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Main Engine Auxiliary Blower Vibration Analysis

  • 1.  Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-11-2024 23:03

    Greetings Dear Members ,

    I would like to ask your opinion about Ship Main Engine Auxiliary Blower Vibration analysis .This Blower Motor monitored by online wireless tri-axial Vibration sensor and we have been monitoring this ships equipment from the shore .

    We  have observed a high Vibration trend on this Blower Motor and observed dominant 1XR.P.M Peak .We suggested them to open and check for Unbalance / impeller fouling .

    Please find the below attached images for your reference .Recently

    Trend
    Spectrum
    Blower 1
    Blower 2

    they opened the equipment and send the following images .



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    kishore kumar agguna
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  • 2.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-12-2024 06:09

    Hi

    So, what opinion exactly are you seeking?

    If you analyzed well? or if the impeller looks wrong?



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    Shittu olakunle
    Reliability Engineer
    United Kingdom
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  • 3.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-13-2024 23:25

    shittu olakunle,

    What is the "stuff" on the blade's back-plate?

    Looks like the fan is fairly dirty. Has it been cleaned and tested again after cleaning?



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    Ralph Stewart
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  • 4.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-14-2024 17:00

    Hi Kishore,

    Agree with the other two posters its not clear what you're asking but as you assume its impeller imbalance at a 1xRPM.

    In terms of sources of fouling:

     - depends how long you've been monitoring/took the contract but could be general cleanliness/build up - if the blower has ever been cleaned this would likely have been at dry-dock.  If it is indeed the vessel named on the VA plot, this would have probably been 3 - 4 years ago at her second special survey docking.  ANy issues with engine room ventilation/pressure?  When was the last time the blower was cleaned or replaced?

     - this could also be carbon build up - unlikely as the air flow is the wrong way but dont rule it out.  What are the results of the last scavenge space/under piston inspections, how is the liner/piston ring condition?  Cylinder lubrication?  Looking for indications of combustin gas blow-by,

    Any more information/a clearer question would be really helpful.

    Gareth



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    Gareth Ward
    Chartered Engineer
    Enthusiast of all things Asset Management
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  • 5.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-14-2024 21:34
    Edited by kishore kumar agguna 01-14-2024 21:35

    Good Day Sir ,

    Well noted your feedback .

    We suggested them to clean and assemble the blower , as you know it is not possible to balance the impeller onsite ( that can be only done while Vessel dry-dock) .

    Is this kind of depositions on Main Engine Auxiliary impeller is indicating any issues with the Scavenging air passage issues .

    When ever we suggest about any checks , they said found no issues ( even in this case also ) .As we know this kind of deposition on impeller could cause impeller unbalance .

    I will update about current Vibration trend , once we receive the data from the vessel .



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    kishore kumar agguna
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  • 6.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-15-2024 01:48

    I think the trend data will be valuable. Did it suddenly increase - some sort of "damage" or incident, or did it trend up - fouling or blockage.



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    Byron Martin
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  • 7.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-15-2024 02:24

    Good Day ,

    Sir .

    This equipment trend is in alert since a month and we have been sending alert report to check this Blower .Recently the have opened and send this pictures , we have not received updated Vibration data yet after assembly .



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    kishore kumar agguna
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  • 8.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-15-2024 05:28
    Thanks. There are only a few things that can go wrong with a simple machine like this;
    1. Bearing fault, failure or looseness
    2. Looseness of impeller or motor cooling fan on shaft
    3. Imbalance of rotor or motor cooling fan 
    4. Crack in impeller
    5. Mounting fault
    6. Run out of impeller
    But to produce 1x with no harmonics or sidebands, only 3 and 6 are likely.



    Byron Martin
    Sent from my Galaxy





  • 9.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-15-2024 23:45

    Good Day ,

    This Blower impeller opened for inspection and you can see its condition in attached Photography .No cracks , looseness observed and abnormalities found on impeller other than carbon deposition .



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    kishore kumar agguna
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  • 10.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-16-2024 11:03
    Have you conducted a resonance bump test to check for any resonance or multiples of a resonance near the fan running speed?
    Balancing can reduce the 1X levels but any slight change can cause the resonance to increase the vibration levels.

    Jim Cerda
    JJC Consulting




  • 11.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-16-2024 04:14

    Bearing in mind the opinions of other contributors, more information is required (including the absolute vibration trend) to better analyse the concern raised. I could understand how it feels to learn that no problem was found after giving professional advice. In my journey in the field of rotating equipment condition monitoring, I have come across numerous instances where high 1x amplitude vibrations were caused by foot related issues. I will suggest carrying out proper soft-foot checks and thorough inspection of the skid/pedestal upon which the unit is mounted. Consider motion amplification technology to visualise the vibration if the problem persists.



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    CELESTINE ESO
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  • 12.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-16-2024 06:52

    I agree with Celestine Eso that it is most likely a structural looseness issue (being on the non-drive end side and also only in one direction with a single peak at running frequency). Besides checking the skid/pedestal for loose bolts or cracks in the structure as recommended, wedging a piece of wood between the two skids (at the point furthest away from the bolted interface - in the area below the motor fan) to stiffen the structure in the horizontal direction can be tried to see what impact it has on the vibration.



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    Willem Vegter
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  • 13.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-17-2024 14:56

    As stated in a previous comment it could be a foot related resonance generated by a soft foot condition. if you have access to a dual channel analyser this can be verified by taking Phase and amplitude measurements at the 1x motor speed . take readings between the base and each of the 4 motor feet in the vertical plane placing one transduce on the motor foot and the other on the motor base. if you have one or more locations that have 180 phase difference between the motor foot and base this would confirm you have a soft foot issue.



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    Mick Steimel
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  • 14.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-16-2024 07:19

    I forgot to add - has anyone checked the motor fan?  I have (rarely) seen a motor fan impeller break up and give high 1x



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    Ron Frend
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  • 15.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-16-2024 07:25

    Looks like my first reply was lost so here it is again. 

    3 things to check

    1)  Carry out a static balance check on the assembled rotor.  This is only a single plane balance issue if there is a problem with the blower impeller so you can do a quick balance by spinning the rotor and see if it keeps stopping in the same location.  If it does then either add a weight at the top or remove material from the bottom until the stop position becomes random - just like balancing your car tyre.

    2) Do a lift check on the rotor to see if the bearings is about to collapse. I've seen this several times when the cage is about to collapse.

    3) Check for bent rotor by using a Dial Test Indicator (DTI) gauge on the impeller both vertically and axially.

    It's all very well being a vibration expert but you have to get your hands dirty too to fully analyse the issues.

    Good luck

    Ron



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    Ron Frend
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  • 16.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-16-2024 07:31

    I also agree with Gareth Ward.  Scavenge air is not usually perfectly clean so it's quite likely that build up on the impeller is from airborne dirt and oil in the engine room atmosphere.  What will often happen is the dirt builds up uniformly (so no increase in 1x) but when the thickness of the dirt gets too much, some dirt will drop off and you get what seems like a sudden unbalance vibration.

    It's good practice to clean the rotor regularly - how often depends on how dirty the engine room air is.



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    Ron Frend
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  • 17.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-17-2024 10:12
      |   view attached

    kishore,

    I just noticed your motor is a 2 pole 3000 rpm speed.

    Please see the attached doc file.

    Thanks, Ralph



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    Ralph Stewart
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    Attachment(s)



  • 18.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 01-18-2024 01:45

    Well Noted , Thank you .



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    kishore kumar agguna
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  • 19.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 28 days ago

    kishore kumar agguna

    Have you been able to obtain data with higher resolution to confirm there is not an electrical problem with the motor?

    Thanks



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    Ralph Stewart
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  • 20.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 27 days ago

    Good Day ,

    Ralph Stewart .

    Please refer the attached images for your reference

    Velocity
    Acceleration
    Envelope


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    kishore kumar agguna
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  • 21.  RE: Main Engine Auxiliary Blower Vibration Analysis

    Posted 27 days ago
      |   view attached