Monthly Bearing Maintenance Equals Big Savings

Case Study by: Chuck Peterson, Peterson Predictive Maintenance

Challenge:
Large plant in Kansas was over greasing motors and had to replace motors once every 2 or 3 years. When bearings were perceived to be needing lubrication, they were greased. Most plant technicians assumed that bearings should be greased monthly regardless of lubrication inspections. This can cause major damage and help towards the failure of the machine.
The unplanned downtime and new motor replacement issue was costing the plant a fortune.


Shaft end of this 25 HP motor with the end bell removed and the over greasing is evident. Fan end of the same motor with the end bell removed, here again the over greasing is evident.

Solution:
Mr. Peterson immediately placed the plant on a monthly maintenance schedule where he or, at times an assigned plant technician, performed bearing maintenance including lubrication. The program started off by using ultrasound instruments to set up baselines for the bearings.  It also included a review and selection of specific types of grease for each type of bearing and application.  Inspection routes were set.  A procedure for inspecting new motors was put in place to ensure if a particular motor was ready for service.

Ultrasound inspection guns were used to analyze the condition of each motor, which helped to accurately determine those that did not need and those that were in need of lubrication. Under lubricated bearings were tagged and a lubrication schedule was set for only those bearings. Others that were running smoothly were left alone until a future inspection.

Results:
Since routine bearing inspections with ultrasound were being conducted, this plant has not had to replace a motor in more than 5 years. At this rate, it is projected that the plant may not have to replace any motors for approximately 10-15 years, even those initially projected to last a total of 5 years.

When shutting down a motor, it will be down for a least a day and that is if the plant has another motor available. Otherwise it is a minimum of 4 days. If the average plant makes $100,000, simply shutting down the motor could cost this plant $400,000 lost plus the charge to fix the motor – all due to putting the wrong, or too much grease in the motor. The motors are also being properly greased. Because they are not over greased, they are not pulling more amps, thus reducing energy consumption as well. Now that the proper maintenance plan is in place using ultrasound, the savings are astronomical.

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