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Asset Condition ManagementPosts About vibration/alignment/balance
Subsynchronous vibration multistage high pressure centrifugal pump
Registered Member @Registered Member Hey Ayman, thanks for replying. I haven't got the critical speed data from factory and haven't been able to check it myself on site [ more ]
Registered Member @Registered Member Hey Ralph, thanks again for replying. I attached the wrong files, my bad. Attached the sectional drawing. For the trouble in viewing images have you try to re-login? For the spectrum, as I could tell there is no sidebands, at first I thought I saw sidebands too, but turns out it is subsynchronous peak at 69 Hz, pump 1X is at 88.9 Hz. For change in operation, as you can see in my other attachment files, there is change in flow and pressure but it was affected by the speed... [ more ]
Registered Member I am totally confused as to what is wrong with this thread and the replies and why I can not see all the the replies,or my last image I posted. I am posting the image again. Seems as though, somehow, I have been partially block out of the thread or there may be something wrong with my computer.???????????????????????? Thanks for any help on why this might be happening. If I am "blocked-out", tell me and I will cease to question this problem. Here is the image I posted earlier. Thanks. [ more ]
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Asset Condition ManagementPosts About vibration/alignment/balance
Omnitrend Help
Registered Member Dave, yes, watched it. There are things in Omnitrend that are very bothersome and I’m beginning to think it is the fault of using Microsoft Access. Emonitor is still the best by far, and they use a commercial third party database , like Gupta. If you change a collection spec, they all change. Could not duplicate that in OT. I built an alarm band spec in the alarm editor and it looked great. I went back out to look at the data and the RMS bands at the higher frequencies had all shifted! I’ve... [ more ]
Registered Member https://www.youtube.com/watch?v=4dOUlxYDgHM Came across this hour long video, may have what you are looking for Dave [ more ]
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Asset Condition ManagementPosts About vibration/alignment/balance
CTA - Cyclic Time Average (SKF)/Contribution Profile
Registered Member Thanks John, I am using @ptitude Analyst from SKF. This is a tool for analysis gear tooth defects.But i am not sure about the interpretation. following the tecknical paper about. https://skftechnicalsupport.ze...-SKF-ptitude-Analyst [ more ]
Registered Member I am not really familiar with the software you are using but can you do multiple revolutions of the circular plot? I’m used to seeing about 8 revolutions. If they lay more or less on top of each other it is an indicator of something related to the rotor. In the case of a gear, perhaps something related to the hob. If the pattern constantly rotates, then perhaps related to a bearing on the rotor. [ more ]
Registered Member In this shaft 33. Please look at the picture. Thanks. [ more ]
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Reliability Engineering for MaintenancePosts about Capital Projects
Relation between facility uptime and Maintenance Strategy

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Asset Condition ManagementPosts About vibration/alignment/balance
Oscillating overall vibration of Motor
Registered Member Many good suggestions have already been given by the forum members. What I advise is to compile the suggestions into a checklist to systematically go through them. In order to eliminate some of the mentioned possibilities, there is a need to take additional measurements with specic configurations or perform more tests. For example, to verify the sidebands and confirm the frequencies, I would take high-resolution data with a high number of averages say 50. I would also perform a shutdown test... [ more ]
Registered Member Thinh, Hello, I have a couple of questions. See the M2V Point Spectrum image. Referencing to Point # M2V The sideband frequency appears to be of a low frequency range, similar to, # of poles times slip frequency, {(1800 –1780)}x 4 = 80 cpm/60 Hz = 1.33 Hz. But this particular pattern could be because you captured this spectrum at just the β€œright” time to give the impression of electrical problems. Have you more data, on a different day, on this point M2V? But on the other hand, if this is a... [ more ]
Registered Member The beat, in my opinion, is coming from: loose bearing fit to shaft/housing in motor, soft foot, worn coupling or the 2 running pumps are beating with each other. The imbalance from 1 pump eventually lines up with the imbalance from pump 2 then eventually the separate again runs smoother. Your recent plot, thank you, shows a "skirt" just to the left of 1x rpm, this is typically a natural frequency. So when the pump starts, just before full speed, the vibration will increase, then drop... [ more ]
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Asset Condition ManagementPosts About vibration/alignment/balance
Multiple speed correction calculation Required
Registered Member There are balance software that can use multiple speeds. I gather that the high-speed balance machine doesn't consider mulitple speeds. [ more ]
Registered Member When you use the term "operating speed" are you referring to the test speed in the balancing tunnel which can at times be different than the final machine operating speed? [ more ]
Registered Member Here, https://www.maintenance.org/to...ackage-rotor-balance [ more ]
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Employment OpportunitiesReliabilityResumes
Project Engineer – Asset Management (Aurora Water)

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Asset Condition ManagementPosts About Lubrication and Oil Analysis
Refrigerant/Chiller lube oil sampling

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Asset Condition ManagementPosts About Lubrication and Oil Analysis
Greasing type air blower

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Asset Condition ManagementPosts About vibration/alignment/balance
Vertical thermal offset for wind turbines
Registered Member Correct. It is a fixture that rotates so you don' t need to rotate the gearbox shaft, which would be almost impossible, considering the blades would still be out there sitting in the wind! [ more ]
Registered Member In a planetary arrangement (fixed annulus/ring) the gearbox may also have an alignment fixture so check with the OEM. [ more ]
Registered Member The results are in !!! 2.0 mm offset was dialed into the laser with the wind turbine cold. Ran for 1 hour to come to temperature and the final offset was just 0.11 mm!!! I love it when science works. [ more ]
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Reliability Engineering for MaintenancePosts about Root Cause Analysis
MHI geared compressor impeller removal from pinion rotor
Registered Member Hello All, Do you have any experience on MHI geared compressor ? If possible, PLS help to take a look at the following question and provide some help . Thanks----- So far I still cann't get any support form MHI, it is really bad . Have a good weekend! LUX [ more ]
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Asset Condition ManagementPosts About vibration/alignment/balance
How to calculate residual unbalance from vibration data after balancing
Registered Member Balance grade as defined in ISO 21940-11 is in mm/s. If you read the standard, it should answer your questions. 1. There used to be an Annex (if I recall correctly) in an old ISO 1940 that reminded one that it was not possible to relate vibration to balance grade. 2. 2.5 mm/s - See ISO 21940-11. 3. Question not well defined. Basicly the balacne grade, G, is the permissible mass eccentricity multiplied by the rotational speed (max) in rad/sec. More in ISO. [ more ]
Registered Member https://www.hornusa.com/filead...ical_Info_-_2015.pdf [ more ]
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Reliability Engineering for MaintenancePosts about Root Cause Analysis
Pitting corrosion on an Integrally geared compressor

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Asset Condition ManagementPosts About vibration/alignment/balance
Electric Motor Sub 1X Vibration
Registered Member They changed the compressor and noticed after that. But who knows, maybe it has always been like that but wasnΒ΄t noticed until replacement of compressor. This motor has 6316 bearings. And in evening the technical manager sent me these pictures. It seems the axle is damaged ( Grey Area ) but bearing seems ok. [ more ]
Registered Member Has it always exhibited this phenomenon or is this new? If you zoom in, is it exactly 30 Hz or something slightly below 30? VFD? On 60 cycle rating is 290 kW (388 HP). Does it have rolling element bearings or fluid film bearings? [ more ]
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Asset Condition ManagementPosts About vibration/alignment/balance
Electrical Motor vibration Issue
Registered Member Re: Electrical Motor vibration Issue [ more ]
Registered Member Abu Nafi, Thanks for the reply. Sounds like maybe, if it running good now, it is best to leave it alone for now, huh? Thanks, Ralph [ more ]
Registered Member I still look for the relation, but seems no relation, in the meanwhile I confirm that the Fs .79 What does "Fs .79" Refer to? I think, .79 Hz refers to Slip frequency, Speed 428.4 and we have Speed in the plate 425 RPM So, we have difference of 3.4 RPM, Fs=Slip#No.pole/60 = .79 HZ Actually, there is a question had slipped my mind days ago, can we distinguish the type of loading that the bearing exposed to (radial or axial?) from the spectrum? if so, how? I am not sure about the "load" from... [ more ]
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Welcome to AMPBook and Article Discussions
Vibration Analysis Cat I Certification Preparation Series (8 Booklets)

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Asset ManagementPosts About Asset Management
The Introduction of the SDIPF Safety Reliability Curve

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Asset Condition ManagementPosts About vibration/alignment/balance
Balancing of flexible rotor on hard bearing balancing machine.
Registered Member Probably I've just seen the small turbine rotors [ more ]
Registered Member If you are talking about field balancing, the end planes may be more accessable. I have seen center planes on steam and gas turbines accessable in the field (not always so easy). I think there are paractical reasons to use the end planes. I remember trying to get the field guy to open a port for a center plane on a steam turbine. He tried for a good while but the port was frozen by rust. We made due with the end planes. This must have be a first mode problem--don't really recall the... [ more ]
Registered Member Bill, I've seen many rotors (stream turbine) that have groves for balancing only at at their ends (first and last wheels), are this places choosed at design because of the modal characteristics expected for the rotor, or a more simple approach because it's easy to work with [ more ]
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Asset Condition ManagementPosts About vibration/alignment/balance
What can be cause of Vibration amplitude fluctuation at 3rpm?

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Asset Condition ManagementPosts About vibration/alignment/balance
Vibration Analysis Report

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