From iFlipr
Flexible metal conduit and liquidtight flex must besupported at intervals not to exceed
4 1/2 feet and within1 2 inches on each side of every outlet box or fitting.
Tasking, estimating and reporting are always done in X hour mandays, regardless of the length of the workday.
8
Which of the following ABFC series provides the facility code for an electrical power plant?
800
Block Diagram
A block diagram is a simple drawing showing the relationships of major parts of a wiring circuit or system.
What does NAVFAC P-437 Volume 1 contain?
Contains reporducible engineering drawings organized in three parts, Part1 Componet; Part 2 Facility Drawings and netwrorks; Part 3 Assembly drawings
Early Start + Duration =
Early Finish
Armature types used in DC generators
Gramme-ring and drum type(used in most applications)
Late Finish - Duration =
Late Start
What Facilities Planning Guide gives you planning information, such as crew size, man-hours, land area, and fuel?
NAVFAC P-437, Vol. II
Which of the following publications is a detailed, itemized line-item print out of the material in each ABFC?
OPNAV 41P3B
Which of the following publications ist he basic document that identifies the structures and supporting utilities of the ABFC system?
P-437
Connection Diagram
The connection diagram shows all the internal and external connections. The circuitry can be traced more easily than on the wiring diagram.
ROTOR CONSTRUCTION
The salient-pole rotor is used in slower speed alternators. The turbine driven-type is wound in a manner to allow high-speed use without flying apart.
Schematic Diagram
The schematic or elementary diagram isa drawing that shows the electrical connections and functions of a specific circuit arrangement.
Wiring Diagram
The wiring diagram is almost a picture drawing. Its hows the wiring between components and the relative position of the components.
What are Construction Activities?
They are master activities are further broken down into construction activities. generally less than fifteen days in duration and require the same resources through the entire duration.
Grounding conductor means
conductor used in connecting equipment in the circuit of a wiring system to a grounding electrode or electrodes.
Grounded means,
connected to the earth or to some other conducting body that serves in place of the earth
ELEMENTARY GENERATOR
consists of a single coil rotated in a magnetic field. It produces an ac voltage.
TWO-PHASE ALTERNATOR
consists of two phases whose windings are so placed around the stator that the voltages generated in them are 90º out of phase.
SINGLE-PHASE ALTERNATOR
has an armature that consists of a number of windings placed symmetrically around the stator and connected in series.
COMPOUND-WOUND DC GENERATORS
have both series field windings and shunt field windings. These generators combine the characteristics of series and shunt generators. The output voltage remains relatively constant for all values of load current within the design of the generator. Compound generators are used in many applications because of the relatively constant voltage.
SHUNT-WOUND DC GENERATORS
have field windings and armature windings connected inparallel (shunt). The output varies inversely with load current.
SELF-EXCITED GENERATORS
have field windings and armature windings connected inseries. Outputs vary directly with load currents. Series-wound generators have few practical applications
MOTOR REVERSAL
in a dc motor can be accomplished by reversing the field connections or by reversing the armature connections.
VOLTAGE CONTROL
in alternators is accomplished by varying the current in the field windings,much as in dc generators.
Grounded conductor means,
is a circuitconductor that is intentionally grounded
Motor reaction
is caused by the magnetic field that is set up in the armature. It tends to oppose the rotation of the armature, due to the attraction and repulsion forces between the armature field and the main field.
SLIP
is the difference between actual rotor speed and the synchronous speed in induction motors. Slip must exist for there to be torque at the rotor shaft.
Commutation
is the process used to get direct current from a generator
Multipole Generator
is the result of adding more field poles to a dc generator. They have much the same effect as adding coils to the armature. In practical generators, the poles are electromagnets.
SYNCHRONOUS SPEED
is the speed of stator field rotation. It is determined by the number of poles and the frequency of the input voltage. Thus, for a given motor, synchronous speed is constant.
Field Excitation
is the voltage applied to the main field windings. The current in the field coils determines the strength and the direction of the magnetic field.
COMPOUND MOTORS
one set of field windings is connected in series with the armature, an done set is connected in parallel. The speed and torque characteristics are a combination of the desirable characteristics of both series and shunt motors.
SEPARATELY EXCITED GENERATORS
receive current for field coils from an outside source such, as a battery or another dc generator.
A Basic Dc Generator
results when you replace the slip rings of an elementary generatorwith a two-piece commutator, changing the output voltage to pulsating dc.
The relationship between poles, frequency, and synchronous speed is as follows:
rpm=120f/p
Magnetic induction
takes place when a conductor is moved in a magnetic field in such a way it cuts lines of flux lines, and voltage (emf) induced condutor
Armature Reaction
takes place when armature current causes the armature to become anelectromagnet. The armature field disturbs the field from the pole pieces. This results in a shift of theneutral plane in the direction of rotation.
VOLTAGE REGULATION
the change in output voltage of an alternator under varying load conditions.
Inductance is
the characteristic of an electrical conductor that OPPOSES CHANGE in CURRENT
SHUNT MOTORS
the field windings are connected in parallel (shunt) across the armature coil.The field strength is independent of the armature current. Shunt-motor speed varies only slightly with and changes in load, and the starting torque is less than that of other types of dc motors
SERIES MOTORS
the field windings are connected in series with the armature coil. The field strength varies with changes in armature current. When its speed is reduced by a load, the series motor develops greater torque. Its starting torque is greater than other types of dc motors. Its speed varies widely and between full-load and no-load. Unloaded operation of large machines is dangerous.
THREE-PHASE ALTERNATORS
the windings have voltages generated in them which are 120º out of phase. Three-phase alternators are most often used to generate ac power.
Isometric Diagram
used to show the electrical wiring system in multilevel buildings. Appliances sometimes have an isometric diagram glued to an access panel so that it may be referred to for a quick look at an entire wiring system.
MULTIPLE COIL ARMATURE
(adding coils to the armature) decreases the ripple voltage inthe output of a dc generator, and increases the output voltage.
Armature Losses
1. Copper losses are simply 12R (heat) losses caused by current flowing through the resistance ofthe armature windings.2. Eddy currents are induced in core material and cause heat.3. Hysteresis losses occur due to the rapidly changing magnetic fields in the armature, resulting inheat.
What is the minimum safe distance for working around an energized conductor less than 125,000 volts.
10 Feet
How long should the Embarkation Petty Officer will hold the duty and who gets assigned the position?
14 months and Senior First Class EO or CM
Minimum service drop for public streets and parking areas subject to truck traffic
18 feet.
When are tentative load plans submitted?
24 to 30 hours
What is the minimum safe distance for working around an energized conductor less than 250,000 volts.
25 Feet
The Construction Electrician Oriented Assemblies are grouped into which ofthe following numbered groupings?
30,000-39,999
ROTATING ARMATURE-ALTERNATOR
a loop rotating through a stationary magnetic fealties cutting action of the loop through the magnetic field generates ac in the loop. This ac is removed from the loop by means of slip rings and applied to an external load.
AMPLIDYNES
are dc generators that are designed to act as high-gain amplifiers.
AC SERIES MOTORS
are nearly identical to the dc series motors. Special construction techniques allow ac series motors to be used as UNIVERSAL MOTORS, operating on either ac or dc power.
EXCITER GENERATORS
are small dc generators built into alternators to provide excitation current to field windings. These dc generators are called exciters.
SYNCHRONOUS MOTORS
are specifically designed to maintain constant speed, with the rotor synchronous to the rotating field. Synchronous motors require modification (such as squirrel-cagewindings) to be self-starting.
INDUCTION MOTORS
are the most commonly used of all electric motors due to their simplicity and low cost. Induction motors may be single-phase or multiphase. They do not require electrical rotor connection. Split-phase motors with special starting windings, and shaded-pole motors, are types ofsingle-phase induction motors.
Compensating Windings and Interpoles
are used to counteract the effects or armature reaction. Supplied by armature current.
What are Master Activities?
careful review of the plans and specs, the job is broken downinto discreet activities