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Tagged With "Apollo Root Cause Analysis"

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Re: Are we trending away from skilled labor?

MotorDoc ·
OK, now let us get into the 1980's (great music, etc.): In 1983, a consultant by the name of Goldratt published 'The Goal' that outlined his Theory of Constraints (TOC). TOC identified several principles for making a company competitive: 1. Reduce inventory; 2. Improve throughput; and, 3. Reduce operating costs At the time, companies were rather inefficient with both labor and management. He saw, and states, that if you claim that you have reduced operating costs it must have also removed...
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Re: Electrical Equipment PM Checks in a Dusty Dry Environment

MotorDoc ·
Please find the following attached document. I have several others to add. Note: There is a new IEEE standard in the voting process, right now, that covers condition-based testing and troubleshooting of electrical motors and related systems. The PAR number is P1415. Howard
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Re: Electrical Equipment PM Checks in a Dusty Dry Environment

MotorDoc ·
You can also find related documents on: http://www.motordiagnostics.com/presentations.htm Howard
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Re: What wrong with this Root Blower.

PEERA ·
Dear Ralph, I have the root blower number is Ito Blower Type: IRS – 150L, speed 1160 Rpm, Serial number: 2420194. On 5 Oct 2005 I had take data of this blower and it remains running. I give comment to our customer this machine is in stage 3 that mean monitoring very closely. If I have more time I will give data of this root blower to our friend. If who have any comment please send it to my email address. Peeray@tgi.or.th Have a nice day. Peera
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Re: Shock Pulse Method (SPM) reference value in dB definition

Miguel Kovac ·
The db scale is a logarithmic scale relative to some reference. In sound measurement the db scale is referenced to a specific sound pressure level. In machinery analysis the db scale is used to express the ratio between two voltages, an output and an input, so db=20 log voltage ratio. SPM register mechanical shock speed wich produce impact, impact produce molecular aceleration, aceleration only dependof shock speed (no depend of mass). Molecular aceleration produces a wave compression wich...
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You’re Making It Too Complicated

Reliability ·
We make problem solving more complicated than it needs to be
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Re: natural frequency calculations

electricpete ·
In Den Hartog page 154 I find an equation which ends up being identical to the one provided by Steve. w = 22.4/L^2 * sqrt(E*I/mu) 22.4 is 4.730041^2 1/L^2 outside the root is equivalent to 1/L^4 inside the root. mu is Den Hartog's symbol for mass per foot which is A*rho E is an easy one. 30E6 psi for steel. There will be a lot of units to convert which is not too tough. The part I can't figure is the I. For simple rectangular beam we use b*h^3/12. And you can break up your L-shape into 2...
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Re: natural frequency calculations

electricpete ·
Thanks Patrick. With the axis on the centroid it seems like the effect of both halves of the L has big effect on I (different than what I thought initially). Maybe that is the philosophy of I-beams. It gets strength from the top and bottom horizontal pieces for bending in vertical direction even though the horizontal piece by itself would have very little strength for bending in that direction? I see one error in my calculation already. For area, I used A=11.75*0.25 inch^2. It should have...
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Re: Wind turbine on-situ balancing

Arne Lindholm ·
Hello JazzChan, all rotor designs tend to utilize laws of physics as much as possible. The wind rotors usually have a fixed speed (newer have variable) and one of the limiting factors is the tip speed. Same issues appy to a helicopter rotor. So in relation to the design, the balancing is an important issue for both. I would apply the same rules for balancing limits as for any rotor with consideration taken to the speed. If you study a few mills in a row, you will notice how most can stop in...
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Re: Impending cage failure are hard to detect

electricpete ·
In a deep groove ball bearing, misalignment of inner ring and outer ring would definitely stress the cage but I don't think that is as much a factor for spherical roller bearings which are very tolerant of this type of misalignment. Some excerpts from SKF Publication PI 401 E 1994 "Bearing Failures and their causes", Page 43, section titled "Cage damage" "Excessive speed - If the bearing is run at speeds in excess of that for which the cage is designed,the cage is subjected to heavy forces...
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A concern for integrally geard compressor with vaned diffuser at the last stage

lux ·
quote/As an impeller blade moves past an internal clearance such as a diffuser vane, a wake is generated that produces a pressure pulse. The frequency of the pressure pulsations is equal to the impeller running speed multiplied by the number of...
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A Different Root Cause Analysis Experience

Rolly12 ·
Dear All, May I post this question on How far is your team going to analyze for the root cause ? And how do you define your Root Cause ? Does FMEA, 5 why, Failure Analysis, Pareto, and other techniques are really meant to address the Root Cause ? My...
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A screw compressor was seized

Vastocean ·
Dear friends! In these days I experienced a rotor failure on our screw compressor. Please find an attached file to evaluate. During the inspection period we found out some foreign objects inside oil piping system and oil filters We suspect that inside...
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Abnormal Behavior of Centrifugal Compressor

Faisal Ali ·
We have Steam turbine driven CO2 centrifugal compressor having 2 casings (LP/HP) with 2 stages in each Casing. Recently abnormal decrease in 3rd stage (HP) discharge temperature observed with increase in pressure. Temp reduced from 180 deg C to 140 deg C and pressure increased to 6 bar g. With this flow (Throughput) reduced upto 6 tons/hr. OEM indicated that Labyrinth seal between 3rd and 4th stage might have damaged which is causing low temp (40 deg C) 4th stage suction gas to mix with 3rd...
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Abnormal Behavior of Centrifugal Compressor

Faisal Ali ·
We have Steam turbine driven CO2 centrifugal compressor having 2 casings (LP/HP) with 2 stages in each Casing. Recently abnormal decrease in 3rd stage (HP) discharge temperature observed with increase in pressure. Temp reduced from 180 deg C to 140 deg C and pressure increased to 6 bar g. With this flow (Throughput) reduced upto 6 tons/hr. OEM indicated that Labyrinth seal between 3rd and 4th stage might have damaged which is causing low temp (40 deg C) 4th stage suction gas to mix with 3rd...
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Abnormal Behavior of Centrifugal Compressor

Faisal Ali ·
We have Steam turbine driven CO2 centrifugal compressor having 2 casings (LP/HP) with 2 stages in each Casing. Recently abnormal decrease in 3rd stage (HP) discharge temperature observed with increase in pressure. Temp reduced from 180 deg C to 140 deg C and pressure increased to 6 bar g. With this flow (Throughput) reduced upto 6 tons/hr. OEM indicated that Labyrinth seal between 3rd and 4th stage might have damaged which is causing low temp (40 deg C) 4th stage suction gas to mix with 3rd...
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Abnormal behavior of Expander

Faisal Ali ·
Hello to all, We are experiencing some unique behavior at our Synthesis gas expander, installed at Ammonia plant. The expander is installed in Cold box, used to cool down synthesis gas first by passing through series of exchangers and then expansion...
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Abnormal vibration at pump.

Ngo Dinh ·
Hi everyone, I am facing a problem with a pump which is restarted with a abnormal vibration. I think that the rubbing is a cause in the case. But I still confuse that it is really by rubbing or this is effect of two frequency of 100Hz and...
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Abnormal vibration at steam turbine after major overhaul.

Ngo Dinh ·
Dear Everybody, I have a case of abnormal vibration at both side of steam turbine which I hope to receive your comment/ideal of the root cause on this issue (pls see in file attachment for your information). Some information as below: The pump is...
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Abnormal vibration (one of the rubbing phenomenon)

Ngo Dinh ·
Happy new year to all of you. Taking the chance of new year coming, I kindly wish you and your family have a new year with full of happiness, health and success. Back to my problem, I would like to discuss with all of you a case which I think that I...
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Abnormally High Amplitude of GMF

Seemant ·
This is a case of vertical geared motor for agitator drive. The pinion is mounted on motor shaft with ball bearings. The No. of teeth on input pinion are 37 and running rpm is 1500. The gearbox ratio is 1500/40 (3 stage reduction) I am observing 1st...
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Re: RMS vs Peak in Bently Nevada

John from PA ·
Understand that the BN monitors are made for the global marketplace and hence are generally capable of RMS and peak detection. Peak detection is commonly used in the US and you will find that in most instances acceptance criteria or OEM recommended limits are specified in peak units. As you've discovered there can be some huge descrepancies by taking the RMS reading and gaining it up by a factor and calling it peak. These descrepancies can be thought of as actual errors, i. e., it isn't much...
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Re: RMS vs Peak in Bently Nevada

John from PA ·
Part 2.
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Re: Looking for input

John Snell ·
There are many applications that can help justify an investment in both the technology and the people"”you!"”to use it correctly. Sounds like you have a good start on the list. But IR must be part of a larger program of "condition-based asset health management" if it is to pay real returns. In other words, you can find all the electrical problems in the world but if no one fixes them or deals with root cause issues, why bother?! Investments in thermographers are vital and many managers gloss...
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Re: Failure of Reciprocating compressor.

CGTCS ·
Stephen, I have done RCA on many failures of this magnitude or greater over the past 30 years. (just to give you my credentials). It is hard to say from one photograph and limited information as I am sure you are well aware. Your best clues lay in the parts analysis. If you see bearings which were hot (blue color) you can start investigating a lubrication problem. I can not say for sure because the photograph is not that revealing but it looks to me that a more likely cause may be a...
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Accelerometer is used for higher frequencies whereas Disp used for Lower freq! Why

Khalid Khattak ·
Following are the equations of Motion for a sinusoidal wave: Displacement: X= A Sin( wt) Velocity: V= Aw Cos(wt) Acceleration: A= -Aw^2 Sin (wt) where A= Max. Amplitude Now the question is that for a single frequency and constant Amplitude, the...
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Re: very low level bearing defect signature during shop run

Walt Strong ·
El'Pete, I agree with most of the comments. I'll just add that another cause of apparent fault frequencies is lubricant contamination. Flushing old lubricant, cleaning internal spaces and passages, and installing a new bearing in a clean environment are all issues with a machine rebuild. It would be good to get to the root cause, or at least verify that the fault frequencies are eliminated after bearing replacement. I guess you are arguing over who pays the bill, you or the motor shop! Walt
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Re: Clamped vs. free beam modal analysis

electricpete ·
So if I understand correctly, you impact the beam at a point and measure ratio of acceleration response at that point to force input at that point (all at the resonant frequency of interest). Then move to the next point and repeat (new point of response measurement and same new point of force input measurement). I don't think that would create a modeshape stricly speaking. Or did you keep the point of impact the same and move the point of monitoring? That would make more sense. Attached is...
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Re: attachment problems

AMP Administrator ·
The problem has been repaired. Root Cause Analysis: Self Induced Error caused by Forum Manager (Me) The server host dropped Microsoft Front Page support and several home page elements were not functioning properly so I redirected what I thought was the home page index to go straight to the forums. Instead - it sent every link in the site to the forum start page. Never a dull moment. Sorry for the problem. Terry O
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Re: Pump With High Vibration

ivibr8 ·
I tend to agree with John from PA. Although the eccentric reducers and geometry is not ideal, I suspect they play only a minor role in the overall vib level. Based on your observations so far, it seems that a Fn at vane pass frequency is more likely to be the root cause of the high vibration. Keep us posted on the bump test results before and after any mods Jim from NY
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Re: Pump With High Vibration

Riyaz Ahmad Dave ·
I know that this is a case of resonance. How do I get rid of it? My understanding is that the natural frequency depends on the equipment, piping, pipe supports, installation etc. Similar pump at another location operates fine. How do I identify the root cause. The guy I am dealing with is a PE for this reason I want to make sure that my findings are accurate. Even if I am not dealing with a PE, I would like to be accurate with my findings. Your thoughts.
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Re: rolling bearing failure analysis documents

ffff ·
Hi There, Any suggestion about the root cause of the pattern on this bearing. Thanks George
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Re: Impending cage failure are hard to detect

VIB.Welt ·
I reviewed many source of cage failure root cause and what I found is: Crack caused by: handling problem or abnormal load. Distortion caused by: handling/mounting problem. Rust, corrosion caused by: rust during storage of lubrication problem. Wear caused by: shortage of lubrication or contamination. Rivet problem caused by: mounting problem or sever load/vibration. ( Form Koyo Ball & Roller Bearings: Failures, Causes and Countermeasures manual ) So the root cause consists of three main...
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Re: Vibration Testing and Motor Testing connection??

Rotate ·
Hi Bexar, Solo (decoupled) of a motor will sometimes identify mechanical problems not associated with load. Load on the motor (coupled) will help identify electrical problems and mechanical problems associated with load. Vibration analysis of machinery problems is often solved by the approach to the problem. When I came into this business, my mentor told me to learn balance and alignment because those were the easiest to eliminate as a source of machinery vibration problems i.e. if you take...
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Re: When did you first hear of Autocorrelation?

John from PA ·
Bill, I heard about it in school, probably 1964-1965, and I take umbrage with being called an "Old F@rt"! Seriously, just how far do you want to go back? S. Crandall, Random Vibrations in Mechanical Systems (1963) or perhaps WAY back to N. Weiner "Generalized Harmonic Analysis" (1930), Acta Mathematica, V. 55, No. 118. But perhaps something a bit more recent (see attachment) for a good understanding.
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Axial Vibration High in Compressor

Gurusamy ·
Dear all In centrifugal compressor ( IR centac) we are facing axial vibration high. The oil pr. 2bar trend maintained..Delta P also Ok. We are getting axial vinb high, what will be the root cause??? Thanks in advance...
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backflow on a compressor train

monitor ·
Hello, Any of you dealt with the fenomena of backflow? We where dealing with it. First instance i was was suggesting about a partial radial rub because this was seen in the reversed side of the full spectrum cascade plot. Becoming know of new...
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Re: sudden high vibs on steam turbine

monitor ·
All, It's not a spiral vibration vs. phases changes continiously. The phase changes and the vibrations also. I noticed the same vibration behaviour on a gasturbine early in 2005. then it was confirmed bij a rub in the buckets (boroscope inspection confirmed it). I do also think it's a rub. A slight rub which caused a slight thermal inbalanced rotor and then stabilized to its normal behaviour. More advanced analyzes revealed even more sudden(potential) rubs. Not only with vibration increases...
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Re: MHM RBM view linked softwares

CraigE ·
We are currently using MHM V5.31 and reporting through RBMView. I am not happy with this reporting package and would like to move towards a web based portal to review results. Has anyone used the Emerson Asset Portal - Machine History Viewer? Does anyone know of other viewer programs that might be able to interface with MHM software that could do a similar role? Thanks in advance Craig
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Re: True Vs Scaled

Pump Guy ·
Vibmaster. You are arguing unnecessarily. This forum is great platform for learning for all of us including me. I have not said there is no term like overall peak. In fact on my post (dated 15 August 2011) just above your post, I explained what overall peak is. It is important for all of us in the vibration world to use correct terminology. The term "Peak" is never used by itself because it does not explain anything. Following terms are used to describe a peak. 1. Overall peak. (TWF) 2.
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Re: RCA Software

mwp ·
Before recommending software, it would be nice to know more about what you plan to do with it. What type of problems are you investigating? How do you see the software helping you perform your job? Software implements a root cause system. The system that would work for you depends on what you plan to investigate. Perhaps you should be picking a root cause system and software? Best Regards, Mark Paradies President, System Improvements The TapRooT® Folks http://www.taproot.com
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Re: Measurement of Refractory Thickness

sachin05 ·
erosion of 50 -70 mm in worst locations were observed.. Spread sheet way is alredy being planeed with inputs from the thermocouples.. penetration is not reqd if the whole thing is insterted in one end and measured on opposite end.. I think for gamma ray we will require both side excess for placing source and the film.. continuous monitoring will be helpful in knowing the root cause of erosion. I am a mechanical guy for U R information..
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Re: Formulas

John from PA ·
Attachment, available in the public domain from HP Agilent, might prove useful if "new" to vibration.
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Re: Paddle Fan Failure due to Resonance

RRS_Dave ·
Danny, That's what a cold weld is, there was not enough heat provided to penetrate the steel to any depth to get the homogenous mixing of parent and filler materials to provide a strong joint. Worse than having slag in a joint in my opinion. This was probably done with a machine and no one knowledgable "looking" at the process. A skilled welder will know in the first two inches whether his heat is right or not. Now, having looked at the pictures, it appears to me this weld was done with a...
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Re: Paddle Fan Failure due to Resonance

electricpete ·
It's a good case, thanks for sharing. Since this question of how blade pass frequency affects the rotor was brought up in another thread… http://maintenanceforums.com/e...20203373#63620203373 it makes for interesting discussion and I'll throw in my two cents fwiw here. I agree with Bill, it's not obvious that the blades will see blade pass frequency forces unless we're talking about torsional resonance involving all blades moving together (so that a force pulse on any blade contributes to...
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Re: Lobes Compressor (A headache!!!)

Imran.Ahmad78@Hotmail.Com ·
HI Reliable Analyst, Can you share root cause of your compressor high vibration if it was solved ? Regards Imran
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Re: Explanation of 2X

Ron Brook ·
If the 2x increases with voltage, you definitely have an iron problem. My guess is the stator is not rigid in the frame. This is the primary excitation source for all vibration at 2x line frequency and the amount of vibration is usually proportional to voltage. So the second the voltage reaches full voltage, that should be the maximum vibration. However, you have a problem that is affecting radial (DE) as well as axial (NDE) and that points towards rotor motion as well as stator motion.
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Re: Motor High Frequency Tone

seandude ·
I performed a rotor balance on the ID fan motor in question from years back and found a damaged/gouged rotor bar. It was sent for repair and the whine disappeared. I believe the rotor bar was the root cause. I have another condenser cooling pump with a similar issue. It has run for years with no ill effects. I will post the data so that other can learn from my experience.
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Re: 1900/65A vs. Microlog CMVA60

John from PA ·
See attached (part 1). In addition this is in two parts so refer to second reply.
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Re: 1900/65A vs. Microlog CMVA60

John from PA ·
See attached (part 2). In addition this is in two parts so refer to part 1 in previous reply.
 
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