All Member Open Forum

The great thing about a pump is that it is well-suited to condition-based monitoring. Align the shafts properly at installation, and then use vibration analysis and ultrasound-based lubrication to monitor. If it is oil-lubricated, do a quick listen with ultrasound when you're there to grease the motor. If the shaft guard is designed correctly (expanded metal sides for ventilation and visibility), you can use a strobe light to inspect the coupling while it is running and you can inspect with infrared. (The clear plastic guards are a neat idea, but they don't allow infrared inspection.)

If the pump and base are designed and installed correctly, there is no reason they should go out of alignment. If they do, the vibration signature will change, and infrared will show that the coupling center (if it's an elastomer) is hotter than the coupling hubs. Extreme misalignment will also cause the two inboard bearings to be abnormally hot also. I don't do alignment checks on my rotating equipment unless I have data that says there is a need to. 

I agree with everything Dale mentions.   We do not do any alignment checks on our pumps unless vibration and bearing temperatures indicate there is a problem.  

------------------------------
Kevin Riner

Sr. Mgr Reliability, Evergy Inc.
------------------------------

Hi Raul,

This is a real opportunity where you can optimize your PMs. It seems like your team does vibration checks every two months which should be able to detect any misalignments with the couplings. One of the main reasons of doing condition monitoring such as vibration checks is to know the potential failure early enough so that once detected, it can be appropriately scheduled and remediated. Hence, I would suggest on doing the coupling alignment only once you get some indications from the vibration checks.

Coupling alignment check is more invasive compared to vibration check, so it opens up more chances of introducing human errors to the pump as well. Besides, you would also need to have some downtime for the coupling check. 

Funny this came up recently in a conversation with some maintenance leads.  

If you have a good vibration analysis and predictive maintenance program, it will find misalignment fairly easy.  If you are having running equipment get misaligned after operating some period of time, there is another fundamental problem - baseplate, installation, etc.

Doing a hot alignment to deal with thermal growth is about the only time I might go back and realign outside of letting my vibration analysis dictate the need.

I've observed OEMs sometimes go overboard on PM checks.  Many still have in their manuals to change oil every 2000 hours but that is extreme overkill.  I've done oil analysis on pumps running synthetic oil after 2 and 3 years with no degradation of the lube oil. 

If you did start down that road of some routine alignment, if you didn't find it misaligned in 3-4 times, you should extend and quite the process.  If you do find something misaligned every time, then some RCFA needs to be initiated to find out what the root causes are.

Good question.