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From the attached document I see that you are pushing your limit of 7.1 mm/sec at 80% speed.  But beyond that we know very little about your installation.   

Can you provide more details; size of motor, RPM, how is motor coupled to fan?

Have you done or observed the fundamental 1st thing often recommended with a motor issue?  That is checking what the amplitude does immediately after removing power.  If the amplitude "hangs" some during the coastdown, then you likely have a mechanical issue; if it immediately drops, then you likely have an electrical issue. 

RM

SANY,

I am guessing this is an Overhung design fan, direct coupled. Is this correct?

My guess is based on the amplitude increases in the axial direction at 75 and 80 percent, showing in you word document.

When you say "3X DOMINANT PEAK (ONLY 3X)" Does this mean there is NOT a 1x and 2x and 4x and 5x, etc., at all?

What is the axial phase difference between the DE Fan and the NDE Fan.

The axial phase difference between the motor DE and the Fan DE?

What is the displacement values on the 1x and 3x in the DE, NDE and Axial at 75%?

Thanks and Have a Great Day,

Ralph

RM

"No 1x or 2x" at all? Even when the spectrum is shown in Micron units instead of mm/sec RMS and the amplitude scale is not controlled by the highest amplitude peak (3X), which might "squeeze" 1x down so as not be able to actually "see" it (1x) as much of a concern? In other words, can you get a 1x reading in displacement?

Have you been able to do a coastdown plot of the amplitude vs rpm, at the very least, from 80% speed, down to zero speed.

What are the RPMs at each Percentage reading you have shown us?

Thanks for the reply,

Ralph

RM

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