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Tagged With "fan"

Topic

1/2X VANE PASS FRECUENCY

ConfMx ·
IN COOLING TOWER FAN, I FOUND FRECUENCY 3X OUTPUT SHAFT GEARBOX, HAVE 6 VANES FAN. ANY IDEA?
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Overhung fan

azizsuahid ·
Hi guys, happy weekend ") i need some help regarding one critical equipment in our plant. It's an Overhung Fan having high overall and ge. At lower frequency side of the spectrum, i can see running speed harmonics as well as of sub-harmonics of 1/3x , this has occurred after assembly and replacement in March 2016. During the balancing work in march, i found so many weights attached to the fan from previous balancing work, we ignored and continued with balancing(adding another weight) , and...
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1200 kW FD Fan Motor dominant peak 100 HZ

y@sh ·
Hello guys , Thank you so much helped me in my previous doubts 1200kw-996rpm-6 pole -BHEL Make Recently i faced some problem of FD FAN motor getting dominant frequency at 100 HZ and abnormal air flow sound observed from the motor. any one suggest me what are the possible defect in the Motor. 1.load condition Ok 2. foundation and structure is normal 3.There is no identification of high temperature According to my knowledge max Electrical defect 1.Pole pass frequency indicates Is there any...
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3x-8x Vibration Trend Abnormal

Vibration Analyst2811 ·
Dears, we need help in regard of the 3x-8x Vibration Trend Abnormal as shown in the attachment for some of rotating equipment this is example of fan there is also some vertical pump and horizontal pump have same issue one more question why the vibration fluctuating too much what the reason and consequences? thanks in advance
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Air Handler Unit High Fan Free End Vibration

Avinash Thawani ·
Air Handler Unit Vibration Issue The vibration readings on the fan free end of the Air Handler AH-15050 have been significantly higher than the baseline during the last 20 days. RMS Acceleration has increased by 100% Raised noise floor in acceleration spectrum for Fan Free End. The spectrum peaks indicates a VFD speed change from 26Hz to 30Hz(gradually). Due to this change we are observing an increase in Accel RMS vibration. Currently the speed of the Motor is 28Hz. In the velocity spectrum...
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Balancing duel rotor variable pitch axial fans

John.OGE ·
We are a coal fired power plant and one of our units has large duel rotor variable pitch axial fans for Induced Draft made by Westinghouse. Does anybody know balancing experts (SME) that are familiar with these kind of units?
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BOILER FORCED DRAFT FANS

chary tatta ·
Greetings Members, The FD Fans on a tanker vessel attached the vibration spectrum and the photos of the FD fans. Vibration on motor HVA is less than Vibration at fan foundation fitted on pads 3 nos on each side. Appreciate your feed back and suggestions for repairs. Kind regards Chary
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CT FAN MOTOR VIBRATION PROBLEM

Kishore kumar ·
Dear Members , We have a CT fan at our customer site with high Vibration Problem ,We dont have provision to take vibration data on CT Fan Gear Box ,we do take Vibration data on Motor .Please Verify the below attached data and General arrangement of the equipment and share your opinions. Motor 37 K.W and Bearings D.E 6313 ,N.D.E 6213 C3 clearance running at 1475 R.P.M .
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Crude Oil Boilers & AQCS

Y7 ·
Greetings,  2 crude oil boilers are used to generate steam and air quality control system AQCS is provided at end of each, the whole system is provided by Macci company. ID fans and FD fans are provided by Boldrochi. The fans encountered several...
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Cold alignment values in preheater fan to kiln

vishal sharma ·
Dear expert Can u suggest me what is the permissible radial alignment in preheater ID fan to kiln. As the temperature in the fan during running condition is almost 300 degree . Because three months before we have a call from the customer from cement plant they were facing high axial vibration in there fan.so we checked the fan vibration reading it's showing 3.6mm/s in radial but axial was 6.3mm/s .so now after three months they call us again because the customer is in shut down they call us...
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Cooling tower Fan catastrophic failure

Akhil Rathore ·
Hello everyone Has anyone experienced a breakdown of a cooling tower ID fan where the fan blades (FRP), the drive shaft (metal) are broken in to pieces. where the vibration was very less (monitored by MCT) and 150 Kw driving motor also having less vibration. see the attached pics
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Re: seal air fan (Radial Fan) Axial Vibration

Walt Strong ·
" that 7.6 orders matching with bearing outer race but after checking the bearing outer races are normal" You have outer race fault frequency with 1xSS sidebands (modulation), so it sure looks like an outer race fault! How did you or someone actually "check the outer race"? Most bearings require destructive disassembly (cut apart) to actually see the full bearing race surface. Don't get lost in a pile of data! Walt
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Re: seal air fan (Radial Fan) Axial Vibration

Shurafa ·
Were these spectra collected before after the "bearing checks"? Did you replace the bearings or you reinstalled them? It looks there is a bearing defect. Regards-Ali M. Al-Shurafa
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Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
Above spectrums are After checking the bearings and alignment and we find inner clearances but there is no outer race defect physically
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Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
We check the bearing clearances with feeler gauge inner and outer
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Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
We disassemble the both de and nde bearing and checked physically but there is no Outer race defect
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Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
bearing images
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Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
BEFORE ALIGNMENT
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Re: seal air fan (Radial Fan) Axial Vibration

electricpete ·
[quote] inner race clearances was 0.3 mm.[/quote] Can you explain more about this measurement? I hope it is not between bearing and shaft (that should not be clearance) What style bearing is it?
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Re: seal air fan (Radial Fan) Axial Vibration

montaser ·
I advice you to make mark using (correction pen) between the bearing outer race and lower part of housing and another mark between bearing inner race and shaft, and keep the fan running for some hours, then stop and inspect the marks position for the possibility of bearing rotation inside the housing.
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Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
Tnq for reply its not b/w shaft and bearing ,clearances are b/w balls and bearing inner ring.
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Re: seal air fan (Radial Fan) Axial Vibration

y@sh ·
thank you sir but it is a heavy equipment . so,it's impossible to open the machine at present conditions.
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Re: seal air fan (Radial Fan) Axial Vibration

Jim1 ·
Oil filled housing? Did you sample the oil? What caused the satin finish on the rollers and inner raceway?
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Re: seal air fan (Radial Fan) Axial Vibration

Walt Strong ·
Y@SH, I looked at your three photos. None of the photos show the surface of the outer race/ring that is in the contact path of the rollers. The bearing would have to be destructively taken apart to do so. Therefore your limited inspection does not prove or disprove an outer race defect. The only way to do that would be to remove the grease and cut the bearing rings apart. You can save that activity for a later date when you change the bearing. If you actually put in new bearing when those...
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Re: Repeated Static Unbalance problem in a 2.4 MW ID Fan

Dave Reynolds ·
What type of fan blades on the fan wheel? Had problem fan with similar issues years ago. Found the airfoil style fan blade had worn holes on the leading edge of the fan wheel, this allowed dirt/dust to buildup inside of each blade. This in turn caused repeated balancing of the fan about every 3-4 weeks. This fan was also center hung dual inlet fan turning 600 rpm with two 250 hp motor driving the fan. Another case history with an airfoil fan blade style, leaking economizer possibly your ESP,...
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Re: Repeated Static Unbalance problem in a 2.4 MW ID Fan

The Maniac ·
Mr. Dave, Thank you for expressing your earnest interest in responding me. The fan blades are fixed backward curved solid airfoil cross section,with two planes separated by a distance of 1.5 m. Regarding the impeller ash deposition, a small loose layer of ash dust observed and that too on the inner side which gets removed by itself when the fan is started in no-load. The Rotor is 16 Tonnes heavy and handles fly-ash and flue gas at 120-135 degree C.The amount of ash handled is quite high...
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Re: Repeated Static Unbalance problem in a 2.4 MW ID Fan

Dave Reynolds ·
How many fans of the 6 are having an issue? 2 fans per "unit" are there 3 units? Are the 2 fans with issues on the same unit? Are there more than the 2 fans with issues and are the symptoms the same? So if I read your post correctly...two previous balance jobs you had the same 120 degree when completed, vibes down to 1 mm/s. You added 5 kgs/11 lbs on one of your balance jobs, then another 15 kgs/33 lbs at the same location as previous balance job? With fan balanced to 1 mm/s the final phase...
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Re: Repeated Static Unbalance problem in a 2.4 MW ID Fan

The Maniac ·
Yes, i acknowledge ur query about the balancing details....there are 4 fans (2 fans per unit) are having the same problem with same symptoms(Getting unbalanced statically at different times), 2 other fans are running without any unbalance problem since commissioning time and running with Max 1 mm/s at any RPM.. In the fan which was balanced recently, the phase after welding remained Same... Ofcourse yes, I agree with u that there is some shift happening, but what could be a possible reason...
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Re: 1200 kW FD Fan Motor dominant peak 100 HZ

Beatnik ·
100 HZ is not pole pass frequency, it's 2 time line frequency. What you have is 2x LF with 1x RPM sidebands, it's not something very common. Look at the discussion on a similar case here: https://www.maintenance.org/top...nds-surrounding-2xlf
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Re: 1200 kW FD Fan Motor dominant peak 100 HZ

Dave Reynolds ·
Take a 200Hz 6400 line 2 avg 50% overlap velocity reading. Need to verify it is truly 100Hz or a multiple of run speed. What type of coupling? What activities have recently occurred to this fan? Load change, shutdown/start backup, etc.. Have you checked for a soft foot on the motor, do you have the rolling element bearings or sleeve/journal bearings? Pole pass=synchronous speed - slip speed X # of poles in motor or 1000-996=4x6poles=24 cpm/.4 Hz pole pass frequency Quick Google search, links...
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Re: 1200 kW FD Fan Motor dominant peak 100 HZ

y@sh ·
Dear DAVE REYNOLDS Coupling type - Spacer coupling , there is no recent activities done on motor , there is no soft foot also . motor base is OK. there is a 3 bearings in motor spherical roller bearings on both sides 1 Ball bearing is on DE side. Thank you so much reply
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Re: 1200 kW FD Fan Motor dominant peak 100 HZ

Dave Reynolds ·
My idea of checking for a soft foot and yours maybe completely different so lets discuss more about your data....you must verify the vibration is truly 100Hz. Is the 100Hz present at all data collection locations and axis on the motor? Is the 100Hz vibration higher in one direction/axis/end of the motor vs the other? While monitoring live time, looking at 100Hz, shut the motor off, if the problem is electrical related the 100Hz will disappear immediately. To the best of my knowledge you can...
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Re: 1200 kW FD Fan Motor dominant peak 100 HZ

y@sh ·
Thank you so much for your brief explanation 100 HZ dominant came from only motor at both De and Nde sides of 3 axis. Turning speed is 994 rpm (16.57Hz )6.04 but its not match with any bearing defect frequencies. after checking with high resolution 100 HZ is not visible in FFT spectrum. I got 96.4 HZ frequency is dominant. Thank you Mr. dave
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Beatnik ·
The bearing defect factor is simply the overall acceleration * crest factor. It's not similar to peakvue. The "equivalent" of peak vue in XPR-300 is enveloppe. You can even get a envellope TWF and trend the peak. I'm not sure about this case in particular. Is it possible that the DE bearing lack load? That or they don't put enough greace in it I guess.
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Vibuser ·
Hello there, Thank you BEATNIK for your reply. We are in discussing on this matter still. When we put grease, it reduced and back to normal. Later in hours it back to RED. It might be from the loose fit? When grease is there, it OK. When grease melted probably it lack cushion/stiffness. Might be it is due to bearing resonance. And if we couple with the fan with slight unbalance, it getting worse. You may see from the chronology in the attachment. I am thinking to just run the unit and...
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Beatnik ·
Do you know how much grease they add?
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Dan Timberlake ·
Is one bearing attracting your attention? The DE bearing perhaps? You said "uncoupled." Is the fan direct coupled, belt drive, or something else ? That's a big old bearing. http://medias.schaeffler.com/m...E-XL-M1;bgGYTj7oJ6kb The basic Dynamic load rating (Cr) is on the order of 460 kN, or about 100,000 lbs. The minimum radial load is about 0.02 X 100,000 = 2000 lbs , in order to preclude roller skidding. Does your motor's rotor weigh at least 4000 lbs/9000 kg ?
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Vibuser ·
Dear BEATNIK, Normally they grease it around 20-30 stroke until the old grease drain out. It was clear that after greasing the G's level reduced but only for a while. Dear Dan, This FD Fan motor is direct coupled to the fan, center hung with pillow block bearings. The weird is that when motor solo run the acceleration is increasing reaching the danger limit set at 4G's I will seek for the motor rotor weight. On the other hand, i found that the spectrum having a hump in the region of...
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Beatnik ·
A lack of load on your NU bearing is certainly a possibility, specially that you say that it's worst when it runs solo, it's similar to a lack of grease in the vibration Spectrum. Skidding is a metal-metal contact after all, it's normal that it shows in the bearing natural frequency aeras (around 3-4k HZ) An option is of course to change the type of bearing the next time you remove the motor (From an NU to a serie 6). Try to find information about the history of the equipement; Have they...
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Vibuser ·
Hi Dan, The total weight of motor is 7100kg, rotor only 1450kg. Fan total mass 24300kg. I did made some comparison with the other motor which also having high g's but reduced after greasing. Attached is the specrum bfore and after greasin for other unit. They are planinng to run again this FD Fan 3A using old motor. New motor sent back to OEM to check what happen to the bearings.
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Walt Strong ·
Vibuser, I agree with your hypothesis about a loose bearing or perhaps incorrect clearance between rolling elements and races. Remember that adding grease also raises bearing temperature, so clearance and looseness can change over time. Walt
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Vibuser ·
May i know what is the minimum bearing clearance should the bearing is said to be loose? Is the bearings totally skidding?
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Walt Strong ·
"May i know what is the minimum bearing clearance should the bearing is said to be loose?" You have to look at the bearing specifications and installation instructions. If a new bearing is simply installed without regard to setting clearance (typically roller bearings for fans), on a worn shaft, or in a worn housing, then poor bearing life can be expected. If frequent bearing failures occur, then the bearing choice, supplier, installation procedure (including shaft and housing condition) and...
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Dan Timberlake ·
Hi vibuser, You asked = "is the bearings totally skidding? " Probably not. But, any departure from pure rolling, (where the balls/rollers and races behave as if they were gears meshed together ) can cause problems. http://www.skf.com/caribbean/p...imum-load/index.html The moment each roller enters the "load zone" can look a little like 0:16 here although without much smoke. https://www.youtube.com/watch?v=sDUFvjVg_pk
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Re: Shock Pulse & Bearing Defect Stages in FD Fan Motor

Vibuser ·
Hi Guys, Personally checked this motor during solo run. Velocity overall just low around 1-2mm/s. Acceleration 10Hz-20KHz still high at 4g's and reduced as low as 0.2g's after greased. After 2hours acceleration increased back to 4g's There is some noise before greasing. DUring running we apply grease and noise reduced. I dont have any clue on this noise. Might be electrical induced? Thank you
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Re: overhang fan vibration!!!

Vibration_guy ·
Please provide Overall Vibration along with acceleration Values of all Point In Three Direction.
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Re: overhang fan vibration!!!

Becar ·
When the fan changes vibration each startup, you probably have one of the following situations: - worn bearing or bearing housing - construction weakness - construction cracks - structural looseness - resonance Visual inspection will be needed.
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Re: overhang fan vibration!!!

Ptayebi ·
Thank you for your respond. Did you check vibration data I was attached? What's your opinion about spectrum and envelops?
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Re: overhang fan vibration!!!

Rotating Guy ·
Hi, As i seen your attached spectrum, i haven't seem anything with the bearing fault as your BC is minimal. i agree with BECAR post. if you could send a picture it will help. Is this vibration is during normal operating condition or just a testing with controlled opening of damper, sometimes i get a high vibration when discharge flow is restricted. regards,
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Re: CT FAN MOTOR VIBRATION PROBLEM

John from PA ·
Have you done anything to investigate the issue? I see a dominant frequency of about 4420 cpm. Have you checked that against the anticipated bearing frequencies?
 
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