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Tagged With "raw"

Topic

Best units for display of orbit plots?

Ralph Stewart ·
This may be a simple question I heard today, but it was asked and I would just like to hear from you guys and your ideas. Which are considered to be the best unit of measurement for orbit plotting? When using an accelerometer: would it be: use stored raw units of acceleration for orbit? Or converted raw units to Displacement during collecting data and then stored? Or converted to displacement from a stored raw acceleration units? Or convert the stored raw units to velocity? Or convert to...
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Cement Plant Air Separator Bottom bearing Condition Monitoring

vipul@cmc ·
Hello , What are the best practical methods for prediction of bearing failures of Cement Plant Air Separator ( Raw Mill or Cement Mill ) Bottom bearing ? Thanks,
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clarification Required On CSI instrument.

Vibration_guy ·
hello. I have some doubt on CSI specifications. 1-What is Raw Speed of data collection and what does this mean 7.0 avg/sec.? 2- Wave form size should be minimum 32KB. What does this mean. Is this of Time Wave form? 3- Limited Noise floor i.e. Less than 0.2 micro volts per root Hz over 1000 Hz frequency range? how to calculate the noise floor? Thanks In Advance. Regards, Ashis
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Re: Cement Plant Air Separator Bottom bearing Condition Monitoring

Walt Strong ·
Can you be more specific about what your issues are? https://www.thecementgrindingo...ep3genb/sep3genb.htm Walt
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Re: Cement Plant Air Separator Bottom bearing Condition Monitoring

veeresh nayak ·
Please anyone reply for this query and I have the temperature problem in our cement mill(VRM) separator bottom bearing
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Re: Cement Plant Air Separator Bottom bearing Condition Monitoring

Dave Reynolds ·
Please help us understand your needs? Slow speed application, what are you trying to find out, failing bearing? The below link is to an ultrasonic sensor permanently mounted listening for changes in friction/rubbing/lubrication that you can tie into a DCS control system. The attached document talks about a wireless sensor that sends information to the cloud, either system would identify changes in bearings. http://www.uesystems.com/produ...ote-monitoring/4cast
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Re: Cement Plant Air Separator Bottom bearing Condition Monitoring

veeresh nayak ·
We have SKS separator rotor shaft bottom bearing temperature issue, Spectrum showing good health of bearing ( 2.7mm/sec max vibration & 0.3G-s peakvue), What we needs to do?
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Re: Cement Plant Air Separator Bottom bearing Condition Monitoring

Walt Strong ·
Veeresh, Perhaps you can include more information about the machine (cut-away drawing and nameplate data). What is the temperature, where is it measured, what is temperature change/trend, has there been a load change on the bearing, does bearing have a history of premature failure?? If I said my car engine has a temperature issue, then what would you say? Walt
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Re: Raw Mill Bag House Fan Vibration Critical Issue

CM Inspector ·
Dear Rizwan , This is common in cement industries,Particularly in Preheater Fans due to high sulphur content and various other Process parameters. But in case of Raw mill Bag house it is the question of effectiveness of the fabric filters, first course of action would be through checking of the filter bags.second would be asking your process people to measure the dust loading and flow measurements to know whether any change happened. if both are ruled out , then if coating is the real issue...
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Re: Best units for display of orbit plots?

John from PA ·
Was the question purposely intended to be limiting to casing measurements?
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Re: Best units for display of orbit plots?

Ralph Stewart ·
Yes they were John. Sorry about that.
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Re: Best units for display of orbit plots?

mirook ·
i think the first two will have same result, either can be used.
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Re: Best units for display of orbit plots?

Shurafa ·
Orbit is basically two waveforms combined. My first choice is to go with what makes the best analysis with the waveform. If, for example I'm concerned with a structural problem (usually a relatively low frequency range), I would use the displacement to analyze the waveform. So would I do for the orbit. Another point to consider is that physical interpretation for a displacement orbit is much more intuitive compared to velocity or acceleration, for most analysts (for sure including myself).
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Re: Best units for display of orbit plots?

John from PA ·
Ali M. Al-Shurafa sums it up nicely but I would like to add that caution should be used in the interpretation of data that involves signal integration. In my experience usually a single stage of integration, say velocity to displacement, can readily be accomplished. But when two stages of integration are needed, i. e., acceleration to displacement, problems can occur.
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Re: Best units for display of orbit plots?

dominich.vo ·
Hi Ralph , I had had a same question with you, but until now can not find the answer. Could I discuss together on this topic ? I see in some general guidelines about vibration monitoring for machine, Choosing unit to monitor depends on speed of machine such as: - with machine below 600 RPM : displacement is more preferable - with machine over 600 RPM : velocity and acceleration However, in the reality, with sleeve bearing in generator (rotating speed = 3000 RPM) , the raw unit is...
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Re: Best units for display of orbit plots?

Steve Ciesla ·
Ralph, I kinda hate answering a question with a question, but what do you (or whomever asked you the question) intend to do with casing orbit plots? Are you trying to infer the rotor movement from the casing measurements? If so, what you see from the casing may or may not reflect what is going on with the rotor. There's been plenty of discussions about shaft relative, seismic, and absolute measurements (including shaft sticks) on the board over the years. Many times we read about the seismic...
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Re: Best units for display of orbit plots?

Ralph Stewart ·
Thanks for the replies. I thought I replied back saying this is question is concerning a large shaker screen, but I do not see it posted. Maybe I never didn't "post it". I know I typed it up though. I am inclined to think that the "casing" readings (only thing able to get since the design is as it is) on the machine would be better if displayed in displacement to give the actual "path" the screen is moving. Seems like acceleration would be nothing but a jumbled up mess unless taken with tach...
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Re: Best units for display of orbit plots?

Walt Strong ·
Hi Ralph, I found this type of measurement to be very challenging on a large shaker-type conveyor. I did integrate the accelerometer output to displacement, but as I recall, there were signal overload issues to contend with. The displacement orbit can be a useful indicator of shaker performance and mechanical condition such as looseness and structural failure. I suggest making some measurements directly in acceleration and calculating the displacement level to compare to your measured...
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Re: Best units for display of orbit plots?

Shurafa ·
Based on my limited experience, there exist some systems allowing integration. Fewer allow differentiation. The online permanently mounted systems have less flexibility in changing measures. I always thought that the function should be available for advanced users as there could be cases with special analysis. With respect to the shaft relative measurement, I think the default should be displacement. This recommendation is based the physics of the clearance (shaft to bearing) and shaft...
Topic

Raw Mill Bag House Fan Vibration Critical Issue

Garry Kristen ·
Hi there, I would like to share the vibration trend of our Raw mill Bag House Fan. the fan has been running with abnormal vibration from 4.5 to 7 mm/sec on Horizontal point NDE bearing HH for last 6 months. the main problem is coating and fine dust that is coming from the bag house chambers due to worn and useless bags. this coating build up on fan impeller rapidly and results the fan is unbalance twice in a week. Then we have to stop the fan for a hour and clean the coating by air pressure...
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Raw Vertical Mill

Hossam 2 ·
Dear Experts i face a problem at a raw vertical mill MAAG Gear model WPU (forcing frequencies are attached at the file) Gearbox type : Epicyclic gearbox problem existence is only on load when the rollers at the grinding table , a unique ferquency shows and its amplitudes fluactuates reaching the alarm level and the shutdown level ,this frequency has a broadband energy and such frequency dosent related to the forcing frequencies at all at the attached file. thanks for help
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Re: clarification Required On CSI instrument.

Bill Kilbey ·
Ashis, Where are the specs. from 1-3 above coming from? Do you have the document? Which CSI instrument? 1. not sure what 7 avg./sec means? The CSI instruments can sample at 100/200 KHz depending on which one you have. The lines of resolution on 2120 was 16400 maximum and the 2130 12,800 in route mode. The time for one average is lines/fmax in hertz, so the time one for average may vary. 2. waveform size 32 KB? Depends on the setting above. 3. some reading for you ...
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Re: clarification Required On CSI instrument.

Vibration_guy ·
yes have the document. CSI 2130 has these specs. help me with the calculation of wave form size. E.g. 1000 hz with 1600 Lines. what will be the wave form size.? And how to calculate the noise floor? What is the resistance in that formula. is it of the Instrument or ant thing else? Noise floor -resistance Please refer Page 7 and 8 in the attached document. Thanks.
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Re: Raw Vertical Mill

John from PA ·
Can you attach the document.txt file as a pdf? I can’t open your document.txt file but no issues with the pdf.
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Re: Raw Vertical Mill

Walt Strong ·
I think I will wait for John to translate the MAAG/SKF bearing data, and for the OP to provide vibration data! Walt
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Re: Raw Vertical Mill

John from PA ·
Easy job Walt, page 2 of the pdf is in English!
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Re: Raw Vertical Mill

Walt Strong ·
Thanks John for correcting my "senior moment". Now, do you have the vibration data? Walt
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Re: Raw Vertical Mill

John from PA ·
Nothing in that file "document.txt" so until we hear from the OP we would only be guessing. It being a weekend, I'd still be guessing.
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Re: Raw Vertical Mill

Hossam 2 ·
Here the file as a pdf ,thanks in advance
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Re: Raw Vertical Mill

John from PA ·
How about giving us a clue as to what that unique frequency might be?
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Re: Raw Vertical Mill

Hossam 2 ·
this unique frequency is load dependent frequency ,, as the grinding rollers are in load position this frequency shows and fluctuates ,, by the time the grinding rollers are in the upper position (no load) this frequency disappear. i have doubts also in the concrete or the soil under the whole structure ,beaneath the concrete. Hossam
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Re: Raw Vertical Mill

John from PA ·
Give us a number!
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Re: Raw Vertical Mill

Hossam 2 ·
Re: Raw Vertical Mill
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Re: Raw Vertical Mill

John from PA ·
By number, I was referring to something like 16.5 Hz, your bevel pinion speed. None of your plots are labeled as to loaded or unloaded. Please attach the plot that shows what you are talking about. To minimize confusion, attach ONLY that plot, none of the other plots.
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Re: Raw Vertical Mill

aziz58 ·
hi hossam does your soil composition and aggregation is same to another plants? and how about mass and speed of soil in input mill? are the same to another
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Re: Raw Vertical Mill

Hossam 2 ·
I didn't attach any plots on NO Load condition all of them loaded condition. Input speed 998 cpm /16.5 hz I didn't mentioned numbers as it was in the attached file. Sorry for misunderstanding by me
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Re: Raw Vertical Mill

Hossam 2 ·
Re: Raw Vertical Mill
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Re: Raw Vertical Mill

John from PA ·
What is the frequency (in Hz) that you are concerned about? Is it the 998 cpm/16.5? Is it some other frequency?
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Re: Raw Vertical Mill

Hossam 2 ·
Another frequency it's almost 680 cpm or 11. 3 hz Thanks
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Re: Raw Vertical Mill

John from PA ·
I don't see anything of concern at those specific frequencies of 990 cpm and 680 cpm. Your warning, if I interpret the plots correctly is at 6 mm/sec and these frequencies are well under 3 mm/sec. What exactly is your concern? By the way, to look at a machine presentating data like you've shown, I would not have a plot out to 60000 cpm. This makes your 1X bevel input appear in the far left portion of the plot, less than 2% of the plot scale.
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Re: Raw Vertical Mill

Hossam 2 ·
Re: Raw Vertical Mill
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Re: Raw Vertical Mill

John from PA ·
what has been the behavior over time of this machine? Is this a new problem, a problem that perhaps had never been observed in the past, or one that occured after some form of mechanical maintenance? On scaling, these are just guidelines. What you look at should be based on the type of machine. In general for a gearbox look out to about 2X+ of mesh. Some people recommend 3X+ of mesh. That would mean for this instance look out to about 600 Hz (36000 cpm) or 850 Hz to about 900 Hz. This would...
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Re: Raw Vertical Mill

Hossam 2 ·
Re: Raw Vertical Mill
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Re: Raw Vertical Mill

John from PA ·
Re: Raw Vertical Mill
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Re: Raw Vertical Mill

Walt Strong ·
" this unique frequency is load dependent frequency ,, as the grinding rollers are in load position this frequency shows and fluctuates ,, by the time the grinding rollers are in the upper position (no load) this frequency disappear. " Have you determined the rotational frequency of the mill's balls/rollers and table? I have worked on a coal pulverizer, and saw two frequencies that were very dominant: roll speed and table segment frequency (#segments x table speed and at x #rollers). The...
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Re: Raw Vertical Mill

Hossam 2 ·
11.38 hz(678 cpm) and its harmonic 22.76 hz (1365 cpm ) thanks
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Re: Raw Vertical Mill

Hossam 2 ·
Re: Raw Vertical Mill
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Re: Raw Vertical Mill

Walt Strong ·
What is the roll speed? From geometry the roll speed can be estimated by the ratio of table diameter (at point of roll contact) to roll diameter times table speed. I assume roll diameter is less than table rotation speed, so rolls would have a higher speed. The table segments are the number of removable wear plates attached to the table. For example, if there were 4 plates/segments, then the 4x table speed may produce vibrations. Similarly the 4 plates/segments passing 3 rolls would produce...
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Re: Raw Vertical Mill

Akhil Rathore ·
I think you need to post a high resolution spectrum which is recorded when the vibrations are high. Also please mark which frequency you are concerned about.
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Re: Raw Vertical Mill

Hossam 2 ·
please check both attachments tilting pads at one them and the other one is the gearbox section showing its internal components ,, i think you mean the tilting pads here by word segments am i right ?
 
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