Airframe Electrical Systems Flashcards
A clipping diode may be installed across the coil of the master relay to eliminate _________
that could damage sensitive electronic components.
Voltage spikes
The term _______ is often used to define a heavy current solenoid, such as the one used to energize the starter.
Contractor
An electrical schematic diagram shows the
________ of all the electrical components and associated wiring in a particular system.
Relationship
In any generator, current will flow whenever there is ________ motion between the wire coil and themagnetic field.
Relative
The strength of the induced current depends on the _______ of the magnetic field and the ______ at which the lines of flux are cut.
Strength , speed
What does each of the three digits represent in the left-hand rule for generators?
A. First finger ____________
B. Middle finger __________
C. Thumb ________________
A. Direction of magnetic flux (north to south)
B. Direction of induced EMF ( voltage)
C. Direction conductor moves through the magnetic field
The coil of wire in a generator where the current is enduced is called the _________.
Armature
The device that converts the AC current produced in the armature into DC current is called the ___________.
Commutator
Current is transferred from the rotating commutator to stationary __________.
Brushes
The principle parts of a small aircraft DC generator are the:
A._____________
B._____________
C._____________
D._____________
A. Field frame
B. Armature
C. Commutator
D. Brushes assembly
The field frame of a generator has two primary functions. They are to:
A. ___________
B. ___________
A. Complete the magnet circuit
B. Provide mechanical support for the other parts
The magnetizing force inside a generator is produced by an electromagnet called a ________ coil and a core called the ________ ________ or ________.
Field, field posts, shoes
Each brush is connected to the external circuit by a flexible braided-copper ________.
Pigtail
Brushes are made of high-grade ________ to prevent undue wear on the _________ yet still have a reasonable service life.
Carbon , commutator
Generators may be constructed in one of three ways. They may be:
A. _________ wound.
B. _________ wound.
C. _________ wound.
A. Series
B. Shunt
C. Compound
_________ wound generators are not used in aircraft because of poor voltage regulation characteristics.
Series
Compound-wound generators combine features of both series and shunt wound generators and may be one of three types: ______ compounded, _______ compounded or ______ compounded.
Flat , under , over
The distortion of the magnetic field between the generator poles caused by the magnetic field created by the armature current is called _______ _______.
Armature reaction
The position where the plane of two opposite coils is perpendicular to the magnetic field of the generator is called the ________ plane.
Neutral
Some generators use __________ to counter the effect of armature reaction.
Interpoles
The speed at which a generator begins to produce its rated voltage is called the _______-_______ speed and is usually about _______ rpm.
Comin-in , 1500
Varying the ______ current controls generator output.
Field
The three relays contained in a three-unit voltage regulator are:
A. ____________
B. ____________
C. ____________
A. Current limiter
B. Reverse current cutout or relay
C. Voltage regulator
DC generators emply a _______ _______ relay between the generator output terminal and the bus to prevent the battery from discharging through the generator.
Reverse current
Residual magnetism may be restored to a generator by ________ the field.
Flashing
A variety of test can be performed on DC generator and motor armatures with a specially designed test unit called a __________.
Growler
Large aircraft use AC alternators because the can produce a ________ amount of power and are _______ in weight.
Large , light
The principle difference between a DC generator and a DC alternator is that the magnetic field is _________ in a generator and ________ in an alternator.
Stationary , moving
The alternating current produced in a DC alternator is changed into direct current with a ________ rectifier.
Solid state
The principle parts of an alternator are the: A. \_\_\_\_\_\_\_\_\_\_ B. \_\_\_\_\_\_\_\_\_\_ C. \_\_\_\_\_\_\_\_\_\_ D. \_\_\_\_\_\_\_\_\_\_
A. Rotor
B. Stator
C. Solid state rectifier
D. Brush assembly
Carbon brushes, riding on smooth _______ _______ carry the field current from the voltage regulator to the alternator rotor.
Slip rings
Solid-state voltage regulators are usually ________ if they fail.
Replaced
A reverse-current cutout relay ________ necessary with a DC alternator.
Is not
A ________ phase alternator is used for almost all aircraft applications.
Three
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.
Y , delta
Modern jet aircraft typically use an _______ cooled ________ alternator.
Air , brushless
On jet aircraft a _______ _______ _______ unit is used between the engine and the alternator to assure a constant frequency output.
Constant speed drive
Alternators used on large aircraft generally supply ______ hertz, _____ phase alternating current.
400 , 3
