Tagged With "Frequency"

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Atlas copco compressor concerning vibration values

Hossam 2 ·
Hello All  my case is an atlas copco compressor GA132w-10 fitted with 3000 RPm Motor ABB  number of male element and female element is not known but i suspect something will show you in the spectrum  ths the sharp frequency is 6XTS i think its related to blade pass frequency the the time diffrence between the impacts in the waveform =0.003418 second  so related to frequency =(1/0.003418)hz=17554.12 cpm if we check which order is this frequency we found that 17554.12/3000...
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Acceptable bearing frequencies

tcvib ·
All, Have a question for the group.  How much vibration, at bearing frequencies, is acceptable in a reconditioned motor?  Have a reconditioned motor  that is indicating loooow (.004 in/sec Pk)amplitude vibration at inner race bearing...
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Bearing Defect Frequencies

Rennie Cachia ·
Hello, Does anyone has the bearing defect frequencies for a UC206 bearing please? This self aligning bearing mounts into a P206 pillow block. Thank you.
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Bearing Defect Frequency

Avinash Thawani ·
Hi, I have the following bearing details, kindly advise me what is the rolling defect frequency. I am running the speed at 19Hz. Hertz CPM Orders Shaft speed frequency 50.000 Hz Inner race defect frequency (BPFI) 247.501 Hz Outer race defect frequency (BPFO) 152.499 Hz Cage defect frequency (FTF) 30.938 Hz Ball spin frequency (BSF) 99.323 Hz Rolling element defect frequency 198.645 Hz
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Belt driven fan high vibration

Ahmed Gomaa ·
Hi all, Could you please help me with this high vibration belt driven fan, where high predominant 1.59 X Motor speed (2363 CPM) @ 14 mm/s, with 1X Motor speed @ 6mm/s in Horizontal (Belt tension direction) and axial DE & NDE. Motor speed: 1485 Speed ratio: 6 Fan speed: 247.5 Motor Pulley diameter: 142.6 mm Fan pulley diameter: 855.6 mm Center distance: 1082 mm Belt length: 3850mm Calculated belt RPM = 172.72 No of blades: 6 GE (enveloping) readings are very low These readings was taken...
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Belt Frequency

Motorman1969 ·
I know this topic has been done over and over on the forums, but i am asking a specific question.   Is it possible to have a 1/2 order of belt frequency?   What I have experienced on one center hung fan, operated via motor and pulley, is a...
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Electric Motor Bearing Grease - quantity and frequency

TroyS ·
I've calculated a whole bunch of grease quantities and ideal intervals for our electric motors in a plant environment.  To manage the work load we've fixed our routes to 60 days.  This is where my question comes in -  I'm not concerned about adjusting the grease quantity down when the calculation tells me to less often.  Example  - calculation tells me to add 100 grams of grease every 120 days and set our program at 50 grams every 60 days.  Where I get concerned...
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Frequency Bandwith

Avinash Thawani ·
Do you think market is large for sensors with 2kHz band width?
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Frequency vs. Plunger force belt tensioning

dgeesaman ·
We are an OEM who build a product with a synchronous power transmission belt.  We use plunger force tools or even thumb pressure to set belts but those don't give a "value" to be recorded on checksheets.   We tried a Gates 308-C Sonic...
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High vibration in vacuum pump

ANNEVIB ·
Hi all! I am experiencing high vibration problem with a condensor vacuum pump in a 500 MW coal fired plant. The vane pass frequency is appearing in spectrum. There are two vacuum pumps out of which only one is kept in service. The same problem...
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high vibration on a centrifugal fan loosed bearing

alainraad ·
how can i change the natural frequencies of a centrifugal fan other then adding weights?
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Gearmesh Frequency Question

P. Hine ·
This is a Centac Air compressor( Mod 2CV25M3E) driven by a 600 HP motor. Any guesses as to what the gear mesh frequency might be? Reading was taken with a 10mV high frequency accelerometer at 12800 lines resolution. I am still trying to find some info...
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HIGH VIBRATION AT GEAR MESH FREQUENCY

dominich.vo ·
Hi all, please help me to diagnose one case about gearbox system. The system has been described in detail on attachment. The spectrum indicate high vibration at Gear mesh freq. (GMF) with harmonics and sideband of rotating speed. Base on spectrum data...
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High Frequency Haystack - is this lack of lubrication

MarkSl ·
Hi I collected data from a 2 week old vertical mixer which is noisy and sounds like a dry bearing. The motor uses sealed bearings so they cannot be lubricated. The high frequency vibration data shows a haystack between 2KHz and 2.5Khz primarily...
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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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natural frequency

alainraad ·
how to change a centrifugal fan natural frequency without adding weights
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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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Re: Belt Frequency

MarkSl ·
Have you removed the belt guard and inspected the belts for damage , pay attention to the join where the ends of the belt meet sometimes this join is not level. Also look at the pulleys for wear, are the belts running on the side of the pulley or the bottom. Check rims speed of the pulleys if this is too high it can cause vibration. Check belt tension, remember to tension on the slackest belt
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Re: Belt Frequency

George Williams ·
Agree, there must be damage on the belt. The half order is caused by a vibration which occurs each time the belt is passing over one of the sheaves which is two impacts per belt rotation.
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Re: Belt Frequency

Steve Ciesla ·
Originally Posted by George Williams: Agree, there must be damage on the belt. The half order is caused by a vibration which occurs each time the belt is passing over one of the sheaves which is two impacts per belt rotation. That would be 2xBF. A 0.5xBF indicates an impact every 2 revolutions of the belt. I'm not sure what would cause that or a 1.5xBF.
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Re: Belt Frequency

George Williams ·
yea, sorry. Monday and quick reply.
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Re: Belt Frequency

grady ·
Are either of the sheaves adjustable? Adjustable sheaves tend to have uneven grooves causing the belts to rise and fall which causes a signature similar to that which you have posted.
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Re: Belt Frequency

John from PA ·
The content at http://reliabilityweb.com/inde...rticles/belt_faults/ might be worth reading.
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Re: Frequency vs. Plunger force belt tensioning

John from PA ·
I have seen a system made by Carlisle used in some refineries. Go to http://www.c-rproducts.com/dow...nstruction_sheet.pdf for the details. Be forewarned, it is much larger and more expensive than methods that directly measure belt deflection vs. force. In addition, some parameters are needed for the specific belt and calculations are then completed.
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Re: Frequency vs. Plunger force belt tensioning

dgeesaman ·
Thanks, this appears to be an optical device. You're right, it's much larger and more costly than a pencil-plunger type of tool. But it's still quite portable. We have been specifying tension settings on these machines for a few years now and always include the calculated frequency. So that's completely known for us and our customers.
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Re: Frequency vs. Plunger force belt tensioning

John from PA ·
Perhaps your people have smartphones with them? http://www.contitech.de/pages/...2_ind/presse_en.html
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Re: Frequency vs. Plunger force belt tensioning

Daniel Clancey ·
Goodyear has 2 products: T e n s ion R i t e ® S t r i ps Designed specifically for use with our single and banded V-belts, TensionRite is a plastic strip that adheres to belts during installation. Simply check the correct tension setting listed on the back of the TensionRite card and tighten the belt. The gauge window will indicate when the desired setting has been reached. Also there is a laser TensionRite ® Belt Frequency Meter which calculates belt tension by measuring span vibrations.
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Re: Frequency vs. Plunger force belt tensioning

Walt Strong ·
There are three types of sensors for use with the "sonic" belt natural frequency method; microphone, accelerometer/contact, and optical. I have used an accelerometer and microphone with my vibration analyzer (CSI 2120) and prefer the microphone. I consider it a very accurate method (especially compared to spring gauge) and easy to use even in tight places. I also use a noise-cancelling microphone and have measured change in belt frequencies (slack and tight spans) during machine operation.
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Re: Frequency vs. Plunger force belt tensioning

dgeesaman ·
Any idea why our demo suggested that the Gates sonic meter was not repeatable or accurate?
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Re: Frequency vs. Plunger force belt tensioning

Walt Strong ·
I've never used the Gates sonic meter, and you are not given any details as to how you are using it. If the meter is not giving repeatable tension values, then either the meter is not functioning properly or you are not using it correctly. Some things that can affect repeatability include: high background sound or vibrations poor alignment of pulleys or sheaves loose sheave on shaft or loose machine base bolts belt is either very loose or very tight Measurement accuracy is another matter. If...
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Re: Frequency vs. Plunger force belt tensioning

dgeesaman ·
So I got my hands on the Gates Sonic meter. I could not discuss the difficulties with it until I saw/tried it myself. Turns out I agree - it does not work well for us. 1) It seems to take very little background noise to throw it off. I was in the shop 10 min before the end of shift - no machines running - no forklifts moving, etc - and the readout was constantly showing a number. I couldn't tell which number was the belt and which number was background sound. 2) The belt I was checking is...
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Re: Frequency vs. Plunger force belt tensioning

Walt Strong ·
I was referring to the force-deflection spring gage as "reference" as less accurate. Walt
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Re: Belt Frequency

Motorman1969 ·
Update::: Customer replaced worn pulleys and installed matched belts. They said they found the grooves of one pulley worn eccentrically.
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Re: Belt Frequency

Robert U. ·
Thanks for the update.
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Re: high vibration on a centrifugal fan loosed bearing

MarkSl ·
What about vibration isolators or spring mounts?
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Re: high vibration on a centrifugal fan loosed bearing

Dave Reynolds ·
Your question is very broad, what data do you have to support their is a natural frequency issue? What type/design is your fan What part of the fan has the natural frequency issue? Shaft Fan wheel Fan base Fan housing/inlet cone Supporting structure To shift a natural frequency you need to know which frequency you are moving, adding mass will lower the natural frequency, adding stiffness in the right locations will raise it. Other fixes are to change the operating speed or add...
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Re: Atlas copco compressor concerning vibration values

Hossam 2 ·
MEASUREMENT POINT OVERALL LEVEL ----------------- ------------- 741.CP114 - Compressor # 5 (05-Jan-16) OVERALL LEVEL M1H 2.463 mm/Sec M1P 1.980 G-s M1V 3.871 mm/Sec M1A 3.530 mm/Sec M2H 2.111 mm/Sec M2P .893 G-s M2V 5.044 mm/Sec M2A 4.309 mm/Sec C1H 3.863 mm/Sec C1P .251 G-s C1V 3.834 mm/Sec C1A 4.898 mm/Sec C2H 7.221 mm/Sec C2P .117 G-s C2V 7.263 mm/Sec C2A 8.093 mm/Sec
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Re: Atlas copco compressor concerning vibration values

Dave Reynolds ·
One reading at one location is difficult to asses a machines health. You do not state what is your symptom? Hi oil temp, poor performance, noise.... Your trend is stable on your one plot you posted, yes air compressors have vane pass/all of them, you have 32 g's pk=pk on your plot, has this value been stable or is it increasing overt time? Was the compressor loaded at the time you took data? Vane pass typically increases and decreases when the compressor is loaded or unloaded, dirty/plugged...
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Re: Atlas copco compressor concerning vibration values

Hossam 2 ·
thank you for your attention firstly the pk-pk value is stable for months 2)no complain came from this compressor but the vibration values was concerning comparing to the other compressors as the values is way smaller than this one 3)the compressor measurements conducted while loading the compressor 4) the atlas copco used to performing their schedueled maintenance each period to change filters..etc. 5)C*p and M*P peakvue values yes and they are stable at the trend over 2 years
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Re: High Frequency Haystack - is this lack of lubrication

Gary Stacey ·
Could very well be lack of lubrication, Would be a good idea to check spectrum for non synch activity. Is demod data available and the bearing details known? If you can pick out any disctinct bearing fault frequencies then damage will have progressed. Lubrication however would stillslow deterioratio. How is the sensor mounted? Stud, magnet or stinger? If the latter then its expect a reduction as freqeuncy response tails off. I have generally found that peak accel resonance is around 3.5-4.5k...
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Re: High Frequency Haystack - is this lack of lubrication

MarkSl ·
Originally Posted by Gary Stacey: Could very well be lack of lubrication, Would be a good idea to check spectrum for non synch activity. Is demod data available and the bearing details known? If you can pick out any disctinct bearing fault frequencies then damage will have progressed. Lubrication however would stillslow deterioratio. How is the sensor mounted? Stud, magnet or stinger? If the latter then its expect a reduction as freqeuncy response tails off. I have generally found that peak...
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Re: High Frequency Haystack - is this lack of lubrication

Gary Stacey ·
Possible early stage bearing failure due to lack of lub. But if you cannot grease there is nothing you can do about it, just continue to monitor. Gary
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Re: High Frequency Haystack - is this lack of lubrication

IrishMark ·
Can you take a live reading of the spectra?
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Re: High Frequency Haystack - is this lack of lubrication

Edwin de B ·
I am afraid it is too late for grease here. Lack of lubrication shows more around 3 kHz. This 2 kHz is response of softer parts than bearing, like machine casing responding to random impacts inside the bearing. Will be bearing damage. But still early. Though I think you should plan a repair.
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Re: High Frequency Haystack - is this lack of lubrication

MarkSl ·
This was a one off test to determine the cause of the noise in a mixer which is only 2 weeks old and they wanted confirmation of a problem, as discussions with the O.E. hadn't gone well so far. I'm thinking about making a few minor changes to the VA setup and going back there and seeing if I can get a clearer explanation. I might also take the ultrasonic data collector and see what that indicates given the fault seems to be in it's early stages.
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Re: High Frequency Haystack - is this lack of lubrication

Ralph Stewart ·
The "haystack" appears to related to the 4th order of the first Gearmesh or the 5th order of the low speed Gearmesh The demod shows "nothing"? What filter setting was used? A setting of 2k to 4K might show something. The "noise" does not seem to be generating very much amplitude in the data (0.12 Gs), unless I am reading the scale wrong. Might be the "noise" is from a higher frequency than the data covers. The "haystack" appears like it might have output speed sidebands in it. Have you check...
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Re: Acceptable bearing frequencies

Danny Harvey ·
I will accept very low amplitudes of bpfo but bpfi with sidebands is pretty sketchy. What is the spacing of the sidebands?
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Re: Acceptable bearing frequencies

Vibe-Rater ·
Normally there wouldn't be noticeable fault frequencies but sometimes there are. From thereon I would be trending to see if there is any deterioration. If not then just keep running. if it is a VFD there might be some edm even shortly after install. I have a particular pump that has repeatedly shown 2x BSF from new bearings and I end up weighing the effort of changing it again against just monitoring it. The one currently in place has been going for more than 3 years. No change. I'm thinking...
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Re: Acceptable bearing frequencies

Dan Timberlake ·
May not be able to make a horse drink, but ..... 2:04 here <cite class="_Rm"> www.youtube.com/watch?v=28khv-BydeY </cite>
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Re: Acceptable bearing frequencies

tcvib ·
Sidebanding is at 1X TS. The motor prior to this one showed the same pattern at install. Over the past 9 months the frequencies were growing so we decided to pull it out. Put the new one in and we have identical pattern to what the old motor was showing at install. This motor is a DC motor. Attached a few spectrums.
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