Motor maintenance is pointless if it doesn’t prevent motor failures. Check your motor maintenance program for the following:
• It includes vibration testing.
• It does not include tightening anything. Tightening the motor mounting bolts to “ensure” they are tight is a downtime-inducing practice. If the motor vibration is within tolerance, don’t mess with the mounting bolts. If it’s out of tolerance, replace them and torque them properly.
• Insulation resistance readings are trended, not merely taken and recorded.
• Temperatures are taken at the bearings, windings, and (if used) gearbox. Preferably on critical motors, these temperatures will be monitored continually.
• Lubrication is done with the correct lubricant in the correct amount, following the correct procedure. Mixing lubricants, overlubricating, or lubricating without opening the grease plug are practices that kill motors every day.
• Voltage imbalance is calculated from measurements taken while the motor is running. This metric should be recorded and trended so that a change can be highlighted for corrective or preventive action even if the imbalance is within tolerance.
• If air filters are used, they are changed.