Tagged With "Frequency"

Topic

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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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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400HP Vert. Pump Motor Slow Beat Frequency

ThomasAH ·
We have 5 identical pumps running side by side all at the same speed, and I know what you're going to say... "Their vibration frequencies are modulating each other!" Unfortunately I don't think that's case (but I could still be wrong). We've only noticed on one of the motors that there is this relatively long beat frequency. See attached. Bearing faults aren't lining up, rotor bar and stator slot frequencies aren't lining up either. The motor is a 400HP, GE L5011VP, 460Volts, 1180 RPM. It is...
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An motor abnormal sound (power frequency 50hz) and vibration fluctuation with the dominant vibration frequency of 100 Hz

Vastocean ·
Hi guys, We are having an issue with a centrifugal pump which needs your advice. The motor has an abnormal sound, the vibration of both motor and pump are fluctuating from 4.6 to 5.7 mm/; the dominant vibration frequency is 100 Hz and the strange frequency range of 2800 to 3500 Hz appears. The brief information of equipment as follows: In May 2016, the vibration increased at both the motor and pump from 3 mm/s to around 6 mm/s and fluctuated from 5.3 to 6 mm/s, the dominant frequency at 100...
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An unknown frequency observed at Gearbox

sany ·
Hi, This is equipment of Steel Industry from Bar Rod Mill unit. Equipment is Mill Stand, Which is having reducer gear. The Input shaft have 24teeth and mating gear has 63teeth. Intermediate having 19,66 teeth and output shaft having 31,31teeth. I didnt have any problem with vibration whenever the higher dia bar is rolled vibration will be 4.0mm/sec peak and during lesser dia bar rolled it will 2.5mm/sec peak. The spectrum is showing a high amplitude dominant peak of 73.1orders of input speed...
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Are the vibration values correct?

jorgeluis-2000 ·
An axis that rotates at 10 RPM (0.16 Hertz) has been monitored with the SKF CMSS 2200 sensor; when looking at the Typical Frequency Response chart it is observed that 0.16 Hertz falls outside the minimum range (0.70 Hertz) of the curve, so my query is: is this transducer not valid for the velocity mode ?, if so, then the values of vibration obtained with this transducer are not correct ?.
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Aproximated bearing fault frequency calculation

Ander ·
Hi guys has someone information about the effectiveness of bearing fault frequency calculation. And the formula to calculate it. I am using the one provided by csi and Charlotte. I am trying to find out the frequency of morgan ntm mill. Thanks.
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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 Frequencies and Running Speed

Nitheesh ·
Hello, Most vibration analysis software have bearing defect frequency markers build into them, where you select the bearing and the fault frequencies are automatically matched. I also see that many software have these defect frequencies in Hz and Not Orders. (Eg: SKF NU 216 Bearing have 2.75 Hz as FTF, 22.9 Hz as FTF Also). And it appears to be a constant. So is bearing defects not related to running speeds? (Eg. NU 216 Bearing can be running at different speeds in different machines).
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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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Bearing fault frequencies for Bosch Rexroth A2V500 Hydraulic pump

BLPayton ·
I have three of the hydraulic pumps listed in the attachment. (Rexroth A2V500HDLOR 5GPK/79) The pump is made in Uchida Japan. Part numbers 1100132855 (ball bearing for main drive shaft); 1303021918 (roller bearing for main drive shaft) & 1606049689 (roller bearing for swivel housing) I am having trouble getting the OEM numbers above translated into a bearing number that I can get fault frequencies for. In my motor circuit analysis Demod spectrum I am seeing non-synchronous peaks on two...
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1X AC line frequency excitation in Motor

The Maniac ·
A centrifugal fan 168 kW, 1480 RPM Overhung with Flexible pin bush coupling was running normal with vibration max 3 mm/s since 4 years. There was a sudden increase in vibration at 2x RPM frequency up to 8 mm/s inin coupled condition at motor NDE side Horizontal and fan NDE vibration observed max 3.6 mm/s with minor looseness symptoms . Motor Solo run was taken and observed with 1x Line frequency(49.97 Hz) observed dominant in spectrum with vibration observed up to 3.4 mm/s in motor NDE...
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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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Bearing VIbration Frequency Database

smartini ·
The Bearing Expert remains the largest single sourced bearing database. Over 800,000 discreet bearing part numbers with dimensions and related bearing frequencies for over 100 manufacturers worldwide. Used in over 60% of largest industrial manufacturers, as the data source for diagnostic and condition monitoring companies, by industry consultants and bearing manufacturers and distributors. Need bearing data for your analysis visit www.sourceindex.com smartini@sourceindex.com
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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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Change in UvDB when Settings in Frequency converter are changed.

Gisli A. Gudm ·
Hi. I am looking for answers or hints why there is such change in Uv when swithching frequency is changed. I was using SDT270 ( Ultrasound ) Please review the spectrum and waveform soundfile Look forward to hear some brainstorming. All best Gisli
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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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coherence measurement

aziz58 ·
dear all some vibration analyzers have coherence parameter . i want to know , can h use this measurement when i have some unknown frequency on machine or other related part to find relation of those frequency with rotational frequency . how can help me this parameter for vibration diagnosis? pls share your experience best regars
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Re: Aproximated bearing fault frequency calculation

rgf12 ·
Do you know the type of bearing and the designation? I have found that the CSI library calculations are close enough for diagnosis as most, if not all bearing faults are non-synchronous. For example if I know the bearing in question is a 6300 series I know to look at area in the signature form 3.3x to around 7.5x for ball pass frequency spikes. Where it gets tricky is when you have a calculated frequency or a multiple that is close to a running speed harmonic. I have a few that fall at 121...
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Re: Aproximated bearing fault frequency calculation

Dave Reynolds ·
2 cents, in your csi bearing dbase, enter a common bearing number like 6313, do not include a manufacturer, and display the frequencies. What you should see is a complete list in the csi dbase of 6313 bearings from all OEM's. If you look at all the bsf, ftf, bpfo, bpfi between all the brg OEM's you can clearly see a common pattern. bpfo is typically 3-5x TS, bpfi is typically 5-8x TS, ftf/cage is .4x TS, bsf is just above 2x TS. As always there are outliers that have a different number of...
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Re: Aproximated bearing fault frequency calculation

Howard Penrose ·
Ander The bearing frequencies associated with failure are normally calculated based upon the geometry of the bearing. As in previous responses, these values tend to be close per bearing size as a direct result of the standards associated with bearing sizes (Ref. ABFMA). Bearing fault tables will include the 1X RPM frequencies associated with the inner race, outer race, cage and balls. You are, in effect, looking for those frequencies, especially in the later stages of failure. These are...
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Re: Examples Of High frequency vibrations?

Dave Reynolds ·
Your request is not something that most people are involved with....most machinery vibrations occur way below 6khz, the range you are requesting belongs in the "ultrasonic" range, typically ultrasonic equipment measures this frequency range. http://www.uesystems.com/resources https://www.maintenance.org/top...ed-us-training-class Dave
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Re: Examples Of High frequency vibrations?

Vibration_guy ·
But sir, If no vibration generates with such high frequency then why the Instrument Manufactures gives instruments with frequency ranges upto 40 khz, 80 khz(for vibration). Are they fooling US?.
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Re: Examples Of High frequency vibrations?

Dave Reynolds ·
Ultrasonic evaluation in the 20-100khz range, is used for air leak surveys, steam traps, lubrication, bearings etc. Your statement "instrument manufacturer" encompasses millions of pieces of test equipment. Some people maybe using an instrument/data collector to identify frequencies in this range, but there would be a very small number of people doing this. Example, jet engine turning 26,000 rpm with 200 individual blades on one rotor, 26kX200/60=86,666hz/86khz or 5,200,000 cpm No one is...
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Re: Line Frequency 50 HZ

Ralph Stewart ·
One of your spectrum notes says "0" RPM. Is this correct? Even when not running it has a 50 Hz Peak in it? Sounds like the VFD Rectifiers (if that is the type system you are using) are somehow "Leaking" Line Frequency through into the motor. I saw this some 30 years ago but do not remember exactly what was wrong, but the electrician fixed it rather quickly. If it is there when not running, there is something really bad wrong.
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Re: Line Frequency 50 HZ

ALI HAIDERR ·
You are right,when motor started vibration goes very high even 0 RPM.It may trip afer 20 or 3 seconds.
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Re: Line Frequency 50 HZ

OLI ·
If you have a motor that normally is fed by a DC supply by a exciter or being a DC motor and your rectifier system fail and resulting in that you feed AC instead it will end giving LF related vibrations and if that is on even when the motor is not running/rotating it will vibrate with LF related frequency. I have once had that, vibrating when not running/rotating until excitation turns off, slightly freeky. Olov
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Re: Electric Motor Bearing Grease - quantity and frequency

Planty ·
Hi There, Depending on the calculation used the returned "interval" may be the L10 or L1 life of the grease. This means by going longer than the calculated relive interval, there is a 10% or 1% chance the grease will fail. There are a lot of other factors at play here, and some calculators have a bit more fat built in, i.e some will give an interval of 1/3rd the "grease life". Grease thickener will have an impact also. Most relube calculators will assume a basic lithium soap/mineral oil but...
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Re: Atlas copco compressor concerning vibration values

DBTCMP ·
These type of compressors are always running like this, I monitor a few and yours look no different by terms of amplitude from this, the levels are high compared to say a fan but you guys really need to stop living by ISO tables, adjust alarming according to the past trends and then worry if something starts to increase noticeably. I use ISO for first 3-4 readings til I get a good trend then adjust alarms thereafter, use envelope or band alarms where possible.
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Frame structure natural frequency

aziz58 ·
Dear all I am looking for safety margin of opearating frequency of machin compare to natural frequency of its frame structure ? As you know we have been many exciting frequency in machin such as gear mesh, blade pass ,.. Which of should be consider for frame structure design ?all of them or only operating frequency Best regards
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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 for cardan shaft failures?

Alvin MC ·
Anybody here familiar with defect frequencies for cardan/Universal joint? Thanks
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Re: coherence measurement

Gary Stacey ·
Coherence is an averaged function looking at the relationship between an input and an output and is used to verify how much the output is related to the input. generally used in frequency transfer functions, impact tests and similar and gives you an idea of the validity of your data. Gary
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Re: coherence measurement

aziz58 ·
thanks sir for example , i see high vibration on slid of pump rather than body of pump. can i put out put channel on skid and input channel on body of pump to realize how much of vibration on skid related to body vibration? best regards
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Re: coherence measurement

ivibr8 ·
Sure, you can do a transfer function of slid (did you mean skid?) compared to pump housing. Coherence is a measure of causality between input and output. Let's say you measure the COH = ~1 between the ?skid? and pump. In this case, the relationship between the two are the same but not sure what useful information that gives me or whether it helps me figure out the problem. As Gary stated, it is used primarily in impact/modal testing to provide confidence in the cause/effect (e.g. impact to...
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Re: coherence measurement

Dave Reynolds ·
http://www.calpoly.edu/~cbirds...ng%20%20Analysis.pdf Top of page 11 Think of it this way, you are comparing two signals and you want to know if the frequency on sensor A is the same as sensor B. IF the frequency is the same coming into both sensors then there should be a coherence value of .95-1.0.....IF the frequency is not the same then coherence could be from .6 to 0..... An indication of a natural frequency in an FRF plot would be a peak present at a given frequency, and at that...
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Re: coherence measurement

aziz58 ·
thanks dear dave for useful information
Topic

Frequency of rotation for installed spare equipment

DHarberts ·
We have several instances in our facility where we have an "installed spare". I believe it would be a best practice to rotate them into operation on some frequency. I would imagine that the frequency would vary depending on the equipment and process but I am struggling to convince the operations group to begin this practice. What are the current practices through out industry and what is everyone's experience with this?
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Frequency Reponse of Bently Nevada 3300 XL Probe

FSX ·
Dear Experts Can some one help me understand attached frequency response curve of Bently Nevada 3300 XL 8mm dia probe I have come across frequency response curves of certain accelerometers which show sensitivity on Y axis and frequency on X-axis. Near resonance frequency there is sharp rise in sensitivity. However the curve given in Bently Nevada 3300 XL 8 mm dia probe shows magnitude in db on Y-axis and frequency on X-axis. I am not understanding what this "db" refers to ? May be noise ? If...
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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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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: Unknown Frequency in Planetary Gearbox

rgf12 ·
Is the peak at 1.7 of GMF? If so that has been known as a "ghost frequency" that Taylor and others attribute to the gear cutting machine. I've only encountered it once. The increase of amplitude is concerning. I would contact the GB manufacturer. Just a guess on my part.
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
What software generated the frequencies? And are you certain the 1st stage is a planetary arrangement (fixed ring or annulus)? The reason I ask is in a planetary arrangement, and for equally spaced planets, the number of teeth in the ring gear (R) is equal to the number of teeth in the sun gear (S) plus twice the number of teeth in the planet gears (P). So R = 2 * P + S. For the 1st stage S = 25 R = 308 P = 141 but 308 ≠ 2 * 141 + 25. It is 307. That would mean you do not have equally spaced...
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
This comment makes it seem like "ghost frequency" will be at 1.7X. This is not the case, although it might be the case for a very specific example in Taylor's book. I suggest you read https://www.bksv.com/media/doc/233-80.pdf , specifically pages 10 & 11.
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Re: Unknown Frequency in Planetary Gearbox

jvaugha1 ·
Thanks for your response. We use CSI 2140 and the Citrix machinery health manager software. I am sure it is a planetary gear with three planets in the first stage and three in the second. The frequencies I provided came from the manufacturer. Since I have been doing this for the last year I was told that the 23 in the order was the pinion but the information given to us from the manufacturer says 25 teeth. Have you ever experienced a difference like this in this style of gearboxes. As far as...
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
if the tooth counts came from the OEM, then likely they are correct. You will note that when I said R = 2 * P + S I clarified that with the statement "for equally" planets. Let me amplify on that just a bit and state "For evenly spaced planets that are engaging the next tooth at the same time, then both the number of sun teeth and ring gear teeth have to be evenly divisible by the number of planets. Since the sun tooth count is 25 (or even 23) and the ring tooth count is 308, then it can't...
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Re: Unknown Frequency in Planetary Gearbox

ADiN ·
The gearbox arrangement is parallel shaft – planetary – planetary. For planetary stages, fixed ring gears and rotating carriers are used. Number of teeth as below: İNPUT : 1487 rpm Input state – 61/26 Medium stage – 23/62/148 Output stage – 38/49/137 recaicev@gmail.com
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Re: Unknown Frequency in Planetary Gearbox

John from PA ·
"ADIN", are you referring to the same gearbox that the OP "jvaugha" was referring to?
 
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