Shunt
C. Compound

Question 16

_________ wound generators are not used in aircraft because of poor voltage regulation characteristics.

Answer 16

Series

Question 17

Compound-wound generators combine features of both series and shunt wound generators and may be one of three types: ______ compounded, _______ compounded or ______ compounded.

Answer 17

Flat , under , over

Question 18

The distortion of the magnetic field between the generator poles caused by the magnetic field created by the armature current is called _______ _______.

Answer 18

Armature reaction

Question 19

The position where the plane of two opposite coils is perpendicular to the magnetic field of the generator is called the ________ plane.

Answer 19

Neutral

Question 20

Some generators use __________ to counter the effect of armature reaction.

Answer 20

Interpoles

Question 21

The speed at which a generator begins to produce its rated voltage is called the _______-_______ speed and is usually about _______ rpm.

Answer 21

Comin-in , 1500

Question 22

Varying the ______ current controls generator output.

Answer 22

Field

Question 23

The three relays contained in a three-unit voltage regulator are:

A. ____________
B. ____________
C. ____________

Answer 23

A. Current limiter
B. Reverse current cutout or relay
C. Voltage regulator

Question 24

DC generators emply a _______ _______ relay between the generator output terminal and the bus to prevent the battery from discharging through the generator.

Answer 24

Reverse current

Question 25

Residual magnetism may be restored to a generator by ________ the field.

Answer 25

Flashing

Question 26

A variety of test can be performed on DC generator and motor armatures with a specially designed test unit called a __________.

Answer 26

Growler

Question 27

Large aircraft use AC alternators because the can produce a ________ amount of power and are _______ in weight.

Answer 27

Large , light

Question 28

The principle difference between a DC generator and a DC alternator is that the magnetic field is _________ in a generator and ________ in an alternator.

Answer 28

Stationary , moving

Question 29

The alternating current produced in a DC alternator is changed into direct current with a ________ rectifier.

Answer 29

Solid state

Question 30

The principle parts of an alternator are the:
A. \_\_\_\_\_\_\_\_\_\_
B. \_\_\_\_\_\_\_\_\_\_
C. \_\_\_\_\_\_\_\_\_\_
D. \_\_\_\_\_\_\_\_\_\_

Answer 30

A. Rotor
B. Stator
C. Solid state rectifier
D. Brush assembly

Question 31

Carbon brushes, riding on smooth _______ _______ carry the field current from the voltage regulator to the alternator rotor.

Answer 31

Slip rings

Question 32

Solid-state voltage regulators are usually ________ if they fail.

Answer 32

Replaced

Question 33

A reverse-current cutout relay ________ necessary with a DC alternator.

Answer 33

Is not

Question 34

A ________ phase alternator is used for almost all aircraft applications.

Answer 34

Three

Question 35

If one lead from each winding of a three-phase alternator is connected to a common point, the stator is ____ connected and if the phases are connected end-to-end the stator is ________ connected.

Answer 35

Y , delta

Question 36

Modern jet aircraft typically use an _______ cooled ________ alternator.

Answer 36

Air , brushless

Question 37

On jet aircraft a _______ _______ _______ unit is used between the engine and the alternator to assure a constant frequency output.

Answer 37

Constant speed drive

Question 38

Alternators used on large aircraft generally supply ______ hertz, _____ phase alternating current.

Answer 38

400 , 3