Tagged With "NDE"

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High horizontal vibration on gearbox

Engr Aamir ·
i have a dynamic separator fan in cement mill area. a motor, gearbox and a fan. gearbox has 2 shafts. i m facing 1x horizontal high vibration 8.5mm/sec and 8mm/sec on shaft 2 DE and NDE side. All other points showing less than 1mm/sec including Motor. also find attachment
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High vib. on gas turbine generator NDE bearing at axial direction

chemical ·
Dear all. I am Vivek mechanical engineer. I found this website as I am facing a problem. I have a 105 bar back presser gas turbine    And  12.5 MW -11 kv generator   Here I start from beginning that we done a turbine overhauling...
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NDE of sleeve bearings

Lukas1311 ·
Industrial standards do not required any NDE tests that has to be performed on large induction motor sleeve bearings as a part of preventive maintenance activities. In our facility we has performed NDE test (UT and PT) since 2010. We use ISO 4386-1 and ISO 4386-3 standards for acceptance criteria. We chose conservatively class B for our acceptance criteria. In few years we found out that most of our sleeve bearings are out of acceptance criteria. So, I am looking forward to hear industrial...
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Re: NDE of sleeve bearings

electricpete ·
At our power plant, we do periodic inspections of certain sleeve bearings and also of course have various monitoring strategies (temperature, vibration, oil sampling). We do not do any periodic N.D.E. and I'm not understanding why it would be required. Blue check is done after bearing replacement. UT is looking primarily for integrity of bond between babbit and base metal. I view it as a quality check or installation check where bad babbit bond would be a result of manufacturing. If cracking...
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Re: NDE of sleeve bearings

electricpete ·
Can you elaborate on the problems you have found?
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Re: NDE of sleeve bearings

Shurafa ·
Sorry but does NDE stand for Non Destructive Examination/Evaluation? I'm familiar with NDTs (PT, Ut etc). In the small machine shop we have in the facility (or at the site), we do not perform such tests on bearing on regular basis. In my company, we have a large repair shop where critical or large equipment are repaired. Even there, NDTs are not parts of the standard checks. Of course, one can use any special tool/test (deemed appropriate) for special cases. How many times, these tests you...
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Re: NDE of sleeve bearings

Lukas1311 ·
First of all, yes we are talking about non destructive examination on sleeve bearings. We should take in consider that we are nuclear power plant with a 35 years in operation. So, there is a quick review of our strategy: - we perform NDT on split sleeve bearings that are installed in horizontal motors - 120 months is frequency for motor overhaul - during motor overhaul we do PT and UT tests - acceptance criteria are ISO 4386-1 (acceptance criteria B1) and ISO 4386-3 (acceptance criteria B)...
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Re: NDE of sleeve bearings

electricpete ·
I reviewed two documents which provide overview of repair activities for electric motors (typically done in repair shop): EPRI TR 1016679 is "NMAC: Repair and Reconditioning Specification Guidance for AC Squirrel-Cage and Salient Pole Synchronous Motors with Voltage Ratings of 2.3 to 13.2 kV" IEEE 1068 (2009) - Standard for repair and rewind of electric motors in the Petrochemical, Chemical, and Process Industires Both documents have fairly detailed instructions for inspecting sleeve...
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Re: High horizontal vibration on gearbox

John from PA ·
I see some impacting going on so I would suggest as a 1st step examine the condition of the teeth. Usually you don't have to disassemble the gearbox but you may have to do some searching to find a means of inspection. That might be a small plate bolted to the casing or in some instances I have even seen relatively large pipe plugs that when removed permit viewing the active contact area.
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Re: High horizontal vibration on gearbox

subh ·
2 shaft means what ... is it the output of gearbox.. M unable to see ur attachment... please send it in JPG form.. If the output shaft is having 8 mm/s vib thn it might be possible that separator blade is getting unbalance
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Re: High vib. on gas turbine generator NDE bearing at axial direction

Gary Stacey ·
What frequency is the axial vibration at? Is there a thrust bearing at no8 bearing location? Gary
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Re: High vib. on gas turbine generator NDE bearing at axial direction

chemical ·
Thanks for reply Pre dominant freq. = 2×line freq. So at 100 hz predominant is come
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Re: High vib. on gas turbine generator NDE bearing at axial direction

Gary Stacey ·
Axial positioning of rotor out i.e. mag centre. What do others think? Gary
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Re: High vib. on gas turbine generator NDE bearing at axial direction

William_C._Foiles ·
Have you checked for natural frequencies? This is important whether the cause is electrical or mechanical.
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impact per revolution??

BalancingVN ·
I took measurement for separator of raw mill at cement plant. No fault was detected at motor, gearbox. But at NDE bearing of separator shaft appears impact/revolution (in transverse direction), separator speed is 119.5 rpm, DE bearing is normal. The data collected at NDE bearing when there is no load. A symtom when loada (feed material) is current of motor is sometimes high (normal is 50A, sometimes is 110A). Please leave comment if you got this case before! Thanks!
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Re: impact per revolution??

vidya Sagar ·
Is this spectrum of gearbox ???
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Re: impact per revolution??

BalancingVN ·
No, that's NDE bearing separator
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Re: impact per revolution??

JUDEMAC ·
Is this Plummer block?
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Re: High vibration in Fan Non DE bearing Horizontal direction

Mukesh Chandrawanshi ·
2x is dominant frequency.. And other multiple harmonic is also appeared
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High vibration in Fan Non DE bearing Horizontal direction

Mukesh Chandrawanshi ·
Hello sir I am facing a problem of vibration in overhung fan, Fan is mounted in concrete base , in all point ie motor bearings and fan DE bearing vibration is good in both direction ( axial & radial) but in Fan NDE bearing vibration is high in horizontal direction, Vibration in fan NDE bearing vibration is 8 mm/s and vertical and axial is less than 2 mm/s Sir i can't understand what is the problem in fan ...can anybody help me ??
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Re: High vibration in Fan Non DE bearing Horizontal direction

Bernard Boueri ·
What is the dominant frequency in your FFT?
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Re: High vibration in Fan Non DE bearing Horizontal direction

Alvin MC ·
Attach the FFT for NDE horizontal
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Re: High vibration in Fan Non DE bearing Horizontal direction

y@sh ·
Once check the pedestal fixing bolts .The high vibration at horizontal and vertical causes unbalance but vibration high in axial direction in overhung fans (directed coupled fans) the unbalance forces acted on shaft to create shaft bending moment causing the bearing house to move axially
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Re: High vibration in Fan Non DE bearing Horizontal direction

Islam mohamed ·
Did you check the shaft tolerance under bearings ? Is the bearing installed directly on the shaft or adapter sleeves is used ? FFT till there is lack of fits .
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Re: High vibration in Fan Non DE bearing Horizontal direction

Mukesh Chandrawanshi ·
Sir, Bearing & housing is newly installed...... And i have already checked bearing clearance....
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Re: High vibration in Fan Non DE bearing Horizontal direction

Alvin MC ·
Agree with Islam...I will check for loose bearing on shaft, and bearing clearance.
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Re: High vibration in Fan Non DE bearing Horizontal direction

Mukesh Chandrawanshi ·
Okk thank you sir... I will check as you recommended..
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Re: High vibration in Fan Non DE bearing Horizontal direction

Islam mohamed ·
The series of harmonics on FFT indicate non linear response results from rotating looseness , you can check internal bearing clearance,wear in bearing housing ,shaft wear under bearing and worn or loose sleeves . Replacing the bearing or check aforementioned point might solve the problem. I don't believe that you have imbalance problem unless you have high axial vibration specially you have overhung fan. I wish you all the best.
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Re: High vibration in Fan Non DE bearing Horizontal direction

Alvin MC ·
You might already checked this but make sure NDE bearing is floating and DE is fixed. Spectrum is clearing showing looseness though not much noise floor. More info about bearing and installation would be useful like Islam mentioned.
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Re: High vibration in Fan Non DE bearing Horizontal direction

Dave Reynolds ·
I assume NDE is the fan bearing bearing next to the fan wheel? Is this a direct drive or belt drive fan? What is the fan operating speed? Any phase data? Have you balanced the fan? Have seen this vibration pattern be pure imbalance due to weak bearing supports. See anything around the bearing supports that looks rusty in color like metal to metal contact or metal to concrete contact. Could the fan bearings not be in proper alignment with each other? Either side to side or vertically? Is...
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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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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: High vibration in Fan Non DE bearing Horizontal direction

Bernard Boueri ·
This would be my approach: What maintenance was done. What were vibration before and after maintenance. how do the FFT compare before and after. Scan all bolted flanges with FRF and check phase across. It would not hurt to do impact test to identify structural natural frequencies. Do phase analysis across entire train especially coupling to check for any misalignment.
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High vibration in Fan Non DE bearing Horizontal direction

Mukesh Chandrawanshi ·
Hello friends We are facing new problem in ventilation fan ... Vibration is high in horizontal direction in each measuring point, and dominant in 3x RPM. Major problem in Fan NDE BEARING ....In all directions (H,V,A).... I attached all data .... What is the reason of this problem???
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Re: High vibration in Fan Non DE bearing Horizontal direction

ivibr8 ·
Hmmm.....well, I still feel strongly about the looseness. The question is where and why. Its difficult to tell you exactly where the looseness is located. Did you open the fan housing and look for any type of looseness of the fan on the shaft? Are there any signs of cracks in the weldments? With power secured, does the shaft turn smoothly with no rubbing or abnormal sounds? Also, while its running, look closely at all "interfaces" that is, housing support to base, base to foundation, etc.
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Re: High vibration in Fan Non DE bearing Horizontal direction

Mukesh Chandrawanshi ·
Dear Jim thank for reply I want to know which type of loose is their, We checked bearing clearance and find within limit , & bearing pedastal bolt is fully tight. Coupling condition & alignment is ok And i just want to know why fan NDE bearing vibration is high.
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Re: High vibration in Fan Non DE bearing Horizontal direction

ivibr8 ·
Mukesh This looks and smells like some severe looseness with all that harmonic activity. I would carefully check bearing support(s) and look for looseness/impacting. Regards Jim P
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Re: High vibration in Fan Non DE bearing Horizontal direction

Mukesh Chandrawanshi ·
Thanks jim .... I would like to ask only one question... Is localised problem..i mean fan NDE side problem???
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Re: High vibration in Fan Non DE bearing Horizontal direction

Shurafa ·
Looseness is probable. Looseness could be between parts that are inspectable externally or it could be an internal problem that can only be verified by opening the parts. Example is bearing inner race OD and shaft. In my word, amplitudes like 24 mm/sec are too high to keep the machine running or keep the operators check the machine. Safety is important. Have you inspected the lubricant (drained the oil to check it)? Any observations like unstable reading, noise, high temperature were...
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Re: High vibration in Fan Non DE bearing Horizontal direction

Alvin MC ·
Agree with Jim...I would even put the analyzer on live mode and stick prob at different spots on base frame and look for any sudden change in amplitude. Lot of times welding cracks are hard to identify just by looking.
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Re: High vibration in Fan Non DE bearing Horizontal direction

Dave Reynolds ·
To prove you do not have loose fits, use a long bar/block of wood/dial indicator. Put indicator at top dead center of the shaft and lift the shaft. If you have more than .003-.005" of up and down play, something is worn/loose The harmonics in you vibration data indicates looseness, sources of looseness could be bearing fit to shaft or housing, loose bearing housing feet, loose fan base, worn coupling, fan wheel loose on shaft to name a few areas of interest Have seen 3x come from loose...
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High Floor Noise On Cold Rolling Mill DC Motor (1400 kW)

Onur Gün ·
With this datas, what is the problem? Is stage four bearing fault possible at NDE? NDE Velocity spectrum (RMS 1,39) NDE Acceleration spectrum (RMS 36,271) NDE Acceleration Time Wave (RMS 44,634) NDE Envelope spectrum (RMS 12,816) NDE Shock Pulse DE Velocity spectrum (RMS 1,37) DE Acceleration spectrum (RMS 2,837) DE Envelope spectrum (RMS 1,179) DE Shock Pulse
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Vibration observed on motor of sump pump

wss ·
High Vibration was observed on all axis of the motor on a sump pump MOTOR reading NDE V : 16.78 mm/s NDE H : 13.33 mm/s DE V : 8.76 mm/s DE H : 7.64 mm/s DE A : 2.84 mm/s PUMP reading DE H : 3.00 mm/s DE V: 2.47 mm/s I did a solo run on the motor and observed the following reading NDE V : 3.82 mm/s NDE H : 0.73 mm/s DE H : 0.17 mm/s DE V : 1.85 mm/s DE A : 0.21 mm/s I did alignment check up and was found ok Should I go for pump overhauling?I will also check for structural resonance. What...
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Balancing of fan

vishal sharma ·
Dear all i am dealing with a RAW mill simple supported system fan 2500 kw motor with 990 r.p.m . The spectrum in DE bearing showing 1X with an amplitude 3.8mm/s overall vibration is 4mm/s in DE bearing in horizontal direction. vertical: 1.2 mm/s Axial: 1.4 mm/s but at NON DE side bearing we are having 5mm/s overall vibration in horizontal direction. the spectrum in NDE bearing showing 1X with an amplitude 3.9mm/s . vertical vibration is :1.8mm/s Axial: 2.4 mm/s by doing time wave form...
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Re: Balancing of fan

vipul@cmc ·
Waht is Displacment on DE & NDE brgs. @1x vibration rpm ? What is Phase diffrence on DE brg.between H & V Directions.? Have you properly cleaned the impller of Fan ?
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Re: Balancing of fan

Ralph Stewart ·
questions: (1) Is it a centerhung or overhung fan? (2) Can you show us the impacting waveform? (3) Have you tried and failed with a single plane balance or are you planning on a single plane first or multi-plane balance first? (4)The 110 degree phase on the DE, what is the 110 referenced to, a refelection "tape" position on the shaft or reference to the NDE bearing? Thanks, Ralph
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Re: Balancing of fan

Walt Strong ·
"So my question is can we perform Dynamic Balancing ??" Yes, if rotor is accessible to add/remove balance weights. "if yes will we get satisfactory results?" Yes, if rotor is clean and no cracks or looseness and bearings are tight and in good condition. You should also inspect bearing pedestals/housing for loose bolts and foundation (steel, concrete, grout) for significant cracks. Walt
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Re: Balancing of fan

vishal sharma ·
1 it is centrehung fan 2. i am planning for single plane balancing but i have some doubt in fan NDE bearing. 3 phase reference 110 on DE side is w.r.t to reflection tape position on shaft.
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Re: Balancing of fan

vishal sharma ·
phase differnce is 110 degree at fan DE side from H & V FAN IS PROPERLY CLEANED NO DUST IS THERE
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Re: Balancing of fan

vipul@cmc ·
You can do single plane balancing
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