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2AX5X Volume 2 Chapter 2
2AX5X Volume 2 Chapter 2 Self-Test Questions
56
Aerospace Engineering
Not Applicable
07/02/2014

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Term
Define electricity.
Definition
A class of physical phenomena arising from the existence and interactions of electric charges.
Term
Of what particles are atoms composed?
Definition
Neutrons, protons, and electrons.
Term
List four examples of insulators.
Definition
Wood, rubber, plastic, and glass.
Term
List four examples of conductors.
Definition
Platinum, gold, copper, and silver.
Term
Where do you normally use semiconductors?
Definition
In solid-state devices.
Term
What is EMF?
Definition
Electromotive force: the electrical pressure that causes electrons to flow through the conductor.
Term
Define electrical current.
Definition
The movement of electrons through a conductor
Term
What factors affect the amount of resistance in a conductor?
Definition
The type of material used, temperature, size.
Term
What unit of measurement is used to express electrical power?
Definition
Watts.
Term
What is a simple definition of magnetism?
Definition
The ability of a substance to attract.
Term
How are artificial magnets classified?
Definition
Permanent or temporary
Term
What is permeability?
Definition
The ease of ability to conduct magnetic lines of force.
Term
What is residual magnetism?
Definition
The amount of magnetism that remains in a temporary magnet.
Term
How is magnetism induced in magnetic material?
Definition
Place in a magnetic field or bring it into contact with another magnet.
Term
Can magnetic lines of force be insulated?
Definition
No
Term
What are the three most commonly used shapes of magnets?
Definition
Bar, ring, and horseshoe
Term
How can a magnet be weakened?
Definition
Heating or excessive jarring
Term
Define flux.
Definition
A term for magnetic lines of force
Term
How is electromagnetism developed?
Definition
By current of electricity
Term
When current flows through a conductor, does a magnetic field exist?
Definition
Yes
Term
What must you know to apply the “left hand rule”?
Definition
The direction of the current flow.
Term
What rule do you use to determine the flux direction of a wire in a loop?
Definition
The left-hand rule
Term
How can an electromagnet’s field strength be increased?
Definition
By using a few turns of wire carrying a larger current or using many turns of wire carrying a small current.
Term
What is the purpose of a conductor?
Definition
Provide a path for electrons to flow with minimum resistance.
Term
Why are protective devices installed in aircraft electrical systems?
Definition
Protect against system overloads and shorts in a circuit.
Term
How much time must pass before resetting a trip-free type circuit breaker?
Definition
After a cooling–off period of approximately 1 minute.
Term
What is the purpose of a current limiter?
Definition
Provide protection against fault currents.
Term
What is the purpose of a resistor?
Definition
Control the amount of current flow in a circuit
Term
Why is alternating current used as the primary electrical power source in aircraft?
Definition
Less power is lost during transmission and the elimination of insulation and brushes.
Term
What is the unit of measurement for frequency?
Definition
Hertz
Term
Define phase relationship.
Definition
A condition in which two moving objects are changing in, or out, of step.
Term
What are the two classifications of AC generation systems?
Definition
Variable-frequency and constant-frequency.
Term
What frequency is used for AC power generation on aircraft?
Definition
400 hertz
Term
How is voltage induced in a brush-type generator?
Definition
DC from an integral exciter generator is passed through windings on the rotor.
Term
What are the three generators that make up a brushless AC generator?
Definition
A permanent magnet generator, an AC exciter generator, and the main AC generator.
Term
What weak point was eliminated by the design of a brushless-type generator?
Definition
Arcing (which more easily occurs in rarefied air).
Term
What are the two main components of an AC generator?
Definition
Rotor assembly and stator.
Term
What three components make up the stator?
Definition
PMG armature, exciter field, and main armature windings
Term
What are the two functions of the CSD governor system?
Definition
To control the drive output speed and equalize the load between generators operating in parallel.
Term
If CSD output rotation drives the generator below 365 Hz, what component removes the generator from the bus?
Definition
Underspeed switch.
Term
If the CSD temperature rises to an overheat condition, what should be done to prevent further damage?
Definition
Disconnect the CSD.
Term
What is installed on most IDGs to provide for easier installation and removal?
Definition
A quick attach-detach clamp
Term
What are the typical functions of a GCU?
Definition
Voltage regulation, frequency and load control, real and reactive load division, over/underexcitation protection, over/underfrequency protection, open phase protection, reverse power protection, differential current protection, engine underspeed protection, generator circuit breaker and bus tie breaker control, no- break power transfer, and generator disconnect control
Term
How is voltage regulation and current limiting accomplished in the GCU?
Definition
By varying the generator excitation field
Term
How does the frequency and load controller for each generator system regulate the frequency of the generator CSD?
Definition
By controlling the magnetic trim head governor on the CSD.
Term
What are the internal components of a battery?
Definition
Plates, separators, and electrolyte.
Term
What are the primary causes of premature failure of a lead-acid battery?
Definition
Abuse, overcharge, low solution, undercharge, and mountings.
Term
What is the fundamental unit of the nickel-cadmium battery?
Definition
The cell.
Term
How are nickel-cadmium cells constructed?
Definition
By inserting positive and negative plates in plastic cases with nylon and cellophane separators.
Term
When does a nickel-cadmium battery’s electrolyte reach its maximum level?
Definition
When the battery is fully charged.
Term
How are motors classified?
Definition
By voltage, current used (AC or DC), and methods of motor excitation.
Term
How can the direction of rotation for a series motor be changed?
Definition
By reversing the current flow in a field winding or reversing current flow in the armature.
Term
What advantage does the series motor have over other types of motors?
Definition
It operates on AC or DC excitation.
Term
How is the field winding of a shunt motor connected with the armature?
Definition
In parallel
Term
What type of  T-R is used to charge a nickel-cadmium battery in many aircraft?
Definition
Charging T-R.
Term
What is another name for a T-R?
Definition
Converter.
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