Motor And Motor Control Circuits And Special Purpose Systems

73 Questions | Total Attempts: 131

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Motor  And Motor Control Circuits And Special Purpose Systems

This volume covers the different aspect of motors and motors controls, electrical procudures used in hazardous locations, applications of special equipment, cathod protection for corrosion control, and alarms systems.


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Questions and Answers
  • 1. 
    In a DC motor, how are coil ends from the amature winding attached to the riser?
    • A. 

      Welded

    • B. 

      Wedge

    • C. 

      Soldered

    • D. 

      Brazed

  • 2. 
    The DC motor with the highest starting torque is the
    • A. 

      Series motor

    • B. 

      Shunt motor

    • C. 

      Universal motor

    • D. 

      Compound motor

  • 3. 
    The DC shunt motor connects the field coils and armature in
    • A. 

      Series

    • B. 

      Parallel

    • C. 

      Series-parallel

    • D. 

      Parallel-series

  • 4. 
    What part of a three-phase motor is connected to the supply voltage?
    • A. 

      Centrifugal switch

    • B. 

      Base

    • C. 

      Rotor

    • D. 

      Stator

  • 5. 
    The component of a three-phase motor connected to the load is the
    • A. 

      Amature

    • B. 

      End bell

    • C. 

      Rotor

    • D. 

      Stator

  • 6. 
    The magnetic field of a three-phase motor rotor is caused by
    • A. 

      Resistance in the squirrel cage

    • B. 

      Current flow in the rotor

    • C. 

      Impedance of the stator

    • D. 

      Voltage in the end bells

  • 7. 
    Which motor would have the highest rpm if each were connected to the same power supply?
    • A. 

      4-pole motor

    • B. 

      6-pole motor

    • C. 

      12-pole motor

    • D. 

      24-pole motor

  • 8. 
    The internal winding of all three-phase motors are
    • A. 

      Either connected in series or parallel

    • B. 

      Either wye or delta connected

    • C. 

      Are always in series with the supply

    • D. 

      Are always in parallel with the load

  • 9. 
    The motor that requires some starting means is the
    • A. 

      Universal motor

    • B. 

      DC shunt motor

    • C. 

      Three-phase AC motor

    • D. 

      Single-phase AC motor

  • 10. 
    A centrifugal switch is used in a single-phase motor to
    • A. 

      Engage the power leads

    • B. 

      De-energize the start windings

    • C. 

      Engage the run windings

    • D. 

      De-energize the field windings

  • 11. 
    The squirrel-cage winding has high-inductive reactance and is placed beneath the
    • A. 

      Left endbell

    • B. 

      Right endbell

    • C. 

      Housing section

    • D. 

      Wound rotor section

  • 12. 
    What should you connect to operate a single-phase dual-voltage motor  on high voltage?
    • A. 

      Run windings in series

    • B. 

      Run windings in delta

    • C. 

      Start windings in parallel

    • D. 

      Start windings in wye

  • 13. 
    Normally, an across-the-line motor control incoporate some type of
    • A. 

      Lightning protection

    • B. 

      Motor overcurrent protection

    • C. 

      Motor speed control

    • D. 

      Frequency control

  • 14. 
    How many basic types of across-the-line motor control are there?
    • A. 

      Five

    • B. 

      Four

    • C. 

      Three

    • D. 

      Two

  • 15. 
    The basic types of overload relays are
    • A. 

      Mechancial and magnetic

    • B. 

      Undervoltage and overcurrent

    • C. 

      Thermal and magnetic

    • D. 

      Single-and three-phase

  • 16. 
    The method used to open the contacts on an across-the -line magnetic controller are
    • A. 

      Magnetic and thermal

    • B. 

      Spring tension and gravity

    • C. 

      Thermal and hydraulic

    • D. 

      Metallic and magnetic

  • 17. 
    What type of motor enclosure is designed to prevent liquids or solids from entering it except at indirect angles?
    • A. 

      Open

    • B. 

      Splash-proof

    • C. 

      Drip-proof

    • D. 

      Explosive-proof

  • 18. 
    What should be your first check on a motor that seems to be overheating?
    • A. 

      Wire size

    • B. 

      Shorted winding

    • C. 

      Ventilation

    • D. 

      Load too big for the motor

  • 19. 
    The end ply of a motor should not exceed
    • A. 

      1/8 of an inch

    • B. 

      1/16 of an inch

    • C. 

      1/32 of an inch

    • D. 

      1/64 of an inch

  • 20. 
    An indication of an open rotor in a squirrel-cage motor is
    • A. 

      Excessive sparking

    • B. 

      The motor speeding up

    • C. 

      Excessive noise and heat

    • D. 

      The motor slowing down under load

  • 21. 
    The conductor common to both the starting and holding circuits is connected to
    • A. 

      L1

    • B. 

      T1

    • C. 

      L2

    • D. 

      T2

  • 22. 
    A motor that operates slowly may have a
    • A. 

      Deficient voltage supply

    • B. 

      Ventilation problem

    • C. 

      Bad conductor

    • D. 

      Blown fuse

  • 23. 
    Motor voltage must be within what percent of the voltage rating
    • A. 

      1

    • B. 

      3

    • C. 

      5

    • D. 

      10

  • 24. 
    A woodworking shop would constitute what class of electrical hazard?
    • A. 

      Class 1

    • B. 

      Class 2

    • C. 

      Class 3

    • D. 

      Class 4

  • 25. 
    Electrical equipment used in class 1 locations must be
    • A. 

      Sparkproof

    • B. 

      Dustproof

    • C. 

      Waterproof

    • D. 

      Explosion-proof