Proper electric motor balancing and precision machine work will extend the life of your motor, particularly the bearing life.

So ask yourself this question, “How much could one extra year of run life on every motor repaired save you?

Answer: 14% if you are averaging 6 years, which could add up to thousands. Over 40% of motor failures are bearing related.

The most prominent causes of the bearing failure include:

• • Contamination
  • Fitting and mount
  • Handling
  • Fatigue
  • Improper lubrication

There is an opportunity to extend bearing life on every motor repair job by employing better practices developed from the best available standards. Unfortunately, many shops have cut-back on these practices (or eliminated them) in order to reduce the repair costs.

4 key areas for adding life to bearings during motor repairs:

• • Accurate measurement - Precision bore gauges should be used to record multi-point measurements of all bearing fits.
    
  • Precision electric motor balancing - Many shops are still using inside micrometers, or they take too few measurements, which leads to inaccurate measurements. Rotors should be balanced in accordance with procedures defined in ISO 1940. This yields a much better result than the NEMA method, which is still used by many shops. In a test conducted in our shop, the ISO method reduced undue bearing force by 49% over the NEMA method. Final balance results should be recorded in units of actual force.
  • Bearing Installation - Installation should be performed in a clean environment by following a written procedure. Professional installation equipment, such as those provided by SKF, will prevent damage, such as overheating or magnetizing. All bearing data, before and after, should be recorded for future reference.
  • Lubrication - Contamination control is improved by limiting exposure to lubricated areas and replacing items that can store contaminants, such as grease piping. Lubricants used should be visible on the motor and documented for reference.