Study individual questions with detailed AI explanations
Showing 577 of 577 questions
A degree of control over the speed of a slip ring induction motor can be obtained by what means?
What is the characteristic of a wound-rotor induction motor, with a high resistance inserted in series with the rotor wi...
As shown in the illustrated wound-rotor induction motor, what statement is true concerning motor lead connections? Illus...
What type of AC motor would use a rheostat in the rotor circuit to vary the speed of the motor?
Which of the following physical characteristics does a three-phase wound-rotor induction motor possess that a squirrel-c...
As part of a routine maintenance program for deck machinery motor controllers, what should be done?
If a spring-set electric solenoid-released brake on a winch fails to hold a load properly when the solenoid is de-energi...
The AC winch hoist controller shown in the illustration has a burned out hoist contactor coil that must be replaced. Bef...
If deck machinery is expected to be idle for an extended period of time, what should be done?
An AC winch hoist controller such as shown in the illustration has welded contacts on the hoist contactor, and the conta...
Relative to the number of turns of a secondary winding of a step-up transformer, what will be the number of turns of a p...
When a transformer is used to step down voltage, what statement is true?
Which of the following statements is true concerning step-down transformer operation?
If the illustrated device in figure "B" has a step-up ratio of 10 to 1 what voltage would be measured at the secondary s...
The transformer diagram shown in figure "B" of the illustration represents what type of transformer? Illustration EL-008...
What is the purpose of a potential transformer in an electric circuit?
Which of the listed figures shown in the illustration represents a three phase transformer connected in a wye-wye config...
What is the primary purpose associated with the use of transformers onboard ships with AC generators?
An autotransformer is equipped with a 50% tap, a 65% tap, and an 80% tap. Which of the following statements is true conc...
Which of the following pictures shown in the illustration is a control transformer, usually used to step down line volta...
If the primary winding of a voltage transformer is connected to a steady DC source, self- inductance and mutual inductan...
If a digital multimeter is set up as shown in figures "A" and "B" of the illustration, what is the status of the silicon...
Which of the procedures or conditions listed could result in damaging a transistor beyond repair?
Using the trouble analysis chart and faults table provided in the illustration, if the gyrocompass was malfunctioning, b...
What effect will increasing the power source frequency have in a capacitive circuit?
When troubleshooting most electronic circuits, what voltmeter characteristic can minimize the 'loading effect'?
What type of DC motor has extremely high starting torque, but has poor inherent speed regulation?
What type of DC motor is never connected to a belt driven load?
The wiring diagram found in figure "C" of the illustration represents what type of DC motor? Illustration EL-0054
How is the speed of a series wound winch motor controlled?
In a series wound motor, the current passing through the field windings also passes through what component?
Which of the following types of DC motors is considered to produce the highest starting torque?
A 480/120 VAC step-down control transformer is configured as shown in figure "E" of the illustration. When 480 VAC is ap...
An open primary coil in a simple potential transformer will be indicated by which of the listed conditions?
A 4160/480Y-277 VAC three phase power transformer bank as configured in figure "3" of the illustration produces the foll...
Which of the pictured motors within the split phase family of single phase induction motors represents a split phase, re...
Which statement is true concerning a split-phase induction motor?
As shown in figures "A", "B", "C", and "D" of the illustration, what is the usual means by which the rotation direction ...
A shaded-pole motor is a specific type of motor included in what class of motor?
Which type of AC single-phase motor will also operate on direct current?
Within the split phase family of single phase motors, what are the operational characteristics of the motor shown in fig...
What type of rotor is most commonly used in the split-phase family of single-phase motors?
What is the main function in the use of a capacitor for starting a single phase motor?
What are the operational characteristics of the split phase motor shown in figure "A" of the illustration? Illustration ...
What is the main purpose of the auxiliary winding on a split-phase, single-phase motor?
What is the primary means by which an electrical maintenance worker is protected from electrical hazards while performin...
At a minimum threshold, how many milliamps of current through the body produces a condition where most people would expe...
Which of the following devices would be forbidden to use as a primary means of electrical isolation?
After prior isolation and lockout/tagout procedures are performed, which electrical device requires discharging any stor...
At a minimum threshold, how many milliamps of current through the body produces a condition where most people would suff...
Before electrical work can be safely undertaken, the equipment must be de-energized, locked and tagged out, and verifica...
At a minimum threshold, how many milliamps of current through the body produces a condition where most people would be u...
Which of the following voltage testers would be associated with high quality, be safe to use, and minimize the electric ...
With all other factors considered equal (such as voltage, conducting path through the body and the duration of contact),...
At a minimum threshold, how many milliamps of current through the body produces a painful sensation that most people wou...
Of the listed factors that influence the amount of RMS voltage induced in the windings of an AC generator operating at a...
A DC generator which is used to supply direct current in order to provide magnetizing current to an AC generator field i...
If the driving torque, such as that produced by a diesel engine, creates pulsations when coupled with a synchronous gene...
How are AC and DC generators similar?
Which of the following statements about a three-phase wye connected alternator is correct?
As shown in the illustration, the change-over switch is what type of device? Illustration EL-0058
What is the purpose of the inner phosphor coating of the fluorescent tube as shown in figure "A" of the illustration? Il...
Which of the following figures shown in the illustration represents incandescent lighting? Illustration EL-0122
Besides the fluorescent lamp itself and possibly a starter, which of the following components is included in a fluoresce...
Incandescent lamps are classified according to the shape of the bulb and the type of service, as well as the size and st...
By what means is an AC generator prevented from becoming motorized?
Diesel-generators #1 and #2 are operating in parallel at near full load capacity. Diesel-generator #1 suddenly trips out...
Two AC generators are operating in parallel and both are equipped with automatic voltage regulators. While standing watc...
While paralleling 2 AC generators using synchronizing lamps only, when will both lamps go dark?
Upon failure of the normal power supply, by what means is the emergency generator placed on the line and connected to th...
When shore power is being connected to a ship in drydock, what must be ensured, assuming that the ship's generators are ...
When paralleling two alternators the synchronizing lamps grow dim and are totally darkened as the synchroscope pointer a...
As shown in the illustrated plots of uncorrected and temperature corrected insulation resistance readings for a particul...
When testing insulation resistance of electric equipment and machinery, ideally when should the insulation resistance be...
When regreasing the electric motor bearing as shown in figure "B" of the illustration, what practice should be avoided? ...
What would be the indication of a grounded switch or cable as measured by a megohmmeter?
Before any work on electrical or electronic equipment is performed, which of the following precautions should be carried...
What should be included in the routine periodic maintenance checks for electrical motors?
If overloading an electric motor becomes necessary in an emergency situation, what should be done to prevent damage to t...
When a compound wound DC motor is differentially compounded, what does this mean?
Which of the listed DC compound motor connection schemes is the most commonly used?
The wiring diagram found in figure "B" of the illustration represents what type of DC motor? Illustration EL-0054
Assuming that a cumulatively compounded DC motor is fitted with interpoles and compensating windings, normally how is th...
When a compound wound DC motor is cumulatively compounded, what does this mean?
In the event of a power failure during cargo loading operations, the movement of an electric powered cargo winch will be...
What statement is true concerning the 'MS 1' contacts of the master switch shown in the illustration? Illustration EL-01...
As shown in the illustration, what is responsible for maintaining the "UV" relay energized when the master switch handl...
When the control handle is in the 'off' position, what is the status of the solenoid actuated brake of an electric winch...
What is the functional purpose of the 'MS 2' contacts in the hoist controller circuit shown in the illustration? Illustr...
As shown in the illustration, how are the rotor windings of the motor configured? Illustration EL-0102
What is the functional purpose of the 'LSL' contacts for the hoist controller circuit shown in the illustration? Illustr...
Which of the listed conditions occur when selection is made for 'third point hoist' on the winch hoist controller shown ...
What type of motor is used in the AC hoist controller as shown in the illustration? Illustration EL-0102
What is the nominal open-circuit cell voltage of one lead-acid storage battery cell?
As shown in the cutaway view of the lead-acid battery in figure "A" of the illustration, if one-half of the battery's ce...
Which of the following statements describes the effects of ambient temperature on local action within lead-acid storage ...
To keep emergency lead-acid batteries in a full state of charge for emergency use, what is normally done?
Assuming that the electrolyte has had sufficient time to be uniformly diffused throughout the cell, if the open-circuit ...
With regard to the maintenance of electrical generating machines with insulated pedestal bearings, what practice should ...
In performing routine maintenance of a ship's service alternator, what should be included?
How may chattering of the collector/slip ring brushes on a generator be remedied?
Which of the following statements, concerning the cleaning maintenance of a brushless generator, is correct?
Which of the following materials is recommended for burnishing the slip rings of an alternator after grinding or turning...
If rotor-to-stator air gap readings for an electrical generating machine have changed significantly from the last readin...
When an alternator is to remain idle for even a few days, what should be done?
Rotor-to-stator air gap readings should be periodically taken for electrical generation equipment. What is the best tool...
What would be the total current in figure "A" of the circuit illustrated if the value of capacitor C1 was 100 microfarad...
In the schematic of the electrical circuit shown in figure "A" of the illustration, what is the value of the total capac...
If a circuit has resistances of 5, 10, and 20 ohms connected in parallel, what is the combined total resistance of the c...
Two 100 watt light bulbs rated at 100 volts are connected in parallel across a 100 volt power supply. What will be the t...
What is the current flowing through R3 in figure "B" of the illustrated circuit when the switch is closed if the battery...
What would be the capacitive reactance of the circuit shown in figure "A" of the illustration if the capacitance of C1 w...
What would be the total capacitance of the circuit illustrated in figure "A" if the value of capacitor C1 was 100 microf...
As shown in figure "A" of the illustration, with the switch closed what statement is true if 'R1' and 'R2' have unequal ...
Four lamps are connected in parallel in a single circuit. If one of the lamps burns out, what will happen to the other l...
What statement is true concerning the total resistance of a parallel circuit?
Which of the following statements is true concerning circuits with parallel connected resistances?
What statement is true concerning the electrical diagram shown in figure "B" of the illustration? Illustration EL-0019 ...
Which of the electrical properties listed will always be the same across each component in a parallel circuit?
What will happen to the total circuit resistance when additional parallel circuits are added to a circuit?
Which statement is true concerning the total power consumed in a parallel circuit?
Which of the following statements concerning a circuit with parallel connected resistors is correct?
As shown in figure "A" of the illustration, the actual rudder angle repeatback signal originates at what device and is d...
When power is restored after a complete power failure, how will the steering gear pump motor which was on-line respond? ...
Referring to the illustration of a steering gear hydraulic power unit motor controller, if the motor is drawing current ...
What is the name of the mechanism used to transmit rudder angle information from the steering gear itself to the wheelho...
When a resistor is used as a shunt and is connected in parallel with a meter movement coil, what capability does this pr...
An internal resistance is placed in series with the meter movement of which of the following instruments?
What practice could potentially damage a multimeter?
What is an ohmmeter used to measure?
In what situation would an electrical phase sequence indicator be useful?
Periodic testing using a special camera may be performed to detect potentially dangerous loose or corroded bus bar and c...
What is the circuit shown in the illustration used to measure? Illustration EL-0024
What is the instrument called a galvanometer used to measure?
What is true concerning the installation of batteries used for diesel engine starting?
Three 12 volt, lead-acid, batteries connected in series will develop how many volts?
Why should battery rooms be well ventilated during the charging of storage batteries?
What is the ampere-hour rating of a lead-acid battery that can deliver 20 amperes continuously for 10 hours?
As shown in the illustration, the wet cell storage batteries are connected in what configuration? Illustration EL-0071 ...
The individual 12 volt lead-acid batteries, when connected as shown in the illustration, as a battery bank would produce...
Which of the following procedures represents the best method to prevent the freezing of batteries continuously exposed t...
Which of the following statements concerning analog and digital devices is correct?
Which line in figure "B" shown in the illustration represents the trailing edge of the wave? Illustration EL-0088
Which of the substances listed can be used to shield sensitive equipment from static magnetic fields?
When placed in a magnetic field, which of the materials listed will maintain the highest permeability?
As shown in the illustrated harmonic analysis diagram, which figure represents the fundamental (or first harmonic)? Illu...
Which of the wave shapes shown in the illustration is termed a sinusoidal wave? Illustration EL-0088
The multiplier prefix 'giga' (G) such as used in "gigabytes" represents what multiplication factor?
Besides checking for grounds, for what other purpose can a megohmmeter be used on a DC motor?
What would excessive sparking at the brushes of a running DC motor be an indication of?
What is the most effective method of locating a loose commutator bar in a DC motor?
How may temporary repairs to an open DC propulsion armature coil be made, allowing continued operation until permanent r...
If a DC motor hums, but does not run when energized, which of the listed conditions could exist?
When using a megohmmeter to determine which shunt field coil is grounded in a DC machine, what must you do?
When a megohmmeter is used to test insulation, what condition causes the gradual rise of the pointer reading as a result...
What is the resistance reading at "1" on the megger scale illustrated in figure "A"? Illustration EL-0044
In which of the situations listed will a megohmmeter give the most accurate readings?
When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is i...
In testing a hand cranked megger prior to use, what statement is true?
As shown in figure "A" of the illustrated motor nameplate, how much current could the motor safely draw on a continuous ...
Which of the following motors has a frame configuration for solid base mounting only? Illustration EL-0184
What is the most practical method of controlling the RPM of a multi-speed AC motor operating at a constant frequency? ...
Regarding an induction motor, what does the power developed by the rotor automatically adjust itself to?
What will be the impact of reduced voltage applied to a motor during the starting period?
Which of the illustrated motors has an open motor enclosure? Illustration EL-0001
Which of the illustrated motors has an open, drip-proof (ODP) motor enclosure? Illustration EL-0001
Which of the following methods should be used to dress the face of silver-plated contacts?
The current at which a magnetic-type overload relay tends to trip may be decreased by raising the plunger further into t...
High-pressure compressed air should not be used to clean electric motors or controller equipment. Why not?
Before working on an electric cargo winch master switch or controller, what should be done?
Why are electric strip heaters used in motor controllers?
If a self-excited DC generator running at rated speed fails to deliver an output voltage, which of the following conditi...
What can cause uneven wear of the commutator surface on a direct current generator?
What may cause brush sparking in a DC generator during commutation?
Hysteresis is one cause of electrical power loss associated with electricity generation equipment. What phenomenon resul...
For the purposes of generating a DC voltage, which of the following factors is subject to vary for a particular generato...
What statement is true concerning the use of commutating poles (also known as interpoles) in DC generators?
What statement is true concerning the use of compensating windings in DC generators?
What is the purpose of the series field used in a stabilized shunt DC generator?
What two factors determine the magnitude of the generated voltage of a DC generator?
What type of motor is generally used in DC propulsion drive systems?
What equipment for modern SCR rectified DC propulsion drive systems is usually included in the package?
In a diesel-electric plant, raising the generator's field excitation current will have what effect on the DC propulsion ...
How is the main propeller shaft rotation of a rectified DC diesel-electric drive normally reversed?
Due to the operating characteristics of the system, time lag fuses (or dual-element fuses) are necessary for use in what...
Which pair of safety disconnect switches shown in the illustration represents the exterior and interior views of a doubl...
What is the characteristic that is associated with an "instantaneous-trip" single-element type fuse?
How are fuses usually rated?
Fuses are sometimes placed in series with a thermal trip-type circuit breaker. What is the purpose of a fuse used in thi...
How may the unit "hertz" be best described?
If the voltage and the current developed in an AC circuit reach their peak values at the same time (with a phase angle d...
What is the opposition to the establishment of magnetic lines of force in a magnetic circuit called?
In the flow of one cycle of single phase alternating current past any given point in a circuit, how many times will the ...
In terms of load type, in what type of alternating current circuit will the voltage always lead the current?
For the purpose of calculating apparent power, which of the following procedures should be used to determine the total l...
AC circuits can possess characteristics of resistance, inductance, and capacitance. In terms of units of measure, how i...
The root mean square (RMS) value of a sine-wave current may also be expressed as what value?
An accidental path of low resistance bypassing the intended path and allowing passage of an abnormally high amount of cu...
What will happen to an electrical coil when the direct current flowing through the coil is increasing?
Which of the following fixed temperature heat-actuated fire detectors is the most prone to false alarms?
A salinity indicator system such as that used to measure the salt content of potable water systems and boiler feed and c...
Which of the following fixed temperature heat-actuated fire detectors can be reused after it has detected a fire?
To facilitate communication between the wheelhouse and the steering gear room in a steering emergency where no external ...
A pyrometer indicating system such as that used for measuring diesel engine exhaust system temperatures uses what techno...
Assuming the vessel has an engine control room, where is an engineers' assistance- needed alarm required to produce an a...
What shipboard system uses the synchronous transmission system?
In a typical fire detection control unit, what would be indicated by an illuminated blue light?
A bearing temperature monitoring system such as that used for measuring selected propulsion plant bearings uses what tec...
Which station's emergency loudspeaker must allow for two-way communication?
The shaft revolution indicator system for a fixed-pitch propeller has which of the following display capabilities?
Grounds occurring in electrical machinery as a result of insulation failure may result from deterioration over time and ...
The leads from an ohmmeter are attached to the leads of the opposite ends of an AC motor stator field coil. If a readin...
As shown in the illustrated diagnostic setup for locating a shorted field coil of a ten- pole synchronous motor, if 240 ...
A lightly loaded three-phase squirrel-cage induction motor, while running, begins to vibrate excessively but continues t...
A split-phase induction squirrel-cage motor will not start and come up to speed, even though the rated voltage, rated fr...
The electrical energy necessary to power a sound-powered telephone's small vibrating bell is obtained from what power so...
Referring to the sound-powered telephone circuit shown in illustration, what statement is true concerning the button on ...
Referring to the sound-powered telephone circuit shown in the illustration, in what component are the sound-powered tran...
Referring to the sound-powered telephone circuit shown in the illustration, what statement is true? Illustration EL-0093...
What type of equipment does the wiring diagram shown in the illustration represent? Illustration EL-0093
What is one function of the movable cams in a drum-type winch motor controller?
Which of the following illustrated manual motor starters represents the wiring diagram illustrated in figure "A"? Illust...
What is the name of the type of motor control circuit that will not permit automatic restarting after power is restored,...
What is the functional name of an electrical device which prevents simultaneous energization of loads thereby preventing...
What is the purpose of an electromagnetic relay?
Which of the following statements represents the main difference between a relay and a contactor?
By what means is a synchronous motor started and brought nearly to synchronous speed?
Concerning the operating characteristics of a synchronous motor, what statement is true?
Occasionally a synchronous motor is configured without an external shaft to drive a load. In this case, the sole purpose...
Assuming that a three phase synchronous motor is separately excited, what statement is true concerning power supplies? ...
Not only can a synchronous motor drive a load with greater efficiency than an induction motor, a fringe benefit of the s...
Electrical wire in general, when used aboard vessels must meet minimum requirements. Which of the following statements i...
According to 46 CFR, Subchapter J (Electrical engineering), regulations prohibit the use of portable electric cord or fi...
According to 46 CFR, Subchapter J (Electrical Engineering), when considering replacement, instrument and control wiring ...
According to 46 CFR, Subchapter J (Electrical Engineering), what statement is true concerning the use of twist-on connec...
According to CFR, Subchapter J (Electrical Engineering), which of the following statements is true concerning flexible e...
The nominal voltage of one cell of a wet cell nickel-cadmium battery is approximately how many volts?
What is the approximate discharge voltage produced by one cell of a wet type nickel- cadmium battery at 75% of charge? ...
What is the most reliable and preferred method for determining the state of charge of a wet cell NiCad battery?
Why are nickel-cadmium batteries superior to lead-acid batteries for standby service?
What material are the plates of a wet cell NiCad storage battery made of?
Assuming that a ship's service generator is directly coupled to the prime mover, what condition must cause a prime mover...
In accordance with 46 CFR, Subchapter J (Electrical Engineering), each diesel engine driven generator prime mover must h...
You are in the planning stages of setting the instantaneous trip of a ship's service generator circuit breaker. Accordin...
There are very specific rules that govern the testing of generators found in the appropriate publication incorporated by...
You are in the planning stages of setting the longtime overcurrent trip of a ship's service generator circuit breaker. A...
The turns ratio of the tapped step-down transformer shown in figure "C" of the illustration is four to one and all taps ...
In figure "1" of the diagram shown in the illustration, the three phase step-down power transformer has a turns ratio of...
In figure "2" of the diagram shown in the illustration, the three phase step-down power transformer has a turns ratio of...
In figure "4" of the diagram in the illustration, the three phase step-down power transformer has a turns ratio of five ...
If the motor shown in the illustration will not start when the "off-run" switch is placed in the run position, which of ...
The motor fails to start on an attempted startup. With the start button depressed, a voltmeter reading between 1 and 5, ...
In order to properly set up programmable motor protection, it is necessary to know the locked-rotor current of a motor. ...
As shown in figure "B" of the typical ground fault relay shown in the illustration, what statement concerning the leakag...
What can be the cause of excessive heat or burning contacts in an operating motor controller?
As shown in the two-speed single winding three phase motor connection diagrams illustrated in figure "B", what is the co...
How is the difference between the synchronous speed of a three phase induction motor and its operating speed correctly e...
In a three-phase, squirrel-cage type, induction motor, how is the primary rotating magnetic field established?
Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency?
The torque-speed and current-speed curves for a three-phase induction motor with a squirrel cage rotor are shown in figu...
Assuming that the 3-phase power source has a phase sequence of A-B-C and that the motor is connected as shown in figure ...
According to 46 CFR, Subchapter J (Electrical Engineering), in response to a loss of normal power or a simulated test, w...
Emergency generators are required to automatically start upon a loss of normal supply voltage, according to 46 CFR, Subc...
According to 46 CFR, Subchapter J (Electrical Engineering), which of the following starting aids is the ONLY method allo...
According to 46 CFR, Subchapter J (Electrical Engineering), emergency diesel engine starting systems are required to hav...
As shown in figure "A" of the illustration, what phenomenon is illustrated with respect to electrical cables and ground?...
Which of the listed pairs of materials make the best insulators?
When a fluorescent lamp has reached the end of its useful life, it should be replaced immediately. If not, what conditio...
What device can be used to check the calibration of a circuit breaker?
As shown in the illustrated steering hydraulic pump motor controller, what statement is true? Illustration EL-0119
If a three-phase motor controlled by the control circuit illustrated in figure "B" of the illustration, is running in th...
Concerning figure "A" of the illustration, if the illustrated PLC ladder diagram is for a simple motor controller, what ...
Concerning the illustrated motor controller circuit, where is the location of the motor "run" indicator light? Illustra...
In general, what type of starter would be used to connect polyphase induction motors to full line voltage at the instant...
In the illustrated solid-state "soft" starter for a three phase induction motor as shown in figure "A", what is the name...
Which of the following pictures represents a magnetic reversing or two-speed motor starter? Illustration EL-0179
Which of the following contactors or relays has a timing function for the transition from start to run? Illustration EL-...
As shown in the illustration, what type of motor and motor starter are featured? Illustration EL-0136
As shown in the illustrated feeder disconnect controller, what statement is true? Illustration EL-0138
Autotransformer starters, sometimes called starting compensators, are sometimes used with larger polyphase induction mot...
As shown in figure "A" of the illustration, what is the purpose of the "test button"? Illustration EL-0178
With what kind of starting equipment are most three-phase induction motors of five horsepower or less started?
Assuming the ladder diagram of figure "1" and the corresponding input/output diagram of figure "2" represents a simple P...
As shown in the illustration, by what means are all the 'MS' contacts opened and closed? Illustration EL-0073
How are the line losses in a distribution circuit kept to a minimum?
Why are large cable sizes often formed as individual conductors comprised of several smaller strands?
What happens to the life expectancy of insulation for each 10oC rise in operating temperature?
When electrical cables penetrate watertight bulkheads, what must be provided for?
Which of the following is the only known perfect dielectric for the purpose of serving as electrical insulation?
Which of the following materials is a good electrical insulator?
How is electrical conductor insulation classed? Example: insulation class H
Why is copper often used as an electrical conductor?
What is "the voltage per millimeter of insulation thickness that the insulation can withstand without breaking down" cal...
Why are armature cores in a DC generator made of laminated steel sheets?
In referring to the illustration of the Ward-Leonard drive system, what type of DC generator is used? Illustration EL-0...
In referring to the illustration of the elementary DC generator, what statement is true? Illustration EL-0028
What is the purpose of the commutator and brushes on a DC generator?
As shown in the illustration of a DC machine which is configured as a generator, what is the polarity of the interpoles ...
How are the field windings of a DC shunt generator connected?
You are reconnecting a three-phase induction motor to the supply line. To prevent possible damage to the load, due to th...
Using the temperature correction factor for the winding insulation temperature graph shown in the illustration, what wo...
What is a useful instrument for checking 3 phase AC motor performance by measuring possible unbalanced currents?
Large machines undergoing a resistance insulation testing using a megohmmeter should be discharged to remove any accumul...
When using the test set-up shown in figure "A" of the illustration, besides the motor windings and the motor feeder cabl...
When you are making a high potential test (megger) on the motor coils of repaired electrical machinery to ground. What w...
Suppose it is desired to connect a dual voltage three phase squirrel-cage induction motor for low volts, but it is undet...
Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? ...
As shown in figure "A" of the ungrounded distribution system with possible ground faults shown in the illustration, unde...
From the information given in the illustration, what would be the ampere capacity at full load of each of the main ship ...
In an ungrounded distribution system, as compared to a normal indication, what is the indication on a switchboard of a c...
As shown in the illustration of a vessels navigational lighting circuit, if port running light "1" burns out, the troubl...
During the start-up of the circuit shown in figure "B" of the illustration, it is noted that the ends of component "4" r...
In order to definitively determine whether or not fuse "1", shown in the illustration is blown using an on-line testing ...
As shown in figure "A" of the illustration, what type of ground fault detection system is illustrated? Illustration EL-0...
Assuming that 450 VAC is the source voltage at the circuit breaker, if 450 volts AC were measured across the load as sho...
The ground indicating light on the main electrical switchboard is indicating a ground. What is the best procedure for l...
On vessels with AC distribution systems, which of the following statements represents the most difficult problem involve...
As shown in the illustrated block diagram for a distributed automation system, what statement is true concerning the uni...
Which of the following devices represents primary storage, where the processor is able to directly read instructions and...
As shown in the illustrated block diagram for a distributed automation system, what statement is true concerning the wor...
Which of the following data communication cable types offers the greatest immunity to electromagnetic "noise"?
Modern ships use multiple computers arranged in a client/server network to perform various shipboard functions. What typ...
What type of local area network physical topology features point-to-point interconnection between all communicating devi...
As shown in the illustration, what statement is true concerning each of the system gateways? Illustration EL-0098
If a computer display is flickering, how may this be remedied?
What Ethernet cabling technology supports the greatest data transfer speeds?
If an 8-bit digital to analog converter (DAC) produces an analog output voltage with a range of 10 volts
What statement is true concerning random access memory (RAM)?
What statement is true concerning read only memory (ROM)?
Why must caution be exercised during the charging of lead-acid storage batteries?
What statement is true concerning the actual mixing process and the container used when mixing electrolyte for a lead-ac...
What statement is true concerning the charging of a 100 amp-hour lead-acid battery?
What is the best method of determining the state of charge of a lead acid storage battery?
Which of the listed battery charging circuits is used to maintain a wet cell, lead-acid, storage battery in a fully char...
What should you be aware of when checking the specific gravity of the battery electrolyte with a hydrometer?
Which of the following statements concerning nickel-cadmium batteries is true?
Which of the substances listed should be applied to battery terminals to help prevent corrosion?
For accuracy purposes, which of the following devices should be used to measure the temperature of a battery electrolyte...
Which of the following activities occurs during the charging process of a lead-acid storage battery?
In figure "1" of the illustration, what type of circuit breaker trip element is featured? Illustration EL-0033
Which figure shown in the illustration represents the schematic symbol shown in figure "2"? Illustration EL-0034
Which of the electronic schematic symbols represents the capacitor illustrated in figure 1 of the illustration? Illustr...
What is the shape of the schematic symbol for an operational amplifier used in an analog circuit?
As shown in the illustrated devices and symbols, which of the symbols shown in the illustration represents a standard no...
Which of the following statements concerning figure "6" of the illustration is true? Illustration EL-0026
Which of the electrical schematic symbols shown in the illustration represents a normally closed limit switch? Illustrat...
Which electrical schematic symbol shown in the illustration represents a normally closed thermostat? Illustration EL-005...
As shown in figure "6" of the illustration, what does the symbol represent as used in electrical drawings? Illustration ...
Referring to figure "2" of the illustration, what type of logic gate is symbolized? Illustration EL-0035
Referring to figure "2" of the illustration, if the inputs at A and B are both "0", what will be the outputs at "C", "D"...
As shown in figure "A" of the illustration, what input conditions are required to produce an output? Illustration EL-024...
As shown in figure "C" of the illustration, what type of timer is represented? Illustration EL-0242
Referring to figure "3" of the illustration, what type of logic gate is symbolized? Illustration EL-0035
As shown in figure "A" of the illustrated PLC sub-circuit, what type of circuit is depicted? Illustration EL-0230
As shown in all four diagrams included in the illustration, what type of logic circuit is represented? Illustration EL-0...
Referring to figure "4" of the illustration, what type of logic gate is symbolized? Illustration EL-0035
As shown in the illustrated block diagram for a programmable logic controller system, in what functional component is th...
Which of the methods listed below is used to provide the rotational torque to cause an AC generator to turn?
From the information given in the illustration, which of the following statements is correct? Illustration EL-0106
How will the value of the output frequency change if the load is removed from a turbo-generator having a governor speed ...
From the information given in the illustration, what would be the maximum output amperage available from the emergency g...
What would be the total power consumed by the circuit as shown in figure "B" of the illustration if the source voltage i...
What would be the total power consumed by the circuit as shown in figure "A" of the illustration if the source voltage i...
What would be the voltage drop across the parallel branches of the circuit shown in figure "B" of the illustration if th...
What would be the total current draw of the circuit as shown in figure "A" of the illustration if the source voltage is ...
Referring to the illustration pertaining to the semi-automatic navigation light panel circuit, assuming that the transfe...
Referring to the illustration pertaining to a steering system hydraulic power unit motor controller, what statement is t...
Referring to the illustration pertaining to the semi-automatic navigation light panel circuit, if the buzzer sounds and ...
Concerning the illustrated fire detection and alarm system, when the system is operating normally and under supervision,...
Referring to the illustration pertaining to an alternator protection and alarm system, what statement is true concerning...
In the diagram of the switchboard shown in the illustration, if one of the turbines should fail due to a throttle trip, ...
What is the name of the part of the shipboard electrical system used to control the distribution of power to the branch ...
In the diagram of the switchboard shown in the illustration, what is the purpose of the current transformers? Illustrati...
The timer element of a reverse power relay cannot be energized unless what condition is met?
What application would the switchboard instrumentation panel shown in the illustration best be suited for? Illustration ...
Which of the following represents a characteristic of an ungrounded electrical distribution system?
In the diagram of the switchboard shown in the illustration, what is the function of the device labeled "Gen. Bkr. Sw."?...
How is a wattmeter electrically connected in a circuit?
It is desired to add additional 120 VAC, 100 watt lighting fixtures in the accommodations, port side fed from circuit No...
According to 46 CFR, Subchapter J (Electrical Engineering) regulations, what is the minimum conductor size associated wi...
You are in the planning stages of making up a portable cable to be used for transmitting power from a battery charger on...
According to 46 CFR, Subchapter J (Electrical Engineering) regulations, receptacle outlets at or above what voltage are ...
According to 46 CFR 111.75-5, what would be the maximum amperage load on circuit No.2
In the illustration of the one-line distribution system diagram, if the ship's service generator on line fails, what sta...
Upon failure of the normal power supply, how is the emergency generator placed on the line to feed power to the emergenc...
What is a purpose of the automatic bus transfer device shown in the illustration? Illustration EL-0014
Referring to the containership one-line distribution diagram shown in the illustration, what statement is true concernin...
Referring to the containership one-line distribution diagram shown in the illustration, what is the purpose of the feedb...
Referring to the containership one-line distribution diagram shown in the illustration, what is the purpose of the trans...
As shown in the illustration of an electrically operated watertight door controller, what type of motor is used to open ...
As shown in the illustration of an electrically operated watertight door controller, how is reversal of the direction of...
As shown in the illustration of an electrically operated watertight door controller, how is the motor stopped automatica...
By what means is the burning of controller contacts due to arcing, when opening, prevented?
A digital multimeter is set up as shown in the illustration to test an individual element of a three-phase immersion hea...
Which of the following conditions will occur if the brake solenoid coil burns out on a cargo winch with an electrical br...
Refer to figure "A" representing an electric oven as shown in the illustration. With the oven turned on, the power avail...
The winch shown in the illustration operates in any of the positions with the master switch in the 'lower' direction, bu...
Refer to figures "1" and "2" of the basic synchronous transmission system shown in the illustration. Figure "1" shows a ...
As shown in the illustration, which brush holder is of the reaction type? Illustration EL-0029
If a DC motor has its armature and field connected across a resistor when the motor is disconnected from its power suppl...
In terms of voltage potential and current sources, how are shunt wound, series wound, and compound wound DC motors desig...
Which of the following statements describes what will happen when both the polarity of the field poles, and the directio...
As shown in figure "B" of the illustration, what does the M-G set's three-phase drive motor mechanically drive? Illustra...
What is an advantage of DC motors over AC motors?
How can the direction of rotation of a DC motor be reversed?
As shown in the illustration, which brush holder would be appropriate to use in a bi- directional motor? Illustration EL...
From the instant of start-up, through the acceleration period, and until the motor reaches rated speed, when is the coun...
The torque produced by a DC motor armature is the multiplication product of two factors, one being the density of the ma...
What is the name of the DC motor speed control method utilized as shown in figure "B" of the illustration? Illustration...
You are in the planning stages of replacing a battery charger, where an exact duplicate of the charger to be replaced is...
Suppose a cargo vessel of 1600 gross tons or more is fitted with emergency storage batteries for the purpose of supplyin...
According to 46 CFR, Subchapter J (Electrical Engineering), which of the following statements concerning battery install...
In accordance with 46 CFR Part 112, a storage battery for an emergency lighting and power system must have the capacity ...
While inspecting the copper commutator bars of a DC generator, you notice a chocolate brown film covering the bars. What...
Incorrect brush pressure can result in accelerated brush wear on a DC generator. What statement concerning brush pressu...
As the brushes ride on the commutator of a DC generator, eventually mica ridges will form between the bars causing spark...
Referring to the illustration of possible brush holder mounting configurations, which figure is the correct method of co...
If a DC generator was disassembled during overhaul, it is important that the brush holder rigging be installed in the ne...
In actual applications, electrical connections associated with 'R1, R2 and R3' of the transmitter to 'R1, R2, and R3' of...
If coil 'R1-R2-R3' on the transmitter in figure "C" shown in the illustration is turned 30 degrees clockwise, how will t...
What does figure "C" of the illustration represent? Illustration EL-0092
An electrical component is connected across a 120 volt 60 hertz AC supply. What is the current drawn by the component if...
What is the total resistance of the electrical circuit illustrated in figure "B" if the resistance of R1 is 2 ohms, R2 i...
How is the power dissipated as heat in a direct current circuit calculated?
In a 60 Hz AC system, what is the duration in seconds for one complete cycle?
An AC generator produces 60 Hz at 1800 RPM. If the generator speed is increased to 1830 RPM, what will happen to the fre...
What is the total resistance of figure "B" of the illustrated circuit if the resistance of R1 is 3 ohms, R2 is 4 ohms, a...
In the illustration, 1, 2, 3 and 4 are 12 volt batteries. What will be the nominal voltage as read by a voltmeter across...
A 125 volt DC motor is rated at 10 kW. What is the current rating of the motor?
In a simple DC circuit, the resistance is held constant while the applied voltage is halved. What will be the effect on ...
If the supply voltage is 220 volts 60 Hz, what is the operating voltage of the motor controller control circuit illustra...
DC propulsion motor brush pressure depends on the brush grade used. In practice with what device is the proper brush pre...
Which of the listed conditions will occur if dirt and grease are allowed to accumulate between the commutator segments o...
What should be used in the cleaning of a DC propulsion motor's commutator face?
In general, what can cause DC propulsion motor brush sparking to be excessive?
How is seating of new brushes on a DC motor commutator accomplished?
Which of the following statements is correct for the illustrated circuit in figure "B"? Illustration EL-0020
Referring to figure "B" of the illustration, what statement is true? Illustration EL-0020
In a series circuit what is the total applied voltage equal to?
Four lamps are connected in series in a single circuit. If one of the lamps burns out, what will happen to the other lam...
In a series circuit, which value will remain unchanged at all places in the circuit?
What statement is true concerning speed control of a shunt wound DC motor?
What type of DC motor has relatively low starting torque, but has excellent inherent speed regulation?
In a shunt wound DC motor, how is the shunt field connected?
What are the characteristics of the field winding of a shunt wound motor?
The wiring diagram found in figure "A" of the illustration represents what type of DC motor? Illustration EL-0054
In an impressed current cathodic hull protection system, what statement is true concerning the composition and arrangeme...
While monitoring an impressed current cathodic hull protection system, which of the following measurements should remain...
Referring to the impressed current cathodic hull protection system shown in the illustration, if required to control the...
Referring to the impressed current cathodic protection system shown in the illustration, if required to control the curr...
In monitoring an impressed current cathodic hull protection system, it is important to insure that the propeller screw r...
What does the circuit shown in the illustration represent? Illustration EL-0085
Which of the following statements represents an application of a silicon controlled rectifier?
What is the functional purpose of the resistor 'RL" placed in parallel to the output of a DC power supply as shown in s...
A signal derived from an amplifier output and returned to the amplifier input is called what type of signal?
The component labeled 'CR1' in the circuit shown in the illustration serves what functional purpose? Illustration EL-008...
In which section of the 24 VDC power supply circuit illustrated does the greatest change in voltage level take place whe...
What is the name for the device shown in figure "A" of the illustration? Illustration EL-0064
A common-emitter circuit has an input voltage of 0.1 volt, an output voltage of 2.0 volts, an input current of 0.5 milli...
Silicon diodes which are designed for a specific reverse breakdown voltage, and are most often used as electronic power ...
What is the correct term for the fluctuation of voltages in figure "H" shown in the illustration? Illustration EL-0085 ...
Refer to the diagram of the AC turbo-electric drive system as shown in the illustration. The propulsion motor operates ...
Refer to the simplified diagram of the AC synchronous electric motor drive system as shown in the illustration. The prop...
In addition to improper brush pressure or seating, what can result in excessive sparking at the brushes of a DC propulsi...
While standing an "at sea watch" onboard a modern rectified DC diesel-electric drive ship you notice the transformer cor...
On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had dr...
By what means is a DC generator prevented from becoming motorized if paralleling is accomplished without an equalizer? ...
With what device is the simplest method of controlling the terminal voltage of compound wound DC generator?
Which of the methods listed is used to maintain equal load sharing between two compound wound DC generators operating in...
Prior to closing the circuit breaker when paralleling two DC generators, what must you be certain of?
Why are external shunts sometimes used with ammeters?
The clamp-on AC ammeter consists essentially of a split-core and a rectifier-type instrument connected to the secondary ...
To properly use a clamp-on-type ammeter to check current flow, what must be done FIRST?
What is an ammeter used to measure?
How should the shunt used in an ammeter be connected?
An AC circuit has a capacitive reactance of 30 ohms in addition to an inductive reactance of 40 ohms connected in series...
In figure "A" of the illustration, 12 volts is applied to the circuit where the resistance of R1 is 10 ohms and R2 is 10...
What will be the total current in figure "B" of the illustrated circuit with the switch closed if the applied voltage is...
As shown in figure "A" of the illustration, what would be the circuit impedance if the capacitive reactance is 10 ohms a...
Which of the following statements correctly applies to bipolar junction transistors?
Which of the pictured solid state semiconductor devices is a light-emitting diode? Illustration EL-0068
What is the name of the component labeled CR1 as shown in section "D" of the regulated DC power supply illustrated? Illu...
What does the symbol in figure "1" shown in the illustration represent? Illustration EL-0065
A silicon controlled rectifier (SCR) is a solid state device used for what functional purpose?
In comparing a semiconductor diode to a vacuum tube diode, what statement is true?
In what applications are germanium semiconductor diodes commonly used?
What is the name of the semiconductor that decreases in resistance with an increase in temperature?
When a self-excited alternator's field has lost its residual magnetism due to a prolonged idle period, it will fail to p...
Under unusual circumstances, it may be required to operate a ship's service generator above its rated kVA. What suppleme...
As shown in the illustrated one-line diagram of a two-tiered emergency power system for a passenger ship, what statement...
Upon loss of field excitation of a generator operating in parallel with others, what must be done?
If it becomes absolutely necessary to run an alternator at lower than 5% below its rated frequency, in terms of output v...
In the illustrated one-line diagram, if the ship's service generator on line fails, what statement is true concerning th...
For a motor rated at 3.3 kV, what would be a minimum accepted insulation resistance to hull ground as tested by an appro...
What is the most common and reliable type of circuit breaker used for high voltage practice aboard ship?
In order for a live-line tester to be used to test and prove dead a high voltage circuit, what must be done to verify th...
When completing repairs on a high voltage circuit where portable grounding straps were used for increased operator safet...
In addition to high voltage circuit grounding with ground-connecting switching devices, for additional operator safety a...
For the purposes of high voltage marine practice, what is the threshold voltage where all voltages below this value are ...
Suppose it is desired to determine the integrity of the insulation of a 4160 VAC motor. What type of insulation resista...
Before work may safely commence on a high voltage system, what must first be done after disconnection and isolation? ...
Some shipboard high voltage systems have the neutral point of the generators bonded to the ship's hull with a neutral gr...
What is a disadvantage to the use of high voltage systems onboard ship?
In an azipod propulsion system, how is the azipod unit itself rotated for the purposes of directing the thrust in accord...
What statement is TRUE concerning the azipod propulsion system?
In an azipod propulsion system, how is direct current delivered to the synchronous propulsion motor rotor for synchronou...
Which of the following statement is TRUE concerning azipod propulsion systems?
In an azipod propulsion system, how is three phase, frequency and voltage controlled power delivered to the synchronous ...
In referring to figure "E" of the illustration, what statement is true concerning the functional purpose of the coupling...
In referring to figure "A" of the illustration, what type of active filter circuit is shown? Illustration EL-0077 ...
How are operational amplifiers, used primarily in analog circuits, characterized?
A voltage amplifier has a calculated voltage gain of 5. Which statement is true concerning input and output voltages? ...
In referring to figure "F" of the illustration, what statement is true concerning the functional purpose of the RC coupl...
In referring to the frequency response filters shown in the illustration, what determines the bandpass or bandstop frequ...
In referring to the graphs shown in the illustration, which of the following figures represents a bandpass filter? Illus...
A six-pole three-phase squirrel-cage induction motor operating at 60 Hz is running at 1155 rpm. What is the percentage ...
What would be the synchronous speed of an eight-pole three-phase squirrel-cage induction motor operating at 60 Hz?
What would be the actual rotor speed for a 4-pole three-phase squirrel-cage induction motor operating at 60 Hz if the ro...
If a 12-pole three-phase synchronous alternator is operating at 590 rpm, what will be its output frequency?
What would be the synchronous speed of a 24-pole three-phase synchronous motor operating at 20 Hz?
What type of electrical diagram for the shunt wound DC motor is shown in the illustration? Illustration EL-0052
What type of electrical diagram for the electrical distribution system is shown in the illustration? Illustration EL-001...
What statement is true concerning the electrical diagrams for the motor controller shown in the illustration? Illustrati...
What type of electrical diagram for the autotransformer type motor controller is shown in the illustration? Illustration...
What type of electrical diagram for the steering control systems is shown in the illustration? Illustration EL-0192 ...
What condition associated with a lead-acid battery cell can cause the plates to partially short-out and cause the cell t...
As the electrolyte level in the cells of a lead-acid battery evaporates over time, what will tend to happen to the speci...
What could prevent a lead-acid battery from accepting a full charge?
When troubleshooting a lead-acid storage battery, what is the best method for detecting a weak or dead cell?
To determine the state of charge of a nickel-cadmium wet cell storage battery during charging and discharging, what is t...
If a digital multimeter set up to measure AC volts reads slightly above 'zero' when its leads are disconnected, what is ...
As shown in figure "A" of the digital multimeter screen shown in the illustration, what would be the significance of the...
Which of the listed statements is correct when using a digital multimeter set up as an ohmmeter?
As shown in figure "D" of the digital power meter shown in the illustration, what type of single phase load is under tes...
When testing a capacitor with a digital multimeter set up as an ohmmeter, what would be the indication on the display wh...
When troubleshooting an electronic circuit, an unreliable high resistance "cold" solder joint can be located with the ai...
A full-wave rectifier has one diode burned out in an open condition, what will be the output characteristic of the devic...
If both the 'high level' and 'low level' alarms come on for the same address of a centralized control console, what is t...
Normally, what is the FIRST step in troubleshooting a transistor mounted on a circuit card?
As shown in figure "A" of the illustrated propulsion motor variable speed drive, what statement is true? Illustration EL...
What is the operating function of a cycloconverter (CCV) as a static power converter used in electric propulsion motor d...
As shown in figure "A" of the illustration, the load-commutated inverter drive illustrated has how many pulses? Illustra...
How is the main shaft rotation on an AC diesel-electric propulsion vessel normally reversed?
The propulsion motor most often utilized in an AC drive system operating in the moderate to high power range is of what ...
As shown in the illustration, if the port propulsion motor field excitation circuit experienced a failure, what individu...
What type of electric propulsion system converter is shown in the illustration? Illustration EL-0155
As shown in figure "B" of the illustration, what statement is true concerning "regenerating" operation? Illustration EL...
While standing an "at sea watch" onboard an AC diesel-electric drive ship with a synchronous propulsion motor, you notic...
By what common means is the speed of the AC propulsion motor on a diesel-electric propulsion ship controlled?
Referring to the illustration what is the position of the three circuit breakers labeled in figure "A", "B", and "C" res...
A thermal-magnetic circuit breaker for a 300 kW alternator is rated at 500 amperes at full continuous load. Which of the...
What is the basic similarity between a circuit breaker and a fuse?
As shown in the illustration, which of the following pieces of equipment is supplied with a circuit breaker providing bo...
The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts. How is this done? ...
Which of the following is a disadvantage of electric drive propulsion systems?
What is one major advantage of a diesel-electric propulsion plant?
Which statement is TRUE concerning electric propulsion drives?
Which of the listed temperature measuring devices installed on a large turbo-electric alternating current propulsion gen...
An electric propulsion drive system in which the propulsion generator supplies power to both the propulsion motor and sh...
Ships requiring rapid maneuvering response with a high degree of main propeller shaft control are most often what type o...
If the cooling water system is isolated for repairs, but it is still desirable to run the alternator pictured in figure ...
If a shipboard AC generator experiences a failure to produce a voltage, what may be the cause?
On a steamship, if No.1 SSTG fails to produce a voltage while in the automatic voltage control mode, but successfully pr...
No.1 SSDG was operating in parallel with No.2 SSDG in supplying the 480 VAC main bus while sharing the electrical load e...
How can the loss of residual magnetism in an alternator or generator be corrected?