Are You Smarter Than Your Electric Motors?

10 Questions | Total Attempts: 171

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Are You Smarter Than Your Electric Motors? - Quiz

Test your knowledge with this PdMA Sponsored Quiz on Electric Motors.


Questions and Answers
  • 1. 
    The General System Limit for voltage Total Harmonic Distortion (THD) is 5%.
    • A. 

      True

    • B. 

      False

  • 2. 
    According to NEMA MG-1 the motor should not be run if phase-to-phase voltage imbalance is greater than 5%.
    • A. 

      True

    • B. 

      False

  • 3. 
    A Polarization Index test must be temperature corrected.
    • A. 

      True

    • B. 

      False

  • 4. 
    Cracked or broken rotor bars at the end ring of a squirrel cage induction motor will cause a reduction in reflected impedance resulting in a lower average inductance as measured from the stator windings.
    • A. 

      True

    • B. 

      False

  • 5. 
    A variable frequency drive, connected to a 60 Hz distribution system, is supplying a 37 Hz output frequency to a squirrel cage induction motor. When performing current signature analysis for rotor evaluation of the squirrel cage induction motor, what would be the peak frequency of the current spectrum?
    • A. 

      41 Hz

    • B. 

      60 Hz

    • C. 

      50 Hz

    • D. 

      37 Hz

  • 6. 
    A fully loaded squirrel cage induction motor exhibits a 10% impedance imbalance and a 10% current imbalance, which fault zone is most likely the problem?
    • A. 

      Rotor Fault Zone

    • B. 

      Stator Fault Zone

    • C. 

      Insulation Fault Zone

    • D. 

      Power Circuit Fault Zone

  • 7. 
    Reactive Maintenance is characterized by run to failure practices. Preventive maintenance is characterized by periodic or time based practices. Predictive maintenance is characterized by practices based on equipment condition.
    • A. 

      True

    • B. 

      False

  • 8. 
    While viewing the current spectrum of a fully loaded squirrel cage induction motor you notice that the pole-pass frequency (Fp) sideband amplitude is 42 db. What fault zone would you be concerned with?
    • A. 

      Rotor

    • B. 

      Stator

    • C. 

      Air Gap

    • D. 

      None of the Above

  • 9. 
    In “Principles of Large AC Motors” by the Electrical Apparatus Service Association (EASA) it is recommended to rotate the shaft monthly.
    • A. 

      True

    • B. 

      False

  • 10. 
    As stated in the EASA literature Understanding Energy Efficient Motors, the number one misconception about energy efficient motors is that “An oversized motor is less efficient.”
    • A. 

      True

    • B. 

      False

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