vibration/alignment/balance

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  • 1.  Immediate replacement of Bearing or subsequent repair?

    Posted 02-02-2024 06:48

    A 250 KW and 1490 rpm motor with deep
    grove ball bearing, 20 G's peakvue at BPFO, BPFI, and BSF further maximum
    amplitude detected in high-frequency regions What do you recommend to replace
    Immediately or wait?



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    tahir dawood anwar
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  • 2.  RE: Immediate replacement of Bearing or subsequent repair?

    Posted 02-03-2024 14:11

    I don't see where you are concluding you have BPFO, BPFI, and BSF from the data you've presented.  Typically the fundamental harmonics of BPFO and BPFI are around 4 - 6 times running speed, you are highlighting something around 54X which who knows what that is.  Post the calculated fault frequencies of both the DE and NDE bearings, do a Hilbert transform on the raw time history data, and run that through a FFT in acceleration units (do not integrate).  Then see what you get.



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    Lyn Greenhill
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    Original Message


  • 3.  RE: Immediate replacement of Bearing or subsequent repair?

    Posted 02-04-2024 17:07

    tahir dawood anwar,

    I see in your Peakvue Waveform data that this bearing is 6322MUC3 bearing with a BPFO of 3.345 Fundamental.

    It is difficult to tell what the other peaks are in all of your posted data without them being marked or labeled, and not having access to the RBM software to analyze the data REAL-TIME so, my question is: Is the outer race defect showing more than the inner ring defect or does the inner race not show at all in the Peakvue or velocity data?

    Also, since this data was taken 13 days ago (January 22,2024).... Is there a change in the data since the 01-22-2024 data?

    If there is no FTF, BPFI, BSF in the data and the basic problem is the BPFO, IMO, the problem may not be a :"change Immediately" situation, but does warrant watching closely.

    Time frame for repair also depends on how critical this machine is to production. 

    When is the next scheduled shutdown? soon? 30 days? 45 days? Etc? Has the current data changed since the 01-22-2024 data was taken? This needs to be confirmed.

    Some of the smaller peaks appear to be possibly FTF in the Peakvue Data. This is Difficult the see if the spectrum is showing FTF, and that makes a difference in how bad the problem is. Once the cage fails, shutdown time is very close. Cage failure or damaged cage means everything else in the bearing rapidly fails also, IMO.

    Can you take some "fresh" data, make sure the FTF is or is not there, Take Peakvue data with several HP Filter settings: 2K, 5K, etc.?

    In your 1st picture of the high frequency peaks, inside the RED bordered area, are these relate to the BPFO? The high frequency peaks are relatively high for velocity data, IMO. I am not very familiar with the mm/sec/sq. scale compared to my in/sec/sq scale.

    The FMAX for your velocity spectrum is about 1.5K Hz, which makes what you see in this velocity high frequency setup, is basically the things that are created by Peakvue data from what Peakvue sees with your HP Filter of 1K for the Peakvue setup. This is why I suggested taking Peakvue with a higher pass filter than 1K to see how strong the rest of the high frequencies show with the Peakvue. All this I have written may be totally wrong, but this is the way I have looked at it since Peakvue came out in the early 1990's..... years ago.

    Peakvue is a great tool but one has to be careful in calling strictly from Peakvue data. IMO

    Marking the different peaks in your spectrums would help show us, who have looked at your data, have a better guess as to  what is what,..... possibly. :)

    Thanks and Have a Great Day,

     Ralph



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    Ralph Stewart
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    Original Message


  • 4.  RE: Immediate replacement of Bearing or subsequent repair?

    Posted 02-04-2024 19:51

    Hi Tahir,

    You can check PeakVue Trend first, if the trend raised slow or fast can get different action. For this case, you already detect bearing deterioration, but still can run for a while. If this pump can stop at anytime, you can wait, and collect more data till the noise can be heard on site and Bearing fault frequency appear at Vibration spectrum low frequency zone. And you can find bearing defect with your eyes after dismental.So you can get a good learning case. If the pump only can stop when the whole process shutdown, it is better to raise notification or Work order to replace bearing at nearest window.

    Kevin



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    kevin zhao
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    Original Message


  • 5.  RE: Immediate replacement of Bearing or subsequent repair?

    Posted 02-05-2024 08:00

    the non-synchronous peaks appearance in velocity spectrum is a clear sign of bearing deterioration.

    if you want to evaluate the severity, go back and check the PK-PK ACC trend and you shall decide what you have to do.

    use auto correlation feature on your peak Vue TWF to know what is the source of repetitive impacts.

    If you want my opinion, procced with changing the bearing.



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    Ayman Gamal
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    Original Message


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