Competence 6

100問 • 2ヶ月前

問題一覧

What will happen if a low impedance connection is accidentally created across a charged capacitor within a high-voltage electrical work?

Large amounts of power can be quickly discharged

When troubleshooting an electronic circuit, a cold solder joint can be located with the aid of an ohmeter. Once the problem has been located, what should you do next?

reheat connection with a soldering tool and recheck with an ohmmeter

What kind of overload relay that is being actuated by an electromagnetic coil ?

Magnetic

What kind of resistance thermometer utilizes semi-conductor material which have a characteristic of a resistance decrease with temperature increase?

Thermistor

What is the ratio of effective value of the counter EMF in volts to the effective value of the current in amperes?

inductive reactance

The amount of sodium phosphate in treated boiler water can be measured by?

Phosphate test

What determines the power factor of an electrical distribution system being supplied by single AC generator ?

By components of the connected load

An instantenous trip type fuse will?

open as soon as the loadcurrent exceeds the set point

What is the transformer winding where power source is connected?

Primary winding

When a solid-state component of an electronic circuit is mounted to a metalic mass, the general purpose of that mass is to

act as a heat sink

A bus disconnect link is used to isolate?

the generator circuit breaker from the bus

After clipping the two leads together, prior to taking a resistance reading with a volt- ohmmilliammeter, the 'zero' setting must be adjusted. If you find the adjustment knob will not return the pointer to 'zero'. it is likely an indicator of ?

Batteries are weak

Electric propulsion coupling excitation is reduced at slow speed to

prevent coupling overheating

Which of the following problems will most likely occur if the starting winding of a split-phase induction motor failed to cutout once the motor was in continuous operation?

The winding will burn out

What do you call the emission of electrons from hot bodies?

radiation effect

Which of the following statements describes teh significance of ombient temperature in relation to the service life of electronic components?

Increase ambient temperature decreases the service life of electronic components

The first requirements for logical trouble shooting of any system is the ability to

recognize normal operation

What is the use of a magnetic blowout coil in a ship's crane using DC motor controller contactor?

prevent contact melting

In SF6 circuit breakers what is the meaning of SF6

Sulfur hexafluoride

When trouble shooting electronic equipment, you should use a high impedance multimeter

so as not to load down the circuit and obtain erroneous voltage readings

How would you show your understanding to a communicatin device that allows to talk to each other with the use of handset, similar to a conventional telephone but without the use of external power ?

Sound-powered telephone system

In a liquid dielectric, which of the following impurity has significant effect in reducing the breakdown strength ?

Dust

A loss of field excitation to an AC generator while operating in parallel will cause to

lose its load, begin to motorize, trip out on reverse power delay, and possibly overspeeding

On an engine throttle control system, the auxiliary control circuit are provided with devices to pervent excessive over travel of the pilot valve by the synchronous motor. These devices are called

limit switches

In a faceplate-type motor starter, the starting arm is held in the 'OFF' position by alan

strong spring

The shunt use in an ammeter should be connected to ?

series with the load and in parallel with the meter movemetn

Which of the following statements concerning analog and digital devices are correct?

The variables in digital systems are fixed quantities, and the variables in analog systems are continuous quantities

What do you call an instrument that used to measure the specific gravity of the electrolyte in a reachargeable battery ?

Hygrometer

To locate a grounded field coil in a synchronous motor, which of the instruments listed could be used ?

megohmmeter

You are attempting to parallel two AC generators, and the synchroscope pointer is revolving past in the clockwise direction. What indicates that the frequency of the incoming machine?

higher than the bus frequency

It is defined as the movement of electrical charge (the flow of electrons) through an electrical circuit is called ?

Current

What represents an application of a silicon controlled rectifier?

To provide DC power for main propulsion motor.

In a circuit that is not energized, which of the listed instrument is used ?

Ohmmeter

How is the operator ensured that he is not in contact with any unearthed conductor before insulation resistance(IR) measurement of a HV system?

Connect the insulation resistance tester to the conductor with safety earth connection ON.

What is the process of breaking up fuel oil into fine particles to ensure good combustion?

Atomization

How do shipboard electrical cables cross-sectional area express?

circular mills

RTD type sensor utilizes which principle in temperature measurement?

Wheatstone bridge principle

What is the first step in removing a generator from parallel operation.?

Decrease the governor setting on the I'off goingl' generator

Which of the following indicate when paralleling two alternators, synchronizing lamps remain lit as the synchroscope pointer approaches the O° position ?

synchroscope is defective or broken

What cause the main feed pump which can handle high temperature water without becoming vapor bound?

Required net positive suction pressure is designed into the system

What is teh degree angle when the voltage and current are out of phase so that the true power is equal to zero ?

The following are main things you should check when synchronizing a generator except for ?

current

What type of widely used thermocouple, also termed as Ni-Chromium/Ni-Alumel, with enhance reliability, preciseness, inexpensie and operate at temperature ranges between 270 to 1260 degc?

Type k

Ammeters and voltmeters use in a sinusoidal AC power system indicates which of the following values of the waveforms measured?

root means square value

The following are rating of circuit breakers except

Rated short ionization current

A triac thyristor functions as a control device and is basically

two-back-to bakc SCR's with a common gate lead

In a three-phase electrical system, three ground detecting lamps are provided. One lamp goes dark and the others increase in brightness. When the test button is pushed, all lamps have equal illunination. You should called that

There is a ground on the line with the dark lamp

While starting synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. What is this an indication of ?

motor has started properly

When using an ohmmeter to test a semi conductor diode, you find a low resistance in both forward and reverse bias direction. This indicates the the diode is.

short

On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had cut-off from synchronizaation with the propulsion generator?

Excessive vibration of the vessel

A field effect transistor function that reduces number of current carries passing through its channel

depletion mode

Which of the listed pairs of materials make the best insulators?

glass and mica

All portable electric tools should have a ground connection to prevent?

electric shock if the tool is shorted

The governor control switch of an alternator is move to the raised position. This action will

raise the no-load speed setting of the governor

Which of the following statements is correct concerning the circuits in a sound powered telephone system?

The common talking circuit is composed of two ungrounded wires

When trouble shooting electronic equipment, you should use a high impedance multimeter.

so as not to load down the circuit and obtain erroneous voltage readings

The standard method of controlling the output voltage of a 440 volt, 60 Hz, AC generator is accomplished by adjusting the

alternator filed excitation

When trouble shooting electronic equipment, the first step to be taken before testing the circuit voltage is to

check teh voltage supply from the power source

What device that gives the information about the speed of a motor in D.C. Generator?

Speedometer

A ship is generating 8MW of power at 440v from 4 diesel generator of 2MW 0.8 power factor each. How much full-load current each generator feeder cable and circuit breaker be able to handle?

3,280 Amperes

It is a type of motor that is almost the sme as an alternator

Synchronous motor

To minimize the magnetic field interaction between electrical conductors in physical proximity it is best to keep them?

at right angle and as far as practicable

To be considered as high voltage system used on board a ship, how much should be the minimum voltage?

1,000V

The magnetic energy of a transformer when created will further induced current in the ?

secondary winding

When the voltage and current developed in AC circuit reached thier peak value at the same time, the power factor is ?

maximum

In general, polyphase induction motors can be started on full line voltage by what means ?

across-the-line starters

What do you call a conductor carrier opposite to the majority current carrier which are represented by the holes in n-type material and free electrons in p-type material?

Minority current carrier

What is being used to indicate whether the alternator is running faster or slower than the other. What is this device installed in the main switchboard?

Synchroscope

When trouble shooting most electronic circuits, "loading effect" can be minimized by using a volt meter with alan

input impedance much greater than the impedance across which the voltage is being measured

On a vessel with turboelectric drive, which of the following condition would indicate that line propulsion motro had dropped out synchronization with the propulsion generator?

Excessive vibration of the vessel

Which of the started pressure condition identifies the boiler design pressure?

The pressure specified by the manufacturer as criteria for boiler design

Regarding and AC generator connected to the main electrical bus; as the electric load and power factory vary a corresponding change is reflected in the generator armature reaction.

Voltage regulator

Which of the following is developed whenever there is a relative motion of action between a magnetic field and a conductor?

electromotive force

Four lamps are connected in parallel in a single circuit. If one of the lamps burns out, the other will

burn with their original intensities

A closed loop control system which enables two or more valves operated by one controller is known as

split range control

On some diesel-electric ships, the DC propulsion motor will only attain half speed when the generator fields are fully excited. Speeds above thsi are obtained by?

raising the generator engine speed

Which of the following may cause a asingle-phase indcution motor fails to start ?

an open in the main winding

A ship is generating 8MW of power at 440V from 4 diesel generator of 2mW 0.8 power factor each. How much full-load current each generator feeder cable and circuit breaker be able to handle ?

3, 280 Amperes

Which of the following statement is true a step-down transformer in an operating AC power circuit?

Voltage decreases as current increases

Why is corrosion due to electrolytic action in modern water-tube boiler is uncommon?

boiler components are generally constructed of similar metals

Listed are the types of circuit breakers except?

Ceramic circuit breaker

Which of the following refers to a characteristics of magnetic line of force?

it travels from north to south through the sorrounding medium of bar magnet

Which of the following values of the waveforms measured in ammeters and voltmeters?

root means square value

When trouble shooting an electronic circuit, a cold solder joint can be located with the aid of an ohmmeter. Once the problem has been located, you should,

reheat connection with a soldering tool and recheck with an ohmmeter

Two paralleled alternators are operating near rated load. If one trips out mechanically which of the listed actions should be taken first?

Strip the board of all nonvital circuits.

Ships fitted with hihg-voltage installations tend to use earthed neutral electrical networks. Which one of the following best describes how excessive fault current are prevented in the event of an earth fault on these ships?

Impedance is placed in neutral earthing line.

Silicon diodes designed for a specific reverse breakdown voltage, become useful as an electronic power supply voltage regulator, called,

Zener diodes

A ground on a particular phase of a three phase low voltage system would be indicated by ?

dark or dim switchboard ground detectinglight

How can the hot spots in the bus bar or surrounding area be checked safely ?

By using infra-red thermal imaging device

In electronic industry, the abbreviation "PCB" commonly means

Printed circuit board

What do you call a direct current passing through a wire coiled around a soft iron core?

electromagnet

In synchronizing a generator with other generator, it is required that the voltae and frequency of the incoming generator is

Equal voltage, Equal frequency

Equal power factors on paralleled AC generator are maintained by an automatic

voltage regulator

When electrocuted, how much current may lead to loss of muscular control ?

25 mA

Which of the following refers to a characteristics of a magnetic line of force?

it travels from north to south through the sounding medium of bar magnet

What do you call a motor using a rheostat in the motor circuit to vary the speed?

wound-rotor induction motor

What is the part of shipboard electrical system used to control the distribution of powe to the branch circuit ?

main switchboard

What is the main reason in using an electronic megger tester essentially for polarization index of Pi test.

Because hand driven megger tester will not be able to give the steady test voltage for longer time

To provide its unique characteristics to analog circuits, the operational amplifier is made up of alan

differential amp, voltage anp and output amp

100

What would you obtain if you measure voltage and current in an inductive or capacitive circuit and then multiply them together

apparent power

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問題一覧

What will happen if a low impedance connection is accidentally created across a charged capacitor within a high-voltage electrical work?

Large amounts of power can be quickly discharged

When troubleshooting an electronic circuit, a cold solder joint can be located with the aid of an ohmeter. Once the problem has been located, what should you do next?

reheat connection with a soldering tool and recheck with an ohmmeter

What kind of overload relay that is being actuated by an electromagnetic coil ?

Magnetic

What kind of resistance thermometer utilizes semi-conductor material which have a characteristic of a resistance decrease with temperature increase?

Thermistor

What is the ratio of effective value of the counter EMF in volts to the effective value of the current in amperes?

inductive reactance

The amount of sodium phosphate in treated boiler water can be measured by?

Phosphate test

What determines the power factor of an electrical distribution system being supplied by single AC generator ?

By components of the connected load

An instantenous trip type fuse will?

open as soon as the loadcurrent exceeds the set point

What is the transformer winding where power source is connected?

Primary winding

When a solid-state component of an electronic circuit is mounted to a metalic mass, the general purpose of that mass is to

act as a heat sink

A bus disconnect link is used to isolate?

the generator circuit breaker from the bus

Batteries are weak

Electric propulsion coupling excitation is reduced at slow speed to

prevent coupling overheating

Which of the following problems will most likely occur if the starting winding of a split-phase induction motor failed to cutout once the motor was in continuous operation?

The winding will burn out

What do you call the emission of electrons from hot bodies?

radiation effect

Which of the following statements describes teh significance of ombient temperature in relation to the service life of electronic components?

Increase ambient temperature decreases the service life of electronic components

The first requirements for logical trouble shooting of any system is the ability to

recognize normal operation

What is the use of a magnetic blowout coil in a ship's crane using DC motor controller contactor?

prevent contact melting

In SF6 circuit breakers what is the meaning of SF6

Sulfur hexafluoride

When trouble shooting electronic equipment, you should use a high impedance multimeter

so as not to load down the circuit and obtain erroneous voltage readings

How would you show your understanding to a communicatin device that allows to talk to each other with the use of handset, similar to a conventional telephone but without the use of external power ?

Sound-powered telephone system

In a liquid dielectric, which of the following impurity has significant effect in reducing the breakdown strength ?

Dust

A loss of field excitation to an AC generator while operating in parallel will cause to

lose its load, begin to motorize, trip out on reverse power delay, and possibly overspeeding

On an engine throttle control system, the auxiliary control circuit are provided with devices to pervent excessive over travel of the pilot valve by the synchronous motor. These devices are called

limit switches

In a faceplate-type motor starter, the starting arm is held in the 'OFF' position by alan

strong spring

The shunt use in an ammeter should be connected to ?

series with the load and in parallel with the meter movemetn

Which of the following statements concerning analog and digital devices are correct?

The variables in digital systems are fixed quantities, and the variables in analog systems are continuous quantities

What do you call an instrument that used to measure the specific gravity of the electrolyte in a reachargeable battery ?

Hygrometer

To locate a grounded field coil in a synchronous motor, which of the instruments listed could be used ?

megohmmeter

You are attempting to parallel two AC generators, and the synchroscope pointer is revolving past in the clockwise direction. What indicates that the frequency of the incoming machine?

higher than the bus frequency

It is defined as the movement of electrical charge (the flow of electrons) through an electrical circuit is called ?

Current

What represents an application of a silicon controlled rectifier?

To provide DC power for main propulsion motor.

In a circuit that is not energized, which of the listed instrument is used ?

Ohmmeter

How is the operator ensured that he is not in contact with any unearthed conductor before insulation resistance(IR) measurement of a HV system?

Connect the insulation resistance tester to the conductor with safety earth connection ON.

What is the process of breaking up fuel oil into fine particles to ensure good combustion?

Atomization

How do shipboard electrical cables cross-sectional area express?

circular mills

RTD type sensor utilizes which principle in temperature measurement?

Wheatstone bridge principle

What is the first step in removing a generator from parallel operation.?

Decrease the governor setting on the I'off goingl' generator

Which of the following indicate when paralleling two alternators, synchronizing lamps remain lit as the synchroscope pointer approaches the O° position ?

synchroscope is defective or broken

What cause the main feed pump which can handle high temperature water without becoming vapor bound?

Required net positive suction pressure is designed into the system

What is teh degree angle when the voltage and current are out of phase so that the true power is equal to zero ?

The following are main things you should check when synchronizing a generator except for ?

current

What type of widely used thermocouple, also termed as Ni-Chromium/Ni-Alumel, with enhance reliability, preciseness, inexpensie and operate at temperature ranges between 270 to 1260 degc?

Type k

Ammeters and voltmeters use in a sinusoidal AC power system indicates which of the following values of the waveforms measured?

root means square value

The following are rating of circuit breakers except

Rated short ionization current

A triac thyristor functions as a control device and is basically

two-back-to bakc SCR's with a common gate lead

There is a ground on the line with the dark lamp

While starting synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. What is this an indication of ?

motor has started properly

When using an ohmmeter to test a semi conductor diode, you find a low resistance in both forward and reverse bias direction. This indicates the the diode is.

short

On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had cut-off from synchronizaation with the propulsion generator?

Excessive vibration of the vessel

A field effect transistor function that reduces number of current carries passing through its channel

depletion mode

Which of the listed pairs of materials make the best insulators?

glass and mica

All portable electric tools should have a ground connection to prevent?

electric shock if the tool is shorted

The governor control switch of an alternator is move to the raised position. This action will

raise the no-load speed setting of the governor

Which of the following statements is correct concerning the circuits in a sound powered telephone system?

The common talking circuit is composed of two ungrounded wires

When trouble shooting electronic equipment, you should use a high impedance multimeter.

so as not to load down the circuit and obtain erroneous voltage readings

The standard method of controlling the output voltage of a 440 volt, 60 Hz, AC generator is accomplished by adjusting the

alternator filed excitation

When trouble shooting electronic equipment, the first step to be taken before testing the circuit voltage is to

check teh voltage supply from the power source

What device that gives the information about the speed of a motor in D.C. Generator?

Speedometer

A ship is generating 8MW of power at 440v from 4 diesel generator of 2MW 0.8 power factor each. How much full-load current each generator feeder cable and circuit breaker be able to handle?

3,280 Amperes

It is a type of motor that is almost the sme as an alternator

Synchronous motor

To minimize the magnetic field interaction between electrical conductors in physical proximity it is best to keep them?

at right angle and as far as practicable

To be considered as high voltage system used on board a ship, how much should be the minimum voltage?

1,000V

The magnetic energy of a transformer when created will further induced current in the ?

secondary winding

When the voltage and current developed in AC circuit reached thier peak value at the same time, the power factor is ?

maximum

In general, polyphase induction motors can be started on full line voltage by what means ?

across-the-line starters

What do you call a conductor carrier opposite to the majority current carrier which are represented by the holes in n-type material and free electrons in p-type material?

Minority current carrier

What is being used to indicate whether the alternator is running faster or slower than the other. What is this device installed in the main switchboard?

Synchroscope

When trouble shooting most electronic circuits, "loading effect" can be minimized by using a volt meter with alan

input impedance much greater than the impedance across which the voltage is being measured

On a vessel with turboelectric drive, which of the following condition would indicate that line propulsion motro had dropped out synchronization with the propulsion generator?

Excessive vibration of the vessel

Which of the started pressure condition identifies the boiler design pressure?

The pressure specified by the manufacturer as criteria for boiler design

Regarding and AC generator connected to the main electrical bus; as the electric load and power factory vary a corresponding change is reflected in the generator armature reaction.

Voltage regulator

Which of the following is developed whenever there is a relative motion of action between a magnetic field and a conductor?

electromotive force

Four lamps are connected in parallel in a single circuit. If one of the lamps burns out, the other will

burn with their original intensities

A closed loop control system which enables two or more valves operated by one controller is known as

split range control

On some diesel-electric ships, the DC propulsion motor will only attain half speed when the generator fields are fully excited. Speeds above thsi are obtained by?

raising the generator engine speed

Which of the following may cause a asingle-phase indcution motor fails to start ?

an open in the main winding

A ship is generating 8MW of power at 440V from 4 diesel generator of 2mW 0.8 power factor each. How much full-load current each generator feeder cable and circuit breaker be able to handle ?

3, 280 Amperes

Which of the following statement is true a step-down transformer in an operating AC power circuit?

Voltage decreases as current increases

Why is corrosion due to electrolytic action in modern water-tube boiler is uncommon?

boiler components are generally constructed of similar metals

Listed are the types of circuit breakers except?

Ceramic circuit breaker

Which of the following refers to a characteristics of magnetic line of force?

it travels from north to south through the sorrounding medium of bar magnet

Which of the following values of the waveforms measured in ammeters and voltmeters?

root means square value

When trouble shooting an electronic circuit, a cold solder joint can be located with the aid of an ohmmeter. Once the problem has been located, you should,

reheat connection with a soldering tool and recheck with an ohmmeter

Two paralleled alternators are operating near rated load. If one trips out mechanically which of the listed actions should be taken first?

Strip the board of all nonvital circuits.

Impedance is placed in neutral earthing line.

Silicon diodes designed for a specific reverse breakdown voltage, become useful as an electronic power supply voltage regulator, called,

Zener diodes

A ground on a particular phase of a three phase low voltage system would be indicated by ?

dark or dim switchboard ground detectinglight

How can the hot spots in the bus bar or surrounding area be checked safely ?

By using infra-red thermal imaging device

In electronic industry, the abbreviation "PCB" commonly means

Printed circuit board

What do you call a direct current passing through a wire coiled around a soft iron core?

electromagnet

In synchronizing a generator with other generator, it is required that the voltae and frequency of the incoming generator is

Equal voltage, Equal frequency

Equal power factors on paralleled AC generator are maintained by an automatic

voltage regulator

When electrocuted, how much current may lead to loss of muscular control ?

25 mA

Which of the following refers to a characteristics of a magnetic line of force?

it travels from north to south through the sounding medium of bar magnet

What do you call a motor using a rheostat in the motor circuit to vary the speed?

wound-rotor induction motor

What is the part of shipboard electrical system used to control the distribution of powe to the branch circuit ?

main switchboard

What is the main reason in using an electronic megger tester essentially for polarization index of Pi test.

Because hand driven megger tester will not be able to give the steady test voltage for longer time

To provide its unique characteristics to analog circuits, the operational amplifier is made up of alan

differential amp, voltage anp and output amp

100

What would you obtain if you measure voltage and current in an inductive or capacitive circuit and then multiply them together

apparent power