Tagged With "Problems"

Topic

fluid coupling mounting

alainraad ·
there is any problem if a fluid coupling is mounted in the wrong direction? the input on the gearbox shaft and the out on the motor? the coupling is flender fludex FAD 297. for me i think that there is no problem, in case that the gearbox shaft can...
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High pressure gear pump vibration problem solved

Alvaro Loayza ·
Hello everybody, A few days ago i posted a topic about a problem we had in our high pressure gear pumps. Here is the original post: http://www.maintenance.org/topic/high-gear-pump-vibration I want to share with you the way that we solved this high vibration problem. After checking pad oil piping at discharge in both fixed and floating mill bearings, we noticed that high vibration was still significant and even higher on hosepipes that were connected in every pump discharge connection. So I...
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GEARBOX PROBLEM IN STEEL PLANT

dominich.vo ·
Hi all,  I get a problem to monitor a gearbox with variable speed in steel plant. The detail has been described in attachment. the spectrum data shows many of harmonics of turning speed .  So, what's problem with this gearbox and what generates harmonics in spectrum data?   Thanks and regards ! 
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Problems with TPI UltraII

PillarofIN ·
I am having data transfer problem with Test Products International UltraII vibration monitor and C-TrendII software. My monitor syncs with the software and fill a sync folder. No readings appear in the software. The nest time I try to sync...
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Re: High pressure gear pump vibration problem solved

John from PA ·
You probably should have added the content above concerning the resolution to the original thread. By use of the terms "oil flux" do you mean "oil flow"?
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Re: High pressure gear pump vibration problem solved

Dan Timberlake ·
piping elbows' tending to straighten in response to pressure has caused me some mischief several times in the past. Your situation seems more like an internal "acoustic" response of the oil column within the pipe. Hard to keep them separate sometimes.
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Re: GEARBOX PROBLEM IN STEEL PLANT

MarkSl ·
Hello, Do you have the gear tooth details for the gearbox so you can determine the speeds of each shaft. Once you have determined these forcing frequencies and the gear mesh frequencies are you only seeing harmonics of the turning speed. Multiple harmonics of the input shaft would possibly indicate looseness maybe a bearing/s is loose in the housing.
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Re: GEARBOX PROBLEM IN STEEL PLANT

John from PA ·
49 x 32 yields exactly the ratio of 1.53125 that is specified. But I'm hesitant to apply that to any analysis without further knowledge of the gearing. Generally speaking side bands are indicators of pitch line runout and the spacing of the peaks helps identify the rotor with the issue. But I have never seen so many sidebands and especially many in excess of the fundamental rotation speed amplitude, which I assume is 1000 RPM based on the data.
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Re: GEARBOX PROBLEM IN STEEL PLANT

dominich.vo ·
Hi John, i have updated gearbox's drawing. How could you know that is 59x32 yield ? @@ 1000 RPM only set up data, it 's not real turning speed. the output shaft is running with 5 class of speed as mention on 1st attachment. i guest that the output shaft No.2 has problem about installation. History information shows that the mill roller shaft (connect with gearbox's output) has been broken and move all gearbox a distance 20 mm. the output shaft was bent and machined . the bearing at GB7 was...
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Re: GEARBOX PROBLEM IN STEEL PLANT

John from PA ·
The gearbox data (tiff files) is of little if any value. They are too small to see any detail and if enlarged virtually useless. Just a suggestion, when you add something, open what you've added and see if it is what you expected.
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Re: GEARBOX PROBLEM IN STEEL PLANT

Jack1954 ·
What does the time wave of this gearbox look like. Possibly a chipped tooth on the input gear. If input speed is the spacing in the spectrum. Is this a sudden event following relatively good data or is this a first time analysis? It actually looks like severe looseness but I would expect a higher raised noise floor.
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Re: fluid coupling mounting

John from PA ·
Originally Posted by alainraad: there is any problem if a fluid coupling is mounted in the wrong direction? the input on the gearbox shaft and the out on the motor? the coupling is flender fludex FAD 297. for me i think that there is no problem, in case that the gearbox shaft can support the coupling weight. The best advice would be for you to check specifically with the OEM. Having said that, the manual for that drive states "The drive should preferably take place via the hollow shaft (106)...
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Re: Problems with TPI UltraII

John from PA ·
"They" being the US people? I'd try emailing the people on the other side of the pond.
Topic

current fluctuation

raymundus ·
i have a problem related to current fluctuation in the Air Preheater motor, anyone know about the root cause of it? I have asked the electrical maintenance person, he said that the fluctuation is not caused by inverter of it. inverter has worked well. i have input information that this problem caused by gear box problem. but the problem is, the system is online so we are not posible to check it, i think we have to ensure if the problem is come from gear box by doing individual test. anyone...
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Re: current fluctuation

Walt Strong ·
Check if motor current has periodic fluctuations and compare period to preheater rotation speed. Preheater fouling or damage could cause unbalance or rubbing. Observe motor and gearbox vibrations by touch and measure vibrations and possibly contact ultrasound to detect any motor or gearbox faults. Walt
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Re: current fluctuation

Panta ·
It may be related with fluctuations of voltage on the motor. If the load is constant and temporary voltage drops to consequently reflect that motor must take more current .
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Re: current fluctuation

Walt Strong ·
My calculations with your data: Preheater speed: 1.11 rpm /60 = 0.019 Hz ~ 0.02 Hz Current amplitude frequency: 1/25 seconds = 0.04 Hz Conclusion: Current fluctuations are about 2x preheater speed (2 events per rotation), so possible air seal rub or other fouling/damage issues with preheater. "Can the gearbox abnormality checking be done by non-individual test." I am not sure what you mean by this question. No instruments are needed if for observation of gearbox vibrations and sound by touch...
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Re: current fluctuation

raymundus ·
In some sequence, the period of fluctuation is 25 seconds, the preheater speed is 1.14 rpm, i suppose that the period of fluctuation is the half of preheater period rotation. Can the gearbox abnormality checking be done by non-individual test. But i think, we don't have the tool
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Re: current fluctuation

raymundus ·
Yes, i have simple analysis related to my problem, the rotation speed is 1.14 rpm, so the period is approach to 52.63 s, the period of the fluctuation is 26 s, 1/2 rotation period. So i think that fluctuation is in the seal gap clearance that not properly adjusted. Radial seal is located on the 0, 180 and 230 degree...
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Re: current fluctuation

electricpete ·
Have you checked whether it might be pole pass frequency? (example 3598.8 rpm on 2-pole 60hz motor has pole pass frequency 2*1.2 cpm = 2.4cpm = 0.04hz... would have to be a large and/or lightly-loaded motor)
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Help with problem on Cat II test

Huddle_House ·
I am no stranger to vibration but was studying over this information for my upcoming CAT II test and ran across this problem that I cannot understand how they got the answer... it seems so simple but I have yet to find out how to work it out correctly. Can anyone help me to see how they arrived at this answer?
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Re: Help with problem on Cat II test

John from PA ·
I get about 9.2 hz based on about 5-1/2 cycles occuring in 0.6 seconds.
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Re: Help with problem on Cat II test

Huddle_House ·
Thanks...yeah I'm getting that too but the answer key says "B"... 11.59 Hz ???
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Re: Help with problem on Cat II test

Walt Strong ·
John, I did not prepare the test and apparently neither did you; although your attachment differs from OP! No test instructions were provided by OP. The question appears to be multiple choice with no 5th choice for "none of the above". You can argue that the question is poorly worded or that you are more correct than Answer-B. You also assumed that a peak occurred at Time = 0.0, but that cannot be proven without seeing the what occurred before that. I choose Horseshoes on this one! Walt
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Re: Help with problem on Cat II test

John from PA ·
Walt, stick to the game of horseshoes where being close counts! See below for my take on the question
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Re: Help with problem on Cat II test

Walt Strong ·
First of all, the only close answer is 11.59 Hz. My quick estimate was 5 cycles in about 0.5 seconds or 10 Hz. I would not be concerned about 1/100 of a Hz or even 1/10 Hz when trying to visually convert a waveform to frequency. Walt
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Re: Help with problem on Cat II test

John from PA ·
What I sourced and the OP sourced can be found in the Vibration Institute sample exam for Cat II. I added the red vertical line which indicates time at 0.5++ and didn't mention that it was "my edit". But remove that line and you have exactly what the OP posted. As far as making the assumption that a peak occurred at t = 0, many instruments use the 1st negative going portion of the signal as t = 0. But you make a good valid point so lets start at the zerro-crossing at the right axis as t = 0.
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Re: Help with problem on Cat II test

Walt Strong ·
John, Without a digital waveform and cursors and knowing the actual/intended instructions, you are still playing horseshoes! I passed the CAT II exam a century ago, before samples were offered. Keep at it, so you can get 0.001 precision. Walt
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Re: Help with problem on Cat II test

Walt Strong ·
Ralph, I like your answer of 11.53 Hertz, since it is close to Answer-2 at 11.59 Hz. I guess VI expects a CAT-II person to sharpen their visual waveform skills to 0.01 precision before proceeding on to CAT-III. This is a waste of time, but amusing! Horseshoes Walt
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Re: Help with problem on Cat II test

William_C._Foiles ·
It is not how many peaks in the time. It is how many cycles. It looks to be less than 10 Hz as others have said. To count the cycles one can start with the first peak and label it 0. 1 on the second peak becomes the first cycle. Cycles as in cycles per unit time.
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Re: Help with problem on Cat II test

Walt Strong ·
Re-Engineer, Why are you multiplying the frequency by 1.4? Walt
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Re: Help with problem on Cat II test

RE-Engineer ·
fundamental frequency is how many cycles per one second here we have 5 cycles per 0.6 second So it will be (5/0.6)* 1.4 = 11.66 Hz
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Re: Help with problem on Cat II test

Huddle_House ·
Sorry for the late response but "Thanks" to Walt, Re-Engineer, William, and john for all of the help and information with this. I appreciate it guys.
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Re: Help with problem on Cat II test

mirook ·
the question has no right answer, you can email VI tell them.
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Re: Help with problem on Cat II test

Lou Pag ·
I believe that at present there is only 3 organizations that are accredited in the world to ISO. The V.I. , Bindt, and Möbius Institute. Technical Associates, Full Spectrum Disgnostics, Update international and any others, and CMVA in Canada, are not accredited as far as I know. They align or conform their certification schemes to ISO documents but no one seems to care one way or the other that they are not accredited. Candidates from Non- North American countries put more importance on...
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Re: Help with problem on Cat II test

John from PA ·
Check http://www.technicalassociates.net/certification.html . I do find interesting that when you look at the schedule, items are referred to as Analysis I, Analysis II, Analysis III, etc. I wonder why they aren't using the common terminology Level I, Level II, etc.? Be advised as well that this whole process can be confusing. See the thread at https://www.maintenance.org/top...5#399590942963090365 for a discussion that should be of interest.
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Re: Help with problem on Cat II test

Huddle_House ·
Ok will do...thanks again.
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Re: Help with problem on Cat II test

Huddle_House ·
I agree that the correct answer is not one of the choices given. I was unaware of people not pursuing a V.I. certification. I need to get a CAT II Certification that is ISO certified. Who would you suggest?
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Re: Help with problem on Cat II test

Lou Pag ·
I see approx. 5.75 cycles in 0.6 seconds. A reasonable answer would be 9.6 Hz. Is this question still a practice question for Category II certification? From the V.I.? If so, I hate to beat a dead horse, but it is no wonder that so many vendors opted to no longer pursue a V.I. certification from 1994 onward for a number of years. One way to fix this error, would be to add another answer "e. None of the above".
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Re: Help with problem on Cat II test

John from PA ·
Check Mobius at http://www.mobiusinstitute.com...detail.asp?LinkID=21 . I see a class in Edmonton Alberta Canada coming up in mid-September. What a beautiful time of year to be busy studying.
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Re: Help with problem on Cat II test

Lou Pag ·
Möbius is a Very good suggestion as an alternative for certification. Hey this is 2016. The V.I. Has changed a lot since 1994. Maybe it is just the review questions for CAT II that need a little tweaking.
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Re: Help with problem on Cat II test

Huddle_House ·
Ok thanks guys...I will check into it. Is Technical Associates of Charlotte ISO certified? any thoughts on them?
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Re: Help with problem on Cat II test

William_C._Foiles ·
I don't always provide comment to these non-technical remarks. But why not; it is the political season here. One does need an accrediting body in their country or get accreditation elsewhere. This can limit some places. However, I see that the Vibration Institute is giving accredited training around the world. Mobius does the same. I do not oppose the marketplace that provides these services. When the customer obtains or believes he receives value and the vendor helps by participating in the...
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Re: current fluctuation

Lampard Nguyen ·
Hello RAYMUNDUS , Can you give me namplate motor RPM or number of motor poles? If your motor has 4 poles, 0.02Hz vibration can cause 0.04Hz fluctuation in motor current. In my oppinion, this case is of your Preheater damage, broken impeller. High unbalance will cause high fluctuation of current. Good luck!
Topic

motor vibration at 3XTS

Hossam 2 ·
Good Afternoon guys i have a problem related to a motor vibration which is summarized in a dominant 3XTS on motor side in the horizontal direction while 1X and 2X barely visible overhung fan variable speed up to 600 rpm coupling is flexible 14 rubber element and this rubber is new the alignment within tolerance 0.1mm while the max, allowable is 0.5 the shaft has coupling has run out problem 0.25mm and shaft has center runout between the bearings 0.3 mm and near the free bearing 1.7mm i know...
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Re: motor vibration at 3XTS

John from PA ·
No attachment. You might check to see if the 3X is mechanical or electrical in nature and let us know. To check, while the machine is running and producing the 3X, shut off the power but observe at the same instant of power being cut if the 3X still exists, or immediately drops out. If it drops out then the problem is likely to be electrical, if it remains it is more likely to be mechanical.
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Re: motor vibration at 3XTS

Shurafa ·
Are you sure it is exactly 3.0 X speed? Based on 600 rpm, 3X= 1800 cpm or 30 Hz. Im not sure if 30 Hz is a common symptom of an electric problem. Are there any additional information you can provide? Any data you can post here? Regards- Ali M. Al-Shurafa
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Re: motor vibration at 3XTS

Hossam 2 ·
These images Are contain almost all the info thank u guys
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Re: motor vibration at 3XTS

Hossam 2 ·
I already made this test and the problem is not electrical as the peak still exists and drops gradually
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Re: motor vibration at 3XTS

Hossam 2 ·
I already posted a pic contains all the info i know Thanks
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