FUNCTION -5 (ELECTRICAL)

61. Which of the following statements represents an application of a silicon controlled rectifier?
    1. To provide DC power for a main propulsion motor.
    2. For use as a voltage reference diode.
    3. For sensing flame in an automated burner.
    4. To eliminate power supply hum.

ANS.: A

62. When paralleling an AC generator with live bus bars, which of the following precautions are applicable?
    1. Generator frequency should be slightly lower than bus bar frequency
    2. Generator frequency should be slightly higher than bus bar frequency
    3. Generator voltage should be in phase with bus bar voltage
    4. Generator voltage should be out of phase with bus bar voltage

ANS.: B,C

63. For leading power factor circuits, which of the following can be used?
    1. Shunt Capacitors only
    2. Shunt Reactors only
    3. Either Shunt Capacitors or Shunt Reactors
    4. Neither Shunt Capacitors nor Shunt Reactors

ANS.: B

64. A fuse that blows often should be replaced only with a fuse of
    1. the recommended current and voltage rating
    2. higher current and voltage rating
    3. higher current and lower voltage rating
    4. lower current and higher voltage rating

ANS.: A

65. Brushless generators are designed to operate without the use of
    1. brushes
    2. slip rings
    3. commutators
    4. all of the above

ANS.: D

66. Fuses placed in series with a thermal trip type circuit breaker are used for
    1. Time-delay protection
    2. Short-circuit protection
    3. Short duration surge protection
    4. Sustained overload protection

ANS.: B

67. In what range of voltages is the transistor in the linear region of its operation?
    1. 0 < VCE < 0.7 V
    2. 7 < VCE < 1.4 V
    3. 7 < VCE < VCE (max)
    4. 0 < VCE < VCE (max)

ANS.: C

68. The greatest detrimental effect on idle electrical equipment, such as cargo pump motors, is the
    1. Loss of residual magnetism.
    2. Absorption of moisture in the insulation.
    3. Insulation varnish flaking.
    4. Dirt collecting on the windings.

ANS.: B

69. Ammeters and voltmeters used in sinusoidal AC power systems indicate which of the following values of the wave forms measured?
    1. Peak value
    2. Root-mean-square value
    3. Average value
    4. Maximum value

ANS.: B

70. Which of the following statements concerning analog and digital devices are correct?
    1. The variables in digital systems are fixed quantities and the variables in analog systems are continuous quantities.
    2. There are no basic differences between the two systems.
    3. Analog devices are superior in accuracy compared to digital devices.
    4. Operations in a digital device are performed simultaneously.

ANS.: A

71. 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 the
    1. Motor has started properly.
    2. Field windings are grounded.
    3. Slip rings are dirty.
    4. Power transmission cables are grounded

ANS.: A

72. When the current through the coil of an electromagnet reverses, the direction of the magnetic field also reverses.
    1. True
    2. False

ANS.: A

73. A magnetic blowout coil in a DC motor controller contact or functions to
    1. Open contact rapidly.
    2. Reduce contact wear.
    3. Adjust opening spring tension.
    4. Provide “snap-action” in the contactor

ANS.: B

74. In a PNP transistor, the p-regions are
    1. Emitter and Base
    2. Base and Collector
    3. Emitter and Collector
    4. Emitter, Base and Collector

ANS.: C

76. In refer compressor what are the readings we are entering in logbook
    1. W temp
    2. W Pressure
    3. Condenser temp
    4. Condenser leak

ANS.: 1, 2, 3

79. With reference to a Data Logger for a refrigeration system, which of the following parameters should be monitored?
    1. Room temperature.
    2. Liquid Line temperature.
    3. Recharge temperature.
    4. Solenoid valve operation.

ANS.: 1, 2, 4

80. With reference to a Data Logger for a refrigeration system, which of the following parameters should be monitored?
    1. Sea water temperature and pressure.
    2. Condensing temperature
    3. Refrigerant leakage
    4. Evaporating temperature

ANS.: A,B,D

81. AC circuits possess characteristics of resistance, inductance, and capacitance. The capacitive reactance of a circuit is expressed in
    1. ohms
    2. mhos
    3. henrys
    4. farads

ANS.: A

82. The shunt used in an ammeter should be connected in____________.
    1. series with the load and in parallel with the meter movement
    2. parallel with the load and in series with the meter movement
    3. parallel with the load and in parallel with the meter movement
    4. series with the load and in series with the meter movement

ANS.: A

83. Brushless generators are designed to operate without the use of ___________.
    1. brushes
    2. slip rings
    3. commutators
    4. all of the above

ANS.: D

84. Which of the following physical characteristics does a wound-rotor induction motor possess that a squirrel cage motor does not?
    1. Slip rings
    2. End rings
    3. A centrifugal switch
    4. 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_________.
    1. reduces magnetic pull on the plunger and requires more current to trip the relay
    2. reduces magnetic pull on the plunger and requires less current to trip the relay
    3. increases magnetic pull on the plunger and requires more current to trip the relay
    4. increases magnetic pull on the plunger and requires less current to trip the relay

ANS.:  D

86. Protection against sustained overloads occurring in molded-case circuit breakers is provided by a/an _________.
    1. over voltage release
    2. thermal acting trip
    3. thermal overload relay
    4. current overload relay

ANS.: B

87. Which of the listed logic gates is considered to be a BASIC building block (basic logic gate) used in logic diagrams?
    1. NAND
    2. OR
    3. NOR
    4. All of the above.

ANS.: B

88. When choosing a battery for a particular application, major consideration should be given to the battery’s
    1. amp-hour capacity
    2. terminal polarity
    3. stability under charge
    4. ambient temperature rise

ANS.: A

89. The rated temperature rise of an electric motor is the _____________.
    1. average temperature at any given latitude
    2. normal temperature rises above the standard ambient temperature at rated load
    3. average temperature rises due to resistance at 10% overload
    4. permissible difference in the ambient temperature 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 ____________.
    1. dry cell batteries
    2. the ship’s service switchboard
    3. the emergency switchboard
    4. the speaker’s voice

ANS.: D