An open coil in a transformer will be indicated by which of the listed conditions? A. 'zero' resistance accompanied by high inductance B. no resistance accompanied by stray inductance C. infinite resistance in addition to no inductance D. infinite resistance in addition to normal inductance

An open coil in a transformer will be indicated by which of the listed conditions? A. 'zero' resistance accompanied by high inductance B. no resistance accompanied by stray inductance C. infinite resistance in addition to no inductance D. infinite resistance in addition to normal inductance
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Answer: C
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When troubleshooting motor controllers, a shorted relay or contactor coil is often indicated by _______________. A. a resistance reading of 'infinity' on an ohmmeter B. charred insulation and/or a blown control fuse C. a reading of 'zero' on a megger from one of the coil's leads to ground D. a higher-than-normal voltage reading across the winding

Description : When troubleshooting motor controllers, a shorted relay or contactor coil is often indicated by _______________. A. a resistance reading of 'infinity' on an ohmmeter B. charred insulation and/or a blown ... of the coil's leads to ground D. a higher-than-normal voltage reading across the winding

Last Answer : Answer: B

Which of the listed electrical devices is represented by the symbol shown in the illustration? EL-0055 A. Fixed resistance resistor B. Coil with magnetic core C. DC motor or generator shunt field D. Transformer

Description : Which of the listed electrical devices is represented by the symbol shown in the illustration? EL-0055 A. Fixed resistance resistor B. Coil with magnetic core C. DC motor or generator shunt field D. Transformer

Last Answer : Answer: D

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? A. No grounds exist B. All three phases are grounded C. The test switch is faulty D. The current transformers are shorted out

Description : 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? A. No grounds exist B. All three phases are grounded C. The test switch is faulty D. The current transformers are shorted out

Last Answer : Answer: A

On a switchboard, if all three ground detection lamps remain burning at half intensity when the test button is depressed, which of the listed conditions is indicated? A. No grounds exist. B. All three phases are grounded. C. The test switch is grounded. D. The current transformers are shorted.

Description : On a switchboard, if all three ground detection lamps remain burning at half intensity when the test button is depressed, which of the listed conditions is indicated? A. No grounds exist. B. All three phases are grounded. C. The test switch is grounded. D. The current transformers are shorted.

Last Answer : Answer: A

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Last Answer : Answer: B

An increase in which of the listed conditions will increase the speed of a synchronous motor? A. Frequency B. Voltage C. Armature current D. Inductance

Description : An increase in which of the listed conditions will increase the speed of a synchronous motor? A. Frequency B. Voltage C. Armature current D. Inductance

Last Answer : Answer: A

A low voltage source is being used for testing armature coils. A coil short circuit will be indicated by a _______. A. high voltage reading, while the other coil readings will have an equal or lower value B. low or zero voltage reading, while the other coils will have higher readings C. fluctuating voltmeter reading, while the other coil readings are steady D. steady voltmeter reading, while the other coil readings are fluctuating

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If you disconnect and arrange both ends of a three conductor cable, without any contact between the individual conductors, an indicated ohmic value between the ends of a single conductor would indicate ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited

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Last Answer : Answer: A

The true power indicated by a wattmeter depends on the current flow through the load, the magnitude of the potential across the load, and the _____________. A. power factor of the load B. angle of coil displacement C. inertia of the movable coil D. high resistance from the load

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Last Answer : Answer: A

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Description : Three factors responsible for the change in voltage as load is applied to an AC generator are: 1) the drop in resistance in the armature circuit, 2) the change in flux, and 3) the ____________. A. armature winding speed B. inductance load drop C. coil pitch factor D. armature reactance voltage drop

Last Answer : Answer: D

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Description : Alternating current circuits develop resistance, inductance and capacitance. The inductance of a coil is expressed in _____________. A. ohms B. mhos C. henrys D. farads

Last Answer : Answer: C

Which of the following conditions indicates a short circuited capacitor when checking its condition with an ohmmeter? A. The capacitor shows charging, but the final resistance reading is appreciably less than normal. B. The reading is practically zero and remains there. C. The capacitor shows no charging action, but indicates a very high resistance. D. The pointer moves quickly to the low resistance side of the scale, then slowly recedes toward infinity.

Description : Which of the following conditions indicates a short circuited capacitor when checking its condition with an ohmmeter? A. The capacitor shows charging, but the final resistance reading is appreciably less ... moves quickly to the low resistance side of the scale, then slowly recedes toward infinity.

Last Answer : Answer: B

If a DC motor runs faster than designed, with all other conditions being normal, the possible cause could be a/an ______________. A. shorted shunt field coil B. open armature coil C. reversed commutating pole D. overload

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Last Answer : Answer: A

As shown in the illustration, which of the operations listed will happen when the 'jog button' is pushed? EL-0010 A. Coil 'CR' closes the normally open 'CR' contacts. B. Coil 'M' opens contact 'M'. C. Coil 'M' closes contact 'M'. D. Contact 'M' remains open despite the jog button being pushed.

Description : As shown in the illustration, which of the operations listed will happen when the 'jog button' is pushed? EL-0010 A. Coil 'CR' closes the normally open 'CR' contacts. B. Coil 'M' opens contact 'M'. C. Coil 'M' closes contact 'M'. D. Contact 'M' remains open despite the jog button being pushed.

Last Answer : Answer: C

The winch shown in the illustration operates in any of the positions with the master switch in the 'lower' direction, but will not 'hoist' in any of the master switch hoist positions. Which of the listed faults could be the cause? EL-0102 A. Master switch contact 'MS3' may have defective springs. B. Contactor '3M' coil could have an open winding. C. Contact '2M' in the power circuit may be badly corroded. D. Series relay 'FR' may be open.

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Last Answer : Answer: A

A three-phase, induction-type motor experiences an open in one phase. Which of the listed automatic protective devices will prevent the machine from being damaged? A. Overspeed trip B. Thermal overload relay C. Three-pole safety switch D. Magnetic blowout coil

Description : A three-phase, induction-type motor experiences an open in one phase. Which of the listed automatic protective devices will prevent the machine from being damaged? A. Overspeed trip B. Thermal overload relay C. Three-pole safety switch D. Magnetic blowout coil

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Description : 57 In a transformer the resistance between its primary and secondary is A. Zero B. 1Ω C. 1000 Ω D. Infinite

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Description : When working on electrical circuits containing large capacitors, in addition to deenergizing the circuit, which of the listed precautions should also be taken? A. Keep all radio equipment ... capacitor insulation resistance. C. Ground the capacitor terminals. D. Check capacitor circuit polarity.

Last Answer : Answer: C

A flickering ground detection lamp on a DC system would indicate a _____________. A. multiple-ground condition in the distribution system B. ground in an armature coil of an operating machine C. ground in a motor accompanied with a short D. short between two adjacent bars of the generator commutator

Description : A flickering ground detection lamp on a DC system would indicate a _____________. A. multiple-ground condition in the distribution system B. ground in an armature coil of an operating machine C. ground in a motor accompanied with a short D. short between two adjacent bars of the generator commutator

Last Answer : Answer: B

A ground in an electrical circuit outside the engine room _____________. A. cannot be detected under normal conditions B. is of no consequence to engineering personnel C. is indicated at the branch circuit breaker panel D. is indicated by the ground detecting lamps on the main switchboard

Description : A ground in an electrical circuit outside the engine room _____________. A. cannot be detected under normal conditions B. is of no consequence to engineering personnel C. is indicated at the branch circuit breaker panel D. is indicated by the ground detecting lamps on the main switchboard

Last Answer : Answer: D

Why the input resistance of an ideal OPAMP is infinite and output resistance is zero? secondly, how can we measure these resistances(input and output) in case of an ideal OPAMPand Real OP-AMP in the following conditions when 1- load is not connected. 2- load is connected.

Description : Why the input resistance of an ideal OPAMP is infinite and output resistance is zero? secondly, how can we measure these resistances(input and output) in case of an ideal OPAMPand Real OP-AMP in the following conditions when 1- load is not connected. 2- load is connected.

Last Answer : Ans- Ideal OP-AMP is a power ful concept. If one goes through the history of amplifying devices it becomes clear that less it loads the previous stage better the output signal. ie ... . Can refer application notes by device manufacturer available in internet for more precise and practical solutions.

Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? A. Higher than normal operating temperature. B. Excessive vibration at normal speed. C. Sparking at the brushes. D. High megger readings.

Description : Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? A. Higher than normal operating temperature. B. Excessive vibration at normal speed. C. Sparking at the brushes. D. High megger readings.

Last Answer : Answer: A

The efficiency of a transformer is mainly dependent on (A) core losses. (B) copper losses. (C) stray losses. (D) dielectric losses.

Description : The efficiency of a transformer is mainly dependent on (A) core losses. (B) copper losses. (C) stray losses. (D) dielectric losses.

Last Answer : Ans: A Core loss has prominent value over other losses

One item listed on the name plate of a cargo pump motor is 'degrees centigrade rise.' This number is based on _____________. A. normal temperature change from cold to hot B. an ambient temperature of 40°C C. minimum heat rise from no load to full load D. maximum degrees centigrade rise from absolute zero

Description : One item listed on the name plate of a cargo pump motor is 'degrees centigrade rise.' This number is based on _____________. A. normal temperature change from cold to hot B. an ambient temperature ... . minimum heat rise from no load to full load D. maximum degrees centigrade rise from absolute zero

Last Answer : Answer: B

Magnetic controller contacts may become welded together during operating conditions as a result of _____________. A. high spring pressure B. high ambient temperature C. an open coil D. low voltage on operating coil

Description : Magnetic controller contacts may become welded together during operating conditions as a result of _____________. A. high spring pressure B. high ambient temperature C. an open coil D. low voltage on operating coil

Last Answer : Answer: D

With both ends of a three conductor cable disconnected and arranged without the conductors touching each other, an ohmmeter reading of 'zero' ohms between the ends of one conductor would indicate _____________. A. continuity B. a partial ground C. the resistance is infinite D. a short circuit

Description : With both ends of a three conductor cable disconnected and arranged without the conductors touching each other, an ohmmeter reading of 'zero' ohms between the ends of one conductor would indicate _____________. A. continuity B. a partial ground C. the resistance is infinite D. a short circuit

Last Answer : Answer: A

When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter pointer _____________. A. fluctuating around a constant resistance reading B. dipping towards 'zero', then rising slowly C. kicking slightly downscale as voltage is applied D. continually rising as the test voltage is applied

Description : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter pointer _____________. A. fluctuating around a ... slightly downscale as voltage is applied D. continually rising as the test voltage is applied

Last Answer : Answer: C

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 _____________. A. dipping toward zero then raising slowly B. continually rising as test voltage is applied C. kicking slightly down scale as voltage is applied D. fluctuating around a constant resistance reading

Description : 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 _____________. A. dipping toward ... kicking slightly down scale as voltage is applied D. fluctuating around a constant resistance reading

Last Answer : Answer: C

A infinite resistance is considered as a/an a) Closed path(short circuit) b) Open path c) Not defined d) Ammeter with zero reading

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Last Answer : b) Open path

Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Last Answer : Answer: D

The inductance of a coil is measured in _____________. A. ohms B. volts C. henries D. amperes

Description : The inductance of a coil is measured in _____________. A. ohms B. volts C. henries D. amperes

Last Answer : Answer: C

Mention the inductance value of the peterson’s coil.

Description : Mention the inductance value of the peterson’s coil.

Last Answer : L=1/3wc2

Which of the listed conditions might contribute to very rapid wearing of a DC machine's commutator bars? A. A grounded commutator bar B. Using improper carbon brushes C. Aligning the front and rear mica V-rings improperly D. An open circuit in the armature

Description : Which of the listed conditions might contribute to very rapid wearing of a DC machine's commutator bars? A. A grounded commutator bar B. Using improper carbon brushes C. Aligning the front and rear mica V-rings improperly D. An open circuit in the armature

Last Answer : Answer: B

A coil =of inductance `L=50muH` and resistance =`0.5Omega` is connected to a battery of emf=5A. A resistance of `10Omega` is connected parallel to the

Description : A coil =of inductance `L=50muH` and resistance =`0.5Omega` is connected to a battery of emf=5A. A resistance of `10Omega` is connected parallel to the

Last Answer : A coil =of inductance `L=50muH` and resistance =`0.5Omega` is connected to a battery of emf=5A. A resistance ... is (0.02)x in mJ. Find valuie of x.

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Description : A transmitted signal 5 meters in wavelength is received by an antenna coil having a 50-Ω resistance and a 0.01 H inductance. What is the capacitance of the tuner shunting the antenna coil at this point? A. 0.704 fF B. 0.704 μF C. 0.704 nF D. 0.704 mF

Last Answer : A. 0.704 fF

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Description : A coil of inductance 240 mH and resistance 75 Ohm is connected in parallel with a capacitor across a 30 V, variable frequency supply. The current drawn by the circuit is found to be minimum when the supply frequency is 1 kHz. The ... (A) 40, 400 Hz (B) 10, 100 Hz (C) 20, 50 Hz (D) 50, 20 Hz

Last Answer : A coil of inductance 240 mH and resistance 75 Ohm is connected in parallel with a capacitor across a 30 V, variable frequency supply. The current drawn by the circuit is found to be minimum ... supply frequency is 1 kHz. The approximate values of Q-factor and bandwidth are, respectively 20, 50 Hz

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Description : When both the inductance and resistance of a coil are doubled the value of?

Last Answer : When both the inductance and resistance of a coil are doubled the value of time constant remains unchanged.

Which of the listed statements is correct when using an analog multimeter as an ohmmeter? A. The pointer should be adjusted to zero each time a new resistance range is selected. B. The pointer will move to infinity when the meter is not in use. C. Ohmmeters are not sufficiently sized to measure conductor insulation resistance. D. All of the above.

Description : Which of the listed statements is correct when using an analog multimeter as an ohmmeter? A. The pointer should be adjusted to zero each time a new resistance range is selected. B. The ... C. Ohmmeters are not sufficiently sized to measure conductor insulation resistance. D. All of the above.

Last Answer : Answer: D

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Description : Which of the devices listed is indicated by the electronic symbol lettered as 'A', shown in the illustration? EL-0016 A. Thyristor B. Diode C. Capacitor D. Transistor

Last Answer : Answer: B

Which of the devices listed is indicated by the symbols lettered 'A' to 'F', shown in the illustration? EL-0016 A. Diodes B. Linear inductors C. Capacitors D. Transistors

Description : Which of the devices listed is indicated by the symbols lettered 'A' to 'F', shown in the illustration? EL-0016 A. Diodes B. Linear inductors C. Capacitors D. Transistors

Last Answer : Answer: A

As shown in the illustration, which of the listed types of motor controllers and starters is indicated? EL-0012 A. Across-the-line B. Capacitor C. Autotransformer D. Part-winding

Description : As shown in the illustration, which of the listed types of motor controllers and starters is indicated? EL-0012 A. Across-the-line B. Capacitor C. Autotransformer D. Part-winding

Last Answer : Answer: C

An iron cored inductance coil can be modelled, over a normal operating range of networks ,as

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Last Answer : An iron cored inductance coil can be modelled, over a normal operating range of networks ,as linear bilateral element

A ground is indicated by the ground-detecting system on the main electrical switchboard. The FIRST step in locating the actual ground is to _____________. A. close all circuit breakers in the distribution panel until the ground detector indicates normal B. open the individual circuit breakers, one by one until the ground detection system indicates normal C. change over generators D. check each circuit with a megohmmeter

Description : A ground is indicated by the ground-detecting system on the main electrical switchboard. The FIRST step in locating the actual ground is to _____________. A. close all circuit breakers in ... ground detection system indicates normal C. change over generators D. check each circuit with a megohmmeter

Last Answer : Answer: B

I13) In an ideal transformer A. windings have no resistance B. core has no losses C. core has infinite permeability D. all of the above

Description : 13) In an ideal transformer A. windings have no resistance B. core has no losses C. core has infinite permeability D. all of the above

Last Answer : D. All of the above

As shown in the illustration, which listed action will occur first when push button 'Q' is depressed? EL-0017 A. Contacts 'H-1', 'H-2' and 'H-3' close. B. Contact 'H-4' closes. C. Operating coil 'C' energizes. D. Switch 'R' opens.

Description : As shown in the illustration, which listed action will occur first when push button 'Q' is depressed? EL-0017 A. Contacts 'H-1', 'H-2' and 'H-3' close. B. Contact 'H-4' closes. C. Operating coil 'C' energizes. D. Switch 'R' opens.

Last Answer : Answer: C

If the motor shown in the illustration will not start when 'Q' is depressed, which of the listed components should be checked FIRST? EL-0017 A. Fuses 'F-1' and 'F-2'. B. Operating coil 'C'. C. Contacts 'H-1', 'H-2', and 'H-3'. D. Contact 'H-4'.

Description : If the motor shown in the illustration will not start when 'Q' is depressed, which of the listed components should be checked FIRST? EL-0017 A. Fuses 'F-1' and 'F-2'. B. Operating coil 'C'. C. Contacts 'H-1', 'H-2', and 'H-3'. D. Contact 'H-4'.

Last Answer : Answer: A

Which of the listed procedures is the best way to tell if a motor has become overloaded? A. Measure the current flow and compare it with the motor full load current flow as shown on the nameplate. B. Feel the motor and judge by the temperature. C. Watch for telltale signs of smoke coming from the motor. D. Periodic opening of the O/L relay coil

Description : Which of the listed procedures is the best way to tell if a motor has become overloaded? A. Measure the current flow and compare it with the motor full load current flow as shown on the nameplate. ... Watch for telltale signs of smoke coming from the motor. D. Periodic opening of the O/L relay coil

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Which of the instruments listed could be use to locate a grounded field coil in a synchronous motor? A. Ammeter B. Voltmeter C. Megohmmeter D. Frequency meter

Description : Which of the instruments listed could be use to locate a grounded field coil in a synchronous motor? A. Ammeter B. Voltmeter C. Megohmmeter D. Frequency meter

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