Motors Book - Chapter 7

15 Questions | Total Attempts: 140

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Motors Book Quizzes & Trivia

Questions and Answers
  • 1. 
    The ___ is constructed of laminated iron sheets to minimize eddy current losses.
    • A. 

      Brush

    • B. 

      Discharge resistor

    • C. 

      Slip ring

    • D. 

      Stator

  • 2. 
    ___ windings, or damper windings, are squirrel-cage conducting bars placed in slots on the pole faces and connected at the ends.
    • A. 

      Magnetic

    • B. 

      Pony

    • C. 

      Amortissuer

    • D. 

      Field

  • 3. 
    Synchronous motors that typically run faster than about ___ are considered high-speed synchronous motors.
    • A. 

      450 mph

    • B. 

      450 rpm

    • C. 

      1,000 mph

    • D. 

      1,000 rpm

  • 4. 
    When ___ are used, the rotors do not need to be excited.
    • A. 

      Static exciters

    • B. 

      Permanent magnets

    • C. 

      Brushless exciters

    • D. 

      Motor-generator sets

  • 5. 
    The ___ typically is a shunt- or compound-wound DC generator with the armature in parallel with the shunt field and its shunt-field rheostat.
    • A. 

      Exciter generator

    • B. 

      Servomotor

    • C. 

      Motor-generator

    • D. 

      Slip ring

  • 6. 
    ___ rotors are simpler than excited rotors and have minimal maintenance requirements.
    • A. 

      Squirrel-cage

    • B. 

      Wound-rotor

    • C. 

      Permanent magnet

    • D. 

      None of the above

  • 7. 
    A ___ exciter is an AC generator and rectifier mounted on a motor shaft.
    • A. 

      Bearing

    • B. 

      Pony

    • C. 

      Thermal

    • D. 

      Brushless

  • 8. 
    A common type of relay used with synchronous motors is a(n) ___ relay.
    • A. 

      Polarized field frequency

    • B. 

      Loss-of-excitation (field-failure)

    • C. 

      Out-of-step

    • D. 

      All of the above

  • 9. 
    A(n) ___ relay is an overload relay that is used to protect a synchronous motor from damage induced currents caused by the rotor falling out of step with the rotating stator field.
    • A. 

      Out-of-step

    • B. 

      Loss-of-excitation

    • C. 

      Synchronous overload

    • D. 

      Discharge

  • 10. 
    A(n) ___ resistor is a resistor used to discharge any AC potential that builds up in the amortisseur winding of a rotor in a synchronous motor.
    • A. 

      Direct

    • B. 

      Discharge

    • C. 

      Winding

    • D. 

      Amortisseur

  • 11. 
    The simplest starting method for a synchronous motor is ___ starting, where the motor is wired directly across the line conductors.
    • A. 

      Reduced-voltage

    • B. 

      Direct online (DOL)

    • C. 

      Low-speed

    • D. 

      High-speed

  • 12. 
    The type of torque that is important to understand for synchronous motors is ___ torque.
    • A. 

      Reluctance

    • B. 

      Pull-in

    • C. 

      Pull-out

    • D. 

      All of the above

  • 13. 
    ___ torque is the maximum torque required to accelerate a synchronous motor into synchronization at the rated voltage and frequency.
    • A. 

      Reluctance

    • B. 

      Pull-out

    • C. 

      Pull-in

    • D. 

      Field

  • 14. 
    ___ torque is provided by the interaction of the stator field and the rotor field windings.
    • A. 

      Synchronous

    • B. 

      Excitation

    • C. 

      Lagging

    • D. 

      Starting

  • 15. 
    The power factor of a synchronous motor is determined by the amount of ___ power applied to the rotor.
    • A. 

      AC

    • B. 

      True

    • C. 

      DC

    • D. 

      Apparent

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