The more you understand the motor, as well as the motor circuit for that matter, the better your analysis of test data will be when conducting condition monitoring testing. Assisting in this effort is the National Electrical Manufacturers Association (NEMA) which has been instrumental in helping standardize motor nameplate information.

Prior to NEMA, motor nameplate information varied from manufacturer to manufacturer.  However, even with the amount of information provided on today’s motor nameplates, it is wholly inadequate for a thorough analysis of your motor data.

Even though motor nameplates provide a plethora of information, they are still incomplete for a proper and thorough analysis.  Additional information is needed to have a highly effective motor testing and evaluation program.

Acquiring much of that data, however, can be difficult.  The best method is to require your motor vendors to provide the information as part of the procurement process.  Other required information can also be provided when a motor is sent in for reconditioning or rewind from the motor repair facility.

As a minimum we recommend that you try and obtain the following:

• Rotor Type
  • Barred
  • Cast
  • Bar Arrangement
• Rotor Bar Design
• Rotor Core Material
  • Epstein Test Parameter for Core Loss evaluation
• Stator Core Material
  • Epstein Test Parameter for Core Loss evaluation
• Number of Rotor Bars
• Number of Stator Slots
• Bearing Information
  • Number of rolling elements
  • Race diameters
  • Contact angles
• Allowable number of starts in a time period
• Winding Type
  • Lap
  • Concentric
• Winding construction:
  • Random
    • Type of magnet wire (normal or surge suppression)
  • Form

Remember, your evaluation of acquired test data will be better and more effective when you know more about the motor and motor circuit you are testing.