June 13, 2018
Just Get It Running, We’ll Fix It Later!
By Mac MacCormack
Sound familiar? I can’t tell you how many times I personally have heard this over the years. I am sure many of you have as well. The issue is, scheduled downtime seems to be put on the back burner so to speak, to meet production goals. And as it has become all too familiar, fixing it later just becomes another costly unscheduled downtime.
One area that gets pushed off to the fix it later category is precision shaft alignment of rotating equipment. With the VibrAlign Verti-ZontalTM process, this does not have to be the case. One can reasonably expect to complete a precision shaft alignment in one or two moves and be finished, thus eliminating the fix it later mentality.
Recently, during a training session, we were preparing to perform the field portion of the training and a breakdown occurred. Perfect time to put the fix it right the first-time method to the test. The picture below shows that this motor pump assembly was visibly misaligned, didn’t even need to put a straight edge on this one.
The team decided to put the laser on to record the misalignment “as found”. This was the result.
Three times out of tolerance on the vertical angularity, nearly seven times out of tolerance on the vertical offset, twelve times out of tolerance on the horizontal angularity and over fifteen times out of tolerance on the horizontal offset. The coupling manufacturer stated maximum allowable misalignment for the insert to be .025” offset and .109” angularity. These numbers indicate when you can expect the coupling to fail they are not acceptable precision shaft alignment tolerances for the machine.
This is a picture of that insert.
Thankfully this was the weak link that failed before causing more extensive damage to the rest of the equipment. So, an attempt to perform a precision alignment was made. And here are the results.
The alignment was now well within tolerance in the vertical position, but there was no change in the horizontal position. This machine was severely bolt bound! An attempt was made to move the stationary machine using the FeetlockTM function, available in the NXA, but was unsuccessful due to excessive pipe strain.
This is a classic case of why we hear just get it running, we’ll fix it later. The good that came out of this exercise? There is now a clear understanding of the root cause of this failure and what needs to be done to prevent future failures.
In conclusion, a job plan was made and carried out to correct these issues immediately instead of continually experiencing repeated unscheduled downtime on this piece of equipment. Unfortunately, I was unable to stay until completed, however my understanding is all was completed in about two and a half hours.
Still don’t think there is time to do it right the first time?