Tagged With "Spectra"

Topic

Breakthroughs in the Past Decade

Shurafa ·
Hello. If you are asked to think about the major developments in the field of vibration analysis introduced over the past 10 years, what would you list? What I’ve seen (and my exposure is limited) is more of a “system development” but not a lot of breakthroughs on the analysis itself. New products (hardware and software) are released such as laptop/tablet based solutions with more flexibility functions. Some are wireless and some use the cloud. More manufacturers and startups. But on the...
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Re: Breakthroughs in the Past Decade

William_C._Foiles ·
I may have some bias here, but I believe this reference has been followed with other uses. The methods can deal with vibration data - is good for forced response. The basic math is very old, but the uses are more up-to-date. This paper talks about the use of the Singular Value Decomposition. Journal Engineers' Australian Journal 2004 Title Practical Applications of Singular Value Decompositions in Rotordynamics Authors C. Hunter Cloud, William C. Foiles, Guoxin Li, Eric H. Maslen, and Lloyd...
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Re: Breakthroughs in the Past Decade

rgf12 ·
I think one area that is coming to the forefront is the use of "big data" and advanced pattern recognition. Our fleet has installed thousands of vibration and temperature sensors that are fed into a central monitoring and diagnostic center where they are using the large data set to determine early warning of rotating equipment faults. When fully implemented and fine tuned we believe this system will recognize patterns that will give a notification to each program owner that there is...
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Re: Breakthroughs in the Past Decade

Shurafa ·
Hello Bill . Though I'm sure your paper is of a great value, I cannot count it here since it was issued in 2004 and we talk about the last decade. I did not know you have joint papers with Dr. Hunter. Interesting. Hello rgf12 , The Internet of Things is moving fast in many areas but not enough yet in the vibration analysis- at least I've not seen a mature system on a commercial scale. Do you think this new approach will involve fundamentally different analysis to evaluate the condition or to...
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Re: Breakthroughs in the Past Decade

candy ·
http://www.intechopen.com/book...on-analysis-research
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Re: Breakthroughs in the Past Decade

rgf12 ·
The analysis of machinery faults will not fundamentally change, what we are striving for is a modeling of each machine and the early identification of any condition that is outside the model using the large data set. We (the computer system) looks at overalls, high frequency, crest factor and specific bands of vibration to trigger a alert that is sent to the responsible analysts for review and diagnosis. In an ideal setup it makes the routine walk around data collection a thing of the past.
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Re: Breakthroughs in the Past Decade

William_C._Foiles ·
As I mentioned, that was the paper. I have seen more recent work from Schenck. I have had correspondence with someone who has atarted using these ideas in a commercial rotordynamic program. I hope to see more uses. From the tone of the reply - "I am sure ..." - the message has not spread everywhere.
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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
Topic

Set up for Gearbox Vibration Measurement point

Mrunal Dave ·
Dear Vib Legends, We are about to set up the vibration measurement points for gearbox (N1: 1488 rpm, no of teeth unknown) with the following : 1. Velocity spectrum (Fmax 120000 cpm, 3200 and 6400 lines, 4 linear Averaging with hanning window) 2. Acceleration and Env Spectra: Your inputs are required. Please advice. We are awaiting for some reference set up examples. 3. Time waveform analysis: Fmax 5850 Hz, 4096 samples. Please suggest if required some correction or your inputs please for the...
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Re: Set up for Gearbox Vibration Measurement point

Mrunal Dave ·
Thanks John and DBTCMP, We are trying hard to get these data. Will update as soon as we get it. N1 is measured RPM of motor shaft i.e. input / high speed shaft of gearbox.
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Re: Set up for Gearbox Vibration Measurement point

DBTCMP ·
Your at nothing until you identify the gear teeth and intermediate shaft speeds, spend your time getting that information, as for setup, the information you discover in the first part of my answer will guide the direction of this, hat basis are you going to use the setup you outline?
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Re: Set up for Gearbox Vibration Measurement point

John from PA ·
You've provided N1 = 1488 RPM. Is that a measuremed speed or off the nameplate?Is there nameplate data that would give you the output speed?
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Re: Set up for Gearbox Vibration Measurement point

Akhil Rathore ·
If you can share the make model of the Gearbox, Also number of teeth is utmost necessary to setup the database as well as to analyse the vibration data captured. You cannot move a step ahead without this.
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Re: Set up for Gearbox Vibration Measurement point

John from PA ·
Do you know if this is a speed increaser or decreaser? What is being driven?
Topic

Interpretation of Spectra

MARCO20002000 ·
Srs. Forum: Good afternoon, in the company in which I work failed the two bearings of the electric motor for lack of grease; attached acceleration and acceleration envelope spectra taken on various dates; as reported by the monitoring staff indicate that there is no bearing anomaly in the spectra; however I am observing that these spectra are indicating that there are lubrication problems in the bearings. I will appreciate your technical comments on this. Regards
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Re: Interpretation of Spectra

ramonruiz ·
Dear Marco, The word failure in Ball bearings depends of severity (amplitude) and kind or frequencies appeared in spectrum, the spectrum attached by you still no show frequency con dangerous amplitude to say ¨Failure¨, but 3rd stage of bearing failure is in process. Look the next severity chart of IRD Mechanalysis (pag. 5) and select the frequency of bearing appear in spectrum after you can determine the severity of damage. the OverAll vibration depends of Fmax that you are selected for take...
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Re: Interpretation of Spectra

MARCO20002000 ·
Mr. Ramón: Good morning, thanks for your reply; What I have tried to say, is that the bearings failed because they had no grease (attached photographs of the two bearings of the electric motor) and one of the bearings came out with the cage broken and the other bearing came out hardened (could not be rotated manually ), my query went in the following direction: Do the spectra displayed both acceleration and acceleration envelope indicate lubrication problems ?. I will appreciate your...
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Re: Interpretation of Spectra

MARCO20002000 ·
Mr. Ramón: The bearings failed the 24/01/19 and the last vibration data was the 26/12/18. Attached file with the different vibration monitoring of different dates.
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Re: Interpretation of Spectra

ramonruiz ·
HI Marco, we need more to do more deep analysis. 1.- please more details of motor. 2.- type of load , is it constant or variable?, belt t or coupling transmission, for example. 3.- velocity spectrum and waveform the last reading 4.- accelerometer data sheet 5.- if it is possible, photo of motor 6.- Environmental condition (temperature, dust, etc). 7.- The relubrication is possible? 8.- Historical temperature of bearings (trend).
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Re: Interpretation of Spectra

ramonruiz ·
Mr. Marco Im looking with more details the vibration reading date.. can you say us the failure date. In september 2018 spectrum , we can observe random peaks (like noise) from 1.5kHz to 5 KHz, likely due to lubrication problems. the last reading was september 2018.
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Re: Interpretation of Spectra

MARCO20002000 ·
Mr. Ramon: Attached as requested. Regards
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Re: Interpretation of Spectra

ramonruiz ·
Dear Marco as we can see, acceleration spectrum and envelope spectrum not represent real condition of bearing, also it means and I can suppose the radial direction load is very low with respect to axial load. please can you send Velocity spectrum and waveform.. also, please can you send axial vibration reading. is the axial load very high with respect to radial load in bearing? kind of coupling? the load is constant? can you send more detail of the equipment coupled (driven). best regards.
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Re: Interpretation of Spectra

ramonruiz ·
Dear Marco, As we can see, vibration analysis didn't show enough evidence of the state of deterioration of the bearings to anticipate the failure, therefore, I propose the next step, make an analysis of bearing failure, then rule out manufacturing defects, load evaluation axial since this type of bearings do not support large axial loads, only a percentage of the radial load, also, investigate why not was lubricated at first time, etc. Prior conclusions to failure analysis and questions:...
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Re: Interpretation of Spectra

MARCO20002000 ·
Mr. Ramón: Attached Waveform Time and Spectrum Speed. Best regards.
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Re: Interpretation of Spectra

Rotating Guy ·
Marco, I used enveloping for detecting bearing fault and correlate it to TWF for determining lack of grease. regards, RG
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Re: Interpretation of Spectra

DBTCMP ·
gE should be measured in Peak for starters in the spectra shown its displayed in RMS....the setup shown is wrong!!!! you always measure gE in Peak or peak to peak with the average set to 1. You have a telltale haystack in the acceleration at the 'golden' 180,000 cpm area of the spectrum( for 50 Hz electrical supply machinery) which points to a bearing issue, most likely electrical related shaft current( In my experience with SKF microlog) Lubrication issue would show raised even noise floor...
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