The machine is question here is a packaged unit consisting of 2 75 HP Toshiba motors and two horizontal split case pumps. One of the pump also has a backup natural gas engine. All of this is prebuilt at the factory and trucked to the site. The vibration levels at one of the motors and pumps exceeded 1.0 in/sec in the horizontal and approached 1.0 in the vertical. Virtually all vibration is at 1X. While measuring phase at the pump I took a vertical reading at the pump bearings and then at the suction side pipe flange and found these to be about the same but taking this reading at the discharge side pipe flange I got a signficant shift. Could this be the result of pipe strain? Also is 1X the typical result of pipe strain? I am curious because it strikes me as amazingly lucky to build this at the factory, truck it to the site, drop it on the floor which at some points contacts the bottom of the skid and at other points has a 1/4" gap and have it bolt right up the the building piping.

Thanks for your thoughts on this

dj

Don,

It has been my experience that packaged equipment like you describe requires re-alignment after transportatiion. I have been in situations where alignment was done in the shop and then the assembly was set in place and output shaft alignment done (gearbox) only to find that the drive had shifted badly during transportation, so badly that it could no longer be aligned to the engine without removing it and enlarging the holes.

Unless the pumps were pinned, I would suspect misalignment.

Danny is exactly right. You'll have to address several problems. The skid needs to be set properly and sitting to elevation level. Disconnect the piping and perform shaft-to-shaft alignment after the skid is set. When completed, align the pipe to the pump. Bring flanges parallel and at proper gap and be able to wiggle a bolt in every hole freely. Now plumb-up the piping without deflecting the indicators.

Danny and Sam are right, been there a couple of time, don't trust shop alignment, it may be good at shop but it does move in transportation and installation.

D James,
I agree with the other posters regarding alignment, it should be rechecked on site. However, I have seen inconstrustion the piping made up first and then they lay the equipment in.
You may find a copy of API 686 helpful as it gives the specifications that you should shoot for with respect to parallel and angular offset at the pipe flanges.

Regards,

Thanks to all. It appears we are all in agreement that most likely this package was not properly installed. I do know that the engine to pump and motor to pump was recently aligned by a competitor. I did not witness this alignment and have no reason to suspect incompetence, but I doubt it was done in the manner suggested by Sam i.e. disconnect the piping then align. But back to my origninal question. Will or can pipe strain result in large 1X vibration and what can cause my vertical bearing and suction flange phase to be equal while my discharge flange phase is out 150 degrees?

Thanks

dj

The pipe will and can cause the huge 1X and your phase characterists can be generated by such phenomenon. Expect case distortion and to the point that it can egg shape the outer race and cause brg-brg misalignment.

dj,
Think of the pipe strain as similar to misalignment across a coupling. We expect to see a 180 degress phase shift +/- 30 degrees across a coupling with misalignment.
A flange with pipe strain will have a resultant force at that flange acting in one direction, assuming a offset for example, then there is the excitation force of the residual unbalance as the machine rotates. These forces during one cycle of revolution at will work together and oppose each other causing the rocking motion.
This is my layman's explanation of the situation.
Regards,
James