data was collected on kiln cooler fan and i had bearing faul frequencies on the sideband of blade pass frequency...would it effect bearing thourughly...till now i thnk yes and i should go for bearing inspection as envelope Filter 30k to 600K CPM increased upto 4.06gE.help needed.

here the data..lines=800
Fmax= 60KCPM

high_envelop_3.doc (116 KB, 43 downloads)

Those apparent sidebands you see are more likely 1x runspeed sidebands. It is a coincidence that two of the bearing defect frequency multiples are a close match on 2xBlade Pass. At 800Lines of Resolution it is really difficult to separate them. If you look closely there are similar sideband peaks on the other BladePass multiples.

Just because the defect frequency markers LOOK like sidebands does not mean they are. Do the math...subtract and add runspeed from the 2x Bladepass and see if those numbers are close matches for those apparent bearing defect frequencies...I think you will find they are runspeed sidebands. Do the same for the apparent sideband peaks on the other BladePass Peaks and see if they are spaced at runspeed. If this pattern shows in velocity as well as enveloped acceleration it could indicate issues with the blades. I am not familiar with the amplitude values presented by gE so can't speak to the severity of the problem. I do not see this as a likely bearing fault. There MAY be an FTF peak showing but the resolution in the Word doc is not good enough for this old man to see for sure. Calculate the numbers, don't rely only on the marker matches.

Good Luck & Good Hunting

Hi dana,

well we inspected that bearing last day and its outer race slipped and polished, like a bearing free in housing.Impeller is ok