Tagged With "NDE"

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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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Vibration at 5X NDE AND DE V for Centrifugal Pump

wss ·
Vibration was observed in a recently overhauled centrifugal pump in 5X at pump NDE and DE V.FFT is attached There is no chance of vane pass effect since the pump was overhauled recently and no damages where observed.
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High horizontal vibration in fan

vishal sharma ·
Dear experts After solving my preheater fan and raw mill system fan problem with your precious recommendation now I want share my new problem that’s I am facing now a days i have two bag filter fan both are 18kw motor. both have overhung impeller.During continues monitoring fan A has high horizontal vibration 12 mm/s at fan NDE side with 1x domination in FFT spectrum. So first I check alignment of fan and I found it’s okay so I start single plane balancing and after balancing vibration...
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Vibration analysis

Tsietsi ·
below are the data for the industrial motor coupled to a centrifugal pump motor speed 1487RPM bearing are white metal bearings both NDE and DE power is 970 kW please assist me with the analysis attached there is a funny noise from the motor when running
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High vibrations on Alternator NDE

Chetan Patil ·
Hello Team, Once again I am coming here with similar kind of machine and vibration problem. EMD engine with an Alternator (with single bearing at NDE) RPM : 900 RPM Alternator: 600V, 2525KVA, 1400kw, 60 HZ Engine vibrations are within range (around 8-9 mm/s) Alternator NDE is vibrating with High vertical (24 mm/s , purely 1X) & Axial (16 mm/s with 1X = 8.6, max peak 12 mm/s @7182 cpm and minor 2X,3X, 4X) vibrations. (due connectivity issue at offshore I counldn't upload the spectrum...
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Electrical Motor NDE high vibration

Thimba ·
Dear all, I'm monitoring the vibration of a 1.2MW vertical submerged pump(RPM: 595/ 9.917 Hz ). The motor 1x radial vibration appears to be high in one direction (pump discharge side). Radial vibration at 90 deg seems relatively low. I have checked the alignment at the coupling and any structural looseness and all seems ok. The Motor acceleration spectrum shows harmonics of 734 Hz with a 2xline frequency side-bands. I'm assuming this is rotor bar or a winding slot pass frequency. I'm not...
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Strange harmonics on horizontal pump

Kamilu ·
Hi all, it is my first post here, thank you in advance for all the answers. I have been monitoring 45 kW pump, ~1480 RPM and i have seen strange harmonics approx. at ~6,31 RPM, strongest on DE pump and motor side. I have checked bearings in manufacturer catalog and it says that these should be : Motor : 6313 DE/NDE Pump: QJ 313 DE / 2213 NDE None of the bearings fault frequencies match with 6,31 harmonics. The closest one are 2x BPFO motor bearing at 6,142, and pump BSF at 6,661. Pump vane...
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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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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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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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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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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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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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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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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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High Radial Vibration on Water Injection Pump (WEIR PUMP)

Ken5yne ·
My Fellow Colleague, Been battling with a water injection pump for weeks now, the pump is a centrifugal multistage pump with 6 stages driven by a siemens electric motor through a lufkin gearbox . The pump had failed early this year due to process issue, pump was run for a long time without load, signal was sent to the breaker to trip pump, but it did not trip, luckily the pump was hand tripped by an operator, when we started, the pump refuse to turn, so we got another bundle which has been...
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Pump vibration in horizontal direction

Sunny123abc ·
Can anyone please explain the below spectrum of the pump vibration in horizontal direction? The spectrum is attached. Please tell what is wrong with the pump NDE side?
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Vertical Motor NDE high vibrations

Nagaraja ·
Dear Members, This is a vertical motor driving a pump. Motor speed 1000 rpm, After measurements this looks like a clear case of mounting resonance. Vibrations are high along Motor NDE along vertical direction. I tried with a DVA which did not work. Site balancing attempt brought down the vibs by 50%. However with load the vibrations again went upto 20 mm/sec. Motor is behaving in a same way with or without coupling Anyone came across such case earlier. Any kind of suggestion is welcome.
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Stronger vertical than horizontal NDE side and the opposite DE side.

Kamilu ·
Hi. What could be possible, general reasons that there is much larger vertical vibration than horizontal NDE side of a machine, and much larger horizontal vibration than vertical DE side? Ratios are about 3-4/1. And what if there is opposite of this situation? (stronger horizontal NDE and vertical DE)? I experience this pattern on two sets of machines (motor +fan). They are driven via belt transmission. One set (motor + fan) is experiencing the first way, and second set of machines is...
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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: 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: Vertical Motor NDE high vibrations

Shurafa ·
Neat report. I would recommend to do impact tests to determine the natural frequencies. This information helps to see how much your efforts result in shifting the natural frequency. Also, to verify that the motor is not influenced by beating. I suggest to take a long waveform or a trend over enough time. If there are nearby machinery, try to stop them to confirm that the vibration is/is not transmitted. Regards- Ali M. Al-Shurafa
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Re: Vertical Motor NDE high vibrations

Kishore kumar ·
Dear Sir , Do blue match at Motor mounting flanges contact area . Add required shim at non contact / poor contact area ,tight all nut bolts .
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Re: Vertical Motor NDE high vibrations

Nagaraja ·
Blue matching done. Contact area is close to 80-85%. The only way is to provide additional rigidity or stiffness to shift the natural frequency above 1000 rpm. Which can be done through FEA route. If anyone carried out such analysis on a similar system Pls share. We are working on FEA to resolve this issue. I don't think there is any other method to sort out this problem. Can't give any isolation (material) between motor flange and stool as it will disturb the shaft length with coupling. ...
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Re: Vertical Motor NDE high vibrations

John from PA ·
New machine or an old machine with a new problem?
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Re: Vertical Motor NDE high vibrations

Nagaraja ·
This is a new machine. Motor is fine.. It's a case of mounting resonance issue so we are planning to take FEA route for a permanent solution Nagaraja
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Re: Vertical Motor NDE high vibrations

Vastocean ·
I agree with Mr. Ali M. Al-Shurafa’s recommendation, do a bump test of the machine can help support findings and suspected causes. A minimum separation margin of 10 percent shall exist between the natural frequency(ies). VastOcean
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

chary tatta ·
Greetings team Very Interesting case. only 5X dominating. No problems noticed in spectrum. All unique components are in good condition. 3.84 mm/s at 5X is still in normal condition. However, the cause of 5X dominant can appear due to flow conditions like impeller stall. Check the pump suction and delivery valves, system flow conditions (full flow or throttled flow) Load on motor etc., Pleased to see such isolated case. regards Chary
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

wss ·
Dear Mr.Chary, Its 4.8mm/s now.We are planing to take it down once it peaks over 5.5mm/s and give a check of the valves and other flow condition.The check valve on discharge line is normally on full open or full closed condition.
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

chary tatta ·
GREETINGS WELL NOTED. THANKS FOR YOUR FEEDBACK. PLEASE FOLLOW THIS METHOD AND TRY HOW YOUR VIBRATIONS ARE INDICATING. 1. CLOSE DISCHARGE VALVE AND START THE PUMP AFTER FEW SECONDS AT FULL SPEED AT MAXIMUM PRESSURE MEASURE THE VIBRATION SLOWLY OPEN DISCHARGE VALVE AND MEASURE THE VIBRATION. IF FLOW INCREASING TIME VIBRATION RISING IT IS RELATED TO FLOW SURGES CAUSING THE VIBRATION. IF STEADY AT EVERY DISCHARGE VALVE POSITION THEN THE VIBRATION IS NOT FLOW RELATED. ALSO TAKE RUN UP AND COAST...
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Re: Balancing of fan

vishal sharma ·
the problem has solved. we did two plane balancing now the vibration reduced from 7mm/s to 2 mm/s. fan DE: 1.8mm/s fan NDE: 2.1 mm/s thanks for your suggestions.
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Re: Balancing of fan

Walt Strong ·
Vishal, Thank you for your feedback. Walt
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Re: Vibration analysis

Walt Strong ·
What does funny noise sound like? Did you measure sound to determine the dominant frequency? Do both the motor and pump have journal bearings (white metal), or perhaps the motor has ball/roller bearings? Walt
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Re: Vibration analysis

Rotating Guy ·
TSIETSI Hi, below comment is for clarification; 1. Does the funny noise occur during start-up? 2. Does your attached spectrum is taken during your so called funny noise? 3. Does the funny noise didn't disappear during operation? 4. Whats is the recorded enveloping acceleration for motor drive side and non-drive side? also the timewaveform? any significance changes in trend history? For me, when i encountered abnormal noise like a sound pressure noise at motor, i do phase analysis for motor...
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Re: Vibration analysis

Kishore kumar ·
Dear Tsietsi , Is that motor has a fan along with internal air circulation type ? , if so it might be due to air circulation or air turbulence issue with in the Fan casing . Did taken Fan reading while decoupled ? , is there any sound like this ? Please check these parameters and share your motor image . <form action="https://www.maintenance.org/record-share!execute" class="" data-ajax-form="" id="shareContentActionForm" method="post" name="shareContentActionForm"> </form>
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Re: Vibration analysis

Rohit02 ·
With reference to the attached spectrums 1. In one of the image RPM is showing as 985. What is this spectrum is there any speed reduction in machine train? 2. What type of a pump is it? no of vanes, no of diffuser, between bearings or cantilever? 3. As mentioned about the funny noise from motor, as I could read all the spectrums corresponds to pump side. Kindly clarify whether these spectrums are of pump or motor. If these are of pumps kindly attach some spectrum of motor to identify the...
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Re: Vibration analysis

Tsietsi ·
Hi Kishore the motor is water cooled. kindly receive the attached picture and the time wave form and velocity spectrum from both bearings. NDE and DE white metal bearings.
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Re: Vibration analysis

Tsietsi ·
it looked like a Rotating looseness, i stand to be corrected but after bearing inspection, DE bearing looked like it got damaged by misalignment and NDE bearing like overload. please receive the attached pictures
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Re: Vibration analysis

Walt Strong ·
What are the blue boxes on each bearing housing? Walt
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Re: Vibration analysis

vigneshpillai ·
send the details of velocity value both DE,NDE Acceleration value both DE,NDE
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Re: Electrical Motor NDE high vibration

Becar ·
About acceleration: It is very likely you have to deal with RBPS. To confirm RBPF you should have all the data to calculate it. Do you have any measurement history? It is not necessary the amplitudes are too high for this machine. Some high resolution spectra should help you to see the exact matching with the multiple of rotation frequency. It could also be the change in load between your two measurements. Velocity: The situation described shows high possibility of resonance present. You...
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Re: Electrical Motor NDE high vibration

Akhil Rathore ·
This to me looks more of a resonance issue rater RBPF. please give more details How old is this equipment setup? I mean the motor & pump. what is the trend of vibrations? are they high since commissioning or its a recent increase. If you are concerned about RBPF & do not have the number of rotor bars, you can still go for motor current signature analysis. Thanks Akhil
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Re: Electrical Motor NDE high vibration

Thimba ·
Thank you both for your comments. Here's a bit of background about the setup. Pump was commissioned back in 2008. The pump was overhauled back in 2013 due to pump failure due to bearing defect and again in 09/2018 (suspected from vibration analysis which turned out to be the case in 2018). This 1x vibration increase only occurred since the September bearing change. The condition monitoring program has only been going since August 2018 so not much data to go with. We do however have a twin...
 
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