Marine Electro Technology217

MEO CLASS IV PART-BMARINE ELECTRO TECHNOLOGYWRITTEN QUESTION BANK

1. Which of the following statements is true concerning a poly-phase synchronous propulsion motor?

A. The motor is started as an induction motor.

B. Resistance is gradually added to the rotor circuit.

C. The starting current is held below the rated current.

D. The field winding is energized for starting purposes only.

ANS: A

2. When reading electrical motor controller diagrams, it helps to know that _____

A. current paths in the control circuit are drawn as heavy lines and in the power circuit as lighter lines

B. current paths in the power circuit are drawn as heavy lines and in control circuit as lighter lines

C. circuits subject to 500 volts or greater are drawn as heavy lines and below 500 volts as lighter lines

D. circuits subject to 500volts or greater are drawn as light lines and below 500 volts as heavy

ANS: B

3. Alternating current circuits develop resistance, inductance and capacitance. The inductance of a coil is expressed inA. ohms B. mhos C. henrys D. farads

ANS: C

4. Large cable sizes are formed as individual conductors that may be comprised of several smaller strands to

A. obtain the flexibility required for easy handling

B. reduce the overall weight of the wire run

C. reduce the number of supports needed for a horizontal overhead run

D. all of the aboveANS: A

5. Which of the following is having Di-Electric Constant 80?

A. Air B. water C. Mica D. Castor oil

ANS: B

6. Where a thermal-acting breaker is required to be used in an area of unusually high, low, or constantly fluctuating temperatures, an ambient compensating element must be used. This element consists of a

A. cylindrical spring on the contact arm

B. conical spring on the contact arm

C. second bimetal element D. second electromagnet

ANS: C

7. Which of the following precautions should you take when securing propulsion generators and motors for an extended period of time?

A. Disconnect the brush pigtails from their contacts and circulate air through the units.

B. Disconnect the brush pigtails from their contacts and discharge carbon dioxide into the units to keep them dry.

C. Lift the brushes from commutator collector rings and use the built-in heater to preventmoisture accumulation.

D. Lift the brushes from commutator collector rings and circulate cool dry air through the units.

ANS: C

8. The direction of magnetic flux changes when the direction of current is reversed.

a. Trueb. False

ANS: A

9. In a Transistor (If Multi choice add option A)

A. PNP and NPN are two basic typesB. Emitter, Collector and Base are the basic Elements.C. Collector separates Base and EmitterD. Emitter separates Base and Collector

ANS: B

12. If a Motor is not rotating in the E/R, you will carry out the following Checks (multiple choice, 3 Questions of same type but Options were different)

A. Check for the isolation B. Rotate the Coupling with your handC. Check for the Circuit breakerD. Remove the fusesE Look for the Overload TripF. Visually inspect the motor terminalsG. Visually Inspect the Starter TerminalsH. Carry out Infinite Resistance Test

ANS: ALL

14. Arrange the following in Increasing Order of their Doping Strength. A. Collector, Emitter, BaseB. Base, Collector, EmitterC. Emitter, Base, CollectorD. Emitter, Collector, Collector Base, Collector, Base

ANS: B

15. Which of the listed precautions should be taken when cleaning the internals of a motor with compressed air?

A. Open the machine on both ends so as to allow the air and dust to escape.

B. Be certain that the circuit breaker is opened and tagged on the feeder panel.

C. Be certain that the air is clean and as dry as possible.

D. Ensure that the fuse in the motor is removed ANS: A B & C

16. A molded-case breaker provides protection against short-circuits by using a/anA. Shading coil. B. Arc quencher. C. Electromagnet. D. Holding coil.

ANS: C

17. PN diode advantage over vacuum diode?(a)Longer Life,b) No warm up time c) Less delicate d) All of the above

ANS: D

22. Time delayed or delayed action-type fuses are designed to _____________.(A) Prevent grounds in branch circuits (B) prevent opens in motor circuits(C) permit momentary overloads without melting(D) guard lighting and electronic circuitsANS: C23. Silicon diodes designed for a specific reverse breakdown voltage, become useful as an electronic power supply voltage regulator, called _____________(A) Tunnel diodes (B) hot-carrier diodes(C) compensating diodes (D) Zener diodesANS: D

24. Which of the following statements best describes the material known as varnished cambric?(A) Felted asbestos sealed with varnish.(B) Cotton cloth coated with insulating varnish.(C) Rubber insulation coated with a layer of tin.(D) Paper impregnated with mineral oil, specially wrapped with nonmetallic tape, and coated with varnish.

ANS: B25. A synchronous motor maintains synchronism with the rotating field because(A) Field strength varies directly with rotors lIp(B) DC current applied to the rotor coils causes the rotor magnets to lock in with the rotating flux of the stator(C) the stator poles are dragged around due to the flux created by the excitation current(D) the stator flux rotates in the opposite directionANS: B26. The part of a fuse that melts and opens the circuit is made of (A) Copper and antimony(B) Steel and Babbitt(C) Aluminum or beryllium alloy(D) Zinc or an alloy of tin and leadANS: D27. The apparent power in inductive circuit A. True power B. Lead C. Inductive D. ReactiveANS: D

29. If current reverses, the magnetic field also reverses; true (or) falsea. TRUEb. FALSEANS: B33. Which of the listed precautions should take while cleaning poly phase motor internals with compressed air? (Multiple ans)A. Open the machine as both ends so as to allow the dust to escapeB. Be certain that the circuit breaker is opened, tagged as the feeder panelC. Be certain that air is clean and as dry as possibleD. Ensure that the fuse is removedANS: A B & C

34. Which of the following capacitor is having highest dielectric constant?A. Air gapB. GlassC. PaperD. PolyesterANS: B35. A delayed action fuse is most frequently used in which of the listed circuit?A. Lighting circuitB. Motor circuitC. Electrical heaterD. Padar circuitANS: B36. The current in a semiconductor is produced byA. ElectronsB. NeutronsC. ProtonsD. HolesANS: A & D37. If an intrinsic semiconductor is doped with a very small amount of boron then the extrinsic semiconductor set formed, the no. of electrons and holes willA. Both decreases B. Increase and decreaseC. Both increasesD. Decrease and increaseANS: D39. When the current through the coil of an electromagnet is reversed, the direction of magnetic field also reverseda) TRUEb) FALSEANS: A40. A poly phase motor driving an engine room pump fails to start, when trying to identify the cause of failure, which of the following steps are applicable. (Multiple choice)A. Visually examine the motor for open circuit faultB. visually examine the starter for open circuit faultC. Reverse the direction of current for its workingD. Perform the infinite resistance testANS: A B & D41. Which of the following physical character does around rotor induction motor possess that squirrel cage motor does notA. Slip ringsB. End ringsC. A centrifugal clutchD. End platesANS: A42. Which of the following conditions will occur when solenoid coil burns out of a cargo winch with an electrical brake.A. The brake will be set by spring force.B. The motor will over speed and burns outC. The load suspended by the cargo boom will failD. Nothing will happen; the winch will continue to operate normallyANS: A43. A low voltage protection circuit is used in electric motor starting equipment to A. Trip circuit contractor when the motor over speed due to low voltageB. Trip circuit contractor when the motor develops short circuit due to low voltageC. Allows the motor to restart automatically on restoration of voltage without manual resettingD. Prevent motor from restarting automatically

ANS: D44. Determine the order of doping in transistor (from high to low)A. collector, base, emitterB. Emitter, collector, baseC. Base, emitter, collectorD. collector, emitter, baseANS: B45. The opposition to the magnetic lines of force in magnetic is called A. ResistanceB. Reluctance C. ImpedanceD. InductanceANS: B46. Factors varies potential of a PN junction depend on (multiple ans)A. Type of semiconductor materialB. Amount of dopingC. TemperatureD. NoneANS: A B & C48. A poly phase motor driving engine room pumps fails to start, checksA. Insulation is openB. No restriction for movement of motor /pumpC. Check overload relay tripD. Battery fully charged ANS: A B & C49. Poly phase motor fails to start, precautions to take before checkingA. Isolate motorB. Remove fuseC. Post caution signD. Ensure starter/motor terminals are liveANS: A B & C50. Which of the following statement is true (*)A.PNP & NPN are different transistors B. Emitter, base and collector are basic elementsC. Base separates, emitter, collectorANS: A B & C51. Purpose of silicon control rectifier (*Multiple choice)A. A.C to D.C convertorB. High voltage standANS: A & B52. Generator paralleling A. Incoming generator freq is less than bus bar frequencyB. Incoming generator frequency is greater than ANS: B

54. The induced voltage across a stationary conductor in a steady magnetic field is zero. (*)a. TRUEb. FALSEANS: A55. Which of the listed devices is used to measure pressure and convert it to an electrical signal?A. -TransducerB. -ReducerC. -TransformerD. RectifierANS: A56. In three phase electrical equipment, the immediate action in the event of fuse blowing in one of the phases would bea. to replace with a fuse of correct ratingb. to replace fuses on all three phasesc. to try to repair the fused. to investigate the fault that led to blowing the fuseANS: D57. Top of FormWhich of the capacity has dielectric constant of 1.0000? Dielectric materialis one that reduces the electrostatic force when placed between charges.a. air gap = 1.006b. vacuumc. waterd. electrolytesANS: B59. A poly-phase motor driving an engine room pump fails to start. When trying to identify the cause of failure, which of the following steps are applicable? (Multi choice)A. Visually examine motor for open circuit faults.B. Visually examine starter for open circuit faults.C. Reverse the direction of electrical supply to check if it works.D. Perform the infinite resistance test.ANS: A B & D

60. Tightly knit metal braid wire can be used with a printed circuit board whenA. Conductor flexibility is requiredB. De-soldering components in the circuitC. Electrically produced magnetic fluxes would cause inaccuracies in adjacent componentsD. Reactance in the circuit must be kept to a minimumANS: B61. Which of the following statements represents an application of a silicon controlled rectifier?A. To provide DC power for a main propulsion motor. B. For use as a voltage reference diode.C. For sensing flame in an automated burner. D. To eliminate power supply hum.ANS: A62. When paralleling an AC generator with live bus bars, which of the following precautions are applicable? (Multi choice)A. Generator frequency should be slightly lower than bus bar frequencyB. Generator frequency should be slightly higher than bus bar frequencyC. Generator voltage should be in phase with bus bar voltage D. Generator voltage should be out of phase with bus bar voltageANS: B & C63. For leading power factor circuits, which of the following can be used?A. Shunt Capacitors onlyB. Shunt Reactors onlyC. Either Shunt Capacitors or Shunt ReactorsD. Neither Shunt Capacitors nor Shunt ReactorsANS: B64. A fuse that blows often should be replaced only with a fuse ofA. the recommended current and voltage ratingB. higher current and voltage ratingC. higher current and lower voltage ratingD. lower current and higher voltage ratingANS: A65. Brushless generators are designed to operate without the use ofA. brushes B. slip rings C. commutators D. all of the aboveANS: D66. Fuses placed in series with a thermal trip type circuit breaker are used forA. Time-delay protection B. Short-circuit protection C. Short duration surge protection D. Sustained overload protectionANS: B67. In what range of voltages is the transistor in the linear region of its operation?A. 0 < VCE < 0.7 VB. 0.7 < VCE < 1.4 VC. 0.7 < VCE < VCE (max)D. 0 < VCE < VCE (max)ANS: C68. The greatest detrimental effect on idle electrical equipment, such as cargo pump motors, is theA. Loss of residual magnetism. B. Absorption of moisture in the insulation. C. Insulation varnish flaking.D. Dirt collecting on the windings.ANS: B69. Ammeters and voltmeters used in sinusoidal AC power systems indicate which of the following values of the wave forms measured?A. Peak value B. Root-mean-square value C. Average value D. Maximum valueANS: B70. Which of the following statements concerning analog and digital devices are correct?A. The variables in digital systems are fixed quantities and the variables in analog systems are continuous quantities.B. There are no basic differences between the two systems.C. Analog devices are superior in accuracy compared to digital devices.D. Operations in a digital device are performed simultaneously.ANS: A71. While starting a main propulsion synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. This indicates that theA. Motor has started properly. B. Field windings are grounded. C. Slip rings are dirty.D. Power transmission cables are grounded.ANS: A72. When the current through the coil of an electromagnet reverses, the direction of the magnetic field also reverses.a. True b. False ANS: A73. A magnetic blowout coil in a DC motor controller contact or functions to A. Open contact rapidly. B. Reduce contact wear. C. Adjust opening spring tension. D. Provide "snap-action" in the contactor.ANS: B74. In a PNP transistor, the p-regions areA. Emitter and BaseB. Base and CollectorC. Emitter and CollectorD. Emitter, Base and CollectorANS: C76. In refer compressor what are the readings we are entering in logbookA. S.W tempB. S.W PressureC. Condenser tempD. Condenser leak ANS: A B & C79. With reference to a Data Logger for a refrigeration system, which of the following parameters should be monitored?A. Room temperature.B. Liquid Line temperature.C. Recharge temperature.D. Solenoid valve operation.ANS: A B & D80. With reference to a Data Logger for a refrigeration system, which of the following parameters should be monitored?A. Sea water temperature and pressure.B. Condensing temperatureC. Refrigerant leakageD. Evaporating temperatureANS: A B & D81. AC circuits possess characteristics of resistance, inductance, and capacitance. The capacitive reactance of a circuit is expressed inA. ohms B. mhosC. henrys D. faradsANS: A82. The shunt used in an ammeter should be connected in____________.(A) series with the load and in parallel with the meter movement(B) parallel with the load and in series with the meter movement(C) parallel with the load and in parallel with the meter movement(D) series with the load and in series with the meter movement

ANS: A83. Brushless generators are designed to operate without the use of ___________.(E) brushes(F) slip rings(G) commutators(H) all of the above

ANS: D84. Which of the following physical characteristicsdoes a wound-rotor induction motor possess that asquirrel cage motor does not?(A) Slip rings(B) End rings(C) A centrifugal switch(D) End plates

ANS: A 85. The current at which a magnetic-type overload relay tends to trip may be decreased by raising the plunger further in to the magnetic circuit of the relay. This action_________.(A) reduces magnetic pull on the plunger and requires more current to trip the relay(B) reduces magnetic pull on the plunger and requires less current to trip the relay(C) increases magnetic pull on the plunger and requires more current to trip the relay(D) increases magnetic pull on the plunger and requires less current to trip the relay

ANS: D86. Protection against sustained overloads occurring in molded-case circuit breakers is provided bya/an_________.(A) over voltage release(B) thermal acting trip(C) thermal overload relay(D) current overload relay

ANS: B87. Which of the listed logic gates is considered to be a BASIC building block (basic logic gate) used in logic diagrams?(A) NAND(B) OR(C) NOR(D) All of the above.

ANS: B88. When choosing a battery for a particular application, major consideration should be given to the battery's (A) amp-hour capacity(B) terminal polarity(C) stability under charge(D) ambient temperature rise

ANS: A

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

ANS: B

90. The electrical energy necessary to transmit a person's voice over a sound-powered telephone circuit is obtained from ____________.(a) dry cell batteries(b) the ship's service switchboard(c) the emergency switchboard(d) the speaker's voice

ANS: D

91. Local action in a nickel-cadmium battery is offset by _____________.(a) separating the positive and negative plates with plastic spacers(b) separating the positive and negative plates with resin impregnated spacers(c) adding a small amount of lithium hydroxide to the electrolyte(d) trickle charging

ANS: D92. The freezing point of the electrolyte in a fully charged lead-acid battery will be _____________.(a) higher than in a discharged battery(b) lower than in a discharged battery(c) the same as in a discharged battery(d) higher than in a discharged battery, but the specific gravity will be less

ANS: B

93. Which of the following represents the accepted method of cleaning dust and foreign particles from electrical equipment while limiting damage to electric components?(A) Carefully wiping off the components with a soft cotton rag.(B) Blowing a high velocity stream of compressed air rapidly across the component(C) Using a vacuum cleaner to remove debris from the components.(D) Using carbon tetrachloride as a cleaning solvent to clean the components.ANS: C94. Regarding an AC generator connected to them am electrical bus; as the electric load and power factor vary, a corresponding change is reflected in the generator armature reaction. These changes in armature reaction are compensated for by the _____________.(A) governor speed droop setting(B) voltage regulator(C) balance coil(D) phase-balance relay

ANS: B95. In an induction motor, rotor currents are circulated in the rotor by _______(A) slip rings and brushes(B) an armature and brushes(C) inductive reaction of the rotating stator field(D) external variable resistors

ANS: C96. An electrical device which prevents an action from occurring until all other required conditions are met is called a /an ___________.(A) limit(B) monitor(C) modulator(D) interlock

ANS: D97. A circuit breaker and a fuse have a basic similarity in that they both _______(A) can be reset to energize the circuit(B) should open the circuit when overloaded(C) will burn out when an over current flow develops(D) all of the above

ANS: B98. The electrolyte in a lead-acid storage battery consists of distilled water and _____________.(A) hydrogen chloride(B) calcium chloride(C) sulfuric acid(D) muriatic acid

ANS: C

99. The full torque electric brake on an electric cargo winch functions to _____________.(a) act as a backup brake in the event the mechanical brake should fail(b) automatically hold the load as soon as current to the machine is shut off(c) automatically govern the lowering speed of the load(d) automatically govern the hoisting speed of the load

ANS: B

100. When troubleshooting most electronic circuits, "loading effect" can be minimized by using a voltmeter with a/an ___________________.(a) input impedance much greater than the impedance across which the voltage is being measured(b) input impedance much less than the impedance across which the voltage is being measured(c) sensitivity of less than 1000 ohms/volt(d) sensitivity of more than 1000 volts/ohm

ANS: A

101. An electric tachometer receives the engine speed signal from a _______________.(a) small generator mounted on the engine(b) bimetallic sensing device(c) stroboscopic sensing device(d) vibrating reed meter generating a voltage proportionate to engine speed

ANS: A

102. A semiconductor that decreases in resistance with an increase in temperature is known as a ___________.(a) resistor(b) thermistor(c) diode(d) thermopile

ANS: B

103. The shunt used in an ammeter should be connected in____________.(a) series with the load and in parallel with the meter movement(b) parallel with the load and in series with the meter movement(c) parallel with the load and in parallel with the meter movement(d) series with the load and in series with the meter movement

ANS: A

104. An operating characteristic appearing on the name plates of shipboard AC motors is _____________.(a) the type of winding(b) input kilowatts(c) temperature rise(d) locked rotor torque

ANS: C

105. Low horsepower, polyphase, induction motors can be started with full voltage by means of ___________.(a) compensator starters(b) autotransformer starters(c) across-the-line starters(d) primary-resistor starters

ANS: C

106. Moisture damage, as a result of condensation occurring inside of the cargo winch master switches, can be reduced by __________________.(a) installing a light bulb in the pedestal stand(b) coating the switch box internals with epoxy sealer(c) venting the switch box regularly(d) using strip heaters inside the switch box

ANS: D

107. Where a thermal-acting breaker is required to be used in an area of unusually high, low, or constantly fluctuating temperatures, an ambient compensating element must be used. This element consists of a ______________.(a) cylindrical spring on the contact arm(b) conical spring on the contact arm(c) second bimetal element(d) second electromagnet

ANS: C

108. Which of the following statements represents an application of a silicon controlled rectifier?(a) To provide DC power for a main propulsion motor.(b) For use as a voltage reference diode.(c) For sensing flame in an automated burner.(d) To eliminate power supply hum.

ANS: A

109. The electrolyte used in a nickel-cadmium battery is distilled water and ______________.(a) diluted sulfuric acid(b) potassium hydroxide(c) lead sulfate(d) zinc oxide

ANS: B

110. Which of the damages listed can occur to the components of a winch master control switch, if the cover gasket becomes deteriorated?(a) Overheating of the winch motor.(b) Contamination of lube oil.(c) Sparking at the winch motor brushes.(d) Rapid corrosion of switch components.

ANS: D

111. An accidental path of low resistance, allowing passage of abnormal amount of current is known as a/an ____________.(a) open circuit(b) short circuit(c) polarized ground(d) ground reference point

ANS: B

112. A resistance in a circuit of unknown value is to be tested using the voltmeter/ammeter method. Therefore, the meters should be connected with _____________.(a) both meters in series with the resistance(b) both meters in parallel with the resistance(c) the ammeter in series and the voltmeter in parallel with the resistance(d) the ammeter in parallel and the voltmeter in series with the resistance

ANS: C

113. SOLAS regulations state that a normal source for emergency loads and power on a cargo vessel must be supplied from ____________.(a) emergency generator supply to the emergency switchboard(b) emergency generator supply to the main switchboard(c) battery supply to the main switchboard(d) ship's service generator via the emergency switchboard

ANS: D

114. A storage battery for an emergency lighting and power system must have the capacity to _____________.a. close all watertight doors twiceb. open all watertight doors four timesc. open and close all watertight doors in six consecutive cycles within a 20 second periodd. none of the above

ANS: A

115. SOLAS regulations require emergency diesel engine starting systems to have sufficient capacity to provide power for at least ____________.A. three continuous starting sequencesB. six consecutive cranking cyclesC. nine repeated starts under loadD. twelve cranking periods of 5 seconds

ANS: B

116. Which of the following statements is a Safety regulation concerning emergency generator diesel engines? (SOLAS / Cargo Ship Safety Construction Rules)A. The fuel must have a flash point not less than 750F.B. Emergency diesel engines must be capable of operating under full load in not less than 30 seconds after cranking.C. The starting battery must produce 12 consecutive cranking cycles.D. Emergency diesel engines must operate satisfactorily up to a 22.50 list.

ANS: D

117. While on watch in the engine room at sea with only one ship's service shaft generator on line, the entire plant suddenly blacks out without warning. After restoring power, the cause for this casualty could be attributed to which of the following faults?A. The micro switch at the generator speed trip vibrated open, allowing the main breaker to open via the under voltage trip.B. Someone pushed the trip button to the "shore power" breaker.C. The main air compressor suddenly stopped.D. The standby generator started automatically and became motorized.

ANS: A

118. The function of a rectifier is similar to that of a _______.(a) trap(b) regulating valve(c) check valve(d) Filter

ANS: C

119. The basic control action of a magnetic amplifier depends upon _____________.(a) variations in the load capacitance(b) changes in inductance(c) type of core material(d) construction of the core

ANS: B

120. The seven segment arrangement for numerical display on consoles, test meters and other applications can be either ________________.(a) UJT or BJT(b) BCD or OCD(c) JFET or IGFET(d) LED or LCD

ANS: D

121. A silicon controlled rectifier (SCR) is a solid state device used to change ________________.(A) DC to AC and control relatively low load current(B) AC to DC and control relatively high load current(C) DC to AC and control relatively high load current(D) AC to DC and control relatively low load current

ANS: B

122. Which of the following conditions will occur if the solenoid coil burns out on a cargo winch with an electrical brake?(a) The brake will be set by spring force.(b) The motor will over speed and burn up.(c) The load suspended from the cargo boom will fall.(d) Nothing will happen; the winch will continue to operate as usual.

ANS: A123. 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?(a) Normal charging circuit(b) Quick charging circuit(c) Trickle charging circuit(d) High ampere charging circuit

ANS: C

124. The full torque electric brake on an electric cargo winch functions to A. -act as backup brake in the event the mechanical brake should failB. -automatically hold the load as soon as current to the machine is shut offC. -automatically govern the lowering speed of the loadD. -automatically govern the hoisting speed of the loadANS: B125. An electric tachometer receives the engine speed signal from a A. -small generator mounted on the engineB. -bimetallic sensing deviceC. -stroboscopic sensing deviceD. -vibrating reed meter generating a voltage proportionate to engine speed ANS: A

126. A semiconductor that decreases resistance with an increase in temperature is known as a A. -resistorB. -thermistorC. -diodeD. -thermopileANS: B

127. The shunt used in an ammeter should be connected in A. -series with the load and in parallel with the meter movementB. -parallel with the load and in series with the meter movementC. -parallel with the load and in parallel with the meter movementD. -series with the load and in series with the meter movementANS: A

128. Brushless generators are designed to operate without the use of A. -brushesB. -slip ringsC. -commutatorsD. -all of the aboveANS: D

129. In the event of a power failure during cargo loading operations, the movement of an electric powered cargo winch will be stopped by A. -a manual override switchB. -the weight of the load on the boomC. -a spring set brakeD. -a hand operated band brakeANS: C

130. A ground can be defined as an electrical connection between the wiring of a motor and its A. -shunt fieldB. -circuit breakerC. -metal frameworkD. -interpoleANS: C

131. The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the A. -prime mover speedB. -exciter output voltageC. -load on the alternatorD. -number of polesANS: B

132. Which of the following statements represents the main difference between a relay and a contactor?A. -Contactors control current, relays control voltage.B. -A relay is series connected and contactor is parallel connected.C. -Contactors can handle heavier loads than relays.D. -Contactors are made from silver and relays are made from copper.ANS: C

133. The electrolyte used in a nickel-cadmium battery is distilled water and A. -diluted sulfuric acidB. -potassium hydroxideC. -lead sulfateD. -zinc oxideANS: B

134. Which of the damages listed can occur to the components of a winch master control switch, if the cover gasket becomes deteriorated?A. -Overheating of the winch motor.B. -Contamination of lube oil.C. -Sparking at the winch motor brushes.D. -Rapid corrosion of switch components.ANS: D

135. An accidental path of low resistance, allowing passage of abnormal amount of current is known as a/an A. -open circuitB. -short circuitC. -polarized groundD. -ground reference pointANS: B

136. A resistance in a circuit of unknown value is to be tested using the voltmeter/ammeter method. Therefore, the meters should be connected with A. -both meters in series with the resistanceB. -both meters in parallel with the resistanceC. -the ammeter in series and the voltmeter in parallel with the resistanceD. -the ammeter in parallel and the voltmeter in series with the resistanceANS: C

137. A direct current passing through a wire coiled around a soft iron core is the description of a simple A. -magnetic shieldB. -electromagnetC. -piezoelectric deviceD. -electromagnetic domainANS: B

138. The use of four diodes, in a full-wave bridge rectifier circuit, will A. -provide unidirectional current to the loadB. -allow a very high leakage current from the loadC. -convert direct current to alternating currentD. -offer high opposition to current in two directionsANS: A

139. A magnetic blowout coil in a DC motor controller contractor functions to A. -open contact rapidlyB. -reduce contact wear C. -adjust opening spring tensionD. -provide "snap-action" in the contractorANS: B

140. The method used to produce electron emission in most vacuum tubes is known as A. -photoelectric emissionB. -secondary electric emissionC. -cold cathodic electric emissionD. -thermionic emissionANS: D

141. Which of the listed devices is used to measure pressure and convert it to an electrical signal?A. -TransducerB. -ReducerC. -TransformerD. -RectifierANS: A

142. Grounds occurring in electrical machinery as a result of insulation failure are usually caused by A. -deterioration due to ageB. -excessive heat C. -vibrationD. -all of the aboveANS: D

143. The amount of voltage induced in the windings of an AC generator depends on A. -the number of conductors in series per windingB. -the speed at which the magnetic field passes across the windingC. -the strength of the magnetic fieldD. -all of the aboveANS: D

144. The device that most commonly utilizes the principle of electromagnetic induction is the A. -diodeB. -transformerC. -transistorD. -rheostatANS: B

145. A tubular fuse should always be removed from a fuse panel with A. -a screwdriverB. -a pair of insulated metal pliersC. -any insulated objectD. -fuse pullersANS: D

146. One factor that determines the frequency of an alternator is the A. -number of turns of wire in the armature coilB. -number of magnetic polesC. -strength of the magnets usedD. -output voltageANS: B

147. Which of the motors for the devices listed below is fitted with an instantaneous overload relay?A. -FanB. -PumpC. -WinchD. -Machine toolANS: C

148. Which of the following statements concerning an analog device and a digital device is correct?A. -The variables in digital systems are fixed quantities, and the variables in analog systems are continuous quantities.B. -There are no basic differences between the two systems.C. -Analog devices are superior in accuracy compared to digital devices.D. -Operations in a digital device are performed simultaneously.ANS: A

149. The number of cells in a 12-volt lead-acid battery is A. -three cellsB. -four cellsC. -six cellsD. -twelve cellsANS: C

150. When choosing a battery for a particular application, major consideration should be given to the battery's A. -amp-hour capacityB. -terminal polarityC. -stability under chargeD. -ambient temperature riseANS: A

151. Electrical leads and insulation on a motor should be painted with A. -heat-resisting acrylicB. -heat-resisting aluminumC. -insulating varnishD. -insulating white leadANS: C

152. Voltage generator by most AC generators is fed from the machine to the bus by means of A. -brushes on a commutatorB. -brushes on slip ringsC. -slip rings on a commutatorD. -direct connections from the statorANS: D

153. A circuit breaker differs from a fuse in that a circuit breaker A. -melts and must be replacedB. -is enclosed in a tube of insulating material with metal ferrules at each endC. -gives no visual indication of having opened the circuitD. -trips to break the circuit and may be resetANS: D

154. Incandescent lamps are classified according to A. -shape of bulb and type of serviceB. -size and style of baseC. -operating voltage and wattageD. -all of the aboveANS: D

155. As a general rule, the first troubleshooting action to be taken in checking faulty electric control devices is to A. -draw a one-line diagram of the circuitryB. -test all fuses and measure the line voltage C. -take megger readingsD. -insulate the apparatus from groundANS: B

156. An electrical device which employs a stationary armature and a rotating electromagnetic field is used aboard ship as a A. -magnetic amplifierB. -ship's service alternatorC. -three-wire DC generatorD. -saturable core reactorANS: B

157. The state of charge of a lead acid storage battery is best indicated by the A. -testing of the individual cell voltagesB. -ampere hour capacity of the batteryC. -specific gravity of the electrolyteD. -total cell voltagesANS: C

158. The first requirement for logical troubleshooting of any system is the ability to A. -collect all available data on a casualtyB. -recognize normal operationC. -identify the probable cause of a symptomD. -isolate the faulty componentANS: B

159. The load sharing characteristics of two diesel generators operating in parallel are mostly dependent on their governor A. -load limit settingsB. -idle speed settingsC. -speed limit settingsD. -speed droop settingsANS: D

160. The open circuit voltage of a fully charged lead-acid battery cell isA. -1.5 vB. -1.8 vC. -2.0 vD. -2.3 vANS: C

161. In an AC generator, direct current from a separate source is passed through the windings of the rotorA. -by means of slip rings and brushesB. -by means of a commutatorC. -by means of rotating bar magnetD. -to minimize the danger of arc overANS: A

162. A delayed-action fuse is most frequently used in which of the listed circuits?A. -lighting circuitB. -motor circuitC. -electric heater circuitD. -radar circuitANS: B

163. Which of the listed procedures should be carried out to prevent moisture damage to electrical apparatus during extended periods of idleness?A. -fill the motor housing with CO2 to inert the spaceB. -strap silica gel around the commutatorC. -place heat lamps in the motor housingD. -cover the equipment with a canvas tarpaulinANS: C

164. A fuse of recommended current and voltage ratings that blows often should be replaced only with a fuse ofA. -the same ratingsB. -higher ratingsC. -higher current and lower voltage ratingD. -lower current and higher voltage ratingANS: A

165. Which of the listed conditions is an advantage of a PN diode over a vacuum diode?A. -longer lifeB. -no warm up timeC. -less delicateD. -all of the aboveANS: D

166. The freezing point of the electrolyte in a fully charged lead-acid battery will beA. -higher than in a discharged batteryB. -lower than in a discharged batteryC. -the same as in a discharged batteryD. -higher than in a discharged battery, but the specific gravity will be lessANS: B

167. To repair a small electrical motor that has been submerged in saltwater, you shouldA. -wash it with fresh water and apply an external source of heatB. -renew the windingsC. -send it ashore to an approved service facilityD. -rinse all electrical parts with a carbon tetrachloride cleaning solvent and then blow dry the motor with compressed airANS: A

168. The basic measuring unit of inductance is theA. -coulombB. -ohmC. -faradD. -henryANS: D

169. Which of the listed precautions should be taken when cleaning the internals of a motor with compressed air?A. -open the machine on both ends so as to allow the air and dust to escapeB. -be certain that the circuit breaker is opened and tagged on the feeder panelC. -be certain that the air is clean and as dry as possibleD. -all of the aboveANS: D

170. The purpose of DC generator brushes is toA. -neutralize armature reactionB. -conduct electric current to an outside circuitC. -convert DC current to AC currentD. -provide excitation to a DC generatorANS: B

171. Fuses are rated inA. -voltageB. -amperageC. -interrupting capacityD. -all of the aboveANS: D

172. Power transformers are rated inA. -kilowattsB. -ampere-turnsC. -kilowatt-voltsD. -kilovolt-amperesANS: D

173. Alternative current circuits develop resistance, inductance and capacitance. The inductance of a coil is expressed inA. -ohmsB. -mhosC. -henrysD. -faradsANS: C

174. A lead-acid battery is considered fully charged when theA. -electrolyte gasses freelyB. -battery charger ammeter indicates a positive readingC. -terminal voltage reaches a constant value at a given temperatureD. -specific gravity of all cells reaches the correct value and no longer increases over a period of 1 to 4 hrs.ANS: D

175. The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation valuesA. -immediately after shutting down the machineB. -every time the brush rigging is adjustedC. -immediately after starting up the machineD. -every 30 days whether the machine is in use or notANS: A

176. High vacuum diodes, gas-filled diodes, and germanium semiconductor diodes may all be used asA. -potentiometersB. -rectifiersC. -power sources D. -photocellsANS: B

177. The apparent power in a purely inductive circuit is also known asA. -true powerB. -lead powerC. -induced powerD. -reactive powerANS: D

178. Which of the following devices will prevent a DC generator from becoming motorized? (If AC generator means Ans C)A. -overcurrent relayB. -motorization tripC. -reverse power relayD. -reverse current relayANS: D

179. A grounded switch or cable will be indicated by a meg ohmmeter reading ofA. -infinityB. -zeroC. -being unsteady in the high rangeD. -being unsteady in the low rangeANS: B

180. Regarding battery charging rooms, ventilation should be providedA. -at the lowest point of the roomB. -horizontally near the batteriesC. -at the highest point of the roomD. -only when charging is in progressANS: C

181. The main difference between an electron tube and a transistor is theA. -type of function they can performB. -reaction of electron flow through a gas or vacuum in a transistorC. -reaction of electron flow through a semiconductor when placed in a tubeD. -reaction of electron flow through a semiconductor used to form a transistorANS: D

182. A generator has been exposed to water and is being checked for its safe operation. Therefore, it is necessary toA. -check for shorted coils with a growlerB. -take moisture readings with a hydrometerC. -test insulation values with a meggerD. -ground the commutator, or slip rings and run it at half load for 12 hoursANS: C

183. Before testing insulation with a meg ohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to test, because theA. -static charge of the machine may give a false readingB. -armature will have a greater number of leakage pathsC. -insulation may be damagedD. -insulation may be covered with moistureANS: A

184. In a DC series circuit, all the conductors have the sameA. -power expended in themB. -voltage drop across themC. -resistance to current flowD. -current passing through themANS: D

185. 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 tripB. -thermal overload relayC. -three-pole safety switchD. -magnetic blowout coilANS: B

186. Most three-phase induction motors used for driving engine room auxiliaries are started byA. -resistor startersB. -across-the-line startersC. -impedance startersD. -reactor startersANS: B

187. When electrical cables penetrate watertight bulkheads,A. -they should be grounded on either side of the bulkheadB. -they must be bent to a radius of six diametersC. -a watertight stuffing tube capable of accepting packing should be employedD. -they should be secured by a clampANS: C

188. Across-the-line starters are used with AC motors to provideA. -reduced starting currentB. -regulated starting currentC. -high starting torqueD. -controlled starting accelerationANS: C

189. Most conductive materials such as copper, aluminum, iron, nickelA. -increase in resistance with increased temperatureB. -increase in resistance with decreased temperatureC. -decrease in resistance with increased temperatureD. -decrease in resistance with decreased temperatureANS: A

190. The electrician reports to you that he has obtained low (but above 1 megohm) megger readings on the windings of a deck winch motor. Upon checking the records of that motor, you find the readings have consistently been at the same level the last six years. You should, therefore, recommend that theA. -motor be replacedB. -windings be driedC. -windings be cleanedD. -readings are acceptableANS: D

191. Line losses in a distribution circuit are kept to a minimum byA. -adding rubber insulation conductors to the circuitB. -using higher current and lower voltageC. -increasing the number of thermal relays in the circuitD. -using higher voltage and lower currentANS: D

192. Adding resistance in series with the field winding of a DC shunt motor without a load, will cause the motor speed toA. -increaseB. -decreaseC. -remain the sameD. -fluctuate rapidlyANS: A

193. The function of the compensating windings used in a DC generator is toA. -prevent cross-commutationB. -increase armature coil strengthC. -increase field strengthD. -neutralize armature reactionANS: D

194. Capacitors are used on the output of the power supply in today's consoles toA. -filter out "ripple"B. -prevent overloadsC. -act as a permanent loadD. -decrease the average value of the output voltageANS: A

195. The purpose of a motor under voltage protection device is toA. -prevent high armature current when power is restoredB. -start the motor at a very low voltageC. -trip the load off the motor in case of fireD. -protect personnel from low voltage shocksANS: A

196. In testing a three-phase delta winding for an open circuit using a meg ohmmeter, you mustA. -test each phase with all connections intactB. -measure the voltage across the open connections while testingC. -test the windings as parallel groups to avoid short circuitingD. -open the delta-connections to avoid shunting the phase being testedANS: D

197. The direction of rotation of an induction motor isA. -opposite to the rotating field B. -the same as the direction of the rotating fieldC. -determined by the number of polesD. -determined by the staggering of the brushesANS: B

198. mercury filled thermometers should never be used to determine the temperature of the battery electrolyte because accidental breakage of the thermometer can causeA. -severe sparking and explosionsB. -rapid oxidation of battery platesC. -contamination of the electrolyteD. -corrosion on the battery terminalsANS: A

199. The purpose of a main switchboard circuit breaker's revers-power trip is toA. -prevent main circuit overloadB. -protect the circuit breaker blowout coilC. -prevent alternator motorizationD. -prevent low voltage trip outANS: C

200. When charging lead-acid batteries, the charging rate should be reduced as the battery nears its full charge toA. -prevent damaging battery platesB. -allow equalization of cell voltagesC. -reduce lead sulfate depositsD. -increase lead peroxide formationANS: A

201. Regarding an induction motor, the power developed by the rotor automatically adjusts itself to A. -power required to drive the loadB. -speed required to drive the loadC. -current flow in the motor statorD. -torque developed by the rotating fieldANS: A

202. The purpose of a magnetic relay is toA. -open a circuit only in the event of overloadB. -remotely open and close contactsC. -provide overcurrent protection during startingD. -relay voltages at increased powerANS: B

203. A semiconductor is a material with aA. -conductivity higher than a normal conductorB. -conductivity higher than a normal insulatorC. -high conductivity at low temperaturesD. -low conductivity at high temperaturesANS: B204. The winding resistance of a coil can be increased by _______ the number of turns or using a ______ wire.A. increasing, thickerB. decreasing, thickerC. increasing, thinnerD. decreasing, thinnerANS: C

205. The most common source of excitation for synchronous motors is a/an _____________.(A) low voltage battery(B) motor attenuator set(C) DC exciter generator(D) AC supply

ANS: C

206. On an engine throttle control system, the aux control circuits are provided with devices to prevent excessive over travel of the pilot valve by the synchronous motor these devices are called.A. overlap sensorB. limit switchC. over travel relayD. proximity switch ANS: B

207. The speed of the squirrel cage induction motor is determined by A. Dia of statorB. No of stator polesC. Rotor winding resistanceD. Bar resistance of conducting rotor ANS: B

208. The method used to produce electron emission in most vacuum tubes is known as A. Photo electric emissionB. Secondary electric emissionC. Cold cathodic electric emissionD. Thermionic emission

ANS: D

209. A reverse current relay prevents dc generator motorization automatically by option A. Redirecting up prime mover, B. Securing the exciter generator, C. Tripping the circuit breaker.

ANS: C

210. Di electric constant of 3.6 A. WaterB. PaperC. ElectrolyteD. Air

ANS: B

211. RMS value of a sine wave current is expressed as A. Average value,B. Max valueC. Effective valueD. Instantaneous value

ANS: C

212. Which of the following statements comparing transistors and vacuum tubes is correct?A. Both transistors and vacuum tubes have a cathode that must be heated to give off electrons.B. A vacuum tube must have a heated cathode, where transistors do not.C. Neither transistors nor vacuum tubes require heat for electrons to flow.D. The anode of both transistors and vacuum tubes must be heated to give off electrons.

ANS: B

213. Electric and electro-hydraulic steering gear motors are required by Coast Guard Regulations (46 CFR) to be _________.A. protected by a circuit breaker set at 125% and a thermal overload deviceB. provided with a running motor overcurrent protection deviceC. served by a single two conductor cableD. served by two feeder circuits

ANS: D

New Questions

1. What happens to the strength of electromagnetic field when current passing through an inductor is halfed? A. B. C. 2D. 4

ANS: A

2. To prevent the race of DC series, motor what arrangement should make? 1. Always start at heavy load1. Use a strong series weak shunt compound DC motor1. Use a weak series strong shunt compound DC motor1. AllANS: A

3. If thyristor is used in place of starter (mcq) 1. Cost decreases1. Space decreases1. As load increases frequency increases uniformly1. Maintenance decreases

ANS: A B & D

4. For incoming generator which of the statements are true? 1. If Incoming generator voltage is increased, then it will have motoring effect.1. If voltage is decreased, then it will cause black out.1. If frequency do not match, then it will run slowly. 1. If frequency do not match, then will run fast.

ANS: B

5. Pure inductive power is called 1. Reactive power1. True power1. Set power

ANS: A

6. Zener diode is used as 1. Voltage regulator1. Rectifier

ANS: A

7. How with the help of pressure electrical signal is converted? 1. Transducer1. Tuctile sensor1. Reactor1. Dont remember1. Only i1. I & ii1. Only iv1. Ii & iv

ANS: A

8. Which statement is true in relation to AUTO TRANSFORMER? (mcq) 1. More effective than conventional transformer1. Any fractional voltage can be applied 1. Can be used both for A.C and D.C1. Less excitation needed.1. LOW COST1. SMALL SIZE

ANS: A B D E & F

9. For a turbo electric propulsion generator which can be fitted? 1. Co2 system1. Moisture something1. Stator winding temperature sensor1. All

ANS: D

10. Class B AMPLIFIER advantage? 1. Very low standing bias current.1. Negligible power consumption without signal.1. More efficient than Class A.1. Can be used for much more powerful outputs than class A ANS: A B C & D11. How is natural cooling of transformer done? 1. Air blast1. Oil cooling1. Water cooling1. None

ANS: A

12. Atoms are bonded by? 1. Valence electrons1. Neutron1. Proton1. Not known

ANS: A

13. If in an electromagnetic coil current is then its energy stored will be? 1. 1. 1. Twice 1. No change

ANS: A

14. For half wave rectifier ripple factor is? (for full wave- 0.482) 1. 1.411. 1.211. 1311. 1.51

ANS: B

15. To satisfy amplification, transistor amplifier must satisfy? 1. Forward biasing of output circuit.1. Reverse biasing in input circuit.1. Operate at set point1. All

ANS: C

16. Which of the following are true for Thermistors (mcq)

1. Thermistors are semiconductors devices1. In a Positive temperature coefficient (PTC) thermistors, resistance increases with temperature increase1. ve temperature coefficient (NTC) thermistors, can be used as replacement of fuse.1. PTC thermistors can be used as resistance thermometers in low temperature environments. 1. NTC thermistors are generally used for monitoring coolant and engine lube oil temp in automobiles.

ANS: A B & E

17. Which trip is present in emergency generator? 1. Over voltage trip1. Under voltage trip1. Over speed trip 1. None

ANS: C

18. NER- what is true for high voltage circuit? 1. To limit max load current1. Neutral earth resonance1. Main switchboard earthed1. Not known

ANS: A

19. Which of the following is not self-starting motor? 1. Squirrel cage motor1. Synchronous motor1. Induction motor1. Split phase motor

ANS: B

20. In capacitor, energy stored is? SURE 1. Potential energy1. Electrostatic energy1. Kinetic1. Not known

ANS: B

21. For t/c, leak current in P-N diode is produced by? 1. Heat energy1. Chemical energy1. Barrier potential1. Not known

ANS: A

22. Motor overhaul is to be done which statements are true?1. Stator should be isolated1. Tag on overall ship1. Not known

ANS: A

23. Electric motor stator- true statements? (mcq) 1. Generator used only with slip rings motors.1. Freq. convertor can be used as starter.1. Auto transformer act as rheostat starter1. Not known

ANS: B & C

24. Limit switch E/n throttle ---> limits pilot v/v moment

25. Squirrel cage used in synchronous motor for? 1. Improving p.f1. Uniform balancing1. Just for starting1. Not known

ANS: C

26. Which of the following will prevent a DC generator from becoming motorized? 1. Overcurrent relay1. Motorization trip1. Reverse power relay1. Reverse current relay

ANS: D

27. For leading power circuits which of the following can be used? 1. Shunt capacitors only1. Shunt reactors only1. Either shunt capacitors or shunt reactors1. Neither shunt capacitors nor shunt reactors

ANS: B

28. To repair a small electric motor which was submerged in saltwater, you should 1. Wash it with f.w and apply an external source of heat.1. Renew the windings1. Send to ashore to an approved service facility1. Rinse all electrical parts with a carbon tetrachloride cleaning solvents and then blow dry the motor with compressed air

ANS: A

29. An operating characteristic appearing on the name plates of shipboard AC motor is ___________ 1. Type of windings1. Input kw1. Temp rise1. Locked rotor torque

ANS: C

30. Fuses replaced in series with thermal trip type ckt breakers are used for? 1. Time delay protection 1. Short ckt protection 1. Short duration surge protection 1. Sustained overload protection

ANS: B

31. To prevent the race of DC series, motor what arrangement should make? 1. Always start at heavy load1. Use a strong series weak shunt compound DC motor1. Use a weak series strong shunt compound DC motor1. All

ANS: A

32. Current applied to lead acid battery would lead to 1. Higher thermal voltage1. Lower terminal voltage high charging1. Increase generation of H2 gas1. Decrease in specific gravity of electrolyte

ANS: C

33. Across the line starters are used with AC motors to provide 1. Reduced starting current1. Regulated starting current1. High starting torque1. Controlled starting acceleration

ANS: C

34. In an earth neutral system, an earth fault will occur only1. 1 fault in 1 line1. 2 fault in two line 1. Two fault in 1 line1. Dont know

ANS: A

35. Which statement is true for any storage battery 1. Amp hr. efficiency of alkaline battery is high than lead acid battery1. Watt hr. efficiency of alkaline is more than lead acid battery1. Alkaline battery can left in any state of charge or discharge1. All

ANS: C

36. Which of the following is true about star delta starters (mcq) 1. Popular bcoz relatively inexpensive1. Gives lower starting current than DOL1. Can only be used with induction motor delta connected in supply voltage1. Typically used to start the motor with lower voltage

ANS: B C & D

37. Which of the following are true for shipboard storage batteries? 1. Construction should be so as to prevent emission of spray1. If voltage is above 200v insulation stands must be used1. The deck below the cells should be protected with acid resisting or alkaline resisting materials 1. Battery banks above 2 kw should be kept in battery room only1. Emgy batteries should never be stored in battery room

ANS: A C & D

38. In common collector transistor collector amplifier voltage gain 1. Cannot exceed unity1. Depends on output impedance1. Depends on output signal 1. Always constant

ANS: A

39. Which statement is true for reactor starter for electrical motor 1. Minimal reduction in starting torque available1. Starting current is limited in proportion to voltage1. Advantage of this method is its low cost in comparison to other starters1. In reactor starter, a Coil with iron core is connected in parallel with motor during starting

ANS: B & C

40. Which statement is true about any soft starters used in electrical motor 1. Soft starters are based on semiconductors1. Used to control the stopping of motor1. Use of soft starters initially result in lower motor torque1. Soft starters progressively increase motor voltage with causing torque or current peak

ANS: A B & C

41. Voltage generator by most AC generators is fed from the machine to the bus by means of 1. Brushes on commutator1. Brushes on slip rings1. Slip rings on commutator1. Direct connection from stator

ANS: D

42. Which of the following are true about a temp measuring ckt employed in in a data logger system? 1. A Wheatstone bridge can be used in conjunction with a Wheatstone bridge induction thermometer1. Thermometer is energized using a constant current source and voltage developed is measured in potentiometer type method 1. Inductance of thermometer will change with change in temp1. 1 only1. 2 only1. 1 & 2 only1. 1 & 3 only1. 2 & 3 only

ANS: D

43. Dis advantage of ward Leonard system (mcq) 1. Motor generator set requires lot of space1. Overall efficiency of the system is low especially when lightly loaded1. System operates in very narrow speed range1. Requires high maintenance1. Speed regulation is difficult to achieve as motor acceleration is uniform 1. expensive

ANS: A B D & F

44. Which of the following are benefits of modifying ward Leonard control system by replacing motor set with a thyristor speed controller 1. Enhanced speed regulation by making the motor acceleration uniform 1. Increases efficiency of system especially lightly loaded1. Reduces the overall cost 1. Reduces system maintenance 1. Increases operating speed range of system1. Reduces overall space required

ANS: B C D & F

45. Arrange the following in correct sequence foe achieving correct KW sharing when an AC generator is paralleled with live bus bar and generator has some owe factor as others in system 1. Synchronize the incoming generator in terms of voltage, frequency and phase.1. Trim voltage of the machine which has/ have lower load current to increase excitation1. Increase speed on incoming machine while lowering than that of others connected to system1. Adjust machine voltage to keep overall system efficiency ready.1. Adjust the governor control switch on main switch board to increase the fuel to its prime mover 1. Adc1. Aebc1. Aecb1. Aec1. Adbc1. Acbd

ANS: D

46. which of the following is true for syncronoscope (mcq) 1. one of the coil in the armature is fed through a capacitor while other is through resistance1. the coil produces a three phase rotating field1. the rotating armature has two coils windings perpendicular to each other.1. The field produces by the coils rotates the magnetic armature pointer at a speed relative to the frequency of the bus bar supply1. The coils produce a single phase rotating field.

ANS: C D &E

47. Which of the following are TRUE with regards to a Synchro scope? (MCQ)A. One of the coils in the armature is fed through an Inductor while the other is fed through a Resistor.B. The rotating armature has two coil windings parallel to each other.C. The coils produce a two-phase rotating field.D. One of the coils in the armature is fed through a Capacitor while the other is fed through an Inductor.E. The field produced by the coils rotates the magnetic armature pointer at a speed relative to the voltage of the bus-bar supply.

ANS: A Only

48. Which of the following are TRUE with regards to incorrect synchronization of Alternators? a. If incoming supply voltage is higher than that of bus bar, the alternator will start drawing power from bus bar and start motoring. b. If incoming supply voltage is lesser than that of bus bar, the alternator will start drawing power from bus bar and start motoring.c. If frequencies of bus bar and alternator don???t match, alternator will run on low frequency on synchronization.d. If frequencies of bus bar and alternator don???t match, alternator will run on high frequency on synchronization.e. If voltages are not in phase and circuit breaker is closed, the phase difference will cause overloading and potential black out.f. If voltages are not in phase and circuit breaker is closed, the phase difference will cause low current to flow from alternator and alternator will run on low load.

ANS: B & E

49. Motor having rheostat in motor circuit to vary speed in cell 1. Squirrel cage motor1. Regenerating breaker motor1. Wound round induction motor1. Synchronous motor

ANS: C

50. Mercury filled thermometer should never be used to determine the temp of the battery electrolyte bcoz accidental breakage of thermometer can cause 1. Severe sparking and explosions1. Rapid oxidation of battery plates1. Contamination of the electrolyte1. Corrosion of battery terminals

ANS: A

51. An amplifier is said to suffer distortion when its output is 1. Low1. Different from input1. Noisy1. Larger than is input

ANS: B

52. What happens when battery is excess charged?

1. Electrolyte decreases1. Gassing increases1. Dont remember1. Dont remember

ANS: B

53. Which statements are true of starts used for electric motor. Mcq 1. Rheostat starting can be used with slip ring motors1. Frequency convertor cannot be used as stator1. Soft stator is made of semiconductor1. Advantage of Reactor start is their relatively low cost

ANS: A C & D

54. Max full wave rectifier efficiency possible by two diodes from a sinusoidal wave is (Half wave is 40.6%)a. 80.2b. B.82.1c. C.81.2d. None of the above

ANS: C

55. An amplifier is said to suffer from distortion when its output is a. Lowb. Different from inputc. Noisyd. Larger than is input

ANS: B

56. Common emitter amplifier is characterized by a. Low voltage gainb. Moderate power gainc. Signal phase reversald. Very high output impedance

ANS: C

57. The depletion region in semiconductor diode is due to a. Reverse biasingb. Forward biasingc. Crystal dopingd. Migration of mobile charge carriers

ANS: D

58. Which statement is true for any storage battery

a. Amp hr. efficiency of alkaline battery is high than lead acid batteryb. Watt hr. efficiency of alkaline is more than lead acid batteryc. Alkaline battery can left in any state of charge or discharged. All

ANS: C

59. Which of the following does not change in a transformer? SURE a. Currentb. Voltagec. FrequencyANS: CReversing any two of the three rotor leads on induction motor will _____________.

a. increase motor performanceb. decrease motor performancec. reverse the motord. have no effect on the direction of rotation or motor performance

ANS: C60. Which of the following statements represents an application of a silicon controlled rectifier? A. To provide DC power for a main propulsion motor.B. For use as a voltage reference diode.C. For sensing flame in an automated burner.D. To eliminate power supply hum.

ANS: A

61. Motor having rheostat in motor circuit to vary speed in cell a. Squirrel cage motorb. Regenerating breaker motorc. Wound round induction motord. Synchronous motor

ANS: C62. Which of the following method used for biasing a BJT in integrated circuits is considered independent of transistor beta? A.Fixed biasingB. Voltage divider biasC. Collector feedback biasD. Base bias with collector feedback

ANS: B63. Large cable sizes are formed as individual conductors that may be comprised of several smaller strands to a. obtain the flexibility required for easy handling b. reduce the overall weight of the wire runc. reduce the number of supports needed for a horizontal overhead rund. all of the above

ANS: A64. Which of the following are TRUE with regards to a Synchro scope? a. One of the coils in the armature is fed through a Capacitor while the other is fed through a Resistor.b. The coils produce a three-phase rotating field.c. The rotating armature has two coil windings perpendicular to each other.d. The field produced by the coils rotates the magnetic armature pointer at a speed relative to the frequency of the bus-bar supply.e. The coils produce a single-phase rotating fieldANS: C D & E

65. Which of the following are TRUE with regards to incorrect synchronization of Alternators? a. If incoming supply voltage is higher than that of bus bar, the alternator will start drawing power from bus bar and start motoring.b. If incoming supply voltage is lesser than that of bus bar, the alternator will start drawing power from bus bar and start motoring.c. If frequencies of bus bar and alternator don???t match, alternator will run on low frequency on synchronization.d. If frequencies of bus bar and alternator don???t match, alternator will run on high frequency on synchronization.e. If voltages are not in phase and circuit breaker is closed, the phase difference will cause overloading and potential black out.f. If voltages are not in phase and circuit breaker is closed, the phase difference will cause low current to flow from alternator and alternator will run on low load.

ANS: B & E

66. The main use of a Class-C amplifier is

a. as an RF amplifierb. as stereo amplifierc. in communication sound equipmentd. as distortion generator

ANS: A67. Generator paralleling A. Incoming generator freq is less than bus bar frequencyB. Incoming generator frequency is greater than

ANS: B68. Which of the following is/are necessary precaution(s) for paralleling an AC Generator with live bus bars? I. Generator frequency should be close to but slightly lower than bus bar frequencyII. Generator voltage should be equal to bus bar voltageIII. Current in generator circuit should be less than bus bar currentIV. Generator voltage should be in phase with bus bar voltage

A.I, II, III and IVB.I, II and IVC.I, II and IIID.II and IV only

ANS: D69. In common collector transistor collector amplifier voltage gain a. Cannot exceed unityb. Depends on output impedancec. Depends on output signald. Always constant

ANS: A70. The main use of a Class-C amplifier is A. as an RF amplifierB. as stereo amplifierC. in communication sound equipmentD. as distortion generator

ANS: A71. NER- what is true for high voltage circuit? a. To limit max load currentb. Neutral earth resonancec. Main switchboard earthedd. Not known

ANS: A72. Which statement is true in relation to AUTO TRANSFORMER? (mcq) a. More effective than conventional transformerb. Any fractional voltage can be appliedc. Can be used both for A.C and D.Cd. Less excitation needed.e. Voltage regulation of autotransformer is much betterf. Its size is relatively very smaller.

ANS: A B D E & F73. For a given line voltage, four heating coils will produce maximum heat when connected in a. parallelb. seriesc. same heat in both the timed. none of the above

ANS: A

74. ACB trips at what condition a. reverse currentb. short circuitc. overloadd. low voltage fault

ANS: C

75. With regards to AVR which all statements are true? a. A typical AVR circuit needs two Zener diode, two resistances, one inductor, one capacitor, one transformer and one Diode Bridge.b. The function of the transformer in an AVR is to step down the AC supply coming from the generator terminals and feed this supply to the LC circuit. c. The function of the LC circuit in an AVR is to convert the AC supply coming from the generator terminals into a DC supply. d. Zener diodes are typically used as voltage reference in most modern AVR. e. The function of Diode Bridge is to rectify the signal coming from the LC circuit and apply this to the reference bridge. f. The function of the LC circuit in an AVR is to smooth the signal coming from the diode bridge and apply this to the reference bridge.

ANS: A D & F

76. Which of the following statement is false for lead acid battery? a. when discharge both positive and negative plate contain lead sulphateb. when charged negative plate contain spongy leadc. when charged positive plate lead per oxided. when discharge electrolyte undergoes no chemical reaction

ANS: D77. which of the following prevents moisture condensation in a weather deck switch board SURE 1.installing light bulb in pedestal stand2.coat internal of switch box With epoxy sealed3.venting the switchboard regularly.4 using strip heatera. 2 and 4b. only 4 c. 1,2,3,4 d. 3 and 2

ANS: B

78. TRUE About Battery storage a. Prevention of electrolyte spillageb. Easy accessible from top for maintenancec. But kept on wood or trayd. Alkaline and lead acid battery are kept in a separate roome. But banks more than 2kw kept in proper cover

ANS: A B C D & E

79. Which of the following is true with regards to use regenerative braking in a reversible pole change multispeed type AC induction motor? (Multiple choice question) a. Regenerative braking is used in conjunction with the friction padb. regenerative braking is used as four quadrant controlc. . A motor in one direction can act as generator by reversing its direction through a controllerd. this method returns converts some of the kinetic energy back into chemical energy and feeds into the power supply.e. the power supply needs to be disconnected when motor comes to rest or the motor will turn in opposite direction.

ANS: A C D & E

80. Transformer having laminated core? a. Temp reduceb. Reduce power factorc. Reduce eddy currentd. all of the above

ANS: C

81. For faithful amplification, a transistor must : A. Input forward biasedB. Output reverse biasedC. Work in operating pointD. All of above

ANS: D

82. Class A amplifier coupled with transformer what will be efficiency A)50B)78.5

ANS: A

83. Which allow to equalize power factor of two alternator A.governorB.automatic voltage regulatorC.syncroscope

ANS: B

84. When tow generators are running in parallel and field of one of them is weakened too much then it will SUREa) deliver large share of the total load(b) deliver small share of the total load(c) run in the opposite direction(d) run as a motor in the same direction

ANS: D85. Which of the following are true about a temp measuring ckt employed in in a data logger system 1. A Wheatstone bridge can be used in conjunction with a Wheatstone bridge induction thermometer2. Thermometer is energized using a constant current source and voltage developed is measured in potentiometer type method3. Inductance of thermometer will change with change in temp

a. 1 onlyb. 2 onlyc. 1 & 2 onlyd. 1 & 3 onlye. 2 & 3 only

ANS: D86. The basic control action of a magnetic amplifier depends upon _____________. (a) Variations in the load capacitance (b) changes in inductance(c) type of core material (d) construction of the core

ANS: B87. which of the following is true for syncronoscope (mcq) A. one of the coil in the armature is fed through a capacitor while other is through resistanceB. the coil produces a three phase rotating fieldC. the rotating armature has two coils windings perpendicular to each other.D. The field produces by the coils rotates the magnetic armature pointer at a speed relative to the frequency of the bus bar supplyE. The coils produce a single phase rotating field.

ANS: C D & E88. Which of the following is true regarding distribution system on tankers? a. High voltage distribution system not allowed on tankersb. Earthed neutral system used.c. 3.3kv above insulated neutral system used fwd of the engine room bulkheadd. none of the above

ANS: C 89. Which of the following is/are necessary precaution(s) for paralleling an AC Generator with live bus bars? I. Generator frequency should be close to but slightly lower than bus bar frequencyII. Generator voltage should be equal to bus bar voltageIII. Current in generator circuit should be less than bus bar currentIV. Generator voltage should be in phase with bus bar voltageA. I, II, III and IVB.I, II and IVC. I, II and IIID. II and IV only

ANS: D

90. BJT transistor used as an amplifier it operates in a.cut offb.well saturationc.well in saturationd. active region

ANS: D

91. ambient temperature rise in transistor a. life lossb.life increasesc.stable

ANS: A

92. fuse materialsANS: Lead, Tin, Zinc, Silver, Aluminum, Copper, Antimony

93. the amount of current needed for full protection in case of iccp system for a particular ship will be most affected by a. wetted surface areab.quality and condition of protection pain coatingc.speed of the shipd.sea water temperature

ANS: A B C & D94. which of the following consider to be the safest protection from static electricity discharge when connecting or disconnecting cargo hose and metal arms? a.insulatiing flange on the length of the non-conducting hoseb.switching off ICCPc.ship shore bonding cabled.non of this above

ANS: C (Add A for MCQ)95. Class A amplifier percentage? a. 78.8%b.50%c.25%d.75%

ANS: C96. In properly biased npn transistor most free electron from emitter a. recombine with hole and baseb. recombine with emitter itselfc. stopped with emitter itselfd. pass through the base to collector

ANS: D97. which of the following true regards to syncronoscope SUREa. the coil produce 3 phase rotating fieldb.the coil produce a 2 phase rotating fieldc.the coil produce 1 phase rotating fieldd. the rotating armature has 2 coil winding perpendicular to each othere.the rotating armature has coil parallel to each other

ANS: C & D98. Characteristic of laser light

a. Coherentb. Collimatedc. Monochromaticd. all the above

ANS: D

99. which of the following used in earth neutral system a.netural earthing resistor'b.fusec.overcurrentd.transformer

ANS: A

100. 3 phase insulated earth system one of the path contact with hull a.earthedb.short crt or groundedc. a and bd.none of the above

ANS: A101. which of the device protect the generator over load a. relay on switchb.governorc.ACBd.overspeed trip on prime mover

ANS: D102. which is true a. over current relay act faster than Fuseb. over current relay trip the contactor on over load depend on over load settingc. fuse meant for protection against over load upto staled currentd. none of these above

ANS: B103. n type semiconductor doping substance a.antomyb.phosporsc.arsecnicd.all the above

ANS: D

104. class B amplifier outputa.distroation freeb.out put of full wave rectifierc. output of half wave rectifier

ANS: CNote: output is positive half cycle

105. while doping the semiconductor is adding impurities, why it is called impurities a.it change the crystal structure of the semiconductorb.it change the chemical free semiconductorc.it prevent the flow of free electrons

ANS: A

106. wound rotor motor changing the speed torque characteristic control and speed control purposea. use AVR with motor b. use changing no of poles in a motorc. use external resistor in a rotor circuitd. use external resistor in a stator circuite. thyristor in combine with motor.ANS: C

107. Ground occur in the electrical machinery as a result of insulation failure.

a. deteration through moistureb. excessive heatc. external period of vibrationd. all of the above

ANS: D

108. Unique feature of a cc transistor amplifier circuit is

a. step up the impedance levelb. dose not increase the signal voltagec. act as an impedance matching deviced. all of the above

ANS: D

109. capacitor and resistor connected in series with the sine wave generator frequency is set so that the capacitor reactance is equal to the resistance and thus equal amount of voltage appears across each component, what happen when frequency. What happens if the frequency is increased?

a. Voltage across the resistor became higher than voltage in the capacitorb. voltage across the capacitor became higher than voltage in the resistorc. voltage across capacitor remain same as the voltage across the resistord. cannot determine

ANS: A

110. Advantage of nickel cadmium battery

a. high voltageb. fewer cell needed for same voltagec. full charge for long timed. less expensive

ANS: C

111. 3 phase, if it is connected insulated neutral earth system to the ship hull short crt

a. earth faultb. both a and bc. neither a or b

ANS: A

112. 3 phase, if it is connected insulated earth system to the ship hull

a. short crtb. earth faultc. both a and bd. neither a or b

ANS: B

113. What will be in motor, for electro steering gear?

a. Fuseb. overload Alarmc. overload tripd. power failure alarm

ANS: D

114. impurities in semiconductor

a. dopingb. biasingc. alloyingd. none of the above

ANS: A

115. Capacitor banks are connected with ac induction motor A.in parallel.B.in series.C.not connected at]D.can be connected either way series / parallel.

ANS: A

116. A control action which produces a corrective signal relative to thelength of time the controlled variable has been away from the set point, is known as

a. Integral actionb. Proportional actionc. Rate actiond. Derivative action

ANS: A

117. What happens to the amount of energy stored in the electromagnetic field when the current through an inductor is cut in half?a. Is reduced to one fourthb. Is reduced to one halfc. Doubles d. Quadruples

ANS: A

118. Doping materials are called impurities because theya. Decrease the number of charge carriersb. Change the chemical properties of semiconductorsc. Make semiconductors less than 100& pured. Alter the crystal structures of pure semiconductors

ANS: D

119. The output of class B amplifier a. Is distortion freeb. Consists of positive half cycle onlyc. Is like the output of a full wave rectifierd. Comprises short duration current pulses

ANS: B

120. Which of the following are not appropriate precautions to be taken prior to the overhaul of the motor on a ship?i. Prove dead at starter / motor terminalsii. Post caution signs all over the shipiii. Make sure work area is cleariv. Remove overload relayv. Isolate the motorvi. Remove motor fusesA. iv and viB. i and iiC. i and vD. ii and ivE. iii and vi

ANS: D

121. What is residual magnetism?a. Magnetism in a solenoid coilb. Magnetism in a natural magnetc. Magnetism remaining after magnetic field is removedd. None of the above

ANS: C

122. Which of the following is / are true about earthing of high voltage installations?a. High voltage installations should not be earthed at the star point of the generatorb. Neutral earthing resonance can be used for earthing high voltage installationsc. The value of the NER is usually selected to limit current to the full load current value d. NERs can be substituted with earthing arrangements at circuit breakers in high voltage installations to achieve the same effect

ANS: B & C

123. The circuit efficiency of a class A amplifier can be increased by usinga. Low DC power inputb. Direct coupled loadc. Low rating transistord. Transformer coupled load

ANS: D

124. The negative plate of a nickel cadmium battery after discharge consists of __________a. Nickel hydroxideb. Cadmium hydroxidec. Potassium hydroxided. Cadmium

ANS: B

125. Which of the following is / are true about regulation concerning shipboard storage batteries?a. Construction should always be so as to prevent emission of sprayb. If voltage is above 220 V, insulation stands must be usedc. The deck below the cells should be protected with acid resisting or alkaline resisting materiald. Battery banks above 2KW should be kept in the battery roome. Emergency batteries should never be stored in the battery room

ANS: A C & D

126. Which of the following are TRUE with regards to Bi-metal strips? (MCQ)a. Bi-metal strips are generally used for temperature sensingb. During higher than normal current flows, the bi-metal strip will bendc. Bi-metal strips are generally used for voltage regulations d. Bi-metal strips are generally used as thermal elements in an over current protection relaye. Bi-metal strips are generally used for power control

ANS: A B C & D

127. Which of the following system is normally used in high voltage (3.3 KV and above) generation and primary distribution?a. AC single phase two wire insulatedb. AC three phase three wire insulatedc. DC two wire insulatedd. AC three phase three wire, neutral earthed

ANS: D

128. Which of the following protection devices are not provided for motors used in operation of electro hydraulic steering gears?a. Fusesb. Overload alarmc. Overload tripd. Power failure alarm

ANS: C

129. Which of the listed devices may be installed on a large turbo electric alternating current propulsion generator?I. Temperature detector coils inserted in the stator slots for measuring stator temperatureII. Electric space heaters to prevent condensation of moisture III. A CO2 fire extinguishing systemA. I, II and IIIB. I and IIC. II and IIID. III onlyE. I and III

ANS: A

130. The depletion region in semiconductor diode is due to a. Reverse biasingb. Forward biasingc. Crystal dopingd. Migration of mobile charge carriers

ANS: D

131. Which of the following statement is false?a. An insulated distribution system needs two earth faults on two different lines to cause a earth fault currentb. An earthed distribution system requires only one earth fault on one line to cause a earth fault currentc. An insulated system is more effective in maintaining continuity of supply to electrical equipmentd. None of the above

ANS: D

132. Current flow in a semiconductor depends on the phenomenon ofa. Driftb. Diffusionc. Recombinationd. All of the above

ANS: D

133. The purpose of a cage rotor winding placed on the rotor of a synchronous motor is toa. Provide excitation to the DC fieldb. Start the machine as induction motorc. Contribute extra torque at synchronous speedd. Prevent the machine from falling out of step

ANS: B

134. Which of the following is / are true of starters used for electric motors?a. Capacitor start can be used only with slip ring motorsb. Rheostat starters are based on semiconductorc. Frequency converters can also be used as startersd. The effect of an auto transformer start is similar to that of reactor start

ANS: C & D

135. A LED emits visible light when its ___________a. PN junction is reverse biased b. Depletion region widensc. Holes and electrons recombined. PN junction becomes hot

ANS: C

136. Which of the following can cause Grounds occurring in electrical machinery as a result of insulation failure?I. Deterioration through extended useII. Excessive heatIII. Operating in extremely cold conditionsIV. Extended periods of vibrationA. I and II onlyB. II and IV only C. I, II and IIID. I, II and IVE. I, II, III and IV

ANS: E137. For faithful amplification, a transistor must a. Input forward biasedb. Output reverse biasedc. Work in operating pointd. All of the above

ANS: D138. In a system of standby synchronizing lamps fitted in conjunction with a synchronoscope to synchronize an AC GeneratorLamp #1 is connected between S line of live bus bars and S line of incoming alternator,Lamp #2 is connected between R line of live bus bars and T line of incoming alternator,Lamp #3 is connected between T line of live bus bars and R line of incoming alternator.Which of the following is the right trigger for choosing the circuit breaker?1. When lamp #1 is dark and lamp #2 and #3 are equally bright1. When lamp #1 is dark, lamp #2 is low in brightness and lamp #3 is very bright1. When all three lamps are equally bright1. When all three lamps are darkANS: A139. Proper storage battery maintenance would include a. Maintaining a high charging current at all timesb. Maintaining connections tightc. Checking weight of batteries from time to timed. All of the aboveANS: B140. The circuit efficiency of a class A amplifier can be increased by using a. Low dc power input b. Direct coupled loadc. Low rating transistord. Transformer coupled loadANS: D141. Maximum reverse voltage that can be applied to the PN Junction without damage is termed as: -a. Reverse bias voltageb. Peak inverse voltagec. Breakdown voltaged. Zener voltageANS: B

142. The width of the depletion layer of a PN Junction a. Decreases with light dopingb. Increases with heavy dopingc. Is independent of supply voltaged. Is increased under reverse biasANS: D

143. Power transformers are rated ina) kilowattsb) ampere-turnsc) kilowatt-voltsd) kilovolt-amperesANS: D

144. The purpose of a main switchboard circuit breakers reverse-power trip is toa) prevent main circuit overloadb) protect the circuit breaker blowout coilc) prevent alternator motorizationd) prevent low voltage trip outANS: C

145. The charge of an alkaline battery is determined with aa) hydrometerb) ammeterc) voltmeterd) hygrometerANS: C

146. If the pointer fails to come back to zero when the megger is not in use it meansa) the megger is out of calibrationb) this is normalc) the hairsprings are burnt outd) the pointer is stuckANS: B

147. the power factor of an induction motor operating at full load is-a) leadingb) laggingc) unityd) no changeANS: B

148. In a 3 phase delta connection, the line current will be the product of phase current anda) 1.501b) 2.216c) 1.414d) 1.732ANS: D

149. The principal difference between a 3 phase squirrel cage induction motor and a single phase induction motor is-a) one is a split phase motor using a capacitor, while the other uses an inductorb) one has a revolving field which drags the rotor slightly behind it, while the other runs in step.c) there is no differenced) one needs DC excitation, the other need no excitationANS: A

150. Which of the following devices are used for protection of AC propulsion motors and generators?a) jamming relaysb) low voltage releasec) timing relaysd) phase balance relaysANS: D

151. 2 alternators are operating in parallel. If there is an increase in load and decrease in voltage, the AVR willa) cut out the field resistanceb) cut in the field resistancec) cut in armature resistanced) cut out armature resistanceANS: A

152. A galvanometer is used to measure-a) small voltagesb) small currentsc) large currentsd) large voltagesANS: B

153. In a 3 wire system the earth wire is coloreda) redb) blackc) whited) greenANS: D

154. A power factor meter in ECR shows-a) true powerb) apparent powerc) relationship between volts and amperesd) relationship between true power and apparent powerANS: D

155. Before synchronizing alternators, they must havea) load equalizedb) same frequencyc) same voltaged) same amperageANS: B

156. The advantage of DC motors over AC motors is that, they have-a) higher speedsb) handle heavier loadsc) have better speed controld) have a longer lifeANS: C

157. Which of the following is not required for synchronizing alternators?a) same voltageb) same phase rotationc) same speed expressed as frequencyd) same KW ratingANS: D

158. Temperatures in AC generators are indicated by-a) imbedded thermocouplesb) deep well thermometersc) pyrometersd) standard thermometersANS: A

159. If the resistan