OIC-EW MARINA REVIEWER / QUIZ COMPETENCE 6 - PART 4 - Seaman Kowts

COMPETENCE 6 – Operate Electrical, Electronic and Control Systems

Results

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#1. If a magnetic controller contact fails to pick up when the operating coil is energized, what could be one possible cause?

low spring pressure

low applied voltage to the coil

residual magnetism of the contact faces

dirty contact faces

Incorrect!

#2. If the excitation of an alternator operating in parallel is decreased below normal and the other above normal, what will be the result on the alternator with the excitation decreased below normal?

power factor will change in the leading direction

power factor will change in the lagging direction

ampere load will be greatly increased

kilowatt load will be greatly decreased

Incorrect!

#3. If many turns of an alternating current coil for a contactor become short circuited, what will happen to the coil?

it will have a higher resistance value

it will probably burnout immediately

it will operate on reduced current

it will experience a temperature will drop

Incorrect!

#4. How would a DC ammeter designed to directly measure current be connected?

in series with a circuit

in parallel with a circuit

with internal shunts only

without regard to polarity

Incorrect!

#5. How many possible states does a binary logic circuit have?

One

Two

Three

Four

Incorrect!

#6. If the contacts of a motor starter or controller fail to drop out when the ’stop’ button is depressed, what could be the cause?

stop contacts are carrying insufficient current

starter shading coil is broken

stop contacts have become welded together

starter shading coil is loose

Incorrect!

#7. How would you increase the frequency of an operating AC generator?

increase the field excitation

decrease the field excitation

increase the number of magnetic poles

increase the speed of the prime mover

Incorrect!

#8. If a DC motor runs faster than designed, with all other conditions being normal, what could be the possible cause?

open shunt field coil

open armature coil

reversed commutating pole

overload

Incorrect!

#9. If an electric motor fails to start, what should you check FIRST?

phase sequence

motor winding resistances

fuses or circuit breaker as applicable

line frequency

Incorrect!

#10. If an unloaded DC compound motor’s shunt field were weakened by excessive rheostat resistance or by an open circuit, how would the motor respond?

over speed due to reduced CEMF

stop because of low flux

continue to run at base speed

slow down and overheat

Incorrect!

#11. If a short circuit in the armature of a DC motor occurs what would be the result?

run fast

hum when energized

spark at the brushes

fail to start

Incorrect!

#12. How will a molded-case circuit breaker with a thermal trip unit react immediately after it has tripped, as a result of an overloaded motor circuit?

The breaker cannot be reset to the ON position until the thermal element cools down.

The breaker handle will lock in the OFF position.

The breaker handle will lock in the TRIPPED position.

The thermal element must be replaced after an overload trip has occurred before it can be restored into service.

Incorrect!

#13. If all three ground-detection lamps continue to burn at equal intensity after the test button is depressed and released, which of the listed conditions is indicated?

No grounds exist

The test switch is faulty

The current transformers are shorted out

All three phases are grounded

Incorrect!

#14. If the centrifugal switch or relay used for cutting out the starting winding of a split-phase induction motor fails to open once the motor is in operation, what will be the result?

the motor will over speed

the motor will immediately stall under load

the motor torque will be above normal at rated speed

the starting winding will burn out

Incorrect!

#15. Hysteresis is one cause of electrical power loss associated with electricity generation equipment. What phenomenon results in hysteresis?

arcing at the brushes

pulsating terminal current

heat generated by magnetic polarity reversals

excessive field current

Incorrect!

#16. How will the value of the output frequency change if the load is removed from a turbo generator having a governor speed droop setting of 3%?

It will remain unchanged

It will decrease by approximately 3%.

It will become variable.

It will increase.

Incorrect!

#17. If a magnetic controller relay fails to drop out when the coil voltage is removed from the relay, what is the probable cause?

excessive spring tension

over voltage

excessive current

welded contacts

Incorrect!

#18. How should the shunt of a DC ammeter be connected?

in series with the load and in parallel with the meter movementf

in parallel with the load and in series with the meter movement

in parallel with the load and in parallel with the meter movement

in series with the load and in series with the meter movement

Incorrect!

#19. If field excitation is suddenly lost to an alternator operating in parallel with another alternator, what will happen to the alternator that has experienced a loss of field excitation?

It will supply excessive current to the bus.

It will operate at the same load, but with reduced voltage.

It will lose its load and tend to over speed.

It will become overloaded and slow down.

Incorrect!

#20. Humming or buzzing of electric contacts is a symptom of what condition?

power failure to the operating coil

low voltage on the operating coil

a control circuit ground

a control circuit overload

Incorrect!

Finish

There are 20 questions for the actual examination for Competence 6 for OIC-EW with a passing rate of 70%. This means that you are only allowed to make 6 mistakes.

DISCLAIMER

The questionnaires contained in this “reviewer” are extracted from the post released by MARINA on their official website and other review materials. Please note that Seaman Kowts is not affiliated with, endorsed by, or connected to the official website of MARINA. The information provided on this website is for general informational and educational purposes only and should not be relied upon as official or authoritative. If you require official information or services, please visit the official website or any relevant review center. We do not assume any responsibility or liability for any consequences resulting from the use of information or services provided on this website.

Results

#1. If a magnetic controller contact fails to pick up when the operating coil is energized, what could be one possible cause?

#2. If the excitation of an alternator operating in parallel is decreased below normal and the other above normal, what will be the result on the alternator with the excitation decreased below normal?

#3. If many turns of an alternating current coil for a contactor become short circuited, what will happen to the coil?

#4. How would a DC ammeter designed to directly measure current be connected?

#5. How many possible states does a binary logic circuit have?

#6. If the contacts of a motor starter or controller fail to drop out when the ’stop’ button is depressed, what could be the cause?

#7. How would you increase the frequency of an operating AC generator?

#8. If a DC motor runs faster than designed, with all other conditions being normal, what could be the possible cause?

#9. If an electric motor fails to start, what should you check FIRST?

#10. If an unloaded DC compound motor’s shunt field were weakened by excessive rheostat resistance or by an open circuit, how would the motor respond?

#11. If a short circuit in the armature of a DC motor occurs what would be the result?

#12. How will a molded-case circuit breaker with a thermal trip unit react immediately after it has tripped, as a result of an overloaded motor circuit?

#13. If all three ground-detection lamps continue to burn at equal intensity after the test button is depressed and released, which of the listed conditions is indicated?

#14. If the centrifugal switch or relay used for cutting out the starting winding of a split-phase induction motor fails to open once the motor is in operation, what will be the result?

#15. Hysteresis is one cause of electrical power loss associated with electricity generation equipment. What phenomenon results in hysteresis?

#16. How will the value of the output frequency change if the load is removed from a turbo generator having a governor speed droop setting of 3%?

#17. If a magnetic controller relay fails to drop out when the coil voltage is removed from the relay, what is the probable cause?

#18. How should the shunt of a DC ammeter be connected?

#19. If field excitation is suddenly lost to an alternator operating in parallel with another alternator, what will happen to the alternator that has experienced a loss of field excitation?

#20. Humming or buzzing of electric contacts is a symptom of what condition?

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