A couple of years ago, an electrical testing firm conducted vibration testing on several large loads. These included the four 400-hp motors for the plant air system and several 100-hp motors in a key process area. They recommended corrective measures be taken on all but two of these, and another shop performed the work.
The testing firm recommended annual vibration testing on all of these motors plus all of the motors that were essential to the production lines and conveyor system.
The Plant Engineer wanted this work done by in-house maintenance, so he bought some vibration testers and had the PM procedures revised. Lately, the equipment has been shaking apart. What could be going on?
What is the first thing you do about excess vibration? Tighten the mounting bolts, right? Not if you are properly trained. Why did this problem not appear after an outsourced firm corrected the vibration, but did appear once in-house maintenance took over?
If the mounting hardware is already tight, simply tightening down will probably warp the motor feet causing misalignment and thus more vibration. It will also stretch the hardware past its elastic limit. These two factors combined would explain “equipment shaking apart.”
There is a methodology to assessing and correcting sources of vibration. The Plant Engineer must either pay for training or outsource the work.