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Not too long ago I was called to one of our sister shops to perform a laser shaft alignment on a 3600 RPM skid-mounted end-suction ANSI pump. Easy, right? Honestly, I made a few mistakes right off the bat:
I performed a quick pre-alignment, mounted the equipment and took a reading. The motor needed to come down over 200 mils and move horizontally 406 mils. I wasn’t expecting that. So we took another set of readings with the same results. A quick look at the coupling did not show it being off this much.
So I stepped back and thought…..”What am I missing?”
I wanted to ensure we did not have a laser issue, so we mounted the laser alignment equipment to a piece of stock in a lathe and took some readings. All repeated, three times in succession, so no laser issue! I inspected the shaft and coupling run outs, and did a thorough visual inspection of the entire unit. I pulled the pump off the base, cleaned rust from the base feet, scrapped off a coating on the base, and did the same to the motor. Next I removed both the couplings, looked for burs/dings on the fits, faces and bores. Ensured a slip fit on all coupling hubs, key-ways, and bores. Then I replaced all bolts with new hardened bolts and flat washers – no lock washers! I did soft foot checks on both motor and pump uncoupled from each other, and did find some in the pump. I tightened everything down using a three-pass method, did a final soft foot check, and started a fresh alignment.
This alignment check indicated the motor was 101 high in the front and 103 high in the back, and the horizontal was out 45 in the front and 98 in the back. I made all corrections in about 15 minutes, with one spin of the shaft. Final readings were well within a 3600 spec!
Lessons of the day…
I am not sure what part of my “basics” check list eliminated my trouble spot, but through all of that I got the bad actor out of it!
From VibrAlign – Special thanks to Chris Troutt, Reliability Analyst at BRI (a Cogent Company based in St. Louis, MO) for a great blog post! We want to encourage any of our readers to post comments, questions, case histories and ideas to the blog. We’d love to hear what you have to say!