Tagged With "fault"

Topic

Electric Motor Defect Frequency

Alvaro Loayza ·
I want to share this case that we had 2 weeks ago in our plant. Equipment: 500 hp 1780 RPM Toshiba motor With 6322 Inboard Bearing Fault: BPFI with sidebands at turning speed. Peakvue Amplitud 0.75 G's rms. Report: Scheduled replacement for 30 days. Trend supported recomendation. Results: Maintenance lubricated bearing and amplitud dropped to 0.2 G's RMS. BPFI with sidebands was still present. They replaced motor bearing 45 days later after first report. Visual inspection didn't show any...
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fault housing and bearing

husky100 ·
i got the problem with housing and bearing . they are all totally damaged .Type of the bearing : spherical roller . At first , i checked with the tool to took the reading with vibration and enveloping acceleration . it look like machinery condition checker pen . Sorry i  do not tell the name of the tool . The Recorded reading been collected seem ok . Actually  when i opened the housing , the condition of housing seem seriously damaged . as we seen the vibration at the feet of...
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Large Bearing Fault Frequencies

Costa Ilic ·
Hello to all, I am wondering if you could help in determine large bearing fault frequencies. It is possible to find it online is what detail dimensions of them are in order to estimate it. I am interested in those bearings:  FAG 564647 Split Bearing (700/460 x 245)  FAG 527466 (1000/1210 x 92)  FAG 527463 (670/820 x 69)  And similar bearing that I do not have number, with dimensions (1360/1120 x 106), should be FAG F-801007.ZL. Where to find information about those...
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Pole Pass Reading in Standard Route Readings

oju ·
Was wondering how many here take high res readings to monitor pole pass in their standard route readings? If so have you found issues?
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Smart Vibration Analysis

Reliability ·
From a article posted at Reliabilityweb.com Since leading indicators at inception are not yet typical “wall chart” fault conditions, finding them as they happen requires a really close look at every spectra and a comparison to historical signatures to distinguish them from normal, transient conditions related to load, temperature, process rates, accelerometer data, etc... Read the full article
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Re: fault housing and bearing

IrishMark ·
I know what the tool is and that gE level would be high enough to warrant an inspection, were you able to grease the bearing mid reading? Ideally that tool is ok for assisting in greasing and less critical plant assessment, I wouldn't use it for high criticality machines your better off with a SKF Microlog in that case.
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Re: fault housing and bearing

vishal sharma ·
dear can u tell me the rpm of machine
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Re: fault housing and bearing

vishal sharma ·
dear can u tell me the rpm of machine its seem the highly contaminated grease
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Re: fault housing and bearing

husky100 ·
Dear vishal sharma . it's 3600 rpm . the contaminated grease could not because the client not change type of grease . What i could explain : the rotor is unbalanced and make the vibration , so on ... In fact i do not understand with reading been collected . As Iso 10816 with motor 3600rpm , the bearing seem normal condition. not any doubt the condition of the bearing . So trust absolutely the standard or our feeling about machinery ?
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Re: Smart Vibration Analysis

candy ·
Is this smart vib analaysis include in the vibration certification courses?
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Re: Smart Vibration Analysis

RRS_Dave ·
Narrow band alarms statistically set.
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Re: Pole Pass Reading in Standard Route Readings

Walt Strong ·
I usually make two measurements on the motor case near the terminal box. The first measurement is a high-resolution low frequency velocity spectrum for confirming motor speed and to detect rotor pole-pass sidebands. The second measurement is high-frequency acceleration to detect rotor bar and stator slot passing frequencies along with modulation sidebands. I have detected both electrical and mechanical faults with these type of measurements. There may be other ways to accomplish the...
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Re: Pole Pass Reading in Standard Route Readings

Gary Stacey ·
I do not generally take a high res reading to look specifically for PP symptoms. I will if other issues such as audible modulation make me suspect there may be a developing rotor bar issue or if rotor dynamic eccentricity is suspected. Be interested to know what problems you have detected with the high frequency acceleration reading Walt? I don't doubt you have! Textbook states that RBF with 2x line frequency sidebands = rotor bar issues but I have not had much success with it. I quite often...
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Re: Pole Pass Reading in Standard Route Readings

Dave Reynolds ·
Agree with Gary, we have low frequency hi resolution reading on ALL of our machines, only take it when we have driver and driven speeds that are 100 rpm or less speed difference, hear an audible noise or higher than usual vibration values. Keep in mind, IF you have broken/loose rotor bars, the motor will have poor performance, lose HP, draw higher than normal amps, have a modulating noise coming from the motor, will run hotter than a normal motor, time waveform will have modulation and will...
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Re: Pole Pass Reading in Standard Route Readings

Walt Strong ·
"I will if other issues such as audible modulation make me suspect there may be a developing rotor bar issue or if rotor dynamic eccentricity is suspected." Gary, if you want to rely upon your hearing and some other means of detecting rotor dynamic eccentricity that is fine. If it is convenient for you to go back to the machine and make additional measurements that is fine. If you're making a decision not to take certain data because some faults are very unlikely that is fine. Most of the...
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Re: Pole Pass Reading in Standard Route Readings

Gary Stacey ·
Sorry should have added that I do take high res readings if there has been any change in the routine data such as harmonics, increasing overall etc. With my standard data set we will see 'skirts' around 1x 2x etc which would also prompt investigation. As with Dave I have seen very little by way of rotor bar problems in my 20 years of collecting data. I am just traking one now on a smallish motor - previously we had only ever seen the issue on large FD/ID fan motors and we collected routine...
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Re: Electric Motor Defect Frequency

ivibr8 ·
Best answer will come from the change in spectrum. Have you taken the post-replacement data set yet?
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Re: Electric Motor Defect Frequency

Alvaro Loayza ·
Hello, Thanks for your response Well actually the last spectrum is after bearing replacement. I would want to know if you want to share a similar case in your facilities
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Re: Electric Motor Defect Frequency

Gary Stacey ·
Could be that you has some debris in the bearing that regreasing has flushed out. This has happened to me before which is why amoungst other reasons I suggest greasing as a first option. A distorted inner or outer race can also give you ball passing freqeuncies but usually with only very low harmonics because the signal is more sinusoidal rather than impactive. Gary
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Re: Electric Motor Defect Frequency

Ralph Stewart ·
Quote of Alvaro Loayza , "BPFI with sidebands at turning speed. Peakvue Amplitud 0.75 G's rms." I have been using Peakvue since the first day it was added to the Emerson equipment and I am thinking this ::::: If you called this from the Peakvue data with only a "0.75 G's RMS" value, that is where the "problem" of "nothing" showing comes from in the bearing when it was removed. Very few time do I make a bearing defect call based on Peakvue data. There is one case type from which I feel nearly...
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Re: Pole Pass Reading in Standard Route Readings

electricpete ·
I agree with above. One thing to add is "dynamic eccentricity". We've recently tossed around the idea of whether dynamic eccentricity can cause increased pole pass sidebands around FL in current under load. We had lots of discussion on that but a main point for Gary and I was that we've never seen that. On the other hand, I have seen pole pass sidebands around 1x in vibration on vertical motor at least twice where subsequent refurbishment showed loose housing fit on lower bearing, and the...
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Re: Pole Pass Reading in Standard Route Readings

Walt Strong ·
"On the other hand, I have seen pole pass sidebands around 1x in vibration on vertical motor at least twice where subsequent refurbishment showed loose housing fit on lower bearing, and the symtpom went away after refurbishment. I attributed that to dynamic eccentricity. (btw nothing ever showed in current sidebands)" I have made similar diagnosis on two different motors, one with ball bearings and the other with journal bearings. The diagnosis was confirmed by bearing repairs, and there was...
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Re: Electric Motor Defect Frequency

Justin Adamson ·
I would agree with Ralph. It appears your bearing frequency indication in clearly evident in peakvue, at this early stage I would advise grease and monitor. I only start reporting bearing defects when BPFI frequencies show as harmonics in the high frequency area of acceleration spectrum (3-5Khz +) for a few consistent surveys and consider replacing bearing after BPFI appears in velocity. This is just my experience anyway with mining conveyors and gear boxes
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Re: Electric Motor Defect Frequency

Alvaro Loayza ·
I want to thank all of you for your responses Well, after reading your advices I finally realized that bearing replacement was a premature decision and another convenient action should have been taken. Peakvue is very sensitive and even microgeometric defects may cause this condition high frequency spectrum surveys is a very intersticio option I didn't consider because it's not actually something we do here. Finally, I will get this experience for future similar situations. best regards for...
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Re: Large Bearing Fault Frequencies

John from PA ·
Check the thread at https://www.maintenance.org/top...ies-for-fag-bearings
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Re: Large Bearing Fault Frequencies

Costa Ilic ·
Thanks John, I have tried but there is nothing for this bearings...
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Re: Large Bearing Fault Frequencies

CETMA ·
Most FAG bearing numbers are available at: http://medias.schaeffler.com/medias/en!hp However, the bearings you listed are specialty bearings and their fault frequencies are not listed. You should contact your local Schaeffler representative to get the frequencies.
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Re: Large Bearing Fault Frequencies

John from PA ·
FAG's catalog Bearing Solutions for Large Machinery can be found at http://www.schaeffler.com/remo..._8/tpi_205_de_en.pdf . I haven't taken the time to look through the catalog but perhaps enough information can be determined to enable a manual calculation.
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Re: Large Bearing Fault Frequencies

Costa Ilic ·
John, thanks for suggestion...working link at the moment for FAGs Bearing Solutions for Large Size Machinery is: http://www.schaeffler.com/remo..._8/tpi_205_de_en.pdf but I could not find much detail for manual calculation.
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Re: Large Bearing Fault Frequencies

John from PA ·
The manual method of calculating is available at http://www.ntnamericas.com/en/...ents/frequencies.pdf as well as numerous other sources. If you can't find exact dimensions of the bearings think about whether a spare is available for measurement, and as suggested by someone give Schaeffler a call.
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Re: Screw compressor vibration on-load vs. off-load

OLI ·
I would say you either have a screw-type or a reciprocating (piston) type compressor but that may only be me. In either case difference on/off load can and normally are significant as far as I have seen. Olov
Topic

Screw compressor vibration on-load vs. off-load

abdulbasitb ·
What changes are normally expected in the vibration spectra of a screw-type compressor when it's on-load vs. off-load?
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Re: Screw compressor vibration on-load vs. off-load

abdulbasitb ·
Sorry, I meant screw-type. I've made the correction. I wish to know what fault frequencies you normally find and how the amplitudes vary at the different frequencies, comparing off-load vs. on-load
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Emerson AMS Suite Fault Frequencies

KronoChris ·
Hi all, I'm running into an issue using Emerson's AMS Suite. I've built a few hundred pieces of equipment on this software. I've noticed if I build a piece of equipment , say a fan but I do not know the bearing numbers. One day I stumble across the mfg. and bearing numbers I need. So I'll go into RBM wizard and add the bearing information. I will then exit/save then hit the almighty hammer. I will reload routes, even reboot the software. I will then collect data on that particular fan and...
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Re: Emerson AMS Suite Fault Frequencies

soundhound ·
If you click "Edit MP" at bottom of Configuration Setup for a piece of equipment and expand the tree on the left side do you show a "+" sign next to "unassigned"? If so you need to drag those points to their shafts.
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Re: Emerson AMS Suite Fault Frequencies

Dave Reynolds ·
have you checked the load/unload screen? I believe there is an option to load fault frequencies Dave
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Re: Emerson AMS Suite Fault Frequencies

KronoChris ·
Thanks. It was the "edit mp" tab at the bottom of config.
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Re: fault housing and bearing

Khairul HN ·
Hi Husky, Just to share some knowledge abt tool that u use, SKF CMAS100. Default setting for Enveloping (CL2) reading is for shaft diameter OD 50-300mm & machine speed 500-1800rpm. In that your case is machine speed of 3600rpm, this vibr pen is not suitable. As for my experience, I am not using vibr pen for Enveloping measurement because it will not give either precise nor accurate reading. For vibration (velocity mm/s) is ok. Try ADASH vibr pen for more enhanced features.
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VFD problem?

Lampard Nguyen ·
Dear Experts, Is there VFD problem in following case? Is it Mosfet or Diod fault? Please view up-stream and down-stream current profile of VFD! Thank you!
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Re: VFD problem?

Panta ·
Cando, Which is type and power of your regulator .Theoretically in large High Voltage regulators has several transformers at each stage working together and made output sinusoidal voltage which at one phase obviously lacks. Good luck !
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cepstrum analysis

aziz58 ·
dear all is there any one have experience with bearing or gear fault detection using cepstrum analysis ? pls post sample of graphs best regards
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Re: cepstrum analysis

John from PA ·
Good basic explanation at https://www.bksv.com/media/doc/233-80.pdf
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Re: Chillers and Air Compressors

Walt Strong ·
Let Google be your friend. Good information here: http://www.technicalassociates...t=10&sort=normal Walt
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Chillers and Air Compressors

Avinash Thawani ·
Please can anyone share details about Chillers and Air Compressors. Understand the chiller compressors and identify fault frequencies Understand air compressor and identify the fault frequencies
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Envelope alarms/Severity Assessment and changing bearings

Costa Ilic ·
Hello to all, I believe some of you are in dilemma but I hope so meany of you are much more experience than I am. Making decision of changing bearing base on envelope alarms is not always the best approach but if all envelope filter are set up correctly and it is nice development of bearing fault frequency over life ob bearing what your you advice and do you have a reference to point out for correlation amplitude in envelope spectrum with level of fault in bearing. I am referring to regular...
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Re: Envelope alarms/Severity Assessment and changing bearings

Costa Ilic ·
Thank you BECAR , Your answer is something that I expected, there is no simple and cross-platform rule. I was hoping that there is someone with more experience or knowledge from me or someone has some rule of thumb at least that have been proven in practice...
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Re: Envelope alarms/Severity Assessment and changing bearings

Becar ·
There is such a variety of machine types that envelope standards will never be something to rely on. The only way is setting alarms for each individual machine seperately according history of measurement, experience etc.
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Re: Envelope alarms/Severity Assessment and changing bearings

Rotating Guy ·
Hi, I am using enveloping for deeper analysis but sometimes it doesn't needed or i mean it is confusing, i do usually basic TWF and Spectrum and i can get the bearing fault, usually before i go replacement of bearing i check the amount of impacting if it get worsen. regards
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Re: Envelope alarms/Severity Assessment and changing bearings

Costa Ilic ·
Hello to all, What we are referring here envelope analysis is something we use but not for making decisions in future, using it just as a tool of an early indication of a problem but most of the time we trust more TWF and Spectrum, interesting. Can we say envelope analysis is not so practical tool?
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Re: fault housing and bearing

Anariw ·
Can you post vibration spectrum? Thanks
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