Ultimate Industrial Electrical
Which frequency is a harmonic of 60 Hz? 10 Hz 30 Hz 90 Hz 180 Hz
180 Hz
If a transformer's primary winding has 200 turns and the secondary winding has 600 turns, the turns ratio is ____. 1:4 4:1 1:3 3:1
1:3
The starting torque of a shunt motor is about ____ times the full-load torque. 1.75 2.00 2.75 3.00
2.75
What is the approximate percentage of light reflected by a black colored surface? 3 percent 10 percent 50 percent 80 percent
3 percent
The effect of a harmonic on the current flowing in the supply conductors is approximately ____ percent. 10 3 to 5 40 to 50 90
3 to 5
What is the correct way to write the number 3,404,655 using scientific notation? 3.404655 x 10⁶ 34.04655 x 10⁷ 3.404655 x 10³ 3.404655 x 10⁻⁶
3.404655 x 10⁶
It has been proven that currents as small as ____ milliamperes through the heart, lungs, or brain can be fatal. 15 50 5 25
50
A common design practice is to allow a circuit breaker to carry only ____ percent of its continuous current rating. 60 70 80 90
80
A correction factor is used for the ampacity of conductors in installations where the operating temperature is above ____ degrees Fahrenheit. 32 68 86 100
86
The effect of a harmonic on the current flowing in the neutral conductor is approximately ____ percent. 10 3 to 5 40 to 50 90
90
What is the temperature rating for conductors enclosed in nonmetallic-sheathed cable? 70 degrees Celsius 80 degrees Celsius 90 degrees Celsius 100 degrees Celsius
90 degrees Celsius
The efficiency of a transformer may be as high as ____ percent. 85 90 99 100
99
What purpose does brush-shifting accomplish in a motor? Adjusts the rotor speed Compensates for hysteresis Changes the frequency Allows it to operate on AC or DC
Adjusts the rotor speed
Which NEC Article covers grounding locations and methods? Article 79 Article 220 Article 250 Article 429
Article 250
Heat energy can be measured in ____. degrees Celsius British thermal units ohms watts
British thermal units
____ connect the commutator to the load conductors. Brushes Alternators Laminations Yokes
Brushes
____ fuses are the type most commonly used in industrial installations. Plug Two-way Replaceable Cartridge
Cartridge
____ windings eliminate armature reaction. Compensating Conducting Alternating Brushless
Compensating
____ are similar to the electric furnace, but instead of having all the elements in one location, they are installed in the ducts for each specific area. Electric heating cables Convection heaters Baseboard heaters Duct heaters
Duct heaters
A generator's coils produce the most voltage when they move parallel to the magnetic lines of force. True False
False
A good commutator will have a very dark brown film of oxide. True False
False
A light intensity curve can be used to show that the amount of illumination is independent of the angle from the source. True False
False
A loop distribution system is an electrical transmission system that begins at a central station and supplies power to various substations. True False
False
Another name for metal-clad cable is Romex. True False
False
Armored cable has a flexible metallic enclosure. True False
False
Because the armature of a DC motor is wound in much the same way as a DC generator, the current from the supply must divide and flow through three or more paths. True False
False
Conduction heating is a method by which heat is transferred through the air or a fluid. True False
False
Conduit bodies are used in a conduit system to allow access for the pulling of wires, contain splices, and allow for the mounting of devices (e.g., switches, receptacles, etc.). True False
False
Direct current is less expensive to produce and transmit than alternating current. True False
False
Mirrored glass reflects 99 percent of the light that strikes it. True False
False
Most residential installation circuits are protected against overcurrent by 25-ampere or larger fuses or circuit breakers. True False
False
One advantage of the wound-rotor induction motor compared to the squirrel-cage motor is that it has lower initial cost and maintenance costs. True False
False
One of the rules for residential wiring is to install a 200-ampere, three-wire or larger service for a single-family dwelling. True False
False
Scientific notation uses increments of 1000 as well as word abbreviations to make large and small numbers less confusing. True False
False
Small transformers, such as those used for doorbell and signal circuits, are usually very efficient. True False
False
The nucleus of an atom is made up of protons, which have a positive charge and neutrons, which have a negative charge. True False
False
The phase sequence describes the order in which the currents follow one another. True False
False
The primary goal of the NFPA is "to promote the science and improve the methods of electrical wiring." True False
False
The purpose of grounding is to limit the magnitude of current surges. True False
False
The resistance of a wire is inversely proportional to its length. True False
False
The standard frequency for power distribution in the U.S. is 120 Hz. True False
False
The stationary part of the generator is called the rotor. True False
False
The two main components of an induction motor are the stator and the conductor. True False
False
There is one accepted symbol for a fuse. True False
False
To provide a comfortable area, it is recommended to maintain a temperature of 68 degrees Fahrenheit (20 degrees Celsius) with a relative humidity of 15 percent. True False
False
Two basic types of windings are in general use for DC generator armatures: the lap winding and the parallel winding. True False
False
When transformers are constructed, the windings are often placed on separate legs to minimize flux leakage. True False
False
When using a knife to remove insulation from a conductor, the insulation should be cut at a right angle to the conductor. True False
False
Which type of ground-fault protection is generally used for three-wire, single-phase, and for three-phase installations? GFP GFCI fuse circuit breaker
GFP
What does the abbreviation GFP stand for? Ground-Field Protector Ground-Fire Prevention Ground-Fault Protector Ground-Flux Prevention
Ground-Fault Protector
____ heating is used for metal treatment and in some electric furnaces. Induction Resistance Arc Dielectric
Induction
____ heating is used for drying operations, food warming, and medical purposes. Resistance Arc Induction Infrared
Infrared
____ may be installed in a substation unit. Branch circuit conductors Isolation switches Main supply conductors Utility poles
Isolation switches
___ is the voltage drop caused by current flowing though the resistance of the wires. Power drop Wire drop Line loss Line drop
Line drop
Which type of cable is color coded for easy conductor size identification? USE cable NM cable MC cable AC cable
NM cable
NFPA 79 Electrical Standard for Industrial Machinery is a publication of the ____. Armored Cable Code National Electrician's Association National Electrical Code National Fire Protection Association
National Fire Protection Association
In a delta-connected alternator, the line voltage is equal to ____ times the phase voltage. 1.0 1.25 1.73 2.0
1.0
In a wye-connected alternator, the line voltage is equal to ____ times the phase voltage. 1.0 1.25 1.73 2.
1.73
____ utilizes the fact that current flowing through a material produces heat. Dielectric heating Resistance heating Induction heating Convection heating
Resistance heating
What is one factor that affects the output voltage of an alternator? Resistance of the stator windings The frequency of the emf produced The type of coil connection The phase sequence
Resistance of the stator windings
____ lighting fixtures transmit 60 percent to 90 percent of the light upward. Indirect Semi-direct Semi-indirect General diffusing
Semi-indirect
____ motors are designed to be used for jobs requiring minimum torque. Series Brushless DC Stepping Permanent magnet
Stepping
What instrument is used to determine whether the frequency of an alternator to be brought on line matches the frequency of the bus? Phase sequence meter Prime mover Period meter Synchroscope
Synchroscope
With direct drive, the driving machine and the driven machine may be mounted on the same shaft, or a(n) ____ may be used. reducer pulley shaft coupling gear shaft
shaft coupling
Electrons orbit the nucleus of an atom in arranged rings called ____ . spheres ovals shells capsules
shells
A(n) ____ is a place in the wiring system where conductors of opposite polarity make contact. grounded conductor fuse short circuit circuit breaker
short circuit
A(n) ____ generator is a type of self-excited generator in which the field and armature are connected in parallel. parallel compound shunt series
shunt
What type of electrical drawing is most often used to trace the flow of power through the drawing? pictorial diagram single-line drawing architectural drawing ladder diagram
single-line drawing
Which of these is one of the three common styles of switches used to control lights? single-pole double-pole two-way grounded
single-pole
The difference between the synchronous speed and the rotor speed is called the ____ of the rotor. differential frequency phase difference slip
slip
In a parallel circuit, the total circuit resistance will be ____ the smallest branch resistance. smaller than larger than equal to greater than or equal to
smaller than
A glow switch is also called a(n) ____. preheat energy saver heater starter
starter
If a transformer has a ratio of 10 to 1 (10:1), it is being used as a ____ transformer. step-up step-down buck-boost tapped
step-down
If a transformer increases the voltage, it is called a ____ transformer. step-up step-down buck-boost tapped
step-up
In a radial distribution system, the central station supplies power to the various ____. substations loops residential units industrial installations
substations
In a combination circuit, the ____ of all individual wattages will equal the total circuit wattage. sum difference product ratio
sum
Rigid metal conduit has a(n) ____ raceway of circular cross-section. threadable smooth insulated flexible
threadable
A ____ overcurrent device is a fuse or circuit breaker that opens the circuit much more quickly than the ordinary device does. two three four five
three
There are ____ general types of circuit breakers. two three four five
three
Electrical power, in watts, can be expressed as the product of current, in amperes and electrical pressure, in volts. True False
true
Power is a measurement of the rate of doing work. True False
true
Fuses and circuit breakers have ____ current ratings. two three four five
two
The operation of a motor depends upon the interaction between ____ magnetic fields. two three four six
two
How many paths for current flow are in a parallel circuit? zero one only one or two two or more
two or more
If the ungrounded (hot) conductor comes in contact with a metal enclosure that is not grounded, a ____ will be present between the enclosure and the ground. current voltage resistance reactance
voltage
A generator that maintains a nearly constant output voltage from no load to full load has excellent ____. voltage control voltage regulation efficiency responsiveness
voltage regulation
Arc heating is used in ____. space heating cooking welding medical applications
welding
What is the most frequently used publication of the National Fire Protection Association? The U.S. Electrical Specifications The National Electrical Code The Life Safety Code The Handbook for Electrical Safety in the Workplace
The National Electrical Code
A circuit must contain a minimum of three different elements: a power source, a complete path for current flow, and a load. True False
True
A commutator is a type of rotating switch that changes the connections to the load circuit at the same instant as the emf reverses in the armature. True False
True
A demand factor is the ratio of the maximum load used at any one time to the total connected load. True False
True
A digital multimeter can measure voltage, current, and resistance. True False
True
A ground-fault circuit interrupter is a device that senses a small imbalance of current between the ungrounded (hot) conductor and the grounded (neutral) conductor. True False
True
A megohmmeter can be used to conduct resistance tests to ground.
True
A transformer's audible hum is a result of the laminations and windings vibrating as the magnetic field alternates. True False
True
According to the electron theory of magnetism, electrons produce a magnetic field as they spin. True False
True
Atoms that have from one to four electrons in their last, or outer, shell are generally good conductors of electricity. True False
True
Candlepower and lumens are units of measurement of light emitted from a source. True False
True
Electrical energy is the product of power and time. True False
True
Heat radiation is accomplished when the heat rays are transmitted through space. True False
True
In a brushless DC motor, a special circuit is used to perform the commutation of the applied DC. True False
True
In a schematic diagram, the load is typically located at the bottom or right side of the drawing. True False
True
In a series circuit, the current is the same value throughout the entire circuit. True False
True
In resistance baseboard heating, both conduction and natural convection occur, along with a small amount of radiation. True False
True
In some types of DC motor arrangements, a flywheel assists the motor in driving the load. True False
True
Large industrial establishments may find it more economical to distribute power at voltages higher than 600 volts. True False
True
Line loss is power dissipated as heat. True False
True
Many electrical codes have been developed on the state, local, and national levels. True False
True
Most single-phase systems are supplied from a three-phase primary. True False
True
On the three-phase motor, the windings are arranged to produce a rotating magnetic field when connected to a three-phase source. True False
True
One type of luminaire is indirect. True False
True
Rubber and glass are good insulators. True False
True
Switch symbols are sometimes combined so that a more complex switch can be represented. True False
True
The GFCI operates on the principle that an equal amount of current is flowing through the two wires. True False
True
The coils of an air core transformer are wound on forms made of nonconducting materials. True False
True
The heat pump operates on a principle similar to a refrigerator. True False
True
The induction motor is the most common type of AC motor. True False
True
The rotating field of a large alternator receives its energy from the DC exciter, through slip rings. True False
True
The speed of the rotor of an induction motor depends upon the synchronous speed and the load it must drive. True False
True
The three classes of magnets are natural, artificial, and electromagnets. True False
True
The type of material from which the core is made affects the efficiency of the transformer. True False
True
The wye connection, sometimes called a star connection, is a method of connecting coils together inside the alternator. True False
True
When calculating the load, it is common practice to start with the branch circuits and combine their loads at each panel. True False
True
When considering multiple light sources, the amount of illumination at a given point is the sum of the light rays coming from all the units. True False
True
When magnetism is used to produce electricity, it makes no difference whether the conductor moves through the field or the magnetic field moves across the conductor. True False
True
When using a megohmmeter, an important safety precaution is not to touch the test leads during the measurement.
True
Which type of service entrance cable is identified for underground use? Type USE Type SE Type TL Type UL
Type USE
Underground feeder and branch-circuit cable is known as Type ____ cable. BC UFBC UC UF
UF
A voltage tester is also referred to as a(n) ____. O'scope Megger Meggy Wiggy
Wiggy
A luminaire is _____. a complete lighting unit a method of lighting the power source for a lighting unit the lamp portion of a lighting unit
a complete lighting unit
Arcing at the brushes may be the result of _____ improper voltage a dirty commutator loose parts a dirty lubricant
a dirty commutator
Overheated bearings may be the result of _____. improper voltage a dirty commutator loose parts a dirty lubricant
a dirty lubricant
A(n) ____ is a type of rotating switch stator prony brake armature commutator
commutator
In a balanced three-phase system, the power factor is the____ of the angle between the phase current and the phase voltage. sine cosine tangent hypotenuse
cosine
A ____ overcurrent device is a fuse or circuit breaker that opens the circuit much more quickly than the ordinary device does. current-limiting voltage-limiting fast-acting grounding
current-limiting
The amount of current flowing through a circuit is ____ proportional to the electromotive force (voltage) and ____ proportional to the resistance of the circuit. directly; inversely inversely; directly directly; directly inversely; inversely
directly; inversely
Another name for a rotary converter is a(n) _____ dynamotor multiphase alternator dynamometer alternator
dynamometer
The heat from a(n) _____ is transmitted primarily by radiation. electric baseboard heater heat pump electric furnace electric heating cable
electric heating cable
To prevent the possibility of unwanted load shifting when connecting compound generators in parallel, connect the series field of each machine to a common ____. neutral plane alternating bus equivalent circuit equalizer bus
equalizer bus
What does FMC stand for? flexible metal connectors fireproof mechanical connectors flexible metal conduit fittings made for conduit bodies
flexible metal conduit
The most common type of electric discharge lamp is the ____ lamp. incandescent high energy discharge fluorescent commercial
fluorescent
What unit of measurement is used to measure the amount of illumination on a surface? lumen candlepower watt foot-candle
foot-candle
When using the right hand rule for a motor, the thumb points in the direction of the ____. current field force lines of magnetic flux
force
An electrostatic generator develops a voltage using ____. induction chemicals friction light
friction
When lighting is so bright that it causes eye discomfort, it is said to produce ____. vapor glare intensity absorbed light
glare
The NEC applies to ____. automobiles ships aircraft government buildings
government buildings
In which section of an oscilloscope is the variable sec/div control found? horizontal section vertical section display section trigger section
horizontal section
Time is measured ____ on the oscilloscope graticule. vertically horizontally diagonally in three dimensions
horizontally
To replace lost moisture in the air, a(n) ____ may be used. induction fan exhaust fan humidifier dehumidifier
humidifier
The molecular motion caused by the magnetizing and demagnetizing of a transformer's core results in friction which produces heat. This heat loss plus the power loss caused by the magnetic lag is called the ____ loss. phase copper friction hysteresis
hysteresis
For pure metals such as silver, copper and aluminum, the resistance of a conductor ____ as the temperature increases. increases decreases remains unchanged changes only slightly
increases
Air core transformers are ____. efficient inefficient as efficient as iron/steel core transformers about 30 percent efficient
inefficient
Which law is used to calculate the intensity of light at a given distance from a source? square law inverse square law proportional law spherical law
inverse square law
Transformers used for power distribution are wound on cores made of ____. iron or steel nonconducting materials aluminum antimony
iron or steel
The ____ method for synchronizing alternators is generally used only for small operations or for laboratory experiments. phase sequence frequency meter lamp dark lamp dim
lamp dark
A(n) ____ winding is used to obtain high current capacity. wave lap parallel alternating
lap
At times, lights are controlled by ____ switches and relays. low-voltage inductive high-voltage four-pol
low-voltage
One method of transformer construction is to build up thin, flat sections called ____. intertwined coils pancake coils nested coils laminated coils
pancake coils
Single-phase, ____ motors are started by means of a low-resistance short-circuited coil placed around one tip of each pole.
permanent capacitor reversing resistance shaded-pole
One method of making a single-phase motor self-starting is to apply the ____ principle. phase-splitting current-splitting voltage-splitting resistance-splitting
phase-splitting
A(n) ____ diagram shows the relative physical location of the components, wires, and termination points. schematic ladder pictorial architectural
pictorial
What is one method of cooling a transformer? place in a tank of refrigerant place in an air-conditioned room place in a tank of water place in a tank of oil
place in a tank of oil
What is the most common insulating material used on conductors? copper silk aluminum plastic
plastic
A(n) ____ motor is an AC motor in which the rotor revolves at the same speed as the rotating magnetic field. high-frequency multispeed squirrel-cage polyphase synchronous adjustable-speed induction
polyphase synchronous
An instrument designed to measure torque is called a ____. rotational force meter torquometer torque wrench prony brake
prony brake
If two conductors carrying current in the same direction are placed near each other, the magnetic forces tend to ____. push them apart pull them together have no effect cancel each other out
pull them together
The ____ motor is a single-phase motor that starts based on the principle that like poles repel. universal repulsion-start, induction-run torque reversing split-phase
repulsion-start, induction-run
Which term applies to magnetism that remains in a material after being removed from the magnetizing influence? residual magnetism retentivity permeability magnetic saturation
residual magnetism
Opposition to the flow of electrons is called _____. voltage inductance conductance resistance
resistance
The amount of heat generated by current flowing through a conductor depends on the current value and the conductor's ____. length area resistance inductance
resistance
Which term describes the ability of a material to retain its magnetism after being removed from the magnetizing influence? residual magnetism retentivity permeability magnetic saturation
retentivity
To reverse the direction of rotation of the rotor, you would ____. reverse the polarity of one of the fields reverse the polarity of both of the fields increase the operating frequency attach a permanent capacitor
reverse the polarity of one of the fields
For a baseboard resistance heater, the ____ functions as the operating control. room thermostat humidistat safety control furnace
room thermostat
Frequency is calculated by taking the number of field poles on the alternator, multiplying by ____, and then dividing their product by 120. resistance of the stator windings in ohms winding current in amperes rotor speed in rpm field strength in volts
rotor speed in rpm
In a(n) ____ generator, the magnetization current for the field coils is supplied from a source outside of the generator. This supply may be another DC generator, batteries, or a rectifier. self excited separately excited shunt externally excited
separately excited
A ____ motor has a very high starting torque. series shunt combination permanent magnet
series
In the past, ____ generators were used extensively for series arc lighting, particularly for street lighting. parallel compound shunt series
series
To convert circular mils to circular millimeters, divide circular mils by ____. 10 25.4 1550 2550
1550
How much power is dissipated by an electric oven if 30 A flows through a resistance of 10 ohms? 9.2 W 7.52 kW 9 kW 9000 kW
9 kW
Electrical drawings are typically drawn with all components energized. True False
False
Flexible cords and cables are sufficient for the fixed wiring of a building. True False
False
In a circuit with light bulbs connected in parallel, if one light bulb burns out, all of the light bulbs will fail to light. True False
False
One of the rules for electric charges is that the strength of the attraction or repulsion between charged objects is directly proportional to the distance between them. True False
False
A feeder circuit consists of the conductors between the service equipment and the final branch-circuit overcurrent device. True False
True
Alternating current flows first in one direction and then in the opposite direction. True False
True
Because all materials have some ability to conduct magnetic lines of force, it is not practical to make a magnetic insulator. True False
True
Electrical symbols are a way to convey meaning while conserving space on a drawing. True False
True
The clamp-on ammeter can be used to measure both large and small amounts of current.
True
The total resistance of a parallel circuit is equal to the reciprocal of the sum of the reciprocals of the individual resistances. True False
True
To find the total resistance in a series circuit, you would ____ the individual resistances. add subtract multiply take the reciprocal of the sum of
add
One of the most common types of permanent magnets is made of ____. iron nickel alnico steel
alnico
Which term means coulombs per second? ohm ampere volt resistance
ampere
in a ladder diagram, where is the first component to operate usually located? at the top to the right at the bottom to the left
at the top
A(n) ____ is also known as an electromagnet. armature magnetite ore fragment coil core
coil
Architectural symbols can convey the number of electrical ____ necessary for proper operation of a device or piece of equipment. switches gates connectors conductors
conductors
In which section of an oscilloscope is the intensity control found? horizontal section vertical section display section trigger section
display section
Work equals force multiplied by ____. current power energy distance
distance
A(n) ____ produces a magnetic field.
electric current
In an electrical circuit, which term indicates the voltage generated by the source, such as a battery or generator? electrical pressure electromotive force resistance current pressure
electromotive force
Which of these is an example of a driven machine? steam turbine gasoline engine electric motor elevator
elevator
Efficiency is the ratio of the unused power output to the total power input. True False
false
Energy loss occurs whenever energy is destroyed or consumed. True False
false
One type of architectural drawing is the ____. ladder diagram floor plan pictorial diagram wiring diagram
floor plan
Which term describes the ability of a material to conduct lines of force? residual magnetism retentivity permeability magnetic saturation
permeability
Applying pressure to certain crystals to produce voltage is known as the ____ effect. photovoltaic piezoelectric thermoelectric chemical
piezoelectric
In order for an object to be in a charged state, which two particles must be in a state of imbalance? protons and electrons protons and neutrons neutrons and electrons atoms and molecules
protons and electrons
A(n) ____connected in series with a motor will both limit and control the starting current. alternator torque converter rheostat thermostat
rheostat
What type of drawing shows the actual electrical connections, but not the actual physical location of components? single-line drawing architectural drawing schematic diagram pictorial diagram
schematic diagram
What unit is used to measure rectangular conductors? circular mil square mil AWG area mil
square mil
The ____ of a motor is the amount of torque developed at the instant the motor is energized. starting torque opening torque initial torque rated load torque
starting torque
In a parallel circuit, the ____ of the individual branch currents will equal the total circuit current. difference product sum ratio
sum
In a series circuit, which resistor will dissipate the most wattage? the one with the smallest resistance the one with the largest resistance the second largest resistance they will all be the same
the one with the largest resistance
In a series circuit, which resistor will have the largest voltage drop? the one with the smallest resistance the one with the largest resistance they will all be the same the one with the median resistance
the one with the largest resistance
When using a PIRE wheel, you should select a formula in the quadrant of ____. Power the unknown variable Resistance a known variable
the unknown variable
How many basic types of oscilloscope probes exist? one two three four
three
With which type of drive will the driven gear rotate in the opposite direction from the driving gear? chain drive two-gear drive three-gear drive direct drive
two-gear drive
In which section of an oscilloscope is the variable volts/div control found? horizontal section vertical section display section trigger section
vertical section
An oscilloscope measures ____. resistance power current voltage
voltage
In a parallel circuit, the ____ across the individual branch circuits will be the same. resistance current voltage power
voltage
What does a flat horizontal line used with the symbol for motors and generators indicate? AC DC series field shunt field
DC
A series circuit can have multiple paths for current flow. True False
False
A voltage tester is more accurate in measuring voltage than a digital multimeter. True False
False
Air is the best conductor of magnetism. True False
False
All artificial magnets are permanent magnets. True False
False
The total current flowing in a circuit is equal to the total ____ applied to the circuit divided by the total ____ of the circuit. voltage; current resistance; current resistance; voltage voltage; resistance
voltage; resistance
To calculate the current flowing in a series circuit, divide the ____ by the ____. resistance; voltage power; resistance resistance; power voltage; resistance
voltage; resistance
What is one possible downside of oversizing a motor? wasted power excessive motor heating insulation breakdown tripping overcurrent devices
wasted power
Which technique is used to measure small amounts of current using a clamp-on ammeter? winding the conductor around one jaw of the ammeter placing the conductor between the jaws of the ammeter placing the conductor underneath the jaws of the ammeter winding the conductor around the main body of the ammeter
winding the conductor around one jaw of the ammeter
A pictorial diagram is also called a(n) ____ diagram. ladder component architectural wiring
wiring
For health and comfort, a relative humidity of ____ percent is desirable. 3 to 5 10 to 15 30 to 40 50 to 60
30 to 40
For which temperature is resistivity (K) defined?
32 degrees F 68 degrees F 86 degrees F 100 degrees F
The magnetic field of a two-pole induction motor completes ____ revolutions per minute when supplied with 60 Hz. 60 180 1800 3600
3600
The ____ of a conductor is limited by the temperature that its insulation can tolerate without deteriorating or losing its insulating quality. capacitance ampacity resistivity thermal constant
ampacity
Dielectric heating is based on the principle of ____. resistance forced air inductance capacitance
capacitance
A capacitor-start, induction-run motor called a(n) ____ motor is frequently used for installations requiring higher starting torque than is available from the resistance split-phase motor. induction split-phase single-phase capacitor resistance-start capacitor split-phase
capacitor split-phase
To minimize line drop, electrical services should be installed in a(n) ____ location to minimize the distance to the loads. outdoor top floor central remote
central
The ratio between the light that reaches the working plane and the light produced by the luminaire provides a constant known as the ____. coefficient of utilization efficiency maintenance constant usage coefficient
coefficient of utilization
A(n) ____ control permits all of the lights or specific groups of lights to be controlled from one location. residential selector universal selector two-way master selector
master selector
Fittings are primarily intended to perform a(n) ____ function. design safety electrical mechanical
mechanical
The prime mover in a motor-generator set is the _____. generator motor dynamotor armature
motor
The current decreases as the armature coils of a generator move through the ____ plane. Theoretically, the current drops to zero. null negative neutral neutronic
neutral
To determine the synchronous speed of a motor, multiple 120 by the frequency of the supply current in hertz and divide their product by the ____. output voltage in volts number of poles on the stator resistance of the rotor windings in ohms inductive reactance of the rotor in henries
number of poles on the stator
A(n) ____, highly polished, bright material reflects most of the light that strikes it. translucent colored thin opaque
opaque
One application of a phototransistor is a(n) _____. optical encoder circuit voltage regulator Hall-effect device voltage controller
optical encoder circuit
A(n) ____ is used for installations where heavy loads are used infrequently or where it is apparent that future demand may require additional loading. autotransformer instrument transformer tapped transformer buck-boost transformer
tapped transformer
When alternators are connected in parallel, the phase rotation of the alternator and the distribution bus must be ____. 90 degrees out of phase 120 degrees out of phase 180 degrees out of phase the same
the same
When current and resistance are known, how do you find voltage? Multiply current by resistance Divide current by resistance Divide resistance by current Take the square root of resistance divided by current
Multiply current by resistance
Which is the smallest AWG wire size? No. 0 No. 4 No. 26 No. 50
No. 50
When using an oscilloscope to make measurements, the first step is _____. initializing the scope connecting the probe to the circuit connecting the ground lead to circuit ground compensating the probe
initializing the scope
Before using a digital multimeter, you should ____. check the ground break the circuit compensate the probes inspect the meter and probes
inspect the meter and probes
Which material is often used to protect sensitive instruments from electromagnetic fields? iron nickel alnico steel
iron
According to the left-hand rule for a single conductor, when grasping a conductor in your left hand with your thumb extended in the direction of current flow, your fingers will point in the direction of the ____.
lines of force of the magnetic field
The unit of measurement for flux in a magnetic circuit is called the ____. resistance maxwell gilbert reluctance
maxwell
In engineering notation, 106 is know by the term ____. kilo nano tera mega
mega
What is the unit of measurement for resistance? ohm ampere volt coulomb
ohm