EX. Mod. 11 ch.3 & Mod. 13, 15

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EX. Mod. 11 ch.3 & Mod. 13, 15
2012-02-14 16:16:04

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  1. Power ratio is a term used to express
    what property of an antenna?
  2. A standing-wave ratio (swr) describes
    which of the following quantities?
    • The amount of mismatch between a
    • transmission line and its load
  3. Directivity refers to which of the
    following properties of a radiated beam?
    Narrowness of the beam
  4. Surface angular measurements for
    antenna directivity in radar and
    communications systems are made in
    relationship to which of the following
    Horizontal plane only
  5. Radar range is determined as a function
    of which of the following measures?
    Pulse travel time
  6. The parabolic reflector is often used
    because it produces a radiation pattern
    with which of the following antenna
    Highly directive
  7. In a lens antenna, what is the purpose of
    the collimating lens?
    • It forces radial segments of the
    • wavefront into parallel paths
  8. A lens antenna which accelerates some
    portion of the wavefronts so that all
    wavefronts exit the lens at the same timeis referred to as the
    waveguide-type lens
  9. In a delay-type lens, the amount of delay
    in the phase of the wave passing through
    the lens is determined by which of the
    following characteristics?
    The dielectric constant of the lens
  10. What is/are the basic type(s) of antenna
    array(s) in common use?
    Parasitic and driven
  11. In a frequency-sensitive antenna, the
    physical length of the serpentine section
    and its relationship to the wavelength of
    the applied energy determines which of
    the following characteristics?
    Direction of the beam
  12. In a horizontal-slot antenna, the
    polarization of the energy is radiated in
    what direction?
  13. Modern number systems are built around
    which of the following components?
    Unit, number, and radix
  14. What term describes a single object in a
    modern number system?
  15. What is a number?
    A symbol representing a unit or a quantity.
  16. What term describes the number of
    symbols used in a number system?
  17. What is the base of a number system
    using all the letters of the
    alphabet A=0, B=1, C=2, and so forth?
  18. A number system uses the symbols 0
    through 4. What is its base?
  19. Using positional notation, what two
    factors determine the value of a number?
    Symbol and position
  20. The power of a number is indicated by the
  21. What is the value of 5 times 100?
  22. What term describes the symbol that
    separates the whole and fractional
    numbers in any number system?
    Radix point
  23. What term is defined as a number to be
    added to a preceding number?
  24. In subtraction, the (a) is subtracted from
    the (b).
    (a) Subtrahend (b) minuend
  25. The result of subtraction is known as the
  26. Which of the following terms accurately describes a synchro?
    • Position-sensing
    • Electromechanical
    • Rotary
  27. What are the two general classifications
    of synchro systems?
    Torque and control
  28. What is the difference in application
    between the two classifications of
    Light versus heavy load
  29. Which of the following types of synchro
    devices provides a mechanical output?
    A torque receiver
  30. A 115-volt, 400-Hz torque transmitter
    with a diameter of 2.36 inches will have
    what military standard designation code?
  31. A 3.5-inch diameter differential receiver
    will have what Navy prestandard
    designation code?
  32. What does the arrow on a synchro schematic symbol indicate?
    The angular position of the rotor
  33. What are the two major components of a
    The rotor and the stator
  34. What type of rotor can be composed of a
    single winding or three Y-connected windings?
    Drum or wound
  35. How does the stator of a TX receive
    By a magnetic coupling with the rotor
  36. What part of a synchro provides a point
    for external connections?
    The terminal board
  37. Which of the following terms is defined
    as the amount of load a machine can
  38. Which of the following units should be
    used in measuring the amount of turning
    force of a synchro?
  39. An overloaded synchro will probably
    exhibit which of the following conditions?
    Excessive temperature
  40. A synchro receiver has which of the following characteristics that is NOT found in an ordinary transformer?
    A primary that can rotate in relation to the secondary
  41. Damping is necessary for which of the
    following synchro devices?
  42. The primary purpose of damping is to reduce which of the following conditions in a synchro device?
  43. In a simple synchro system, what leads are connected to the source voltage?
    S1 and S2
  44. When a synchro transmitter, and receiver are in correspondence, what is the relative value of the (a) current through the stators and (b) receiver torque?
    (a) Minimum (b) minimum
  45. What term applies to the angle through which a synchro transmitter rotor is rotated mechanically?
  46. If a synchro receiver is required to rotate in a direction opposite to the rotation of the transmitter rotor, what leads should be reversed?
    S1 and S3
  47. If a synchro receiver and transmitter are always 180 degrees out of phase with each other, what leads are reversed?
    R1 and R2
  48. What type of synchro can accept two signals simultaneously and add or subtract?
  49. What are the two types of synchro devices that will accept two inputs?
    TDR and TDX
  50. What types of synchro devices have (a) one electrical and one mechanical input and an electrical output; and (b) two electrical inputs and a mechanicaloutputs?
    (a) TDX (b) TDR
  51. What determines whether a differential synchro device adds or subtracts its inputs?
    The way it is connected in the system
  52. In a TDX system, for the TR rotor to follow the TX rotor exactly, in what position must the TDX rotor be kept?
    240 degree position
  53. For a TDX system to add its inputs rather than subtract them, what leads must be reversed between (a) the TX and TDX, and (b) the TR and TDX?
    (a) S1 and S3 (b) R1 and R3
  54. For a TDR system to add its inputs rather than subtract them, what leads must be reversed at the TDR?
    R1 and R3
  55. If a TDR system is connected for addition and the TX rotor connected to the TDR rotor turns counterclockwise, in what direction will the TDR rotor field rotate?
  56. Which of the following types of synchros is used in a system requiring large amounts of power and high accuracy?
  57. What are the three types of control synchros?
    CX, CT, CDX
  58. The CX and CDX differ from the TX and TDX because the CX and CDX have which of the following characteristics?
    Higher impedance windings
  59. What is NOT a characteristic of the rotor of a control transformer (CT) rotor?
    It is connected to an ac source
  60. When a control transformer is at electrical zero, the rotor is perpendicular to what winding?
  61. Which of the following terms applies to the output of a control transformer?
    Error signal
  62. If the output of a control transformer is zero, what is the relationship of the rotors of the control transformer and the control transmitters?
    Out of correspondence
  63. Synchro capacitors are used to provide which of the following characteristics in a synchro system?
    Improved accuracy
  64. What synchro devices uses a synchro capacitor?
  65. What type of current is eliminated by synchro capacitors?
    Magnetizing Stator
  66. To maintain system accuracy, where are synchro capacitors physically placed in a synchro circuit?
    Midway between the TX and CT
  67. Synchro systems that transmit data at two
    different speeds are referred to by which of the following terms?
  68. Multispeed synchro systems have which
    of the following advantages over singlespeed
    synchro systems?
    Greater accuracy
  69. What does the gear ratio between the two transmitters in a dual-speed synchro system determine?
    The speeds of transmission
  70. Which of the following synchro systems, if any, should be used to transmit very large quantities?
  71. Which of the following is a disadvantage of a double receiver as compared to two single receivers?
    The entire unit must be replaced if one portion fails
  72. The voltage used to prevent false synchronizations is known by what term?
    Stickoff voltage
  73. What is the reference point for the alignment of all synchro units?
    Electrical zero
  74. What is the most accurate method of aligning a synchro?
    The ac voltmeter method
  75. During synchro alignment, what is the purpose of the coarse setting?
    To ensure a setting of zero degrees rather than 180 degrees
  76. If a synchro receiver is properly zeroed, when do the stator windings have electrical zero voltages?
    When the rotor is at its reference position
  77. When a 115-volt synchro transmitter is
    set on its coarse-zero position, approximately what voltage should be read on a voltmeter?
    193 volts
  78. When a 115-volt source is used during the alignment of a differential synchro, what is the maximum time the circuit can be energized without causing damage to the synchro?
    2 minutes
  79. After a control transformer has been zeroed and clamped down, what is the final step in the zeroing procedure?
    Recheck the zero voltage reading
  80. The output voltage of a control transformer on electrical zero is which of the following relative values?
  81. When a tri-speed synchro system is being zeroed, which synchro should be zeroed first?
  82. What method of zeroing a synchro is the fastest but NOT the most accurate?
    The electrical-lock method
  83. The electrical-lock method of zeroing a synchro requires accessible leads and which of the following conditions?
    A supply voltage to the stators
  84. A synchro is zeroed by the use of a synchro tester. After it is zeroed, the S1 and S3 leads are shorted together, and the synchro tester dial moves. What does this indicate?
    The synchro is not zeroed correctly
  85. If you find that a synchro has bad bearings, which of the following actions should you take?
    Replace the synchro
  86. Which of the following troubles is common in newly installed synchro systems?
    Improper wiring
  87. What type of indicating device is usually installed in the stator circuit of a torque synchro system?
    A voltmeter indicator
  88. A synchro system with four receivers is malfunctioning. All of the receivers have incorrect readings. Which of the following is/are the most likely cause(s) of the trouble?
    The transmitter
  89. An ac voltmeter is connected between windings S1 and S3 of a synchro transmitter. Which of the following rotor positions should give a zero voltage reading?
  90. When a synchro tester is used in place of a synchro transmitter, which of the following precautions will help to keep the tester from being overloaded?
    Use only one syncho receiver