English tests for electrical engineers with the answers. Тесты английского для электромехаников с ответами

A 24-volt lead-acid storage battery consists of: C.12 cells
A "dead board" is:A.a board with no power
A circuit that does not provide a complete path for the flow of current is: B.a closed circuit
A circuit that has one wire in contact with the hull of a ship is a:D.grounded circuit
A DC ammeter is always connected:A.in series with a circuit
A D.C. compound-wound generator that has a voltage drop from no load is said to be:A.under compounded
A D.C. generator that has a voltage rise from no load to full load is said to be:D.under flat compounded
A D.C. series motor should always be mechanically coupled to the load in order to:D.prevent excessive speed
A fully charged battery reads from:A.1.280 - 1.300
A galvanometer is used to measure:D.both A and В
A generator interpole always has the same polarity as the:B.pole preceding it
A generator operates on the principle that:C.voltage is induced when a conductor cuts a magnetic flux
A horseshoe magnet has:D.two poles
A loud buzzing noise in an AC controller is probably caused by:C.high slippage
A megger measures:D.insulation resistance
A mil is:C.1/1,000 inches
A multiconductor cable A.has a number of separate circuits
A reverse power relay is used to:B. protect a generator from a power reversal
A rheostat is a device that regulates the strength of an electric current by:A.varying the resistance in the circuit
A semiconductor that decreases in resistance with an increase in temperature is known as:B.hermistor
A series-wound generator has the field windings in series with the:B.armature
A series-wound motor is used to run a pump driven with a belt. If the belt breaks, the motor will:A.overspeed and run out of control
A short circuit is:D.all of the above
A shorted coil can be detected by:D.both В and С
A shunt motor would be best suited for:A.constant speed results
A shunt-wound generator is the one in which the field windings are in parallel with the:A.armature
A starting resistance used with a large D.C. motor should gradually be:C.cut out of the armature circuit as the motor picks up speed
A synchronous motor differs from an induction motor in that it:D.all of the above
A synchroscope is used to:A.parallel A.C. generators
A transformer works on the principle of:C.mutual induction
A voltmeter is connected in a circuit in:A.parallel
A wattmeter shows the:C.combined volts and amps of load delivery
After having been given an equalizing charge, a lead-acid battery is considered fully charged when the specific readings of all cells taken at half- hour intervals show no change for:D.four hours
All of the following will cause an induction motor to run hot except:D.high power factor
An "exciting current" is required to:B.create a magnetic field
An accidental path of low resistance which passes an abnormal amount of current is known as a/an:B.short circuit
An advantage of a wound rotor motor over an induction motor is:A.high starting torque with low starting current
An ammeter is connected in a circuit in:C.series
An A.C. armature is always the:C.conductor into which voltage is induced
An increase in current:B.increases temperature
An ohmmeter measures:C.resistance
An open coil can be detected by:A.high resistance
An operation characteristic which appears on the name plates of shipboard A.C. motors is the:C.temperature rise
Another name for an A.C. generator is:C.an alternator
As a general rule, the first troubleshooting action to be taken in checking faulty electric control apparatus is to:B.test all fuses and measure the line voltage
As load is added to an AC generator with constant field excitation the prime mover slows down:A.lowering frequency and lowering generated voltage

Before handling or making any connections, a capacitor should be:B.shorted out with a jumper
Before measuring an unknown resistance with an ohmmeter, you should:D.short the test leads and calibrate the meter
Batteries are rated for capacity in terms of:D.ampere-hours

Chattering of the alternator brushes can usually be eliminated by:B.dressing and polishing the collector rings
Counter electromotive force is measured in:A.amps
Current measuring instruments must always be connected in:A.series with the circuit

D.C. generators are rated in:C.Kw
D.C. motors are provided with starters and controllers to:D.start motor at less than line voltage
DC generators are classified according to the manner in which:D.the field windings are connected to the armature circuit
Defects in wiring which permit current to jump from one wire to another before the intended path has been completed are called:B.shorts
Dielectric strength is the:D.strength of a magnetic field
Dirty lead-acid type batteries should be cleaned off with:C.sodium chlorine

Electric current is the flow of electrons through a conductor. This is commonly called:B.amperage
Equal power factors on parallel AC generators are maintained by an automatic:A.voltage regulator
Excitation for an A.C. generator can be taken from a:D.any of the above

Field excitation, where required, is always supplied from a (an):C.direct current source

How is a lead-acid cell tested?A.hydrometer
How is speed changed in a 2-speed induction motor?A.vary the number of poles
How is the rotating field of an alternator excited?B.slip rings insulated from shaft
How is the rotation of a D,C. generator reversed?D.both В and С

If a D.C. generator was rotated in the wrong direction, it would faii to come up to voltage because the:C.armature field would oppose the field current
If a generator docs not generate the trouble may be:c.loss of residual magnetism
If a synchroscope is placed in a circuit in which the frequency of the incoming alternator is equal to that of the bus, the pointer will:D.remain stationary
If a wire is increased in circular mils:D.A and В
If more resistance is applied to the shunt field of a D.C. motor, the motor speed will:B.increase
If the approximate voltage to be measured in a circuit is not known, you should:D.use the highest voltage range on the voltmeter
If the brushes in a generator are not positioned in the neutral plane, sparkling may occur between the brushes and the:B.commutator
If the charging rate to a battery was too high, it would:C.increase the rate of hydrogen liberation
If the excitation of one or two alternators operating in parallel is increased, the:A.power factor will change in the lagging direction
If the length of the wire is doubled and the cross-sectional area is reduced to one-half, the change in resistance will be:B.quadrupled
If the load was removed from a series-wound motor, it would:C.speed up
If the load was suddenly released from a shunt motor, it would:A.continue to operate at the same speed
If the motor fails to run when the switch is turned on, the trouble may be:C.burned out fuses d dirty commutator
If the motor is noisy in operation, the trouble may be:D.a.b,c
If the motor runs faster than name-plate speed, the trouble may be:B.shorted or grounded field
If the motor runs hot, the trouble may be:E.b and с (overload & tight bearing)
If the motor runs slowly, the trouble may be:A.shorted armature or commutator
If the motor sparks, the trouble may be:B.poor brush contact on the commutator
If the needle of a megger does not return to zero, what is the cause?C.normal operation
If the resistance is increased in the shunt field of a motor, the motor will:A.speed up
If the resistance of a circuit is doubled and the applied voltage kept constant, the current will:С. be cut in half
If the temperature varies with such conductors as copper, silver, aluminum, which of the following statements are correct?A.as temperature increases, resistance increases
If the voltage does not build up to a maximum the trouble may be:D.speed of generator too low
If the voltage drops considerably as the load is placed on the generator, the trouble may be:D.a,b,c
If two generators are connected in series:A.voltage is added and current stays the same
If you have two alternators in parallel and one is not working properly, and one alternator cannot handle the load, what would you do?D.cut out some of the branch circuits and secure the faulty alternator
In a 12-volt battery there are how many cells?C.6
In a compound-wound motor, part of the line current flows through the:D.shunt field coils
In a D.C. series circuit, all the conductors have the same:D.current passing through them
In a parallel circuit which of the following is the same throughout the circuit?A.impedance
In a series circuit the total current is:D.none of the above
In a three-wire system, the ground wire is:C.green
In D.C. circuits, power is expressed as the product of:C.volts and amperes
In cold weather the specific gravity of a battery:A.rises
In the following list of instruments, which is not correctly stated?D.ammeter is connected across the circuit
Increasing the number of poles in an induction motor:B.decreases the field speed
Interpoles are connected in:A.series with the armature
Interpoles or commutating poles are connected in compound D.C. generators in:C.series with the armature

Magnetic flux is best insulated by:D.ceramic
Most generators will withstand an overload of:B.25%

On a D.C. generator where is the pigtail located?C.brush holder
One horsepower equals:B.746 watts
One kilowatt is equal to:B.1.33 horsepower
One megohm is equal to:D.1,000,000 ohms
One very important advantage of A.C. over D.C. motors is that:C.for a given power, A.C. motors are smaller than D.C. motors

Prior to starting an A.C. generator prime mover, the voltage regulator cut out switch should be placed in the:A.manual position

Rather then have six leads coming from a three-phase A.C. generator, you can:C.have one lead from each phase connected together
Residual magnetism is the magnetism:C.remaining in the substance after it has been removed from a magnetic field
Retentivity is the power a metal has to retain:B.magnetic lines of force

Salt water in contact with storage batteries will develop:D.chlorine gas
Soft iron is most suitable for use in a:B.temporary magnet
Sparking and grooving of commutator may be caused by:D.any of the above
Starting resistors are used in conjunction with D.C. motors to:A.reduce the heavy starting current
Static electricity is most often produced by.D.friction
Synchronization means:D.cycle for cycle
Synchronous converters are used to:A.change A.C. to D.C.
Synchronous motor speed is controlled by:C.varying frequency or number of poles

The advantage of D.C. motors over A.C. motors is the fact that they:D.offer a better means of controlling speed
The capacity of a lead-acid storage battery is measured in:B.ampere-hours
The conductance of a conductor is the ease with which current will flow through it. It is measured in:B.mhos
The cycles per second of the alternating current from the alternator aboard your boat are determined by:A.the speed of the engine driving the alternator
The direction of rotation of a split-phase induction motor can be reversed by:A.reversing the starting winding leads
The electrical power in kilowatts used by a 220 volt motor drawing 15 amps is:A.3.3
The following formula is used to compute power:C.P= I R
The force that cause free electrons to move in a conductor as an electric current is called________force.C.inductive
The frequency of the alternating current generated by a synchronous generator is governed by the speed and the:D.number of poles
The lead plates in storage batteries are separated by:D.any of the above
The load rating of an A.C. generator is determined by the:A.internal heat it can withstand
The load sharing characteristics of two diesel generators operating in parallel are mostly dependent on their governor's settings.D.speed droop
The magnetic field around a current-carrying wire:C.exists at all points along the length of the wire
The most common type of AC generator found aboard ship is the:D.armature-rotating electromagnetic field-type
The most common type of start used on board ship foe A.C, motor is the:D.across-the-line
The only type of compound generator commonly used aboard ship is the:C.stabilized shunt
The part of a D.C. generator into which the working voltage is induced is the:C.armature
The pole pieces mounted in a D.C. generator are built up of sheet steel laminations riveted together to:B.reduce eddy current losses
The power factor of an A.C. generator may be said to be in unity when:D.voltage and current reach maximum values simultaneously
The proper sequence for securing a D.C. generator in parallel operation is to:C.reduce current to near zero, open circuit breaker, and switch and secure the driving unit
The proportion of the kilowatt load handled by one of a group of paralleled alternators may be increased by increasing its:D.governor setting
The purpose for squirrel-cage windings in a synchronous motor is to:A.provide a means for starting
The purpose of a rectifier is to:A.change A.C. to D.C
The purpose of the commutator and brushes on a D.C. generator is to:A.change A.C. to D.C. current
The rating of an alternator as given on its nameplate, is 800Kw, 0.8 power factor, the significance of this rating is that the alternator:B.can supply an 800Kw, 0.8 lagging power factor load at rated voltage
The resistance of a copper wire to the flow of electricity:C.decreases as the length of the wire increases
The speed of a synchronous motor is varied by:B.changing of the frequency of the number of poles
The state of charge of a nickel-cadmium battery is determined by the use of a (an):B.voltmeter
The total resistance of a parallel circuit is always:C.equal to the reciprocal of the sum of the individual branch
The type of A.C. motor used for high-starting torque and low-starting current is the:B.wound-rotor motor
The unit of electrical current flow is the:D.ohm
The unit of electrical pressure is the:A.amp
The unit of electrical resistance is the:B.watt
The voltage of a D.C. generator depends on which of the following:D.all of the above
The voltage output of a compound D.C. generator is adjusted by a restate placed:A.in series with the shunt field
The voltage output of an A.C. generator is controlled by:A.varying the D.C. exciter voltage
To correct the polarity of a generator, you should:C.lift brushes and apply D.C.
To keep the current through a D.C. voltmeter as low as possible, the moving coil circuit is provided with a (an):C.high series resistance
To reverse a D.C. compound motor:B.interchange armature leads

Voltage generated by most AC generators is brought from the machine to the bus by means of:D.direct connections from the stator
Volts times amps equals:B.watts

When a lead-acid storage battery discharges, what would be the effect the electrolyte?A.specific gravity decreases
What are the commutators made of?B.hard drawn copper bars insulated with mica
What determines the voltage of a lead-acid cell?B.the strength of the electrolyte
What happens in a series circuit when the voltage remains constant and the resistance increases?A.current decreases
What is meant by the slip of an inductor motor?B.difference in the speed of the rotor to the speed of the magnetic field
What is the distinguishing feature of a shunt motor?C.stable speed through a wide load range
What is the primary reason for commutating poles in a D.C. generator?D.prevent sparking of the brushes
What is the probable fault for hot bearings?D.a,b,c.
What is the probable fault for motor overheating?E.b and с (ground fault & mechanical overload)
What occurs during the charging of a lead-acid storage battery?B.positive plates change to lead peroxide
What type of motor makes up the greatest part of the load of three-phase motor?B.a three-phase motor requires auxiliary means of starting and a single-phase motor is self-starting
What will happen to the alternator frequency if the load is removed from a turbogenerator whose governor has a 3% speed drop?D.it will increase

When a synchronous motor is unloaded it would:C.maintain speed
When a transformer is used to step down the voltage, the low voltage winding is:D.the secondary
When an alternator governor control switch is moved to "raise", this will:A.raise the no-load speed setting of the governor
When placed in a magnetic field, what material will have the highest permeability?C.soft iron
When securing an AC generator, you should first:D.reduce the load on the unit
When selecting the size of wire to be used in a circuit, the most important item to consider is the:C.amperage of the circuit
When the armature coils of a D.C. motor cut through the magnetic field, the voltage induced is known as:B.counter EMF
When the ground indicator light comes on, you should:B.check wiring from the main switchboard
When the polarity of the D.C. line is reversed, what does it do to the motors connected?B.rotation is reversed
When two D.C. generators operate in parallel, they are protected against motorizing by:D.reverse current trips
When using an A.C. generator on a three-phase, four-wire system, the neutral wire:D.has current flow when the loads are unbalanced
When using Ohm's Law, E divided by I would solve for:A.amperage
When using Ohm's Law, E divided by R would solve for:C.watts
When would you ground an electric hand tool?C. any machine that operates on over 100 volts
When would you test a motor?B.before it is installed

Which of the following A.C. motors has its rotor energized by D.C.?A.synchronous
Which of the following are not in a D.C. commutator and armature?A.interpole
Which of the following D.C. generators has the largest percentage of voltage drop between no load and full load?C.shunt
Which of the following expressions correctly states Ohm's Law?C.resistance equals volts divided by amps
Which of the following formulas would solve for amperage?D.R minus E
Which of the following groups of motors are D.C. motors?C.series, shunt and compound

Which of the following is not a good conductor of electricity?B.mica
Which of the following is not found on a D.C. generator?C.stationary armature
Which of the following is not found on A.C. generators?B.commutator
Which of the following is the distinguishing feature of a shunt motor?C.it has stable speed through a wide load range
Which of the following statements is true?B.like poles repel each other
Which of the following types of A.C. motors is employed for propulsion modern ship installations?C.synchronous
Which of the following will not cause a generator to vibrate?C.loose pigtails
Which of the following will not cause a hot motor bearing?B.loose brushes
Which term designates across-the line starters that automatically restart the motor after a temporary power failure?D.low-voltage release

Why could exhaust smoke be black?D.a and b (air cleaner clogged & low compression)
Why could exhaust smoke be white?C.low compression
Why is a reverse power relay put in an A.C. generator circuit?A.to prevent it from acting as a motor
Why might a generator not hold load?C.fuel filter clogged
Why might a generator not start?B.fuel supply valve closed
Why would a generator start and stop?D.a,b,c

With A.C. generators, the revolving armature-type generator is not generally used because:D.heavy voltage slip rings and brushes would be required
With an increase in load on a flat-compounded D.C. generator, the voltage will:C.remain the same
With an increase in load on an alternator, to maintain the voltage the voltage the automatic voltage regulator will:D.cut resistance out of the field
With other factors remaining constant, when the applied voltage is doubled, current flow in a given circuit will:D.be divided by four
You would be standing on a rubber mat when you are:D.all of the above

Тесты английского для электромехаников с ответами

English tests for electrical engineers with the answers


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