Tagged With "coupling"

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spring grid coupling suspect

Nagaraja ·
Hi, Got some vibration data in one of the ID Fan assembly, Motor is a 2 pole motor connected to the fan through spring-grid type coupling. Max speed 3000 rpm. The fan is not able to go to full speed due to high vibrations, its a VFD system (variable frequency drive). I did not see any predominant 1X freq component. More no. of multiple harmonics are seen in the spectral data I was able to take the data at 1500, 1800, 1920 and 2100 rpm. I noticed a strange behavior in the system. The...
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Hammer Mill Vibrations

Raul Rios ·
Hello experts! I am examining a hammer mill which is coupled to an induction motor of 200 hp at 1785 rpm. The whole set is supported by anti-vibration joints to the structure of the building. In the spectra that I manage to collect, I see the following: 1.- The mill shows a severe imbalance with amplitude up to 21 mm / sec-rms which is transferred to the motor. 2.- I also see a misalignment between the couplings and corroborate it with the cross-phase measurement in the axial 180 ° out of...
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1X at Hydraulic Coupling

Nera ·
Dear all, We're facing a problem with the Hydraulic Coupling of boiler feeder pump. The absolute vibration taken by CSI2140 is very high at all directions, at the moment, it's more than 10 mm/s. This has happened for a long time and can't find the answer. - Input:1500 rpm; Output: 5971 rpm Only 1X of output shaft dominates. The spectrum is below: But the relative vibration of this shaft (taken by online system) is very small, about 20 um. If you have any ideal, please help me, all opinions...
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Beating phenomenum at Conveyor Drive System with Hydraulic Coupling

Alvaro Loayza ·
Hello everyone, I will explain briefly the problem we have in our conveyor drive system. This is a 800 HP motor driving a gearbox trough a Voith hydraulic coupling. Vibration goes from 8 mm/s (3000T/H) to 11 mm/s (no load) at vertical direction. Spectra shows two peaks, one at coupling input speed and other at its output speed. Diference frequency (SLIP) between them is very small from 5 (no load) to 13 CPM (3000 T/H) considering that it should be like 35 or 40 CPM so beating phenomenum...
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un balance category

aziz58 ·
dear all as you know for measuring relative vibration by proximity sensor on journal bearing use two sensor located by two channel x and y 45 degree from each others. to evaluating un balance (static or coupled ) we measure phase difference between de and nde of shaft.if we have no difference phase between x channel of sensors and have a 180 degree difference between y channel of two sensors.if i evaluate by x channel we have static unbalance but by y channel we have couple unbalance. which...
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Spacer dirt build-up

spherical ·
Hi See the attached image. Has anyone encounter a problem caused by dirt build-up at coupling spacer. Could it affect vibration? Please share your thoughts and experiences. Regards
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Voith Fluid Coupling Failure Modes

ALI HAIDERR ·
Can Please anyone explain the failure modes of Voith coupling? If input speed is 1500 RPM and output speed 11000RPM,How we can selcect Fmax and LOR for vibration data collection? In which units data should be taken i.e Velocity or accelaertion? Number of teeth is unknown to me. How we can calculate GMF? Is voith vibration analysis same as Gear box?
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High vibration on vertical pump of thermal power plant

BalancingVN ·
Hi all, We are facing to vibration problem with vertical pump of thermal power plant. Speed: 1485 rpm - When motor run solo, only 1X is dominant - When motor couples to fluid coupling and gearbox (still uncoupled to pump), all measurement points are still appear 1X dominant, highest is at fluid coupling. All bearings at motor and fluid coupling are new replacement, gearbox is planetary with sleeve bearing. I concluded that motor is unbalanced and there is problem with coupling between motor...
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Intermittent Dips in Vibration Values Across Turbine Coupling

Ingenious ·
Facing problem of intermittent vibration dips across the turbine gear coupling installed between synthesis gas HP turbine & MP turbine. The change in vibration is observed at 1X and phase change also accompany’ s the vibration change. See Annexure-A for machine layout and vibration plots. What can be the potential cause for these vibration dips?
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Vertical Motor High Vibration

Vibration_guy ·
Dear All , I'm Posting The vibration Details of One of my Vertical pump. The pump was running fine. But some days before we opened the Pump as we have been reported to arrest the Water Leakage. But after completing the overhauling work and mounting it on the structure high vibration observed. I have posted all related spectrum s that i have taken during Trial Run in loaded condition. However the vibration is same as No load condition. i'm Suspecting Structural/Base looseness but want to know...
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Sub synchronous vibration and coupling failure

Thimba ·
Dear all, I’m monitoring a 40kW (2975rpm 2 pole) vertical lube oil pump. Please refer to the attached vibration data for the pump. On the 26 th Feb the coupling (Jaw coupling) was visually inspected and found the spider completely damaged and the coupling was replaced. Based on the spectra and time waveform is there any case for concern? What could be causing the modulation at around 3.5Hz? The pump bearing was replaced on 22/11/18 and the coupling was replaced at the time as well. Is there...
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Motor running in offset from magnetic center

Abhi03 ·
Dear All, We have facing a issue with one HT motor with axial fan load. When we start the motor (consider the motor has stopped in offset from magnetic center) it continues to run in offset up to rated speed (996 RPM) condition without trying to attend magnetic center. However when we reduce the speed bellow 500 RPM it comes to magnetic center and continues to run at magnetic center. The motor is designed with floating bearing and load DE side bearing is axial guide bearing. The motor rotor...
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flexible coupling run out correction

vikramdeeps ·
Hello , Guys just want to know the allowable run outs for flexible TB woods Dry Flexible spacer couplings ? And where to check it?Any way to correct the radial run out on coupling OR just replaced it?Coupling drawing in attachment
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Coupling hub OR shaft run out

vikramdeeps ·
Guys , While measuring run out on hub ,,How to confirm the run out is due to shaft bend OR coupling hub problem?
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Field Balancing of Pumps

Taha Bin Mahmood, CMRP ·
Guys, I have had some experience in balancing fans and blowers but haven't had any case of field balancing of pumps. I have heard that some people tone down the asset vibration by adding weights on the coupling rather than adding them to the impeller directly as it would be mighty difficult in case of pumps.... will it work and how? what's the procedure?
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Conveyor Belt Fluid Coupling Issue?

Copper Miner ·
I have a dual drive conveyor that is starting to puzzle me. One side has always had a bit of a resonance, but lately, when the belt is unloaded and first staring up I'm starting to get a pretty violent shudder on the motor and platform. There is one Vibe sensor on the input of the gearbox that shuts the system down at .6 In/Sec. The vibe sensor has been tripping during start ups. Haven't seen any drastic difference in line frequencies to the motors during these occurrences. The shudder...
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U-Joint damage

RRS_Dave ·
I have a customer in the food industry that uses a double U-joint for the coupling between a drive motor and dough mixer gearing (actually it looks like the rear end out of a truck). We of course have trouble with water ingress during the sanitary...
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fluid coupling mounting

alainraad ·
there is any problem if a fluid coupling is mounted in the wrong direction? the input on the gearbox shaft and the out on the motor? the coupling is flender fludex FAD 297. for me i think that there is no problem, in case that the gearbox shaft can...
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Vacuum Pump grid coupling failure

Alvin MC ·
This paper machine vacuum pump set has three vacuum pumps coupled in series to one drive. We broke the coupling to change the middle pump (left on pic) due to BPFO bearing defect and found damaged grid teeth on the opposite pump. i have seen the broken grids before but never the teeth. I wouldn't think alignment was an issue, could be overload??? What you guys thinks?
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Problems in Gear Couplings, and their Remedies

Husnain Shahid ·
Hi all, I am a new member of AMP, and new to the field of Machinery Maintenance as well. I came across a problem related to failure of Gear Coupling in one of our machines. Kindly enlighten me with some guidelines that what the basic steps of troubleshooting should be in this case. Regards, HSH
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motor vibration at 3XTS

Hossam 2 ·
Good Afternoon guys i have a problem related to a motor vibration which is summarized in a dominant 3XTS on motor side in the horizontal direction while 1X and 2X barely visible overhung fan variable speed up to 600 rpm coupling is flexible 14 rubber element and this rubber is new the alignment within tolerance 0.1mm while the max, allowable is 0.5 the shaft has coupling has run out problem 0.25mm and shaft has center runout between the bearings 0.3 mm and near the free bearing 1.7mm i know...
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HIGH VIBRATION IN GAS TURBINE

carlos msr ·
Hello experts The reason for this post is to know your opinion about the trend and the spectra collected in an MS 5001 gas turbine, I would like to know your opinion and to what condition or fault the graphics can relate. In this inspection only those graphics were obtained, the machine does not have a key phasor to know the phase, but even so I consider that a good diagnosis can be made. in my experience, the condition present in the turbine is attributed to an imbalance and thermal...
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collector rotor balancing

hamid.mechanic ·
does collector rotor that couples with a flexible rotor 50Hz, is rigid or flexible? and balance process do only mass residual balancing?(iso1940) Keep in mind that collector from one side couple to the main rotor and another side-mounted on journal bearing.
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Re: U-Joint damage

John from PA ·
Go to http://www.machineservice.com/...ersal-joint-failure/ for various reasons of brinelling in u-joint yokes (beyond the classic "external" source as cause).
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Re: U-Joint damage

Brian Brzinski ·
Hi RSS_Dave, I have worked in the food industry for several years and have seen this type of failure before. Just a few observations, first, in a wash down area open bearing such as those should be wrapped prior to sanitation or wiped instead of washing. Ingress of sanitation chemicals can cause a breakdown in lubrication that wouldn't necessarily be as obvious as washing the grease out of the bearing. Second, have you checked to make sure that someone didn't accidentally use the wrong...
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Re: U-Joint damage

Dan Timberlake ·
I'm having some difficulty with that pptx file. I was going to search using the forged in numbers to see if the U-joints are name brand, or brand C. Are motor amps or something else being monitored ( and hopefully recorded) during production? Was any maintenance done where large assembly torques were generated on the "other" side of the gear reduction, and perhaps the motor or driveshaft were blocked or jammed to resist the torque? First impression is that it looks like some of the...
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Re: U-Joint damage

John from PA ·
Originally Posted by Dan Timberlake: I'm having some difficulty with that pptx file. I was going to search using the forged in numbers to see if the U-joints are name brand, or brand C. Dan, your problem may be the pptx extension indicating one of the later versions of PowerPoint was used. I've converted the presentation to a PDF. Hopefully that won't present a challenge at your end. By the way, in the journal cross joint (sometimes called the "spider") casting I see "SPR" as well as "sd...
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Re: U-Joint damage

RRS_Dave ·
It is a Spicer joint. As far as grease goes, I think they've finally got a good handle on that. We fought the "food grade" in everything for a while, but with a good RE finally got some grease going in places it was needed. Of course, installation could have been a factor, but this one has been in service for a couple of years, and just now started giving me some indication. As far as hand wiping these things, with literally hundreds or thousands or motors, gearboxes, etc. there is no...
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Re: U-Joint damage

Mark R. ·
Dave, In my high school days I would do this same type of thing to the U-joints in my drive line under my Torino. I always thought it was from hitting the throttle to break the tires loose, you know the sudden shock to the drive line. If your unit doesn't "slam" in I'm not sure what it could be. Could the mixer be locking up or something like that to cause a sudden shock?
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Re: U-Joint damage

RRS_Dave ·
I've never heard of it locking up, it's geared very low. However, this thing does mix from 500 to 1000#'s of dough every 10 minutes or so, and it does go into high speed right at the end for a minute just before dumping. There is a shock I would say every time one of the four bars comes around and squishes into this pile of dough. I am interested now in seeing what one of the other two look like. I am going to see if I can get the RE to pull one of the others and take it apart. I'm not...
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Re: Motor running in offset from magnetic center

Dan Timberlake ·
What make and model of coupling?
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Re: Motor running in offset from magnetic center

edisonindia ·
Looks like your fan is creating an axial thrust higher than the normal magnetic thrust to keep it in magnetic center. As long as it is not creating any vibration issues or abnormal bearing temperature rises, it is not a problem.
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Re: Motor running in offset from magnetic center

electricpete ·
A sleeve bearing motor (uncoupled) has it's own range of motion between two limits. These limits are established by shaft shoulders contacting axial face of the bearing… these surfaces are not designed for continuous axial contact and someitimes are called "thrust bumpers". After you the motor to driven equipment, there is new narrower range of motion established by driven equipment axial thrust bearing, allowing for thrust bearing clearanace, coupling endfloat, and possibly thermal...
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Re: Motor running in offset from magnetic center

electricpete ·
Sorry, I didn't see Edison's comments. I agree with him also. My post added some cautions about loading the thrust bumpers because op doesn't completely explain what the condition is.
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Re: Motor running in offset from magnetic center

Abhi03 ·
@Dan, Its a pin-bush coupling with axial backlash limitation. @EDISIONINDIA Thanks a lot for your feedback. We also though for the axial thrust issue but we are worried that it should not damage the bearing axial collar. Also how do we show customer its from the load side that the issue is coming up and what corrective measures should we take? @ELECTREPETE Thanks for your inputs ELECTRIPETE. We are worried for the same issue that it should not damage the bearing axial collar. Any corrective ...
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Re: Motor running in offset from magnetic center

electricpete ·
A coupling used with a horizontal sleeve bearing motor has to be be able to limit travel beyond a certain point in both directions (in order to prevent motor from hitting thrust bumpers). I haven't heard of pin and bush with axial backlash limitation. Examples of pin and bush couplings that is unsuitable to limit endfloat: http://www.vibispa.com/en/pin-and-bush-couplings.html http://www.industry.siemens.co...ing/Pages/rupex.aspx Do you have more details on your specific pin and bush...
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Re: Motor running in offset from magnetic center

edisonindia ·
Mark the coupled running position on the shaft close to the bearing housing with a marker pen. Stop the motor. Rotate the rotor manually to bring it to the marked running position. Open both side bearing tops and measure the shaft shoulder clearances. A minimum of 2 mm shoulder axial clearance is required to prevent bearing rub though ideal will be equal clearances on both sides of the shoulders for each bearing.
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Re: Motor running in offset from magnetic center

Dan Timberlake ·
Here is a theory that I think explains all the symptoms you have described. In other posts it has been determined that the forces a rotor exerts trying to return to mag center are pretty small. In order for the motor to reach its magnetic center the coupling would have to be VERY slippery or flexible axially. Maybe gear type couplings operating at sufficient angle to be in the hydrodynamic range are slippery enough. Elastomer couplings, machinery mounts, etc, in order to be lubrication-free,...
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Re: Motor running in offset from magnetic center

VibeMan81 ·
I think as ELECTRICPETE points out, its probably not a problem. Dans explanation makes perfect sense to me as well. "A lot is possible. But most of the time a little is sufficient."
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Re: Motor running in offset from magnetic center

Abhi03 ·
@ELECTRICPETE ... coupling is Flender rupex RWN Thank you EDINSONINDIA @DAN.. Thank you DAN.. This sounds convincing we will inspect the coupling and check for any rubbing marks..
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Re: Coupling hub OR shaft run out

electricpete ·
For rim runout, try an additional measurement on shaft adjacent to coupling hub.
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Re: Coupling hub OR shaft run out

Shurafa ·
Another useful check is done by a micrometer. If the coupling hub's OD is not consistent (e.g. shape is oval), a part of the runout is from the hub. Regards-Ali M. Al-Shurafa
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Re: Coupling hub OR shaft run out

Walt Strong ·
If you are measuring runout at a single location on the coupling hub then there are these possibilities for excessive runout: 1) the hub surface is not in a circular shape 2) the hub bores off-center 3) the shaft is bent I would not state that the shaft is bent without additional measurements. Walt
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Re: Coupling hub OR shaft run out

electricpete ·
Or check that the sum of rim TIR readings at 12:00 and 6:00 is approx equal to the sum of those at 3:00 and 9:00. If reasonably close, then no mic needed, the hub od is round. But if they differ too much then investigate further with mic.
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Re: Coupling hub OR shaft run out

edisonindia ·
Ovality (?) is different from run-out. You measure the first one with micrometer as mentioned by others here and the second one by turning the shaft. Hub can be oval but still not have a run-out. If you doubt which is causing the run-out, best to remove the hub from the shaft and measure the shaft, hub bore & hub rim individually.
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Re: Coupling hub OR shaft run out

electricpete ·
I agree that ovality is different than runout, but my suggestions is that we can get some info about BOTH from a set of rim TIR readings. Let's say you take dial indicator readings on RIM as rotated every 90 degrees (12:00, 3:00, 6:00, 9:00) with the indicator base mounted stationary. 0, 5, 10, 5. It is 10 mils runout. No indication of ovality. I don't see any benefit to using Mic here. 0, 10, 0, 10. Suggests oval. Followup with mic to confirm.
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Re: Coupling hub OR shaft run out

fburgos ·
measure runout in different locations beginning close to the bearing, if all measurements are high in the same location (12:00 for example) and rising (increments from the bearing to the coupling) it's definitely a bend shaft.
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Re: Problems in Gear Couplings, and their Remedies

John from PA ·
Start with perhaps supplying some photographs and some machine characteristics like transmitted power, RPM, type of lubrication, etc.
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Re: Problems in Gear Couplings, and their Remedies

SASI ·
alignment issues, tooth binding and lubrication are to be checked first
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Re: Problems in Gear Couplings, and their Remedies

Alvin MC ·
Here is a good article on gear coupling reliability http://www.machinerylubricatio...coupling-reliability
 
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