A Short Essay on Greasing Issues

You know, everytime we seem to move forward with improvements to our industry, we seem to work against ourselves in an effort to put us back into the dark ages. For instance, once the tools of RCM and PM Optimization, as well as others, started to make ground and turn things around, ‘specialists’ came out of the woodwork with ‘newer, better’ ways to accomplish these programs. For the most part, these resulted in expensive consulting with few results to show.

For ages, the concept of greasing has bounced back and forth. Over the past decade the manufacturers of ultrasonic equipment suddenly came out with ultrasonic grease guns to assist with lubrication. I am not sure which company did so, but it quickly caught on. The result is that users of the technology, as well as others, have determined that it is correct to add grease to operating electric motors, contrary to scientific studies and literature showing evidence why the machines must be lubricated while they are de-energized. However, as with many other things, sales and marketing often overcome engineering and science in terms of convincing people of right and wrong ways to accomplish things. (Articles on motor greasing can be found in the archives at http://www.motordiagnostics.com).

It should be remembered: of the motor failures due to greasing electric machines, overlubrication is FAR more prevalent than undergreasing. In fact, with some of the new concepts the number of bearing failures appear to be INCREASING not improving.

As of late, we add to this problem with not just vibration analysts making lubrication calls, but REMOTE analysts making lubrication calls. So far, on the service side of the industry, we are seeing this as an increase in equipment failures. Either there are some bad calls in which lubrication is added when it is not necessary (ie: recently ran into greasing recommendations to solve ‘looseness’ that resulted in the following image); or, the concept is not valid.



What has your experience been with lubrication calls using vibration analysis? How about ultrasonic lubrication? Do you have actual measurements of MTBF related to bearings before and after implementation?

For more information on greasing electric motors, go to http://www.motordiagnostics.com and review the archives. Includes articles and presentations related to motor lubrication.