A fuse will 'blow' if _____________. A. an electric motor is stopped suddenly by opening a switch B. the flow of current to the protection device is reversed C. the electrical current exceeds the rated value of the fuse D. unequal resistors are connected in parallel

A fuse will 'blow' if _____________. A. an electric motor is stopped suddenly by opening a switch B. the flow of current to the protection device is reversed C. the electrical current exceeds the rated value of the fuse D. unequal resistors are connected in parallel
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Answer: C
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Related questions

You are using a mechanical voltage tester to check the fuses in a three-phase circuit supplying an electric motor. For which of the following reasons must the motor be stopped during the test? A. Testing an energized circuit presents a hazard to the testing personnel. B. A faulty fuse could go undetected with the motor energized. C. Reversed polarity of the circuit would be indicated by the voltage tester with the circuit energized. D. All of the above.

Description : You are using a mechanical voltage tester to check the fuses in a three-phase circuit supplying an electric motor. For which of the following reasons must the motor be stopped during the test? A. ... circuit would be indicated by the voltage tester with the circuit energized. D. All of the above.

Last Answer : Answer: B

When three resistors with unequal values are connected in parallel, _______

Description : When three resistors with unequal values are connected in parallel, _______ A) The current across the resistors is the same  B) The voltage drop across the resistors is the same C) The voltage drops across the resistors is proportional to the resistance of each resistor D) None of these

Last Answer : When three resistors with unequal values are connected in parallel, The voltage drop across the resistors is the same

An instantaneous-trip-type fuse will _____________. A. open as soon as the load current exceeds its set point B. allow a preset delay between overcurrent and melting C. open a circuit by using a time delay element with a magnetic trip D. reset itself when the overcurrent is corrected

Description : An instantaneous-trip-type fuse will _____________. A. open as soon as the load current exceeds its set point B. allow a preset delay between overcurrent and melting C. open a circuit by using a time delay element with a magnetic trip D. reset itself when the overcurrent is corrected

Last Answer : Answer: A

The function of fuse in an electrical circuit is (a) avoid electric shocks (b) regulate the flow of current (c) break the circuit in case of overloading or short circuiting (d) switch off current

Description : The function of fuse in an electrical circuit is (a) avoid electric shocks (b) regulate the flow of current (c) break the circuit in case of overloading or short circuiting (d) switch off current

Last Answer : Ans:(c)

One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for polarity using a/an ____________. A. iron bar across each field B. magnetic compass placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections

Description : One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for ... placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections

Last Answer : Answer: B

A split-phase induction squirrel-cage motor will not come up to speed, even though the rated voltage, rated frequency, and rated load are applied. The suspected trouble could be due to _____________. A. a faulty centrifugal switch B. broken rotor bars C. worn bearings D. all of the above

Description : A split-phase induction squirrel-cage motor will not come up to speed, even though the rated voltage, rated frequency, and rated load are applied. The suspected trouble could be due to _____________. A. a faulty centrifugal switch B. broken rotor bars C. worn bearings D. all of the above

Last Answer : Answer: D

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, the _____________. A. motor will overspeed B. starting winding will burn out C. motor will immediately stall under load D. motor torque will be above normal at rated speed

Description : 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, the _____________. A. motor will overspeed B ... C. motor will immediately stall under load D. motor torque will be above normal at rated speed

Last Answer : Answer: B

To repair a small electrical motor that has been submerged in saltwater, you should _____________. A. wash it with fresh water and apply an external source of heat B. renew the windings C. send it ashore to an approved service facility D. rinse all electrical parts with a carbon tetrachloride cleaning solvent and then blow dry the motor with compressed air

Description : To repair a small electrical motor that has been submerged in saltwater, you should _____________. A. wash it with fresh water and apply an external source of heat B. renew the windings ... electrical parts with a carbon tetrachloride cleaning solvent and then blow dry the motor with compressed air

Last Answer : Answer: A

Uneven wear of the commutator surface on a direct current propulsion motor can be caused by _____________. A. rapid change in load B. excessive operation at light load C. incorrect brush staggering D. unequal pole spacing

Description : Uneven wear of the commutator surface on a direct current propulsion motor can be caused by _____________. A. rapid change in load B. excessive operation at light load C. incorrect brush staggering D. unequal pole spacing

Last Answer : Answer: C

The air gap provided in induction motors should be checked periodically with a feeler gage to detect an unequal air gap and _____________. A. decreased motor magnetizing current B. hysteresis loses C. increased power factor D. mechanical damage to the rotor

Description : The air gap provided in induction motors should be checked periodically with a feeler gage to detect an unequal air gap and _____________. A. decreased motor magnetizing current B. hysteresis loses C. increased power factor D. mechanical damage to the rotor

Last Answer : Answer: D

The purpose of a motor undervoltage protection device is to _____________. A. prevent high armature current when power is restored B. start the motor at a very low voltage C. trip the load off the motor in case of fire D. protect personnel from low voltage shocks

Description : The purpose of a motor undervoltage protection device is to _____________. A. prevent high armature current when power is restored B. start the motor at a very low voltage C. trip the load off the motor in case of fire D. protect personnel from low voltage shocks

Last Answer : Answer: A

When shipboard electrical distribution circuits are connected in parallel, additional parallel circuits will cause the total circuit resistance to _____________. A. increase, causing a drop in the line current B. increase, causing a decrease in the line voltage C. decrease, causing an increase in the line voltage D. decrease, causing an increase in the line current

Description : When shipboard electrical distribution circuits are connected in parallel, additional parallel circuits will cause the total circuit resistance to _____________. A. increase, causing a drop in the line current B ... an increase in the line voltage D. decrease, causing an increase in the line current

Last Answer : Answer: D

In addition to short circuits and sustained overloads, fuses are likely to blow due to _____________. A. loose fuse clips B. low ambient temperatures C. low contact resistance D. all of the above

Description : In addition to short circuits and sustained overloads, fuses are likely to blow due to _____________. A. loose fuse clips B. low ambient temperatures C. low contact resistance D. all of the above

Last Answer : Answer: A

Severe vibration, accompanied by flashover at the collector rings of an alternator operating in parallel, is a symptom of _____________. A. reverse current motorization B. loss of synchronism C. destructive overspeeding D. reversed polarity

Description : Severe vibration, accompanied by flashover at the collector rings of an alternator operating in parallel, is a symptom of _____________. A. reverse current motorization B. loss of synchronism C. destructive overspeeding D. reversed polarity

Last Answer : Answer: B

The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the 'master switch' housing & control panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Description : The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the ' ... panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Last Answer : Answer: B

If a small electric motor has been submerged in saltwater for a short period of time, you should _____________. A. send it ashore for rewinding B. rinse it with warm freshwater and bake it dry in an oven C. soak it in a bucket of commercial solvent and bake with internal heat D. clean it with carbon tetrachloride and blow it out with compressed air

Description : If a small electric motor has been submerged in saltwater for a short period of time, you should _____________. A. send it ashore for rewinding B. rinse it with warm freshwater and bake it dry ... and bake with internal heat D. clean it with carbon tetrachloride and blow it out with compressed air

Last Answer : Answer: B

If an electric motor fails to start, you should FIRST check the _____________. A. phase sequence B. ampere load C. fuse or circuit breaker D. line frequency

Description : If an electric motor fails to start, you should FIRST check the _____________. A. phase sequence B. ampere load C. fuse or circuit breaker D. line frequency

Last Answer : Answer: C

A battery is connected to a circuit containing three resistors in parallel. The values of the three resistors are 2 ohms, 3 ohms, and 6 ohms. What is the voltage of the battery if the total circuit current is 12 amps? A. 2 volts B. 6 volts C. 12 volts D. 24 volt

Description : A battery is connected to a circuit containing three resistors in parallel. The values of the three resistors are 2 ohms, 3 ohms, and 6 ohms. What is the voltage of the battery if the total circuit current is 12 amps? A. 2 volts B. 6 volts C. 12 volts D. 24 volt

Last Answer : Answer: C

The rated temperature rise of an electric motor is the _____________. A. average temperature at any given latitude B. normal temperature rise above the standard ambient temperature at rated load C. average temperature rise due to resistance at 10% overload D. permissible difference in the ambient temperature of the motor due to existing weather conditions

Description : The rated temperature rise of an electric motor is the _____________. A. average temperature at any given latitude B. normal temperature rise above the standard ambient temperature at rated load ... D. permissible difference in the ambient temperature of the motor due to existing weather conditions

Last Answer : Answer: B

An electrical connection between the wiring of an electric motor and its metal frame is known as a/an _____________. A. eddy current B. ground C. impedance D. flux leakage

Description : An electrical connection between the wiring of an electric motor and its metal frame is known as a/an _____________. A. eddy current B. ground C. impedance D. flux leakage

Last Answer : Answer: B

Which of the following conditions is most likely to occur if a single element fuse were used to replace a blown dual element fuse in a motor controller circuit? A. The fuse will blow when the motor is started. B. The fuse works, but overheats at high motor loads. C. The motor runs at reduced voltage. D. The motor runs normally.

Description : Which of the following conditions is most likely to occur if a single element fuse were used to replace a blown dual element fuse in a motor controller circuit? A. The fuse will blow when the motor ... overheats at high motor loads. C. The motor runs at reduced voltage. D. The motor runs normally.

Last Answer : Answer: A

In the illustrated motor controller, the motor fails to start. A voltmeter reading between 1 and 6 reads line voltage, while the voltmeter reading between 2 and 6 reads 0 VAC. The problem is __________. EL-0007 A. the control fuse is the wrong amperage not allowing full current to pass through B. the stop switch is open C. an open in the 'M' coil, 'Ma' contact/start switch or overload contacts D. fuse '10a' is blown

Description : In the illustrated motor controller, the motor fails to start. A voltmeter reading between 1 and 6 reads line voltage, while the voltmeter reading between 2 and 6 reads 0 VAC. The problem is __________. EL- ... in the 'M' coil, 'Ma' contact/start switch or overload contacts D. fuse '10a' is blown

Last Answer : Answer: B

In order to safely carry out repairs to a generator circuit breaker, it must be isolated from the bus. This is accomplished by opening the _____________. A. reverse power relay B. bus disconnect link C. generator bus fuse connections D. power directional relay

Description : In order to safely carry out repairs to a generator circuit breaker, it must be isolated from the bus. This is accomplished by opening the _____________. A. reverse power relay B. bus disconnect link C. generator bus fuse connections D. power directional relay

Last Answer : Answer: B

The electrical diagram shown in the illustration shows _____________. EL-0021 A. 'R1', 'R2', and 'R3' are connected is series B. 'R1', 'R2', and 'R3' are connected in parallel C. the voltages measured across 'R1', 'R2' and 'R3' will be different if 'R1', 'R2' and 'R3' have different values D. the total resistance equals R1 + R2 + R3

Description : The electrical diagram shown in the illustration shows _____________. EL-0021 A. 'R1', 'R2', and 'R3' are connected is series B. 'R1', 'R2', and 'R3' are connected in parallel C. the voltages measured across ... if 'R1', 'R2' and 'R3' have different values D. the total resistance equals R1 + R2 + R3

Last Answer : Answer: B

If an induction motor were to be operated at 90% rated voltage, _____________. A. there would be an increase in starting torque B. starting current would increase slightly C. synchronous speed would decrease slightly D. the slip would increase

Description : If an induction motor were to be operated at 90% rated voltage, _____________. A. there would be an increase in starting torque B. starting current would increase slightly C. synchronous speed would decrease slightly D. the slip would increase

Last Answer : Answer: D

A circuit breaker and a fuse have a basic similarity in that they both _____________. A. can be reset to energize the circuit B. should open the circuit when overloaded C. will burn out when an over current flow develops D. all of the above

Description : A circuit breaker and a fuse have a basic similarity in that they both _____________. A. can be reset to energize the circuit B. should open the circuit when overloaded C. will burn out when an over current flow develops D. all of the above

Last Answer : Answer: B

A low-voltage protection circuit is used in electric motor starting equipment to _____________. A. trip circuit contactors when the motor overspeeds due to low voltage B. trip circuit contactors when the motor develops a short circuit due to low voltage C. allow the motor to restart automatically on restoration of voltage without manually resetting D. prevent the motor from restarting automatically on restoration of voltage

Description : A low-voltage protection circuit is used in electric motor starting equipment to _____________. A. trip circuit contactors when the motor overspeeds due to low voltage B. trip circuit ... voltage without manually resetting D. prevent the motor from restarting automatically on restoration of voltage

Last Answer : Answer: D

When troubleshooting a motor controller, all indications are that a relay coil should be energized. If there were no magnetic pull, with rated voltage measured across the coil, the most probable cause would be that the _________________. A. coil is open B. control fuse is open C. auxiliary contact in series with the coil is defective D. relay armature is stuck

Description : When troubleshooting a motor controller, all indications are that a relay coil should be energized. If there were no magnetic pull, with rated voltage measured across the coil, the most probable cause ... open C. auxiliary contact in series with the coil is defective D. relay armature is stuck

Last Answer : Answer: A

If field excitation is suddenly lost to an alternator operating in parallel, that alternator will _____________. A. supply excessive current to the bus B. operate at the same load, but with reduced voltage C. lose its load and tend to overspeed D. become overloaded and slow down

Description : If field excitation is suddenly lost to an alternator operating in parallel, that alternator will _____________. A. supply excessive current to the bus B. operate at the same load, but with reduced voltage C. lose its load and tend to overspeed D. become overloaded and slow down

Last Answer : Answer: C

In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors

Description : In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors

Last Answer : Answer: C

When 220V dc shunt alternator generating the voltage at rated value. If direction of rotation is reversed, then alternator will a) Build up its voltage with same polarity b) Build up its voltage with opposite polarity c) No build up of voltage d) None

Description : When 220V dc shunt alternator generating the voltage at rated value. If direction of rotation is reversed, then alternator will a) Build up its voltage with same polarity b) Build up its voltage with opposite polarity c) No build up of voltage d) None

Last Answer : Ans: No build up of voltage

When an operating motor is connected to the controller shown in the illustration, the a path of current flow through the circuit is ____________. EL-0010 A. 'L1', stop button, start button, coil 'CR', 'L2' B. 'L1', stop button, 'CR' and 'M' contacts, 'M' coil, 'OL contacts, the 'CR' coil in parallel, 'L2' C. 'L1', stop button, jog button, 'CR' contact, 'CR' relay, 'L2' D. 'L1', stop button, start button, 'CR' contact, 'M' contact, 'CR' coil, 'L2'

Description : When an operating motor is connected to the controller shown in the illustration, the a path of current flow through the circuit is ____________. EL-0010 A. 'L1', stop button, start button, coil 'CR', 'L2' B. 'L1' ... L2' D. 'L1', stop button, start button, 'CR' contact, 'M' contact, 'CR' coil, 'L2'

Last Answer : Answer: B

If the connections for the field and the armature on a DC motor are reversed, _____________. A. the motor will run as a generator B. the motor will not run C. the direction of rotation will be the same D. the direction of rotation will be reversed

Description : If the connections for the field and the armature on a DC motor are reversed, _____________. A. the motor will run as a generator B. the motor will not run C. the direction of rotation will be the same D. the direction of rotation will be reversed

Last Answer : Answer: C

A three-phase, squirrel cage, induction motor will run hot due to _____________. A. open stator coils B. high power factor C. dirty or corroded slip rings D. reversed commutating poles

Description : A three-phase, squirrel cage, induction motor will run hot due to _____________. A. open stator coils B. high power factor C. dirty or corroded slip rings D. reversed commutating poles

Last Answer : Answer: A

The rotation of a three-phase induction motor can be reversed by _____________. A. interchanging any two of the three line leads to the stator B. disconnecting one of the three line leads to the stator C. switching the shunt field coil leads D. permanently disconnecting any two of the three line leads to the stator

Description : The rotation of a three-phase induction motor can be reversed by _____________. A. interchanging any two of the three line leads to the stator B. disconnecting one of the three line leads to the ... the shunt field coil leads D. permanently disconnecting any two of the three line leads to the stator

Last Answer : Answer: A

The speed of a squirrel-cage motor is usually changed by _____________. A. varying the frequency to the machine B. adding resistance in series with the stator windings C. adding resistance in parallel with the stator windings D. changing the number of connected poles in the stator

Description : The speed of a squirrel-cage motor is usually changed by _____________. A. varying the frequency to the machine B. adding resistance in series with the stator windings C. adding resistance in parallel with the stator windings D. changing the number of connected poles in the stator

Last Answer : Answer: D

The electrical device shown in the illustration is a/an _____________. EL-0077 A. operating coil B. indicating lamp C. motor armature D. potentiometer

Description : The electrical device shown in the illustration is a/an _____________. EL-0077 A. operating coil B. indicating lamp C. motor armature D. potentiometer

Last Answer : Answer: D

Shading coils are installed on AC full-voltage starters to _____________. A. eliminate contact chatter B. dissipate opening contact arcs C. delay current build up in the holding coil D. protect the motor windings from momentary starting current overload

Description : Shading coils are installed on AC full-voltage starters to _____________. A. eliminate contact chatter B. dissipate opening contact arcs C. delay current build up in the holding coil D. protect the motor windings from momentary starting current overload

Last Answer : Answer: A

To limit the current flow through a DC voltmeter to as low a value as possible, the moving coil circuit is provided with a/an _____________. A. high series resistance B. high parallel resistance C. series inductor D. external shunt

Description : To limit the current flow through a DC voltmeter to as low a value as possible, the moving coil circuit is provided with a/an _____________. A. high series resistance B. high parallel resistance C. series inductor D. external shunt

Last Answer : Answer: A

The direction of rotation of a DC propulsion motor can be reversed by __________. A. reversing the field connections B. reversing the field and the armature connections C. wiring the field and armature in parallel D. wiring the field and armature in series

Description : The direction of rotation of a DC propulsion motor can be reversed by __________. A. reversing the field connections B. reversing the field and the armature connections C. wiring the field and armature in parallel D. wiring the field and armature in series

Last Answer : Answer: A

The power factor at which a paralleled AC generator operates is usually adjusted by the _____________. A. connected load B. prime mover speed C. field excitation D. generator's rated voltage

Description : The power factor at which a paralleled AC generator operates is usually adjusted by the _____________. A. connected load B. prime mover speed C. field excitation D. generator's rated voltage

Last Answer : Answer: C

Which of the listed items will stop a motor due to a reduction in voltage and restart it when the voltage is restored to normal? A. Low voltage protection circuit B. Non-renewable link fuse C. Renewable link fuse D. Low voltage release circuit

Description : Which of the listed items will stop a motor due to a reduction in voltage and restart it when the voltage is restored to normal? A. Low voltage protection circuit B. Non-renewable link fuse C. Renewable link fuse D. Low voltage release circuit

Last Answer : Answer: D

ECE Board Exam March 1996 A device to be connected across the headset in telephone receivers to reduce the effects of acoustic shock. A. Ground B. Two rectifiers in parallel with opposite polarities C. Protector D. Fuse

Description : ECE Board Exam March 1996 A device to be connected across the headset in telephone receivers to reduce the effects of acoustic shock. A. Ground B. Two rectifiers in parallel with opposite polarities C. Protector D. Fuse

Last Answer : B. Two rectifiers in parallel with opposite polarities

The total voltage of a series circuit is the _____________. A. sum of the individual voltage drops B. total resistance divided by the total current C. sum of the individual currents multiplied by the number of resistors D. total current divided by the total resistance

Description : The total voltage of a series circuit is the _____________. A. sum of the individual voltage drops B. total resistance divided by the total current C. sum of the individual currents multiplied by the number of resistors D. total current divided by the total resistance

Last Answer : Answer: A

A single-phase induction motor starts, comes up to about 75% rated speed, slows down to a lower speed, and accelerates again. The problem is most likely in the ____________. A. starting winding B. running winding C. starting capacitor D. running centrifugal switch

Description : A single-phase induction motor starts, comes up to about 75% rated speed, slows down to a lower speed, and accelerates again. The problem is most likely in the ____________. A. starting winding B. running winding C. starting capacitor D. running centrifugal switch

Last Answer : Answer: B

In the event of a power failure during cargo loading operations, the movement of an electric powered cargo winch will be stopped by ____________. A. a manual override switch B. the weight of the load on the boom C. a spring set brake D. a hand operated band brake

Description : In the event of a power failure during cargo loading operations, the movement of an electric powered cargo winch will be stopped by ____________. A. a manual override switch B. the weight of the load on the boom C. a spring set brake D. a hand operated band brake

Last Answer : Answer: C

When a battery-charging panel is being used, the batteries will discharge if _____________. A. DC voltage is supplied B. the polarity is reversed C. the voltage fluctuates D. too little current is supplied

Description : When a battery-charging panel is being used, the batteries will discharge if _____________. A. DC voltage is supplied B. the polarity is reversed C. the voltage fluctuates D. too little current is supplied

Last Answer : Answer: B

A supply of 24 V DC is applied across a circuit which consist of three resistors connected in parallel R1= 1.2KΩ, R2= 560 Ω, R3= 2.1Ω and a fourth resistor of 7.8 Ω connected in series with the parallel group. Determine the current, voltage and power across each resistor

Last Answer : Req= (1/1200 +1/560 + 1/2.1)^-1        = 2.1 ohms RT= 2.1 + 7.8      = 9.9 ohms IT = V/R = 24/9.9                = 2.4 A Veq= R I =  2.1 2 ... 7.8         = 12.096 w                 = 44.928 w _________________________________________ By: Ellis-Junior Kamatjipose [email protected]

Consider a circuit with four 10 Ω resistors connected in parallel and the current flowing through the circuit is

Description : Consider a circuit with four 10 Ω resistors connected in parallel and the current flowing through the circuit is 5 A. What will be the current if the above 4 resistors are connected in parallel? A) 5 A B) 50 A C) 500 A D) None of these

Last Answer : Consider a circuit with four 10 Ω resistors connected in parallel and the current flowing through the circuit is 5 A. What will be the current if the above 4 resistors are connected in parallel? A) 5 A B) 50 A C) 500 A D) None of these

Why will too many electrical devices operating at one time after blow a fuse or trip a circuit breaker?

Description : Why will too many electrical devices operating at one time after blow a fuse or trip a circuit breaker?

Last Answer : The load exceeds the limit of the breaker or fuse. For example a20 amp breaker on a 120 volt circuit will handle 2400 watts. Exceedthat wattage and the breaker will trip or the fuse will blow.