High horizontal vibration in fan

Dear experts

After solving my preheater fan and raw mill system fan problem with your precious recommendation now I want share my new problem that’s I am facing now a days

 

i have two bag filter fan both are 18kw motor.

both have overhung impeller.During continues monitoring fan A has high horizontal vibration 12 mm/s at fan NDE side with 1x domination in FFT spectrum. So first I check alignment of fan and I found it’s okay so I start single plane balancing and after balancing vibration reduced from 12 mm/s to 3mm/s.

then another fan B having same specifications having 8 mm/s vibration at fan nde side with 1x domination in the spectrum . So same as previous I check alignment and found ok but when I was trying to do balancing the fan is not responding I am adding calculated weight but vibration is increasing??? So I am in fix what should I do

Original Post
vishal sharma posted:

Dear experts

After solving my preheater fan and raw mill system fan problem with your precious recommendation now I want share my new problem that’s I am facing now a days

 

i have two bag filter fan both are 18kw motor.

both have overhung impeller.During continues monitoring fan A has high horizontal vibration 12 mm/s at fan NDE side with 1x domination in FFT spectrum. So first I check alignment of fan and I found it’s okay so I start single plane balancing and after balancing vibration reduced from 12 mm/s to 3mm/s.

then another fan B having same specifications having 8 mm/s vibration at fan nde side with 1x domination in the spectrum . So same as previous I check alignment and found ok but when I was trying to do balancing the fan is not responding I am adding calculated weight but vibration is increasing??? So I am in fix what should I do?

Setup your analyzer in LIVE MONITOR MODE and then turn off power to the fan and closely observe the AMPLITUDE CHANGES as the fan decreases in speed.

Better yet, if your analyzer has the coastdown function to save the spectrum and phase shifts, set it up to capture the amplitude and phase so you can review it and post the actual coastdown plots of the amplitude and phase, for us to see in your posting.

Thanks and Have a Great Day,

Ralph

 

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