Hello, I am aware that alignment needs to be redone but I am not sure what is optimum period between two alignment?

To elaborate: If I have big machine, 500 kw and have laser alignment how often I should realignment? Ore any other group of machines....

Thanks...

I aligned a vertical pump recently. After the alignment the pump was placed in service for 24 hours. Alignment was checked again. Alignment numbers did not change. The contractor doweled some important locations. The pump was then placed in permanent service. I would re-check the alignment once in 3 months.

Riyaz
Why would you re-check alignment after 3 months?
Why would you expect it may change? esp. since locations are doweled??

Regards
Jim P

Riyaz Ahmad Dave,
I followed an alignment link posted on this forum. The author recommended that after the initial alignment, quickly check for thermal movement after a few hours of runtime. After that, recheck alignment every year, because of the earth settling, and to check if anything has changed. Maybe it is possible on certain machines.
I can post the link to the article again, if you want.

Be sure your laser system isn't affected by axial movements. Check hot alignment with the machines running and NOT with the lasers across the coupling. Use optics or Acculign and you may want to monitor the piping, axials and base, skid, etc...

With the Acculin system you can monitor every month, quarter, six month or year as it is simple, accurate and the maintenance crew can do it.

A properly aligned machine should not have to be aligned again unless vibration or ultrasound measurments indicate the need or if repairs were conducted that would/could change the alignment. We are supposed to be a friend of operations and not a foe!

Walt

Walt Strong,
How do you check alignment with ultrasound? Do you trend, or are there particular sounds to listen for on different type couplings?

Enrique,

You should just monitor your alignment with your vibration data. It will let you know if you need to revisit your alignment.

On really huge machines that are very costly a monitoring system of alignment to monitor machinery shaft-to-shaft alignment, axial movements, piping, foundations and subsidence is justifible as you can monitor even minor change and various factors.

Hi guys,

Can anybody tell me how alignment changes over time if there is no external disturbances? I think itz a waste of time to monitor the alignment unless the machine is a huge one operating at very high speed as what sam mentioned...

In vibration analysis, one of the simple criteria for distinguishing between a 1X due to misalignment or due to unbalance is whether the peak in question came out suddenly and increasing or whether it is there since the machine overhauled..If it came suddenly and increasing, most probably it may not be due to misalignment!!

Please correct me if i'm wrong..

Have a nice day!!