Rotating Machinery

Virginia Balitski, Magna IV EngineeringColumns, Spring 2023 Columns, Tech Quiz

Rotating machinery is an essential component of most power systems, from compressors in petrochemical plants to turbines in hydroelectric generation plants. NETA Certified Technicians must be familiar with the maintenance and possible failure means of various rotating machines.  

  1. What are the two mechanical components of an electric motor?
    a. Magnets and armature
    b. Rotor and stator 
    c. Field windings and electric coil
    d. Motor housing and bearings 
  2. At steady state, at what frequency does a synchronous motor rotate?
    a. The same frequency as the supply current 
    b. A frequency slightly less than the supply current 
    c. A frequency higher that the supply current
    d. Rotation independent of the supply current 
  3. Stator cores of rotating machines are composed of many thin metal sheets called laminations that reduce which of the following?
    a. Damage to the rotor 
    b. Eddy current losses 
    c. Cost of construction 
    d. Overvoltages
  4. ANSI/NETA standards specify insulation resistance tests on induction motors and generators in accordance with which standard?
    a. NFPA 70B
    b. IEC 60044
    c. IEEE 43
    d. ANSI C137.5
  5. Before any testing is done on electric machinery, the winding insulation must be?
    a. At rated voltage
    b. At the same temperature 
    c. Discharged 
    d. Water cooled  

Virginia Balitski, CET, Manager – Training and Development, has worked for Magna IV Engineering since 2006. Virginia started her career as a Field Service Technologist and has achieved NETA level 4 Senior Technician Certification. She has since dedicated her time to the advancement of training and safety in the electrical industry. Virginia is a Certified Engineering Technologist through ASET – The Association of Science & Engineering Technology Professionals of Alberta. She serves on NETA’s Board of Directors, is the current Vice-Chair of CSA Z462, Workplace Electrical Safety, and is a member of the NFPA 70E, Electrical Safety in the Workplace Technical Committee.