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