Skip to main content

MaintenanceForums

Sorted by last update

Asset Condition ManagementPosts About vibration/alignment/balance
Vibration value discrepancy between ADRE and HMI
Registered Member There could be many reasons for amplitude discrepancies. However, I tend to agree with @Registered Member to start by comparing the configurations. Fmin, Fmax, rms, 0-p, type of sensor, power, and scale factor are possible factors to cause discrepancies. I also found very few cases where the rack cards had internal issues. If you have a shaker table or a signal generator, they can be very useful to troubleshoot the case. What do the waveform and spectra contain and are they stable? I guess... [ more ]
Registered Member What is the exact make and model of the accelerometer? Which ADRE are you using; the 408 DSPi or the much older 208P? In the interim, make sure the ADRE and the HMI interface are both configured for the same units. You don't for instance want one configured for RMS and the other PEAK. [ more ]
See all 2 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Rotor bow ge frame 5 gas turbine
Registered Member In my opinion 1 hour may be far too short a time. It could take a day. I've seen results in 4 hours, but if you have the time let it roll. [ more ]
Registered Member We haven't made any inquiry. We just referring to operating manual which mentioned if your shaft suspected to rotor bow , turning at least one hour turning gear . We have done it but vibration has not decreased . Can we conclude bended shaft or permanent bowing ? [ more ]
Registered Member If you have been down since the time this was posted, this would be a cold start. Borescope cannot see all places that the turbine can rub; on gear you may be able to hear a rub--you might go in the exhaust or inlet (if it is not deafining). Not seeing any rubs, is a good sign to place the unit on turning gear (jogging, whaterver you have). (Once someone described to me the rubbing sound on a turbine as whales mating--I wonder how they knew.) You do not have a specific procedure from the... [ more ]
See all 5 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
VFD driven cooling tower fan
Registered Member What is the arrangement of the cooling tower? I have often see the towers utilizing a right angle gearbox have a 1-node torsional around the 10 Hz to 12 Hz region. Noting your comment "The vibration amplitude came down to a normal level after the 2nd VFD replacement", did you see a substantial amplitude change at 900 RPM and or 1100 RPM? If so, a torsional effect may be having some influence. [ more ]
Registered Member More details please: You state high vibration after VFD replacement, then tested at different speeds with same result. Explain please Typically 1x fan/motor speed would increase/decrease with speed change Is position 3 the gearbox input shaft? If so, check the coupling element for damage, check up and down play of input shaft, check gear backlash by rotating driveshaft back and forth, you should barely rotate the shaft and feel the gears making contact. What is the frequency of the sidebands... [ more ]
See all 2 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Predictive Equipment Checkout Aid
Registered Member Thank you Mr. John I prefer to not reinvent the proverbial wheel so I will give that a look see. [ more ]
Registered Member You might want to look into getting a copy of API 686 Recommended Practice Machinery Installation and Design. There are machinery commissioning checklists in Chapter 9, although as I look at what I have it is the 1st Edition (April 1996). The 2nd Edition is from December 2009 and it was reaffirmed in November 2014. It's about $200 but it is a very comprehensive document on installation and design. [ more ]
See all 2 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Overhung Fan High 1x Horiz DE fan Bearing
Registered Member quite well known problem for me. It is beating as the other colleagues said. Change the pulley ratio and you sovle the problem otherwise the only thing you can do is try to balance the best possible both pulleys. Ruben [ more ]
Registered Member James, I would suggest, to supervision, separating the speed of the fan from the speed of the motor, from being a 1 to 1 ration, by changing the pulley size. If it were direct coupled to the motor, this problem would very possibly, not be there. Surely, with it being an air exhaust fan, the fan could be slowed down or increased by 20-50 rpm's or more, unless it must rotate, by law or design, at a minimum of 1480 rpm. If the fan must run a minimum of 1480, I would suggest increasing the fan... [ more ]
Registered Member Everything smells beating, reducing the amplitudes by balancing will improve the overall condition, hard to know the cause, also try improving the stiffness off the structure beneath the fan bearings [ more ]
See all 10 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Sub-Synchronous Vibration (1 - 2 Hz) problem. Electrical noise or Fluid Instability? HELP!
Registered Member The time waveform looks to have a transient at the start of data collection. The meaning of the spectrum is questionable because of this. Does this repeat? With other data? There could be a number of causes. One is a sudden application of the transducer concurrent to the start of data collection. Don't be too quick to collect data after placing the transducer. [ more ]
Registered Member Can you elaborate on what you are referring to when you say “vibration transmitter”? Are you truly using a transmitter or are you using a proximitor wired back to a rack? Perhaps add make and model. [ more ]
Registered Member Yeah, I think the problem is more about noise but instrumentation personnel has replaced cables, sensor, vibration transmitter and the problem still continues. The barrier was also eliminated. [ more ]
See all 8 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Turbine journal bearing High temperature
Registered Member I dont have extensive field experience with gas turbines (others on this forum do), but it seems to me that the orbit displays you provided shows a very high preload in the horizontal direction <--- assuming the 0 deg reference is the top/vertical direction. Do you have orbits and vibration data from before recent inspection for comparison? Orbit shapes will change with speed (and perhaps load) due to the accompanying dynamic stiffness changes. It would be nice to plot these various... [ more ]
Registered Member hello Mr Jim thank you , in above my answer for your question. attached is the alignment report. Regrads [ more ]
Registered Member Am a bit confused....you say X and Y radial plan(e) but axial proximiter? Can you confirm we are talking radial measurements or axial "thrust" measurements On initial glance, this data appears to show your orbit shaft highly preloaded in 0-180 deg direction. Not sure how you set up your probes so I am assuming the horizontal direction. Since you state it was only an inspection, I would assume no work was done to it? yes/no? I would check carefully how you replaced the bearing after... [ more ]
See all 3 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Pfaudler Gearboxes fault frequencies
Registered Member Contacted the number provided and spoke with the service manager. Found out that the individual that I had previously spoken with works in her group. More to follow..... [ more ]
Registered Member I’d call the number I previously provided and ask to speak specifically to the service manager. [ more ]
Registered Member Thank you Mr. John. To be honest I am not sure where the gentleman is out of that I was speaking and am in email contact with. I was given his name and contact information by a Field Service Coordinator from GMM Pfaudler US. [ more ]
See all 4 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Marley 2200 gear reducer GMF
Registered Member Thanks for your help [ more ]
Registered Member Something wrong…1457/210 = 6.938 but up front you said the ratio is 6.12:1. Verify the speeds, confirm this is a single reduction and see if you can get any info that would confirm seven teeth on the pinion. [ more ]
Registered Member This is a spiral bevel. Output speed appears to be about 210 rpm. [ more ]
See all 6 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
1x High Vibration NDE Motor
Registered Member Why use peak hold averages spectrums if you can make waterfall plots, in my opinion 1000hz 400 lines will give you a very fast spectrum and any other harmonics will rise at a resonance "zone" which will give you a better confirmation of resonance Agree with Ralph, phase at feet and what's this motor driving, motor - gearbox - rollers for a pellet press, how is the feeding "controlled" more material will slow down the motor (increased load) once the motor is free it will spin a little faster,... [ more ]
Registered Member Thanks James. This is sort of strange for there to be sidebands off the 1x at such a CLOSE distance........ What is the motor driving, a gearbox? and what is the final rpm of the driven part? If agitator, what is its rpm snd how many blades or paddles? Ralph [ more ]
Registered Member Thanks James, One more question. See the attached doc file questions. Ralph [ more ]
See all 17 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Shaft journal surfaces for proximity probes
Registered Member John, Thank you. Your response is close to what I was thinking, but it is always advisable to get the opinions and thoughts of those folks that know the territory the best. Best Regards, Ron Brook Sent from Mail< https://go.microsoft.com/fwlink/?LinkId=550986 > for Windows [ more ]
Registered Member Ron, chrome is an acceptable method of repair with some caveats. When journals are in need of repair it is common practice to turn them down to some undersize dimension, plate the area with chrome or perhaps tungsten to an oversize dimension, and then grind the area back to the proper dimension. Using proximity probes in the repaired area commonly results in indications of excessive vibration that are not related to the actual dynamics of the rotor. Understanding the problem is relatively... [ more ]
See all 2 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Discussion about phase behavior
Registered Member Probably the balance of the motor is good. I just was curious if the same base and lower vibration was due to uncoupled or different base. Anyway, I had experience with a screw compressor, improving alignment improved the axial vibration, I could not find a solution, I think the problem was in the screws itself, but the motor had lot higher vibration than the compressor side [ more ]
Registered Member Thinh Pham , Here is an early post along the lines of your questions. Looks like it might be from 2010 (12 years ago) It has a few more members responding. But appears to say, more or less what the current replies say. In my opinion, in most cases, phase is not an absolute, "fix-all" tool. Just another tool used with an open-mind when in the search for the real problem. https://www.maintenance.org/to...about-phase-behavior Thanks, Ralph BTW: The balance might be from the driven machine and... [ more ]
Registered Member The solo was not in the same base [ more ]
See all 14 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Influence of temperature on vibration sensor
Registered Member I'm not an expert in cooling towers, but your will have to be little more specific, you said gear, I assume it's a gearbox and the wireless sensor has temperature and vibration at the same time, usually higher temperature means more friction/load, on the other hand less vibration usually means either less l oad or degradation of the condition.... Ok I have no idea what I'm talking about [ more ]
See 1 reply...
Asset Condition ManagementPosts About vibration/alignment/balance
High preload orbit ABB motor
Registered Member If you have oil whirl on a motor, it should not be difficult to correct. The bearings may not be to design, worn/damaged, or improper specification (third party?). [ more ]
Registered Member .43x sounds a lot like oil whirl, how was the alignment corrected Laser? Thermal growth? The waveform on drive end looks like a "w m" pattern, I don't know if it's possible to capture the centerline plot with 2140 without the higher end license and transient [ more ]
Registered Member Just an FYI, generally gearboxes under load, due to the tangential and separating forces, are quite stable and don't exhibit fluid induced instability. The gearbox connected rotor as well, when using fluid film bearings, will be operating at an eccentricity ratio of approximately 0.8. But when a machine is tripped, those forces can be suddenly removed and the gear shaft may suddenly change its position in the bearing. On the motor at 0.43X, has the alignment to the gearbox been checked? I... [ more ]
See all 19 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Cooling Tower Fan
Registered Member Much of the detail in your images is lost due to poor resolution. Can you improve the images? Perhaps put them into a Word doc and then save as a PDF. I also have a question about the gearbox. Based on your motor and fan speeds, the ratio seems to be 8.205. Is the gearbox a single reduction? [ more ]
See 1 reply...
Asset Condition ManagementPosts About vibration/alignment/balance
System1 display minor anomaly
Registered Member Its not working and I checked with the service engineer, as per him the options got deleted accidentally. So now I'm using a different login there this anomaly is not seen. [ more ]
Registered Member Have you tried John's suggestion? Do you see System1 icon on the upper left corner of your screen? Any other strange behaviors? It might be clearer if you can upload the current abnormal screen you see. Regards- Ali M. Al-Shurafa [ more ]
Registered Member It's been 11 years since I've worked with System 1 and as you are aware, some things are done so much that they become what we call "2nd nature." But give this a try and see if it works; take the lower edge of the menu bar, left click and hold the mouse button down, then see if you can drag the lower border downward thus expanding the bar. [ more ]
See all 3 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Raised noise and peaks after repair?
Registered Member I know this is an old post, but i know from seeing this same situation that if the locking collar isn't tightened down properly with a spanner and then locked into place, it will eventually work loose and eat material off of your shaft. as well as cause bearing defects. [ more ]
Registered Member On Friday, I was able to test out a brg adjustment for a short while. I have attached some spectrum before and after adjustment. From the results of the short time testing, and chance that a possible increase of failing may happen with the new settings, I had the adjustment turned back to original starting position. From what you suggested and what the spectrum looks like, I figured there was too much clearance, and by reducing clearance, the results would reduce the noise levels on the... [ more ]
Registered Member I would post a picture of the brgs but for some reason I'm unable to grab the drawing from rexnord's site. I did see it the other day. But, there is set screws that lock the brgs to the shaft. I did use a strob light to check for slipping and did not notice any. Looking at the docs on these brgs,the internal clearance can be adjusted with the spanner nut that is on the one side of the brg housing. When these brgs were installed, the spanner nut adjustment was not adjusted. I located a... [ more ]
See all 8 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Velocity and acceleration in vibration analysis
Registered Member IMO, seek out knowledge from someone who knows more than you do. “The more I learn, the more I realize how much I don't know.” (Albert Einstein) [ more ]
Registered Member It's misfortounate the poor guy got faced with all the turbo machine PhD type guys in looking for an answer. the instrument you have sounds like either a skf quick collect or a Xmas machine advisor Vibe pen, both instruments mainly just tar an overall reading of velocity and enveloped acceleration, you regally need an instrument with a fft display to be able to put in context what you are looking at. The skf quick collect sensor if you have it has a facility to generate a very simplistic... [ more ]
Registered Member Dear Mr JAMESK, Wellcome to this forum.you have plenty of explanation for your question and how you take it all.? when you collect vibration data using any vibration data collector you will get many unwanted noise along with useful data what is required for fault analysis.The problem is that the identifying signal (useful data) is usually drowned out in other noise emanating from the machine. Hope you know about FFT spectrum analysis,where in rotating machine faults are identified for... [ more ]
See all 13 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
SCR Firing Rate
Registered Member @Registered Member thanks for the reminder I put the alarm threshold just 50% above max peak. I am monitoring it on a monthly basis. We'll let you know it something goes wayward. Cheers! [ more ]
Registered Member Can you stick a band alarm and trend it on the peak of interest? If it stays static and doesn't increase might Ben just a matter of keeping an eye on it. [ more ]
Registered Member Thanks Dave at least I can now confirm that SCR is also present in AC motor depending on what system you're using and what for. The small peak on the left of SCR is the 6x RPM. The motor is running 1500 RPM. You're right, I am suspecting also airgap dissymmetry caused by soft foot, unfortunately the company is hesitant to do what you've suggested. Since the amplitude level is still very low ~0.7 mm/sec I don't think I will make a call. [ more ]
See all 6 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Bearing Defect
Registered Member Hi Gents, thank you so much for your feedback, I really Appreciate that. regards Abu Nafi [ more ]
Registered Member Sometimes you see bearing frequency in FFT but not in demodulation/ enveloping when there is no "impacting" like out of roundness bore or cocked bearing you might see BPFO [ more ]
Registered Member From your vibration training, there should be information about stages of bearing failure. There are many variables that affect a bearing fault, many different rpm's, load, environment, etc. As the bearing degrades the vibration pattern changes along with an increase in G values. https://www.midlandsrc.com/wp-...on-Publication-1.pdf https://www.midlandsrc.com/wp-...-Publication-2-1.pdf The attached document is a good reference for additional knowledge, this document is a guideline, not meant... [ more ]
See all 5 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
AMS error V5.6
Registered Member Thanks Dave [ more ]
Registered Member You will need to contact Emerson customer support to get this resolved Dave [ more ]
Registered Member Hi Dave, I did, but no errors showed up, please see screen below: Unable to display database tree structure! DBfix log for 'C:\RBMsuite\CustData\LINE 6 PART (2) DOUPLICATE (1).rbm' created on 21/09/2022 15:24:53 Completed scan of C:\RBMsuite\CustData\LINE 6 PART (2) DOUPLICATE (1).rbm Found Fixed Unresolved Invalid Record Header :0 0 0 Record Number Out of Bounds :0 0 0 External File not Found :0 0 0 RBMview database node problem :0 0 0 [ more ]
See all 4 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
ADRE Sxp and 408 DSPI or SCOUT 140
Registered Member Dear Mr.John thank you so much for your interesting support, I'll appreciate it. Regards [ more ]
Registered Member More importantly, the 408 DSPi needs to be plugged in continuously. As far as other brands working with the Sxp software, that is very doubtful. [ more ]
Registered Member Thank you Mr.John for the interesting feedback, I understood that if I choose Adre, I'll walk around with almost 11 Kg weight to collect the vibration Data, isn't? if yes, is there any portable data collector we can use with Adre (as microlog) to collect data then analyze by Adre ? thank you again. Regards [ more ]
See all 4 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Bearing loaded Axially or radially?
Registered Member Dear Mr.Ali, first of all, I would like to express my gratitude toward your support. few months ago, I experienced a situation when we had an electrical motor 550 kw with 425 RPM drives an alternative compressor, this motor has two rolling bearings in DE side (one's radial ball bearing and the second a roller bearing (skf NU)), in normal situation the radial ball bearing supports axially loading and the roller bearing support radially loading, in abnormal situation, I found a brief report... [ more ]
Registered Member If I understood your question correctly, you already have vibration spectra from a running machine and the machine is undergoing abnormal radial/axial stresses on the radial bearings (or at least you suspect). You are trying to find a sign in the vibration spectra that will tell you if the load is excessive in the radial or axial direction. Correct? This is a generic question. I assume you'll receive only generic comments. If the bearings are normal journal bearings, it's difficult to relate... [ more ]
See all 2 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
300 Hz on AC Motor (50 Hz line frequency)
Registered Member Hoping for some clarification from the best in the industry... ) [ more ]
Registered Member 👍
Registered Member Hi Everyone, I've seen same situation seeing 300 Hz in the spectrum on an AC motor with soft starter. I'm suspecting it is from SCR Firing rate but would it be possible to have SCR on an AC motor? [ more ]
See all 6 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Vibration analysis and diagnostics of multistage Centrifugal Compressor due to rotor - stator rub
Registered Member The OP has not visited these forums since 3/5/22 so I suspect you won’t get an answer to your question. [ more ]
Registered Member Dear SAB262015 , Liquid carry-over can cause un-balance of rotor due to presence of incompressible fluid in Gas. Also the passages of impellers discharge blocked the gas flow. Being very high speed rotor (13,800 rpm), impact is very severe. This unbalance at high speed will create very high radial vibrations which in turn will cause rubbing of seals with Rotor. Change of phase and shift of critical speed is clear evidence of this phenomenon due to stiffness change / rubbing. Any un-balance... [ more ]
Registered Member Were there any obvious material removal from the the corroded impellers ? Were there any machining activities performed on corroded impellers ? If not , I suggest that there is no permanent unbalance and bow in the rotor , However the critical speed shifted to the 1x rpm and amplified the unbalance vector 1x rpm and changed the phase by 90 degree only ( still in critical band ) because of existing rubbing issue (higher stiffness effect ). About speed variation , you should review the... [ more ]
See all 12 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
High Vanepass Vibration in centrifugal pump
Registered Member I have attached identical pump fft,envelop & Acc-Time. As dave mentioned, in this pump waveform limit was within the limit. I don't know why there was a high deflection in waveform of faulty pump,let me see whether i have the other timewaveform data for the faulty pump . [ more ]
Registered Member What Dave mentioned on 80 G p-p (in the waveform compared to other plots) is what triggered my attention and that is why I don't feel comfortable relying only on this data to give a repair recommendation. Regards- Ali M. Al-Shurafa [ more ]
Registered Member Thank you sir for your valuable comment .when the pump was dismantled the pump wearing and wear-plate was damage .This worn out parts lead to vibration which eventually failed the pump?The impeller retainer bolt was damage and impeller was touching the casing while dismantling.We had run vertical pumps with worn out plate nothing has happened ,the flow would reduce gradually but never experienced such drastic failure is it because the pump is installed horizontally . [ more ]
See all 6 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Cooling system Pumps
Registered Member Agree with fitting issue. Highly appreciate your insights Dave. [ more ]
Registered Member My 25+ years of vibration analysis tells me your base is not perfect In my experience electric motors, sitting on a concrete floor, do not vibrate, put the same motor on a weak base and vibration levels can increase 10 times higher. The flywheel is a mass and a shaft, there should not be any turning speed harmonics 1x or 2x The pump you state is good to go.....without data this is assumed That leaves the base and mechanical fits. In my experience by lifting the shaft and using a dial... [ more ]
Registered Member The base and foundation are perfect! Pump NDE bearing changed last Dec and yes, housings are green. Pump has 7 vanes. Looseness has always been present and remained stable so does the TWF p-p value in line with other pumps. Motion amplification could have been very effective and revealing here I suppose. [ more ]
See all 9 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Exhaust Fan
Registered Member Thanks for your valuable advise. Have been trying to highlight the issues, unfortunately couldn't convey the message as the mechanical team wouldn't accept the fact that it could be wrong sleeve or installation issue! [ more ]
Registered Member Dave just how does this endorse you ideas about installing these bearings. [ more ]
Registered Member You should support the shaft to prevent bearing damage. [ more ]
See all 16 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Identified Natural frequencies of Gas Turbine Solar Centaur 50
Registered Member Ok, thanks John [ more ]
Registered Member BrookjeG was last on this forum in May 2014. I suggest you start a new thread as opposed to using this thread, even though there might be similar issues. [ more ]
Registered Member Hi BrookieG Have you talked about axial air compressor rotor that has loose spacers? We have problem of high 2X vibration of GP Centaur 40 split shaft Engines, this vibration is detected by both casing mounted velocity transducers in Horizontal as well as Vertical directions at aft flange of compressor of engine [ more ]
See all 10 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Accuracy of Automated Fault Diagnosis System for Rotating Machines
Registered Member Thank you @Registered Member for the response. [ more ]
Registered Member These systems are very expensive and almost for no use, I can tell you that they cause more problems then before. Sellers will tell you the opposite of course. AI level, wireless capabilities, storage capabilities, high price, educating staff, staff resistance.....20-30 years too soon as electric cars are. Now we see the car batteries are charged with diesel generators. This is no more then commercial fraud. I am writing from my own experience but won't go to details as company names etc. [ more ]
See all 2 replies...
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 ]
See all 4 replies...
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 ]
See all 2 replies...
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 ]
See all 7 replies...
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 “right” 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 ]
See all 7 replies...
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 ]
See all 3 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
Alarm Ge
Registered Member I know a place or two where they have one of those installed [ more ]
Registered Member I added these measurements to an online system that had permanently mounted accelerometers (stud mounted and properly torqued) and STILL did not get repeatable results. [ more ]
Registered Member SKF has mentioned in the past (if I remember) that this is extremely sensitive to sensor position and mounting. This requires faith in a technology that I do not have. I've seen some case histories purported to support this. I wonder how many case histories do not support this. I have seen material supporting/promoting the use on fluid film bearings. ???? [ more ]
See all 13 replies...
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 ]
See all 17 replies...
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 ]
See all 7 replies...
Asset Condition ManagementPosts About vibration/alignment/balance
High axial vibration in a centrifugal fan
Registered Member Is this fan fed from both ends? If yes, then this is usually the result of uneven damper settings, and/or the fan is not centered in the fan housing. [ more ]
Registered Member Strange; 9 mm/sec is 10 divisions? Why not 9 divisions? [ more ]
Registered Member Hi John, that's 9 mm/s RMS, values at discrete frequencies can be roughly estimated from this value. [ more ]
See all 6 replies...

Join Us!

The Association for Asset Management Professionals (AMP) is dedicated to making the world work for everyone, with no one left behind.

The mission is to provide a path to a safe, sustainable, successful workplace and world through reliability and asset management.

AMP is a Florida based 501 (C3) not-for-profit organization that delivers

  • Professional Certification (CRL and CMM)
  • Online Community of Knowledge
  • Competency Based Learning (CBL)
  • virtual Special Interest Groups (vSIG)


 This web site is FREE to use for registered members and has been called the LinkedIn or Facebook for Reliability Leaders and Asset Managers.  The Community of Knowledge is simply fantastic.

The Association of Asset Management Professionals (AMP) is licensed to develop competency based frameworks using Uptime Elements Reliability Framework and Asset Management System and its related Frameworks.

Uptime Elements Reliability Framework and Asset Management System
Uptime Elements Reliability Framework and Asset Management System

Uptime Elements Digitalization Framework
IoT Knowledge Domain

Vibration Elements
Vibration Analysis and Diagnostic Framework
Lubrication Elements
Asset Lubrication Framework

 You are also invited to join the Association of Asset Management Professionals

LinkedIn Discussion Group with 53.000+ members

https://www.linkedin.com/groups/1636387

LinkedIn Company Page as well
https://www.linkedin.com/company/association-of-asset-management-professionals

Join Now

Already a member? Sign In

Upcoming Events

VIRTUAL CMM EXAM
VIRTUAL CRL EXAM

Complete Calendar

Online Now

×
×
×
×
Link copied to your clipboard.
×