Competency 7 part 1
Electrical Engineering Proficiency Quiz
Test your knowledge and skills in electrical engineering with our comprehensive quiz designed for professionals and students alike. Covering a wide range of topics, from motor theory to circuit protection, this quiz is perfect for anyone looking to reinforce their understanding of key electrical concepts.
Key Features:
- 100 challenging questions
- Multiple choice format
- Immediate scoring and feedback
When the equivalent circuit diagram of double squirrel- cage induction motor is constructed the two cages can be considered_____.
In series-parallel
In parallel with stator
In parallel
In series
The part of the shipboard electrical system used to control distribution of power to the branch circuits, is the_____.
Disconnect links
Governor relay box
Bridge control panel
Main switchboard
What gives the information about the speed of a motor in D.C Generator?
Speedometer
Watt hour meter
Potentiometer
Voltmeter
When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter’s pointer?
Kicking slightly. Down scale as voltage is applied
Fluctuating around a constant resistance reading
Dipping toward zero then raising slowly
Continually rising as test voltage is applied
To check the three line fuses of three-phase system consisting of a three-phase motor, you must_____.
Make sure the motor is operating at full load to guard against a false reading
Place the starter in the A stop position
Place the leads across the bottom ends of the fuses
Place the leads across the A hot ends of the fuses
While trouble shooting a circuit in an engine room central control console, a resistor is suspected of being faulty. Which of the following precautions must be observed if an ohm meter is to be use to check its value?
Resistor circuit must be de-energized and at least one end of the component isolated
Meter leads must not be twisted so as to cancel out the individual magnetic fields
Correct polarity must be observed because reverse bias will damage the component
The meter case must be grounded prior to attaching the leads
The division of kilowatt load between two paralleled alternators is determined by the?
Amount of field excitation to the lagging machine
Amount of field excitation to the leading machine
Load-speed characteristics of the governors
Number of field poles per alternator
The insulation resistance of electric equipment and machinery should be tested for lowest normal insulation valves_____.
Every time the brush rigging is adjusted
Immediately after starting up the machine
Every 30 days whether the machine is in use or not
Immediately. After shutting down of the machine
A three-phase squirrel-cage induction motor will run hot due to_____.
High power factor
Dirty or corroded slip rings
Open stator coils
Reversed commutating poles
The automatic voltage regulators provide on switch boards has function to____.
Vary the field excitation to the generators
Regulate diesel generator engine speed
Regulate the AC load on the generator
Protect the switch from excessive current
A molded-case breaker provides protection against short circuits by using?
Electromagnet
Shading coil
Arc quencher
Holding coil
The electrolyte in a lead-acid storage battery consists of distilled water and?
Muriatic acid
Sulfuric acid
Calcium chloride
Hydrogen chloride
Periodic testing of circuit breaker is necessary to assure that a correct rated and properly installed unit____.
Does not exceed its interrupting capacity
Can trip faster as it increase installed unit
Will continue to provide the original degree of protection
Be able to withstand at least 125% of applied voltage
Which of the following statements represents the FIRST step in seating new brushes on slip rings?
Apply seating compound under the brushes and run atno load for 2 hours
Increase brushes against the slip ring with a woodblock
Lay sandpaper between the brush and the slip ring and slide the sandpaper back and forth under the brush.
Electrical leads and insulation on a motor should be painted with_____.?
Insulating varnish
Insulating white lead
Heat resisting acrylic
Heat resisting aluminum
A fuse the blows often should be replace only with a fuse of_____.
The recommended current and voltage rating
Higher current and voltage rating
Higher current and lower voltage rating
Lower current and higher voltage rating
How should controller contacts be routinely cleaned?
Dressing with crocus cloth
Filing with a bastard file
Wiping with a clean dry cloth
Blowing with compressed air
In the circle diagram for induction motor, the diameter of the circle represents_____.
Rotor current
Line voltage
Slip
Running torque
What do you call on a periodic testing by a shore side support technician using a special camera which can detect potentially dangerous loose or corroded bus bar and controller connections?
Visual pyrotronics
Electric vibroanalysis
Corrosion electrolysis
Heat sensitive thermography
The power scale of circle diagram of an induction motor can be found from_____.
No lead test only
Stator resistance test
Stator none resistance test
Short-circuit test only
Which of the following statements is true concerning the cleaning of electrical contacts?
Delicate parts should be cleaned with a brush and approved safety solvent
The content surfaces should be greased to increase contact resistance
Compressed air should be used to blow out metallic dust
Magnetic brushes should be used to removed metallic dust
A device which can be used to check the calibration of a circuit breaker is a____.
Clamp on voltmeter
Standard digital multimeter
500 volt megohmmeter
Portable low voltage high current testing unit
When a lead-acid battery begins gassing freely while receiving a normal charge, what should you do when charging?
Be decreased
Shut off
Be increased
Remain unchanged
You are testing the insulation in an AC generator with a megohmeter. The resistance value of a dry clean winding will_____.
Continue to drop as the potential is maintained becoming fairly steady after 5 to 7 minutes
Remain constant as the temperature of the windings increase
Continue to rise as the test potential is maintained, becoming fairly steady as the leakage current stabilizes
Stabilize after approximately 2 to 4 minutes of fluctuation
Which of the following statements concerning analog and digital devices are correct?
The variables in digital system are fixed quantities and the variables in analog system are continuous quantities.
Analog devices are superior in accuracy compared to digital devices
There are no basic differences between the two systems
Operations in a digital device are performed simultaneously
In the event of a power failure during cargo loading operations, which of the following can stop the movement of an electric powered cargo winch?
A hand operated band brake
A manual override switch
A spring set brake
The weight of the load on the boom
Four lamps are connected in parallel in a single circuit. If one of the lamp burns out, the others will?
All go out
Become brighter
Become dimmer
Burn with their original intensities
What is the cause when an alternator failed to produce line voltage?
Exciter generator failure
Oxidized slip rings
Improperly staggered brushes
A closed circuit breaker
The proper way to apply plastic electrical tape to an electric cable splice is to______.
Apply tape to the braided cover, but avoid touching it
Heat the tape with a soldering iron for good bonding
Wind the tape so that each turn overlaps the turn before it
Apply the tape in one non-overlapping layer only
When a replacing a fuse with one of a higher rating than the original, which of the following is true?
It endagers the apparatus it is supposed to protect
Reduces the possibility of short circuits
It increase the efficiency of the equipment by allowing more current to be used
It creates a larger voltage drop in the circuit being protected
Before reassembling any machinery, what should you do?
Replace all bearing regardless of length of service
Clean any corroded surfaces and file all burrs smooth
Apply a heavy coat of oil to all mating surfaces
Coat all parts with alemite grease
What does the variable resistance placed in the rotor circuit of a wound-rotor induction motor provide?
Voltage control
Use as a split phase motor
Speed control
Frequency control
A temperature instrumentation system for an engine rom console consist of a resistance temperature detector (RTD), a measuring bridge circuit, and a meter (or alarm circuit). Which of the following statements is true concerning the measuring bridge circuit?
The resistance bridge is said to be balanced when its output voltage is zero
The input voltage varies in a linear fashion with temperature
The voltage across the center of the resistance is always constant
The input voltage of the resistance bridge is the constant temperature signal
Which device that commonly utilizes the principle of electromagnetic induction?
Transformer
Transistor
Diode
Rheostat
How much is the typical resistance of the body from hand to foot when dry?
500 ohms
1000 ohms
100 ohms
800 ohms
What motor is fitted with an instantaneous overload relay?
Winch
Fan
Pump
Machine tool
It is a type of temperature sensor that has the characteristic of being very accurate, linear and has a good long term stability.
Silicone junction temperature sensors
Thermocouple
Thermistor
RTD’s
What should you used to determine if a stator coil is grounded?
Ammeter
Megger
Magneto
Ground detection lamp
What will you do if the generator is exposed to rain or any water?
Run the system for 1 hour to test the performance
Use hygrometer to test the moisture
Make a megger test
Check the coil if insulation is pilled up
The charging of lead-acid storage batteries will always result in?
Dangerous acid burns
Increased level of electrolye
The danger of lead poisoning
A dangerously explosive gas being liberated
When charging lead-acid batteries, you should reduce the charging rate as the battery nears its full charge capacity to ______.
Allow equalization of cell voltages
Increase lead peroxide formation
Prevent excessive gassing and overheating
Reduce lead sulfate deposits
Which of the following physical characteristics does a wound-rotor induction motor possess that a squirrel-cage motor does not?
End plates
Centrifugal switch
Slip rings
End rings
An electric tachometer receives the engine speed signal from?
Small generator mounted on the enine
Bimetallic sensing device
Vibrating reed meter generating a voltage proportionate to engine speed
Stroboscopic sensing device
Moisture as a result condensation occurring inside of the cargo switches, can be reduced by?
Installing a light bulb in the pedestal stand
Coating the switch box internals with epoxy sealer
Using strip heaters inside the switch box
Venting the switch box regularly
A temperature instrumentation system for an accommodation refer room consists of a resistance temperature detector (RTD), a measuring bridge circuit and a meter or alarm circuit. Which of the following is true concerning the measuring bridge circuit?
The resistance bridge is said to be balanced when its output voltage is zero
The input voltage of the resistance bridge is the constant temperature signal
The input voltage in a linera fashion with the temperature
The voltage across the counter of the resistance bridge is always constant
If both the “high level’ and alarms come on for the same address of a centralized control console, the most likely problem is a/an ________.
Low level
Failed alarm
Sensor failure
Extremely high level
When trouble shooting electronic equipment, what is the first step to be taken before testing the circuit voltage?
Removed the suspected component
Check the current flow through the circuit
Set the meter to the lowest range
Check the voltage supply from the power source
Electrically operated safety device on auxiliary diesel engines functions to stop the engine by ______.
Shutting off fuel supply
Shutting off lube oil supply
Shutting off cooling water supply
Shutting off air supply
Temporary repairs to an open DC propulsion armature coil can be made by _____.
Disconnecting coil ends, insulating each, and short circuiting the two commutator bars
Removing the sparking brushes
Connecting the coil ends directly to a pair of negative brushes
Grounding the coil ends and short circuiting the commutator bar
What devices is fitted to prevent the generator windings from absorbing moisture while at standstill?
Windings heater
Generator heater
Motor heater
Space heater
A company type of protective covering used on electrical conductors is _____.
Babbit sheating
Silver sheating
Fibrous braid
Plain paper
Which of the following data is required to draw the circle diagram for an induction motor?
No load test only
Block rotor test, no load test and stator resistance test
Block rotor test only
Block rotor test and no load test
A molded-case circuit breaker provides protection against short circuits by using a/an?
Arc quencher
Burn away strip
Shading coil
Electromagnet
What kind of electrical cable that is widely used and is highly resistant to mechanical damage?
Aluminum cable covered with insulation
Cable with lead cover
Cable with plastic insulation
Sheathed cable which is free of metal
The air gap provided in induction motors should be checked periodically with a feeler gage to detect an unequal gap and ________.
Decreased motor magnetizing current
Increased power factor
Hysteresis losses
Mechanical damage to rotor
Regulations required each motor controller to have wiring diagram located ________.
In the engineering office
In the spare parts locker
On the inside of the controller door
Outside door in engine room
If a delicate component must be soldered into a circuit the component may be protected from the heat of the soldering process by ______.
Using a thermal shunt
Pre-oxidizing the leads to be soldered
Coating the leads to be soldered with a light oil film
Operating the soldering gun not more than 60 seconds at a time
Which of the listed procedures should be carried out to prevent moisture damage to electrical apparatus during extended periods of idleness?
Fill the motor housing with C02 to inert the space
Covert the equipment with a canvas tarpaulin
Strap silica gel around the commutator
Place heat lamps in the motor housing
What electrical apparatus can test insulating efficiency in an electric installation?
Megger tester
Potentiometer
Volt meter
Ammeter
The removal of paint from electrical equipment such as generators, should be cautiously undertaken because _______.
The mechanical shock of paint removal lessens the di-electric strength of the insulation
The paint dust is composed of abrasive and semi- conducting materials which impair insulation
Paint dust build up has a tendency to cause corrosion
Phase windings frequently become isolated from each other due to dust interference at the terminals
Which of the following safest precautionary measure is to be done prior working on the motor of the cargo winch?
Inform master that a cargo winch water needs repair
Inform chief officer that winch cannot be used for cargo operation
Switch off main switch and put sign do not switch on.
Put the boom at its rest before work start
A temperature instrumentation system to an engine room console consists of a resistance temperature detector (RTD), a measuring bridge circuit, and a meter (or alarm circuit). Which of the following statements is true concerning the measuring bridge circuit?
The resistance bridge is said to be balanced when its output voltage is zero
The input voltage varies in a linear fashion with temperature
The input voltage of the resistance bridge is the constant temperature signal
The voltage across the center of the resistance bridge is always constant
Complete maintenance of electrical motors should include periodic checks for machine _____,
Vibration
Reactive power
Speed droop
Watertight integrity
64. If a small electric motor is immersed in salt water it should be ___. I washed in fresh water II. Dried in an oven III. Blow air until it dries
II only
Neither I and II
I only
Both I and II
A common type of protective covering used on electrical conductors is _____.
Silver sheathing
Babbit sheathing
Plain paper
Fibrous braid
A self-excited DC generator fails to come up to its normal 440 volts. What could be the probable cause?
Excessive residual magnetism
Excessive brush tension
Low armature speed
Low rheostat resistance
Which of the following materials is recommended for finishing the slip rings after grinding or turning?
Crocus cloth
Canvas wiper
Grade 00 sandpaper
Smooth file
With both ends of a three conductor cable disconnected and arranged without the conductors touching each, and ohmmeter reading of ‘zero’ ohms between the ends of one conductor would indicate ______.
Continuity
A short circuit
The resistance is infinite
A partial ground
To carry out an insulation resistance test, one terminal of the megommeter should be connected to the winding, with the other terminal being connected to the _____.
Power supply
Armature
Variable resistor
Frame of the machine
A current at which a magnetic-type overload relay tends to trip may be decreased by raising the plunger further into the magnetic circuit of the relay. This action will ______.
Reduces magnetic pull on the plunger and requires more current to trip the relay
Increase magnetic pull on the plunger and requires less current to trip the relay
Reduces magnetic pull on the plunger and requires less current to trip the relay
Reduces magnetic pull on the plunger and requires more current to trip the relay
During ,maintenance of circuit breakers, _______.
Always smooth roughened contact surfaces with a file
Never pass more than rated breaker current through the overload heater element
Always apply a thin film of oil on contact surfaces
Inspect for wear and misalignment of main contacts
Electrical insulating rubber gloves should be dielectrically tested every how many months?
3 months
9 months
12 months
6 months
When a nickel-cadmium battery begins gassing while connected to the battery charging circuit, you should ______.
Add potassium hydroxide to each cell to reduce the specific gravity of the electrolyte
Increase the charging rate
Do nothing as this is a normal condition when charging
Add distilled water to each cell to increase the specific gravity of the electrolyte
Any electric motor can be constructed to be?
Overload proof
Short proof
Explosion proof
Ground proof
What indicates the third color band on a resistor?
Second significant figure of the resistance to give the value of zeros
Number of zero following the first two significant figures in the resistance value
Tolerance of the resistor following the first significant figures in the resistant value
First significant figure of the resistance to give the tolerance of the resistor
What is a three-layer bidirectional device used primarily as a triggering device with junctions heavily and equally doped?
UJT
Diac
Op-Amps
Triac
Upon failure of the normal power supply, the emergency generator is placed on the line by the ______.
Power failure alarm bus
Bus the feeder
Automatic bus transfer device
Line connection feeder
Which test on a transformer provides information about the regulation, efficiency and heating under load condition?
Hopkinson circuit test
Short circuit test
Open circuit test
Back to back test
When reading electrical motor controller diagrams, it helps to know that _______.
Current paths in the control circuit are drawn as heavy lines and in the power circuit as lighter lines
Circuit subjects to 500 volts or greater are drawn as light lines and below 500 volts as heavy lines
Circuit subject to 500 volts or greater are drawn as heavy lines and below 500 volts as lighter lines
Current paths in the line power circuit are drawn as heavy lines and in control circuit as lighter lines
A semiconductor that decrease in resistance with an increase in temperature is known as?
Resistor
Diode
Thermistor
Thermopile
Before working on an electric motor starter panel located on the main deck, what should you do FIRST?
Open the circuit breaker and tag out
Heat the switchboard to remove moisture
Drain condensate from the box
Spray the gasket surface with a solvent
Why should you used a high impedance multi meter when troubleshooting electronic equipment?
Whenever a low impedance meter is not available, regardless of the components being tested
So as not to load down the circuit and obtain erroneous voltage readings
Can be used for AC measurements only and a low resistance meter for DC measurements
To prevent excess current flow through the meter that would damage it
It is a type of electrical fault that happens when a phase conductor is completely or partially interrupted:
Open circuit fault
Phase failure fault
Short circuit fault
Earth fault
Which of the following statements concerning the maintenance of solid-silver contacts in relay and auxiliary control circuit is correct?
When black silver oxide is present it should always be removed from the contact surface with coarse sandpaper
They should be filed with a fine-cut file when projections extend beyond the contact surface
When necessary, they should be spray painted with electrical shellac
When necessary, they should always be dressed with a wire wheel
Which of the following statements best describes the material known as varnished cambric?
Rubber insulation coated with a layer of tin
Felted asbestos sealed with varnish
Cotton cloth coated with insulating varnish
Paper impregnated with mineral oil, specially wrapped with nonmetallic tape, and coated with varnish
When removing ball or roller bearing from the shaft of a motor, you should use a ________.
Soft iron pry bar
Wheel puller
Brass mallet
Rawhide hammer
A capacitor can be tested using a megohmmeter or an ohmmeter, if the meter is connected to a shorted capacitor, the meter pointer should ________.
Immediately swing to the maximum resistance value for the capacitor
Immediately deflect to and remain zero
Immediately swing to a high reading and then gradually decrease
First swing quickly to zero, then gradually
Periodic testing of circuit breaker is necessary to assure that a correct rated and properly installed unit __________.
Will continue to provide the original degree of protection
Does not exceed its interrupting capacity
Be able to withstand at least 125% of applied voltage
Can trip faster as it increases installed unit
Encrusted dirt accumulated inside a motor should be removed with a __________.
Fiber scraper
Pointed welding rod
Paint scrapper
Hammer and chisel
Air gap reading should be periodically taken for electrical generation equipment. The best tool to use to take these measurements is a _________.
Inside micrometer
Tapered, long blade gage
Cloth (non-metallic) tape measure
Dial indicator
A common type of protective covering used on electrical conductors is ________.
Rubber or plastic
Babbitt sheathing
Silver sheathing
Plain paper
Moisture accumulating electric motors and generator windings having a cold insulation resistance greater than 50,000 ohms may be baked out with internal heat. This heat can be developed by ______.
Feeding current into the windings at low voltage
Short circuiting the armature and field windings
Short circuiting the field windings and passing current through the armature
Obtaining current from a DC source such as an electric welder and feeding it into the armature while running the motor at full speed
The windings of electric generators during short idle periods should be ______.
Flash with direct current to remove any residual magnetism
Allowed to cool slowly to ambient temperatures
Kept warm by using strip or space heaters
Relieved of all capacitive charge by grounding the conductors
A reversible electric motor with worm gear that is connected to the flywheel to position engine parts is the _____.
Turning gear
Valve gear
Wheel gear
Reversing geer
A switchboard for an AC electrical system requires the use of which of the following devices?
Ohmmeter
Current transformer governor
Frequency meter
Induction voltage regulator
The schematic symbol for an operational amplifier in an analogue circuit is a _____.
Trapezoid
Square
Triangle
Circle
Where a thermal-acting breaker is required to be used in an area of unusually high, low or constantly fluctuating compensating element must be used. What does this element consist of?
Second electromagnet
Cylindrical spring on the contract arm
Second bimetal element
Conical spring on the contact arm
What can you do if the generator is exposed to rain or any water?
Run the system for 1 hour to test the performance
Check the coil if insulation is pilled up
Use hygrometer to test the moisture
Make a megger test
Periodic testing of circuit breakers is necessary to assure that a correct rated and properly installed unit ______.
Does not exceed its interrupting capacity
Can trip faster as load increases
Be able to withstand at least 125% of applied voltage
Will continue to provide the original degree of protection
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