If your business depends on motors, make sure you have a masterful maintenance plan to keep them running in tip-top condition. Motors require both monthly and annual maintenance to ensure that they're running at their peak.
Monthly maintenance
Every month, you should confirm that your system is operating as it should.
1. Observe the motor operation. Verify that motors are operating properly and without excessive vibration or heat.
2. Apply appropriate lubrication. All motor bearings, other than sealed bearings, should be lubricated according to manufacturer recommendations. Keep in mind that over-lubrication can be just as detrimental as under-lubrication. Always use the correct type and intervals.
3. Survey the shaft and bearings. Rotate the shaft manually to check for obvious problems. Make sure the center lines of the motor and the driven shaft are in line with each other.
4. Ensure the electrical is excellent. Watch out for bad connections, poor grounding and shorts to ground. Make sure there is no evidence of damage from stray currents, which can lead to operating issues.
5. Investigate the voltage. Ensure that all phases are in balance. Correct any imbalances over 3% as soon as possible to avoid overheating. It's also smart to check for overload operation, under-voltage or over-voltage on a monthly basis.
6. Evaluate the environment. Ensure motors have good ventilation and the ambient temperature isn't too high to avoid overheating.
Annual maintenance
There are also motor maintenance matters you should revisit every year.
1. Lose your legacy motors. Replace variable frequency drive (VFD) controlled motors with inverter duty motors whenever possible. The drive system should be properly adjusted. Replace standard V-belts with grooved or cogged belts to reduce drive system losses.
2. Inspect the insulation. Perform an insulation resistance test to evaluate the condition of the winding insulation. Measure the resistance between electrically isolated points. High potential and surge comparison winding tests are also useful.
3. Look at the load. Use an optical tachometer or electrical tester to estimate the load. Motors are usually sized to operate at 65% to 100% of load. Motors loaded at less than 40% should be evaluated for possible replacement with properly sized motors to increase their operating efficiency and power factor.
4. Complete the care. Vibration trending and thermal scanning can be used to detect bearing problems and allow for intervention before failure. Add grounding brushes on motor shafts to avoid pitting of bearings from stray currents produced by VFDs. Finally, check for excessive belt tension.
To keep your motors running magnificently, make a masterful maintenance plan.