Is it necessary to know the bearing designation to obtain the condition of the bearing?

Good day, we have several pumps that we do not know the designation of the bearings they use, is there any way to know the condition of the bearing by vibrational analysis without knowing the bearing designation? What you need to know is only if the bearing is in good conditions or not.
I would appreciate your support in this regard.


Original Post

I suggest you download the paper at  You will find some methods to approximate the frequencies when the bearing number is unknown on page 2.  Keep in mind that for these approximations the number of rolling elements "N" needs to be known or estimated.  

Sometimes some detective work will help.  For instance checking previous maintenance records may yield bearing numbers.  Is there a spare parts list in the Tech manual?

Per my working experience, around 60 - 70 % of bearings are ˝unknown˝. Anyway the bearing condition analysis can be relatively easily done and is one of the most basic analysis done in condition monitoring. I suggest some additional education. It is almost impossible to do that with a few posts here. My advice is, don't rely on bearing frequencies too much. 

Some analyzer have overal bearing condition uint .for example bcu or shoch puls technic .you can trending this value .also defect bearing frequency at final of failure stage will be apear  high peaks between (3x_5x) that not synchronized by speed frequency if machine.but if you want to do root cause analysis ,you shoud have complete  information about bearings.

Best regards.


Hi jorgeluis,

Bearing number is easy to know if you have an drawing, try to search for the assembly drawing for the pump to OEM, but if you want to monitor by traditional vibration analysis to examine your bearing condition, i would suggest to get data from TWF and enveloping (horizontal & axial). enveloping much helpful than fft for bearing condition, but always correlate enveloping and TWF.

Note: enveloping may take time depends upon your setting, but i prefer to use HP/LP filter 500/1000, upper frequency 1500 hz, hanning. 


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