Electrical-Electronics-Control Engineering (1/2)

How can the loss of residual magnetism in an alternator or generator be corrected?

No.1 SSDG was operating in parallel with No.2 SSDG in supplying the 480 VAC main bus while sharing the electrical load evenly. As a result of a problem, if No.1 SSDG begins to motorize, but the generator has not yet tripped out by the action of the reverse power relay, what would be the indication of this?

On a steamship, if No.1 SSTG fails to produce a voltage while in the automatic voltage control mode, but successfully produces a voltage while in the manual control mode, what statement is true?

If a shipboard AC generator experiences a failure to produce a voltage, what may be the cause?

Ships requiring rapid maneuvering response with a high degree of main propeller shaft control are most often what type of drive system?

An electric propulsion drive system in which the propulsion generator supplies power to both the propulsion motor and ship service loads is referred to as what type of system?

Which of the listed temperature measuring devices installed on a large turbo-electric alternating current propulsion generator would be the most reliable for monitoring generator temperatures to avoid premature winding insulation failure?

Which statement is TRUE concerning electric propulsion drives?

What is one major advantage of a diesel-electric propulsion plant?

Which of the following is a disadvantage of electric drive propulsion systems?

The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts. How is this done?

What is the basic similarity between a circuit breaker and a fuse?

A thermal-magnetic circuit breaker for a 300 kW alternator is rated at 500 amperes at full continuous load. Which of the following conditions will trip the breaker?

By what common means is the speed of the AC propulsion motor on a diesel-electric propulsion ship controlled?

While standing an "at sea watch" onboard an AC diesel-electric drive ship with a synchronous propulsion motor, you notice that the kwatt load is at roughly 75% of capacity with a leading power factor less than 1. Ideally what would be the character of the power factor associated with the main power distribution including all motors?

The propulsion motor most often utilized in an AC drive system operating in the moderate to high power range is of what type?

How is the main shaft rotation on an AC diesel-electric propulsion vessel normally reversed?

What is the operating function of a cycloconverter (CCV) as a static power converter used in electric propulsion motor drives?

Normally, what is the FIRST step in troubleshooting a transistor mounted on a circuit card?

If both the 'high level' and 'low level' alarms come on for the same address of a centralized control console, what is the most likely failure?

A full-wave rectifier has one diode burned out in an open condition, what will be the output characteristic of the device?

When troubleshooting an electronic circuit, an unreliable high resistance "cold" solder joint can be located with the aid of an ohmmeter. Once the problem has been located, what should be done?

When testing a capacitor with a digital multimeter set up as an ohmmeter, what would be the indication on the display when testing an initially discharged capacitor in good condition?

Which of the listed statements is correct when using a digital multimeter set up as an ohmmeter?

If a digital multimeter set up to measure AC volts reads slightly above 'zero' when its leads are disconnected, what is this a result of?

To determine the state of charge of a nickel-cadmium wet cell storage battery during charging and discharging, what is the most reliable method?

When troubleshooting a lead-acid storage battery, what is the best method for detecting a weak or dead cell?

What could prevent a lead-acid battery from accepting a full charge?

As the electrolyte level in the cells of a lead-acid battery evaporates over time, what will tend to happen to the specific gravity of the electrolyte in the cells as the level drops due to evaporation?

What condition associated with a lead-acid battery cell can cause the plates to partially short-out and cause the cell to fail to hold a charge?

What would be the synchronous speed of a 24-pole three-phase synchronous motor operating at 20 Hz?

If a 12-pole three-phase synchronous alternator is operating at 590 rpm, what will be its output frequency?

What would be the actual rotor speed for a 4-pole three-phase squirrel-cage induction motor operating at 60 Hz if the rotor slip is 3%?

What would be the synchronous speed of an eight-pole three-phase squirrel-cage induction motor operating at 60 Hz?

A six-pole three-phase squirrel-cage induction motor operating at 60 Hz is running at 1155 rpm. What is the percentage slip in this case?

A voltage amplifier has a calculated voltage gain of 5. Which statement is true concerning input and output voltages?

How are operational amplifiers, used primarily in analog circuits, characterized?

In an azipod propulsion system, how is three phase, frequency and voltage controlled power delivered to the synchronous propulsion motor stator windings?

Which of the following statement is TRUE concerning azipod propulsion systems?

In an azipod propulsion system, how is direct current delivered to the synchronous propulsion motor rotor for synchronous operation?

What statement is TRUE concerning the azipod propulsion system?

In an azipod propulsion system, how is the azipod unit itself rotated for the purposes of directing the thrust in accordance with steering commands from the bridge?

What is a disadvantage to the use of high voltage systems onboard ship?

Some shipboard high voltage systems have the neutral point of the generators bonded to the ship's hull with a neutral grounding resistor. What is the purpose of this resistor?

Before work may safely commence on a high voltage system, what must first be done after disconnection and isolation?

Suppose it is desired to determine the integrity of the insulation of a 4160 VAC motor. What type of insulation resistance tester (megger) would be suitable?

For the purposes of high voltage marine practice, what is the threshold voltage where all voltages below this value are considered low voltage?

In addition to high voltage circuit grounding with ground-connecting switching devices, for additional operator safety and confidence, portable grounding straps may be used. What is the proper procedure for connecting these portable grounding straps?

When completing repairs on a high voltage circuit where portable grounding straps were used for increased operator safety and confidence, what is the proper procedure for disconnecting these grounding straps?

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 the ability of the tester to detect a voltage?

What is the most common and reliable type of circuit breaker used for high voltage practice aboard ship?

For a motor rated at 3.3 kV, what would be a minimum accepted insulation resistance to hull ground as tested by an appropriate megger (insulation tester)?

If it becomes absolutely necessary to run an alternator at lower than 5% below its rated frequency, in terms of output voltage, what must be done?

Upon loss of field excitation of a generator operating in parallel with others, what must be done?

Under unusual circumstances, it may be required to operate a ship's service generator above its rated kVA. What supplemental casualty control action will be required?

When a self-excited alternator's field has lost its residual magnetism due to a prolonged idle period, it will fail to produce a voltage. Flashing the field is the procedure used to restore the residual magnetism. Using a 12 volt storage battery, how is this performed?

What is the name of the semiconductor that decreases in resistance with an increase in temperature?

In what applications are germanium semiconductor diodes commonly used?

In comparing a semiconductor diode to a vacuum tube diode, what statement is true?

A silicon controlled rectifier (SCR) is a solid state device used for what functional purpose?

Which of the following statements correctly applies to bipolar junction transistors?

An AC circuit has a capacitive reactance of 30 ohms in addition to an inductive reactance of 40 ohms connected in series. What is the total reactance of the circuit?

How should the shunt used in an ammeter be connected?

What is an ammeter used to measure?

To properly use a clamp-on-type ammeter to check current flow, what must be done FIRST?

The clamp-on AC ammeter consists essentially of a split-core and a rectifier-type instrument connected to the secondary winding of a particular type of transformer. Which type is used?

Why are external shunts sometimes used with ammeters?

Prior to closing the circuit breaker when paralleling two DC generators, what must you be certain of?

Which of the methods listed is used to maintain equal load sharing between two compound wound DC generators operating in parallel?

With what device is the simplest method of controlling the terminal voltage of compound wound DC generator?

By what means is a DC generator prevented from becoming motorized if paralleling is accomplished without an equalizer?

On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had dropped out of synchronization with the propulsion generator?

While standing an "at sea watch" onboard a modern rectified DC diesel-electric drive ship you notice the transformer core temperature slowly rising. What should be your FIRST action?

In addition to improper brush pressure or seating, what can result in excessive sparking at the brushes of a DC propulsion motor?

Silicon diodes which are designed for a specific reverse breakdown voltage, and are most often used as electronic power supply voltage regulators, are specifically what type of diode?

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 milliamps, and an output current of 10 milliamps. What is the power gain?

A signal derived from an amplifier output and returned to the amplifier input is called what type of signal?

Which of the following statements represents an application of a silicon controlled rectifier?

In monitoring an impressed current cathodic hull protection system, it is important to insure that the propeller screw receive the same cathodic protection as the hull. What should be checked for?

While monitoring an impressed current cathodic hull protection system, which of the following measurements should remain constant in a properly operating electronically regulated system?

In an impressed current cathodic hull protection system, what statement is true concerning the composition and arrangement of the anodes?

What are the characteristics of the field winding of a shunt wound motor?

In a shunt wound DC motor, how is the shunt field connected?

What type of DC motor has relatively low starting torque, but has excellent inherent speed regulation?

What statement is true concerning speed control of a shunt wound DC motor?

In a series circuit, which value will remain unchanged at all places in the circuit?

Four lamps are connected in series in a single circuit. If one of the lamps burns out, what will happen to the other lamps?

In a series circuit what is the total applied voltage equal to?

How is seating of new brushes on a DC motor commutator accomplished?

In general, what can cause DC propulsion motor brush sparking to be excessive?

What should be used in the cleaning of a DC propulsion motor's commutator face?

Which of the listed conditions will occur if dirt and grease are allowed to accumulate between the commutator segments of a DC motor?

DC propulsion motor brush pressure depends on the brush grade used. In practice with what device is the proper brush pressure established?

In a simple DC circuit, the resistance is held constant while the applied voltage is halved. What will be the effect on the current flow as compared to the original current?

A 125 volt DC motor is rated at 10 kW. What is the current rating of the motor?

An AC generator produces 60 Hz at 1800 RPM. If the generator speed is increased to 1830 RPM, what will happen to the frequency in Hz?

In a 60 Hz AC system, what is the duration in seconds for one complete cycle?

How is the power dissipated as heat in a direct current circuit calculated?

An electrical component is connected across a 120 volt 60 hertz AC supply. What is the current drawn by the component if the impedance is 200 ohms?

If a DC generator was disassembled during overhaul, it is important that the brush holder rigging be installed in the neutral plane. On larger machines, if the brush rigging and end bells are not match-marked, what is the correct procedure for determining the neutral setting using factory marks?

As the brushes ride on the commutator of a DC generator, eventually mica ridges will form between the bars causing sparking and chipping of the brushes. When this happens the mica must be undercut. To what depth is the mica undercut?

Incorrect brush pressure can result in accelerated brush wear on a DC generator. What statement concerning brush pressure is true?

While inspecting the copper commutator bars of a DC generator, you notice a chocolate brown film covering the bars. What should be done?

Suppose a cargo vessel of 1600 gross tons or more is fitted with emergency storage batteries for the purpose of supplying emergency lighting and power. According to 46 CFR, Subchapter J (Electrical Engineering), the capacity of the storage batteries is such that they should be able to successfully power the emergency loads for a period of 18 hours. Beginning with fully charged batteries, what is the minimum allowable voltage of the batteries after the 18 hour discharge period assuming a nominal voltage rating of 24 VDC and operating at rated capacity?

In accordance with 46 CFR Part 112, a storage battery for an emergency lighting and power system must have the capacity to accomplish which of the following?

According to 46 CFR, Subchapter J (Electrical Engineering), which of the following statements concerning battery installations is correct?

Suppose a cargo vessel of 1600 gross tons or more is fitted with emergency storage batteries for the purpose of supplying emergency lighting and power. According to 46 CFR, Subchapter J (Electrical Engineering), the capacity of the storage batteries is such that they should be able to successfully power the emergency loads for a period of 18 hours. Beginning with fully charged batteries, what is the minimum allowable percentage of the voltage rating of the batteries after the 18 hour discharge period assuming a nominal voltage rating of 24 VDC and operating at rated capacity?

You are in the planning stages of replacing a battery charger, where an exact duplicate of the charger to be replaced is not available. Obviously the charger must be suitable for the battery to be charged. According to 46 CFR, Subchapter J (Electrical Engineering), which of the following is a true statement concerning battery chargers?

The torque produced by a DC motor armature is the multiplication product of two factors, one being the density of the magnetic flux which is dependent upon the field current. What is the other multiplication factor?

From the instant of start-up, through the acceleration period, and until the motor reaches rated speed, when is the counter EMF produced in the windings of a DC motor 'zero'?

How can the direction of rotation of a DC motor be reversed?

What is an advantage of DC motors over AC motors?

Which of the following statements describes what will happen when both the polarity of the field poles, and the direction of current to the brushes of a DC motor are reversed?

In terms of voltage potential and current sources, how are shunt wound, series wound, and compound wound DC motors designed to operate?

If a DC motor has its armature and field connected across a resistor when the motor is disconnected from its power supply, what statement is true?

Which of the following conditions will occur if the brake solenoid coil burns out on a cargo winch with an electrical brake?

By what means is the burning of controller contacts due to arcing, when opening, prevented?

Upon failure of the normal power supply, how is the emergency generator placed on the line to feed power to the emergency bus?

According to 46 CFR, Subchapter J (Electrical Engineering) regulations, receptacle outlets at or above what voltage are required to have grounding poles?

According to 46 CFR, Subchapter J (Electrical Engineering) regulations, what is the minimum conductor size associated with a 25 or 30 ampere lighting branch circuit supplying a non- switched cargo-hold light fixture?

How is a wattmeter electrically connected in a circuit?

Which of the following represents a characteristic of an ungrounded electrical distribution system?

The timer element of a reverse power relay cannot be energized unless what condition is met?

What is the name of the part of the shipboard electrical system used to control the distribution of power to the branch circuits?

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

Which of the methods listed below is used to provide the rotational torque to cause an AC generator to turn?

What is the shape of the schematic symbol for an operational amplifier used in an analog circuit?

Which of the following activities occurs during the charging process of a lead-acid storage battery?

For accuracy purposes, which of the following devices should be used to measure the temperature of a battery electrolyte?

Which of the substances listed should be applied to battery terminals to help prevent corrosion?

Which of the following statements concerning nickel-cadmium batteries is true?

What should you be aware of when checking the specific gravity of the battery electrolyte with a hydrometer?

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 charged state during long periods of disuse?

What statement is true concerning the charging of a 100 amp-hour lead-acid battery?

What statement is true concerning the actual mixing process and the container used when mixing electrolyte for a lead-acid storage battery?

Why must caution be exercised during the charging of lead-acid storage batteries?

What statement is true concerning read only memory (ROM)?

What statement is true concerning random access memory (RAM)?

If an 8-bit digital to analog converter (DAC) produces an analog output voltage with a range of 10 volts (0-9 volts), what is the smallest incremental step in voltage that can be generated at the output?

What Ethernet cabling technology supports the greatest data transfer speeds?

If a computer display is flickering, how may this be remedied?

What type of local area network physical topology features point-to-point interconnection between all communicating devices and is the least vulnerable to a break in communication?

Modern ships use multiple computers arranged in a client/server network to perform various shipboard functions. What type of computer network would most likely be used aboard ship?

Which of the following data communication cable types offers the greatest immunity to electromagnetic "noise"?

Which of the following devices represents primary storage, where the processor is able to directly read instructions and data and directly return results of its computation in fetch/execute cycles?

On vessels with AC distribution systems, which of the following statements represents the most difficult problem involved in obtaining a DC potential suitable for use by computer components?

The ground indicating light on the main electrical switchboard is indicating a ground. What is the best procedure for locating the grounded circuit?

In an ungrounded distribution system, as compared to a normal indication, what is the indication on a switchboard of a current carrying conductor making an accidental electrical contact with a wiring metal conduit?

Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor?

When you are making a high potential test (megger) on the motor coils of repaired electrical machinery to ground. What would a low resistance reading indicate?

Large machines undergoing a resistance insulation testing using a megohmmeter should be discharged to remove any accumulated electrostatic/capacitive charge stored. When should this discharge be performed?

What is a useful instrument for checking 3 phase AC motor performance by measuring possible unbalanced currents?

You are reconnecting a three-phase induction motor to the supply line. To prevent possible damage to the load, due to the wrong direction of rotation, what should be done?

How are the field windings of a DC shunt generator connected?

What is the purpose of the commutator and brushes on a DC generator?

Why are armature cores in a DC generator made of laminated steel sheets?

What is "the voltage per millimeter of insulation thickness that the insulation can withstand without breaking down" called?

Why is copper often used as an electrical conductor?

How is electrical conductor insulation classed? Example: insulation class H

Which of the following materials is a good electrical insulator?

Which of the following is the only known perfect dielectric for the purpose of serving as electrical insulation?

When electrical cables penetrate watertight bulkheads, what must be provided for?

What happens to the life expectancy of insulation for each 10oC rise in operating temperature?

Why are large cable sizes often formed as individual conductors comprised of several smaller strands?

How are the line losses in a distribution circuit kept to a minimum?

With what kind of starting equipment are most three-phase induction motors of five horsepower or less started?

Autotransformer starters, sometimes called starting compensators, are sometimes used with larger polyphase induction motors. What function do they perform?

In general, what type of starter would be used to connect polyphase induction motors to full line voltage at the instant of start-up?

What device can be used to check the calibration of a circuit breaker?

When a fluorescent lamp has reached the end of its useful life, it should be replaced immediately. If not, what condition could the resultant flashing cause?

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

When a megohmmeter is used to test insulation, what condition causes the gradual rise of the pointer reading as a result of continued cranking?

Emergency generators are required to automatically start upon a loss of normal supply voltage, according to 46 CFR, Subchapter J (Electrical Engineering). In conducting a test of the emergency generator automatic transfer of load function, if the normal system supply voltage is 480 VAC, to what value would the normal source output voltage have to rise to trigger the automatic transfer of emergency loads back to the normal power source?

According to 46 CFR, Subchapter J (Electrical Engineering), emergency diesel engine starting systems are required to have sufficient capacity to provide power for at least how many consecutive starts?

According to 46 CFR, Subchapter J (Electrical Engineering), which of the following starting aids is the ONLY method allowed to ease the starting of emergency diesel-generator engines?

Emergency generators are required to automatically start upon a loss of normal supply voltage, according to 46 CFR, Subchapter J (Electrical Engineering). In conducting a test of the emergency generator automatic transfer of load function, if the normal system supply voltage is 450 VAC, to what value would the emergency generator output voltage have to rise to trigger the automatic transfer of emergency loads to the emergency generator?

According to 46 CFR, Subchapter J (Electrical Engineering), in response to a loss of normal power or a simulated test, when will the emergency loads automatically be transferred to the emergency diesel-generator?

Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency?

In a three-phase, squirrel-cage type, induction motor, how is the primary rotating magnetic field established?

How is the difference between the synchronous speed of a three phase induction motor and its operating speed correctly expressed?

What can be the cause of excessive heat or burning contacts in an operating motor controller?

There are very specific rules that govern the testing of generators found in the appropriate publication incorporated by reference. According to 46 CFR, Subchapter J (Electrical Engineering), which agency publishes the rules for the construction and testing of generators?

You are in the planning stages of setting the longtime overcurrent trip of a ship's service generator circuit breaker. According to 46 CFR, Subchapter J (Electrical Engineering), what statement is true regarding the criteria for the longtime overcurrent trip setpoint, assuming the generator is capable of being paralleled?

You are in the planning stages of setting the instantaneous trip of a ship's service generator circuit breaker. According to 46 CFR, Subchapter J (Electrical Engineering), what statement is true regarding the criteria for the instantaneous trip setpoint, assuming the generator is capable of being paralleled?

In accordance with 46 CFR, Subchapter J (Electrical Engineering), each diesel engine driven generator prime mover must have an overspeed device, independent of the normal operating governor. If in testing the overspeed device, what should be the trip point setting in terms of rated speed?

Assuming that a ship's service generator is directly coupled to the prime mover, what condition must cause a prime mover to automatically shutdown?

What material are the plates of a wet cell NiCad storage battery made of?

Why are nickel-cadmium batteries superior to lead-acid batteries for standby service?

What is the most reliable and preferred method for determining the state of charge of a wet cell NiCad battery?

What is the approximate discharge voltage produced by one cell of a wet type nickel- cadmium battery at 75% of charge?

The nominal voltage of one cell of a wet cell nickel-cadmium battery is approximately how many volts?

According to CFR, Subchapter J (Electrical Engineering), which of the following statements is true concerning flexible electric cord and cable used aboard ship?

According to 46 CFR, Subchapter J (Electrical Engineering), what statement is true concerning the use of twist-on connectors?

According to 46 CFR, Subchapter J (Electrical Engineering), when considering replacement, instrument and control wiring in a switchboard is to be of what minimum size?

According to 46 CFR, Subchapter J (Electrical engineering), regulations prohibit the use of portable electric cord or fixture wire aboard ship if that wire or cord is smaller than what size?

Electrical wire in general, when used aboard vessels must meet minimum requirements. Which of the following statements is/are correct?

Not only can a synchronous motor drive a load with greater efficiency than an induction motor, a fringe benefit of the synchronous motor is the ability for power factor correction. What statement is true?

Assuming that a three phase synchronous motor is separately excited, what statement is true concerning power supplies?

Occasionally a synchronous motor is configured without an external shaft to drive a load. In this case, the sole purpose of the synchronous motor is improving overall power factor of an electrical distribution system. What is the name of the synchronous motor so constructed?

Concerning the operating characteristics of a synchronous motor, what statement is true?