Tagged With "Horizontal"

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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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Reg:High vibrations at H.T Motor in Horizontals...

abhiramkompella ·
Dear experts We have Primary air fan of 1675Kw & 1485Rpm ...Motor is of BHEL make and the vibrations of motor are going high i.e., 6.2mm/s at Nde, 5.4mm/s De horizontals at motor...In the spectrum we have 1X running rpm of motor ...The 'g' value of motor bearings are 0.106g no abnormal sound from bearings...We have inspected on "impeller,coupling,looseness,soft foot,alignment and further went for motor solo trial" In the solo trial of motor...
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Vibration Tri Axial Sensor Mounting

Avinash Thawani ·
Hi, What are the pros and cons of RAT vs VAH scheme RAT is Radial Axial Tangential VAH Vertical Axial Horizontal Which one is better for Triaxial
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Why we are mesuring vibration in three directions ?

Ganapathi ·
Dear All, I would like to know below points please anyone can give your valuable answer for below . Why we are measuring vibration readings in three directions ? and what is the reason for measuring vibration in these three directions ? and why we are measuring Acceleration or peak or in Horizontal direction only?
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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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Horizontal Shaft CL movement only on Steam Turbine Governor End

Jonston ·
Recently witnessed a leftward horizontal shaft centreline movement of 130 um during low load operation of above 40MW extraction condensing Steam turbine. This movement happened on on governor or steam inlet end only. Bearing metal temprature increased from normally seen 80 c to max 120c but came back to 99c. Currently at full load shaft position is still maintaining on left ward pad and radial vibration has subsided from 10 microm to 5 micron showing suppression by vaccinity to the clearance...
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45000 dwt Chemical tanker Diesel Generator 4 high vibration on Alternator bearing

chary tatta ·
Greetings team, on 8th July I attended another Chemical tanker and DG no4 alternator bearing Horizontal overall vibration showing 23.4 mm/s in velocity scale. The Marine classification society satisfactory limit is 18 mm/s. Attached the engine and Alternator end vibration spectrum FFT in velocity. All engine details are available in photo sheet. Appreciate your feedback. Kind regards Chary TSR
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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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Fan Vibration Changing by Inlet Gas Temperature.

Ptayebi ·
Dear Experts One of our Exhaust Fan has an interesting vibration behavior. The Vibration of this fan changes with inlet gas temperature change! (It change between 1 to 7 in horizontal vibration at point 4) But this changing is not in same direction, sometimes the vibration increases with temperature increase and some times it is decreases. The Velocity spectrum shows 1X is dominant. Another interesting thing is the magnitude of horizontal and vertical vibration: for point 4 the horizontal...
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high vibration in horizontal plane

vishal sharma ·
Dear experts in our cement plant we have eight cooler fan one of them has high vibration in only horizontal plane: Motor NDE H-10MM/S MOTOR DE H-11MM/S FAN DE H-10MM/S FAN NDE -11MM/S motor kw-132 kw overhung fan In all other direction vibration i.e in (vertically and axial) is below 2mm/s . in FFt spectrum only 1x with an amplitude of 9.2mm/s is dominated in all the direction i.e horizontal. i did cross phase analysis on motor and fan also for checking unbalance but cross phase in all...
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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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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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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 Vibration in Blower Motor Suspended Like Cantilever

Syed Huzaifa Ahmed ·
I work at Cold Rolling Mill. There are several mill motors as big as 2 MW with 15 kW a blower. The blower is attached/suspended horizontally at motor outboard side and acts like a cantilever beam. When I took the vibration for the first time, it was found unacceptable as per ISO 10816 mostly in vertical direction which is higher at outboard than inboard side. But spectrum was smooth and only 1X was observed appearing to me as structural resonance. I feel that it should be normal as in case...
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Re: Vibration Tri Axial Sensor Mounting

ivibr8 ·
With the HVA sheme, it is easier to understand direction/orientation of the plot. With RAT scheme, I always knew which transducer I was going to use Demodulation for (T). Other than that, it really depends on your preference; so I'm not sure there is a right or wrong answer. Always keep good records of exactly where you mounted and how you oriented the pad (assuming that's what you have) so that anyone can properly re-mount and orient it properly.
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Re: Vibration Tri Axial Sensor Mounting

fburgos ·
its all about how you like it, for me t is h and r is v someone like xyz, the convention is between you and your coworkers.
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Re: Vibration Tri Axial Sensor Mounting

Callum S ·
Call it whatever you want but be absolutely certain everyone who may collect the data is on the same page when doing so. Repeatability is paramount.
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Re: Why we are mesuring vibration in three directions ?

John from PA ·
Start with this... http://www.bksv.com/doc/br0094.pdf Very old but still very good for the beginner.
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Re: Why we are mesuring vibration in three directions ?

edisonindia ·
John That one looks very similar to the IRD Mechanalysis notes I have had from late eighties. Who copied whom?
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Re: Why we are mesuring vibration in three directions ?

Shurafa ·
The 3 directions are used to evaluate the motion (vibration) in the space. Usually the largest motion will be the most important and they are almost always unequal. One can record the (translation) motion of the bearing housing in all possible directions which are 3 per basic physics. Recall 3D. This approach is oversimplifying the real physics of the machine but it serves the practical applications. An important assumption is that the bearing housing acts as a rigid object or like a point.
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Re: Why we are mesuring vibration in three directions ?

John from PA ·
I think the Bruel & Kjaer publication I linked to may have been first. I got my copy in the late 1960's when I was initially involved with vibration and acoustics.
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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 ·
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 ·
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 ·
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

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

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

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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Re: 45000 dwt Chemical tanker Diesel Generator 4 high vibration on Alternator bearing

John from PA ·
One thing that might be helpful would be to make the frequency scale 5000 cpm. Your engine plots for instance go to 60000 cpm and virtually everything of interest is crammed into the lower 10% of the plot.
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Re: 45000 dwt Chemical tanker Diesel Generator 4 high vibration on Alternator bearing

chary tatta ·
Greetings Mr. John, Thanks for your follow up. Please find attached at 5000 cpm HVA plot. Regards Chary
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Re: Stronger vertical than horizontal NDE side and the opposite DE side.

William_C._Foiles ·
One of the first things to suspect is resonance.
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Re: Stronger vertical than horizontal NDE side and the opposite DE side.

Kamilu ·
After some digging, I've found in the technical data for this fan/blower some interesting info: -for 9-stage rotor first critical speed is 4706 RPM. in our case it is 5-stage rotor and operating speed 4200 RPM, so it is only about 10% under critical speed of 9-stage rotor... Do You think it is could be too close to critical speed? I've already asked the manufacturer about critical speeds of 5-stage rotor and i hope he will answer. Thanks
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Re: Stronger vertical than horizontal NDE side and the opposite DE side.

William_C._Foiles ·
You should scrutinize the rotordynamics and verify by test. Rotors often have two modes closely spaced. Giving only one critical speed may not reflect the machines dynamics - check further. Are the critical speeds by analysis or test - test at site to verify? 10% is close, but depending upon what the basis for stating the critical speed, the actual margin may be more or LESS than stated. Try to get some data.
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Re: Stronger vertical than horizontal NDE side and the opposite DE side.

Kamilu ·
Thanks for your answers William. Fan manufacturer answered - according to their data, this rotor (5 stage) first critical speed is 8079 RPM, while maximum reccomended speed for ths fan is 4400 RPM. We run it at 4200 RPM. This data is taken from manufacturer - we havent made any tests yet. But there still can be structural resonance, am I correct? Before trying to balance rotor, i would like to perform bump test while running (can't stop machines for now). But we have very basic device...
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Re: Stronger vertical than horizontal NDE side and the opposite DE side.

William_C._Foiles ·
Did you get a rotordynamics report for this machine? Do the coastdown test - take data to verify. What is the machine configuration? Bearing type? 5 sages, length, mass, bearings, shaft diameter - all go into determining the natural frequencies. Support stiffness is important, too. How is the machine mounted? Regardless of the specifics, if you get the data you can determine whether there is a natural frequency or not.
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Re: Stronger vertical than horizontal NDE side and the opposite DE side.

Dave Reynolds ·
Take a set of normal readings or have past history to reference too, yes your setup should work fine for bump test, one bump per avg will work, you should be looking for a small mound/haystack/Hershey kiss to show up at the base of a peak or show up as a separate peak that which is not normally present Dave
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Walt Strong ·
So, this looks like a motor cooling air fan/blower that is mounted to main motor upper air housing. I would not make any modifications without structural vibration test (impact-response), operating deflection shape test (ODS) or running impact test (with negative averaging). Possible corrections (if worthwhile) include adding vertical stiffeners close to motor on air housing, or adding mass to motor, or adding dynamic mass absorber (damper) to motor. Be aware that any change you make can...
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Ayman Gamal ·
I have seen many situations like that, the solution is simple: install base plate as a support under the motor or the blower, the vertical vibration will drop. 2 days ago i have problem like that ,GB attached to motor, the vibration at MNDS vertical was 6.5 mm/s and after installing base plate under GB and weld it to fixed point on the structure, the vibration dropped from 6.5 mm/s to 0.9 mm/s
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Walt Strong ·
It is not obvious whether the motor for cooling fan is an actual photo or a "stock photo" showing general arrangement. Guessing a corrective fix without vibration tests would be unwise. Walt
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Syed Huzaifa Ahmed ·
Great. But in our case, I may not be able to perform similar activity. The management will kill me as modifying the motor design will make the warranty invalid. I just want to know whether this vertical vibration is enough to cause any damage?
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Syed Huzaifa Ahmed ·
The photo I uploaded is of the same type of motor but not the actual photo. The actual looks same however.
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Rotating Guy ·
Hi, It cant be concluded that you have a structural resonance unless you test it. there's a lot of fault which to pertain in 1x dominant. I would suggest you to eliminate the point that causes of 1x. ea. unbalance, resonance and etc. Since your equipment is overhung, it is reasonable a structural issue, but if there is an unbalance, the resonance will be an amplificating factors of unbalance and cause a high vibration. so i suggest you to eliminate the possible cause. For checking the...
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Walt Strong ·
" The management will kill me as modifying the motor design will make the warranty invalid. I just want to know whether this vertical vibration is enough to cause any damage? " 9 mm/sec would not likely cause structural fatigue damage. You could try to get an "extended warranty" if OEM says vibration level is "normal or okay". Corrective actions include: tightening motor base bolts (if loose), trim balance of fan/blower wheel, structural modifications to detune resonance (if present based on...
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Re: Vertical Vibration in Blower Motor Suspended Like Cantilever

Syed Huzaifa Ahmed ·
You are 100% right guys. But since I only have Fluke 810 which is not an advanced vibration analysis tool, I cannot perform ODS, bump test, high resolution, balancing or phase analysis etc. Though I try my best to rule out possible causes by experience, chances, solo tests or visual inspections. And so far though time consuming, I have been very successful. 1X can correspond to the following faults: Thermal rotor bow ---> Ruled out, no temp difference or abnormal temp Unbalance --->...
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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: Reg:High vibrations at H.T Motor in Horizontals...

Walt Strong ·
Have you tried to trim balance fan impeller? Have you conducted impact test on motor and fan in horizontal direction? Walt
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Re: Horizontal Shaft CL movement only on Steam Turbine Governor End

William_C._Foiles ·
Any steam leaks? With the temperature rise, sealing could be a possibility. A leak can cause an apparent change in position.
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Re: Horizontal Shaft CL movement only on Steam Turbine Governor End

vibramac ·
DOR and orbits (filtered and unfiltered) would be helpful!
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Re: High horizontal vibration in fan

Becar ·
- did you check bolts? - increased clearance in bearing/housing/shaft - cracked rotor or construction issues
 
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