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Hello guys,

I would like to ask about vibration problem I found on site.

I found 2x high axial vibration on 22 kW motor running on 2955 rpm coupled on pump

Highest vibration at NDE motor with 14.31 mm/s

I suspect there is bent shaft or cocked bearing because spectrum shows 1x 2x 3x when operated solo run, but since the coupling doesnt have spacer I have to move the motor and only able to test it with loose bolt

My phase measurement as follow

PDE - PNDE Axi. : 46 deg out of phase

PDE Hor. - Ver. : 279 deg out of phase

PNDE Hor. Ver : 278 deg out of phase

MDE - MNDE Axi : 205 deg out of phase

MDE Hor. Ver : 127

MNDE Hor. Ver: 309

I have measured phase on face of bearing (axial) with direction of 12:00 and 03:00 but I lost the data, can we conclude the problem without this phase data?

And also, is there a possibility of twice line frequency vibration?  I don't have much experience on this topic but doesn't twice line frequency usually occur on radial side, does it?

Does looseness also suspected? Based on my spectrum there is harmonic and the pump is installed and grouted on top of previous pump baseplate to accomodate the suction pipe height. The anchor bolt is not installed and the baseplate welded into the existing one, I'm worried if the baseplate is bent causing the level of the pump all messed up because the angular alignment process is quite hard.

Attached my spectrum and photo of pump set

Thank you very much for reading my post and hope too hear from you guys soon

Yafie

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Yafie,

2 cents on your post....the images you have posted are great, can you post images of all sides of pump base.

I see softness in how the current base is suspended above a hollow pocket, does not appear to be level and no axial support for motor.

The solo run of the motor has very high 2x axial, as Ralph stated above, you must make sure it is 2x or 2x line frequency to begin with. As Ralph also stated, loosen one motor foot then retighten, if the vibration dropped this foot is in a bind.

Can not quite see the whole non drive end of motor base support, I do not see any welds in this area? If you live time monitor the axial direction on the motor, use a pry bar on the gap present in the photo, while prying watch to see what happens to vibration, again if it changes this is a soft spot. You can use the motor foot axial direction on either end, no fan cover data. Is there similar gap on the base under the suction side of the pump?

Make sure ALL anchor bolts are tight. Photo shows somebody's shoes, check the base from the ground up, anchors are tight.

Pump shows quite a few harmonics at low levels of run speed. This can come from loose base/pump feet/coupling/bearing to shaft/bearing to housing/impeller to name a few. Quick up and down play check using dial indicator should be less than .002" of play or shaft runout.

Best of luck

Dave

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