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Advanced Maintenance Management

  1. 1. Advanced Maintenance Management 1 My Mission is to Keep Equipment Running
  2. 2. 2 Advanced Maintenance Management Level II Presented by:- Eng. Mohammed Hamed Advanced Maintenance Management Under supervision: Prof. Dr. Attia Gomaa
  3. 3. Advanced Maintenance Management 3 Content: 1. Overview on Predictive Maintenance Techniques 2. Vibration Basics and Machine Reliability 3. Spectrum Analysis & Faults Diagnosis Case Study 4. Basics of Oil Analysis 5. Oil Analysis Case Study 6. Ultrasound Technique 7. Infrared Analysis and its Usage Within the Industrial Processes 8. Introduction to RCM & FMEA 9. A Case of Reliable Improvement by Increasing Detection
  4. 4. Advanced Maintenance Management 4 Overview on the Predictive Maintenance Techniques
  5. 5. Benefits of setting-up a PdM Program: To detect what is out of the human sense. To discover hidden failures. To Detect early failures & monitor the machine health condition. To reduce Maintenance Costs. As a useful tool to improve the machine reliability.
  6. 6. Most Commonly Used Techniques: Four Tools Makes-Up 85% of any Condition Monitoring Program
  7. 7. Advanced Maintenance Management 9
  8. 8. Type of fault Vibration Temp Oil Out of balance xxx ---- ---- Misalignment xxx x ---- Damage of bearing xxx xx x Damage of gear box xxx x xx Belt problems xx ---- ---- Motor problems xx x ---- Mechanical looseness xxx x x Resonance xxx ---- ---- Why use Vibration Analysis?
  9. 9. One of the most benefits of a Condition Monitoring program is to detect potential failures at early state. (FailureResistance)
  10. 10. MTBF Determine the PM Interval using reliability data
  11. 11. Advanced Maintenance Management 14 What is vibration? Vibration can be defined as simply the cyclic or oscillating motion of a machine or machine component from its position of rest. Harmonics: Frequency component at a frequency that is an integer (whole number e.g. 2X. 3X. 4X, etc) multiple of the fundamental (reference) frequency. Frequency: Is the no of cycles (vibrations) per second, measured by hertz (HZ)
  12. 12. Vibration& reliability Vibration analysis alone doesn’t improve reliability, root cause analysis and acceptance testing can help. There are two ways that we can utilize vibration to improve reliability: First , if we study the vibration we can often determine why the fault condition developed in the first place; for example what caused the crack to appear in the inner race of the bearing? If we perform root cause failure analysis we can make chances to our proactive so that the bearing don’t suffer the same fate in the future.
  13. 13. Second, when we overhaul the machine, we can again use the vibration analysis to check that the maintenance repair has been made correctly; and that the machine is correctly aligned and balanced, this called acceptance testing. Vibration is still used to monitor the health of the machine, but if we improved the reliability of the machine we will see fewer faults conditions develop.
  14. 14. Measuring With Smart Sensors “Collecting Data” Analysis With Smart Software
  15. 15. Getting Results Performing Actions accordingly
  16. 16. What to Measure?? We normally measure the vibration speeds in in/sec or mm/s.
  17. 17. Simple Accurate Easy Quick Less Expensive
  18. 18. Professional Detectors/Analyzers Professional More Accurate Software Analysis Automatic Analysis professional results Costly
  19. 19. Measuring at bearing points in three directions: Horizontal Vertical Axial
  20. 20. Measurement Points
  21. 21. Taking readings in three directions gives more information that helps in analysis as some defects comes with predominant vibrations in a particular directions. Axial is the direction parallel to the centerline of a shaft or turning axis of a rotating part. Radial is that direction toward the center of rotation of a shaft or rotor. The Tangential measurement is that measurement that is tangent or perpendicular to the radial transducer.
  22. 22. SensorPositions
  23. 23. Machine Vibration Sources Van Bearing Motor Shaft If vibration amplitude turns to be increased at the bearing frequency, then we can determine what is wrong with the machine.
  24. 24. What are the faults that spectrum analysis can tell us about? Unbalance Misalignment Bent Shaft Cocked Bearing Foundation Looseness Motor Problems Gear Problems Mechanical Looseness
  25. 25. 20000 0.3 0.6 0.9 1.2 1.5 1.8 1xRPM - UNBALANCE 2xRPM - MISALIGNMENT 3-5xRPM - LOOSENESS 5000 10000 15000 Frequency Hz 5-25xRPM 25-65xRPM ANTI-FRICTION BEARINGS & GEARMESH Predefined Spectrum Analysis Bands MM/S
  26. 26. Frequency in terms of RPM Most likely causes Other possible causes and remarks 1x RPM Unbalance 1) Eccentric journals, gears or pulleys 2) Misalignment or bent shaft- if high axial vibration 3) Resonance 4) Reciprocating forces 5) Electrical problems 2x RPM Mechanical Looseness 1) Misalignment if high axial vibration 2) Reciprocating forces 3) Resonance 4) Bad belts if 2x RPM of belt 33
  27. 27. Frequency in terms of RPM Most likely causes Other possible causes and remarks 3x RPM Misalignment Usually a combination of misalignment and excessive axial clearances(looseness) Less than 1x RPM Oil whirl (less than ½ RPM) 1) Bad drive belts 2) Background vibration 3) Sub-harmonic resonance Synchronous (A.C. Line Frequency) Electrical Problems Common electrical problems include broken rotor bars, eccentric rotor, unbalanced phases in poly-phase systems, unequal air gap. 2x Synch. Frequency Torque pulses Rare as a problem unless resonance is excited 34
  28. 28. Frequency in terms of RPM Most likely causes Other possible causes and remarks High frequency (not harmonically related) Bad anti-friction bearings 1) Bearing vibration may be unsteady- amplitude and frequency 2) Cavitations, recirculation and flow turbulence cause random, high frequency vibration. 3) Improper lubrication of journal bearings (friction excited vibration) 4) Rubbing
  29. 29. Frequency in terms of RPM Most likely causes Other possible causes and remarks Many times RPM (harmonically related freq.) Bad gears Aerodynamic forces Hydraulic forces Mechanical looseness Reciprocating forces Gear teeth times RPM of bad gear Number of fan blades times RPM Number of impeller vanes times RPM May occur at 2,3,4 and sometimes higher harmonics if severe looseness
  30. 30. Motor Foundation Bearing FDE Bearing FNDE Casing Man Hole
  31. 31. 1. Using Vibration Spectrum Analysis to Detect Machine Unbalance For all types of unbalance, the FFT spectrum will show a predominant 1. rpm frequency of vibration.
  32. 32. 39 Machine showing significant increase in vibration level at frequency of 25hz indicating unbalance issue. Spectrum chart
  33. 33. 2. Using Vibration Spectrum Analysis to Detect Machine Misalignment Misalignment, just like unbalance, is a major cause of machinery vibration. Some machines have been incorporated with self-aligning bearings and flexible couplings that can take quite a bit of misalignment. However, despite these, it is not uncommon to come across high vibrations due to misalignment. There are basically two types of misalignment:
  34. 34. Flexible Coupling Self Aligning Ball Bearing
  35. 35. Angular Misalignment Forces are at the axial direction 1x & 2x high in spectrum, sometimes 3x Axial Types of misalginment
  36. 36. Offset (Parallel) Misalignment Forces are at the radial direction 2x will be higher than 1x at radial direction Radial
  37. 37. Excessive misalignment leads to several machine damages & stresses: •Bearing Damage •Seals Damage •Bearing Housing Damage •Shaft Damage •Coupling Damage
  38. 38. Precision Maintenance “Shaft Alignment”
  39. 39. Misalignment vs. bent shaft Often, a bent shaft and dominant angular misalignment give similar FFT spectrums. The vibrations are visible in both the axial and radial vibration measurements. It is only with phase analysis that these problems can be resolved further. In a machine with a bent shaft, a phase difference will be noticed on the two bearings of the same shaft. In the case of misalignment, the phase difference is visible on bearings across the coupling.
  40. 40. 3. Detect Transmission Belt Fault Condition Using Spectrum Analysis Equipment : Electric Motor Speed : 1500RPM Power : 10KW V-Belts Type : SPC5300 Pulleys Diameter: 355mm Belt Frequency = 3.142 (D/L) X (RPM/60) Where D is the pulley diameter & L is the belt length Belt Frequency=23.2HZ From the tables of the v-belts specs, length is 1.2m
  41. 41. M NDE Horizontal 4.09 mm/sec M NDE Vertical 0.57 mm/sec M NDE Axial 01.99 mm/sec M DE Horizontal 3.03 mm/sec M DE Vertical 01.57 mm/sec M DE Axial 02.12 mm/sec 52
  42. 42. Belt Faulty condition (tension or need replace) Frequency 23.2hz Spectrum for MDE-H
  43. 43. When belts are worn, loose or mismatched, they may generate harmonics of the belt frequency. Quite often, the 2× belt frequency is dominant. Amplitudes are normally unsteady, sometimes pulsing with either driver or driven rpm. With timing belt drives, it is useful to know that high amplitudes at the timing belt frequency indicate wear or pulley misalignment.
  44. 44. Belt/sheave misalignment Detection of different pulleys misalignments
  45. 45. Pulley Laser Alignment
  46. 46. It’s difficult to detect the exact reason of a bearing failure without having the vibration test applied. The following is a list of the common defect causes: – Ordinary wear. – Too high ambient temperature. – Corrosion. – Reduced lubrication. – Misalignment. – Vibrations. – Damage due to transport. – Bearing currents from frequency converter drive. 4. Detect the Nature of Bearing Failure
  47. 47. Rough defect condition in a bearing When a certain defect is present on a bearing element (example of a rough defect is shown in the above figure )an increase in the vibration levels at this frequency can be noticed, and that’s why frequency-domain analysis of vibration reading is usually carried out to determine the condition of motor bearings. Frequency-domain or spectral analysis of vibration signal is the most widely used approach for bearing defect detection. Example 1500um outer race defect
  48. 48. BPFO=Nb/2(1-Bd/PDcos α)x RPM Formula to calculate the outer race defect frequency: Where: Bd=diamter of rolling element PD=pitch diamter α=the contact angel Nb=no of rolling elements RPM= the shaft rotating frequency. Motor bearing specifications from the tables: Shaft rotating frequency of 24Hz Bearing having 9 balls of diameter (Bd)= 8.5mm Pitch circle diameter (PD)= 38.5mm Contact angle a of 0. RPM= RPM/60 Calculations=9/2 x 24 x(1-0.22) =84.24Hz BPFO (Ball Pass Frequency , Outer race):
  49. 49. Outer race defect frequency 84.24Hz Bearing Health Condition 0.68mm/s
  50. 50. Bearing Condition After 1 month 3.7mm/s
  51. 51. Bearing Faulty Condition Bearing faulty condition
  52. 52. Spectrum & Vibration Analysis BPFO defect of the bearing can be measured at 84.24hz, bearing vibration amplitude showing significant increase at the bearing outer race frequency indicating outer race defect. Recommendation It’s highly recommended to shutdown the machine to replace the defected bearing.
  53. 53. Common Bearing Failure Patterns
  54. 54. 5. Using Vibration Spetrum Analysis to Detect Machine Looseness If we consider any rotating machine, mechanical looseness can occur at three locations: 1. Internal assembly looseness 2. Looseness at machine to base plate interface 3. Structure looseness.
  55. 55. A.Internal assembly looseness This category of looseness could be between a bearing liner in its cap, a sleeve or rolling element bearing, or an impeller on a shaft. It is normally caused by an improper fit between component parts, which will produce many harmonics in the FFT due to the nonlinear response of the loose parts to the exciting forces from the rotor.
  56. 56. B. Looseness between machine to base plate This problem is associated with loose pillow-block bolts, cracks in the frame structure or the bearing pedestal
  57. 57. C. Structure looseness This type of looseness is caused by structural looseness or weaknesses in the machine’s feet, baseplate or foundation. When the soft foot condition is suspected, an easy test to confirm for it is to loosen each bolt, one at a time, and see if this brings about significant changes in the vibration. In this case, it might be necessary to re-machine the base or install shims to eliminate the distortion when the mounting bolts are tightened again.
  58. 58. (Detection of Bearing Looseness) Equipment data: Machine Description: Centrifugal de-gasing fan Horse Power: 350HP Fan speed= 992RPM Flow rate: 300,000 m3/h No of bearing: 6 bearings Bearing designation: 22222EK
  59. 59. General Components of the Fan
  60. 60. Bearing 3-H = 5.965 Bearing 3-V = 8.632 Bearing 4-H = 16.042 Bearing 4-V = 12.828 Bearing 5-H = 5.83 Bearing 5-V = 5.914 Bearing 6-H = 7.812 Bearing 6-V = 6.505 FDE-H = 6.512 FDE-V = 11.878 FNDE-H = 4.805 FNDE-V = 17.869 Vibration Reading
  61. 61. Vibration Result Recommendation:  Check Bearing no. (4) for fixation problem with the base. (Retighten bearing housing bolts & check bearings internal clearance). Maintenance work to be performed: 1-Retightining of bearing bolts & housing. 2-Monitor bearing condition with some other methods (use ultrasonic)
  62. 62. How to Detect Electric Motor Faults by Vibration Spectrum Analysis? Failure Percentage Bearings 44% Stator 26% Rotor 8% Others 22% It’s evident that defects in the bearings represent the widest source of failure to an induction motor, thus more focus was needed on bearings defects in particular. Rotor Shaft
  63. 63. All gearboxes for (trucks, cars, stirrers, turbines, industrial equipment…etc). All engines that use oil (cars, trucks, heavy equipment,….etc). All hydraulic systems.
  64. 64. Advanced Maintenance Management 81
  65. 65. Terminologies Flash Point: the point at which the oil will be turned into vapor or begin to vaporize. Pour Point: the lowest temperature at which the oil will flow. TBN: is the total base number, illustrate the no of he active additives left in the sample of oil to neutralize the acids. By comparing the TBN of a used oil to the TBN of the same oil in virgin condition, the user can determine how much reserve additive the oil has left to neutralize acids. The lower the TBN reading, the less active additive the oil has left.
  66. 66. The viscosity index is a measure of how much the oil's viscosity changes as temperature changes. A higher viscosity index indicates the viscosity changes less with temperature than a lower viscosity index. TAN: is the total acid number, present how this oil is getting oxidized.
  67. 67. Component Type Elemental Analysis Viscosity Water Acid NO Oxidation Particle Count Engine x x x x Hydraulics x x x x x x Gearbox x x x x x Compressors x x x x x x Turbines x x x x x x Basic Tests
  68. 68. Wear particle analysis determines the mechanical condition of machine components that are lubricated Oil Analysis: Sample Survey Results Improvement
  69. 69. Oil Grade: Oil Type: Equipment Type: Oil Specifications: Viscosity@40degC Viscosity@100degC Total Base Number (TBN) Total Acid Number (TAN) Flash Point
  70. 70. Oil Manufacturer: Asmoil Oil Grade : Synthetic Motor Oil SAE 5W-30 Oil type : Engine Oil Filter type : Full Flow Oil Analysis Report: Example.1: Discuss the following report
  71. 71. Parameters Standard acc to SAE for engine grade 30 1-1- 2009 1-1- 2010 Viscosity@40C 90-110cSt 100 98 Viscoisty@100C 9.3-12.5cSt 11.5 8.6 Fuel Content % 0 0 5 Water Content % 0 0 2 TAN -------- --------- -- ---------- TBN 6-8 7 3.82 Flash Point rate for Asmoil 5W-30 grade 375⁰F< 385 375 Rermark: cSt=Centi Stoke
  72. 72. Parameters Standard acc to SAE for engine grade 30 1-1- 2009 1-1- 2010 Viscosity@40C 90-110 100 98 Viscoisty@100C 9.3-12.5 11.5 8.6 Fuel Content % 0 0 5 Water Content % 0 0 2 TAN -------- ----------- ---------- TBN 6-8 7 3.82 Flash Point rate for Asmoil 5W-30 grade 375⁰F< 385 375 Green color indicate good condition, yellow color indicate alarm level, red color indicate that oil must be changed.
  73. 73. Recommendations based on the result:  Viscosity has been broken down at 100degC, oil should be changed due to reduction in viscosity index number which will reduce the friction resistivity of the oil.  Oil is contamination with fuel indicating leakage in the piston rings.  Oil has water contents indicating failure head gasket or worn cylinder head, check for compression ratio of your engine.  TBN is below the oil standard, this indicate wear, oil must be changed.  Flash point is below the oil number, oil can be vaporized easily.
  74. 74. Signs of wear
  75. 75. Sampling Methods: The frequency of sample analysis from your equipment depends on the machine type, machine application and condition, operating environment and other variables. For example, many machines that operate in harsh environments, such as heavy equipment in mining or construction, require short oil sampling intervals - every 100 to 300 operating hours
  76. 76. Advanced Maintenance Management 93
  77. 77. Condition Oil program Vibration program Correlation Water in oil Strong Not applicable Water can lead to a rapid failure. It is unlikely that a random monthly vibration scan would detect the abnormality. Greased bearings Mixed Strong It makes economic sense to rely on vibration monitoring for routine greased bearing analysis. Many lube labs do not have enough experience with greased bearings to provide reliable Information. Vibration VS Oil Analysis
  78. 78. Condition Oil program Vibration program Correlation Greased motors- operated valves Mixed Weak Actuators are important machinery in the nuclear industry. Grease samples can be readily tested, but it can be difficult to obtain a representative sample. It can be hard to find these valves operating, making it difficult to monitor with vibration Techniques. Shaft cracks Not applicable Strong Vibration analysis can be very Strong effective to monitor a cracked Shaft.
  79. 79. Condition Oil program Vibration program Correlation Lubricant condition monitoring Strong Not applicable The lubricant can be a significant cause of failure. Resonace Not applicable Strong Vibration program can detect a resonance condition. Lube analysis will eventually see the effect. Root Cause Failure Analysis Strong Strong Best when both programs work together.
  80. 80. Condition Oil program Vibration program Correlation Gear wears Strong Strong Vibration techniques can link a defect to a particular gear. Lube analysis can predict the type of failure mode. Alignment Not applicable Strong Vibration program can detect a misalignment condition. Lube analysis will eventually see the effect of increased/improper bearing load.
  81. 81. Advanced Maintenance Management 98 RCM Reliability Centered Maintenance The RCM philosophy employs Preventive Maintenance (PM), Predictive Testing and Inspection, Repair (also called reactive maintenance) and Proactive Maintenance techniques in an integrated manner to increase the probability that a machine or component will function in the required manner over its design life cycle with a minimum of maintenance. The goal of the philosophy is to provide the stated function of the facility, with the required reliability and availability at the lowest cost. RCM requires that maintenance decisions be based on maintenance requirements supported by sound technical and economic justification.
  82. 82. A rigorous RCM analysis is based on a detailed Failure Modes and Effects Analysis (FMEA) and includes probabilities of failure and system reliability calculations. The analysis is used to determine appropriate maintenance tasks to address each of the identified failure modes and their consequence As with any philosophy, there are many paths, or processes, that lead to a final goal. This is especially true for RCM where the consequences of failure can vary dramatically. Rigorous RCM analysis has been used extensively by the aircraft, space, defense, and nuclear industries where functional failures have the potential to result in large losses of life, national security implications, and/or extreme environmental impact. Advanced Maintenance Management 99 Equipment or Maintenance Reliability Definition: The instantaneous likelihoods of failure for a specific piece of equipment during a specific time period.
  83. 83. RCM Analysis The RCM analysis carefully considers the following questions: • What does the system or equipment do; what is its function? • What functional failures are likely to occur? • What are the likely consequences of these functional failures? • What can be done to reduce the probability of the failure, identify the onset of failure, or reduce the consequences of the failure • To ensure realization of the inherent safety and reliability levels of the equipment. • To restore the equipment to these inherent levels when deterioration occurs. • To obtain the information necessary for design improvement of those items where their inherent reliability proves to be inadequate. • To accomplish these goals at a minimum total cost, including maintenance costs, support costs, and economic consequences of operational failures. RCM Goals Advanced Maintenance Management 100
  84. 84. Indentify System & Boundary Indentify Sub System and Components Examine Function Identify Consequence of Failure Define Failure & Failure Mode ------------------------ •System Input •System Output •Resources •Constraints To what level? •Inconsequential •Primary or Support •Continuous or Intermittent •Active or Passive Failures: •Hidden Failures •Potential Failures Environmental, Health & Safety Operational/Mission •Availability •Quantity •Quality Cost ------------------------ ------------------------ ------------------------ ----------------------- Reliability Analysis Advanced Maintenance Management 101
  85. 85. Will the failure have a direct effect on environment health or safety Is there an effective PdM technology or approach? Develop & schedule PdM task to measure condition Develop Condition Based Task Will the failure have a direct & adverse effect on mission quantity or quality? Will the failure result in other economic losses (high cost damage to equipment or system) No Candidate For Run to Failure Is there an effective Interval Based Task Develop & schedule Interval Based Task Re design system or accept the failure risk No Yes Yes Yes No No Yes Yes Maintenance Analysis No Advanced Maintenance Management 102
  86. 86. Will the failure of the system or equipment item have a direct & adverse effect on safety or critical mission function Is this item expendable Can redesign solve the problem effectively and cost effective Accept Risk Is there a PdM technology that will monitor condition and give sufficient warning of an impending failure Redesign Is PdM cost and priority justified Define PdM task and schedule Is there an effective PM task that will minimize functional failure Define PM task and schedule Is installed redundant cost and priority justified Install Redundant Unit Yes Yes Yes Yes Yes Yes No No No No No No No Yes Abbreviated decision tree used to identify the maintenance approach Advanced Maintenance Management 103
  87. 87. Advanced Maintenance Management 104 What are the Main Differences Between RCM and TPM?
  88. 88. Asfour Training Session 105 TPM RCM The main target is basically restoring the equipment to the basic condition Identify the failure modes and quantify the failures as a cost. Minimize the risk of failure and likelihood of failure for critical/safety hazard components and optimize the maintenance performance Promote the use of planned or preventive maintenance Promote the use of predictive maintenance Involve using autonomous maintenance to reduce the maintenance resources usages and costs. TPM includes eight pillars including safety, education, quality, PM, autonomous maintenance, support systems, focused improvement, and initial phase management. Involve using a special analysis process to determine the best maintenance approach to use based on the cost analysis. Then some tools can be used to minimize the risk of failures for high safety, production, cost components such as FMEA and RCFA. Increase the overall productivity of the process or machine by enhancing maintenance, reducing unscheduled downtime, increasing production capacity, and quality (example OEE) Improve the reliability and life time of the product or machine. This can be done through improving the maintenance, the manufacturing process, and the design process by applying some total quality management tools. Invented by JIPM Invented by aerospace & aircraft industries
  89. 89. Predictive Maintenance Embraced by Plant Maintenance Technique Application Pumps Electric Motors Diesel Generators Condensers Heavy Equipment/ Crane Circuit Breakers Valves Heat Exchangers Electrical Systems Transformers TankPiping VIB Analysis • • • • Oil Analysis • • • • • Wear Analysis • • • • IR Analysis • • • • • • • • • • • Ultrasound • • • • • • • • • Non-Destructive testing (Thickness) • • • Visual Inspection • • • • • • • • • • • • Motor Current Analysis • Advanced Maintenance Management 106
  90. 90. KPI Description MTBF Mean Time Between Failure No of failures addressed by root cause analysis >75% Ratio of PM work orders to CM work orders generated by PdM inspection OEE (Overall Equipment Effectiveness) Availability x Reliability x Quality (85%) Percent of Faults Found in Predictive maintenance Survey (Vib, IR, UT, OA) No of faults found/ No of devices checked (target <3% Percent of equipment covered by condition monitoring Target= 100% Reliability of critical equipment 99% Facility Availability >98% Availability of critical equipment >98% Percent emergency maintenance <5% Percent planned maintenance 90% Reliability KPIs Advanced Maintenance Management 107
  91. 91. A proactive tool to minimize the risk of failures Advanced Maintenance Management 108
  92. 92. Advanced Maintenance Management 109 FMEA can provide the answer to many problems: •How can we prevent this problem from occurring again int he future? •How can we minimize the risk of this potential failure? •How can we produce an error-free product? •How can we reduce the warranty costs? •How can we improve the safety condition in the workplace?
  93. 93. What is Failure Mode Effect Analysis FMEA? An FMEA is a systematic method for identifying and preventing product and process problems before they occur. FMEAs are focused on preventing defects, enhancing safety and increasing customer satisfaction. FMEAs are conducted in the product design or process development stages, although conducting an FMEA on existing products and processes can also yield substantial benefits. What is the purpose of a FMEA? Preventing the process and product problems before they occur is the purpose of Failure Mode Effect Analysis. Used in both the design and manufacturing process, they substantially reduce costs by identifying product and process improvement early in the develop process when changes are relativity easy and inexpensive to make. Advanced Maintenance Management 110
  94. 94. FMEA as a part of a Comprehensive Quality System Can FMEA be used a lone? While FMEAs can be effectively used a lone, a company won’t get maximum benefit without systems to support conducting FMEAs. Two things are necessary needed: 1. A reliable product or process data. Without this data, FMEA becomes a guessing game based on opinions rather than actual facts. Without data the team may focus on the wrong failure modes or missing significant opportunities to improve the failure modes that are the biggest problems. 2. Documentation of procedures. In the absence of documents and procedures, people working in the process could be introducing significant variation in to it by operating it slightly different each time the process is run. Advanced Maintenance Management 111
  95. 95. Advanced Maintenance Management 112 FMEA is one of the ISO 9001:2000 requirements as you must have a system capable of controlling process that determine the acceptability of your product or services.
  96. 96. Benefits of Failure Modes Effect Analysis “FMEA” The object of an FMEA is to look for all of the ways a process or product can fail. A product failure occurs when the product does not function as it should or when it malfunction in some way. •Contribute to improve design for product & process. -Higher reliability -Better Quality -Increase Safety •Contribute to cost saving. -Decrease development time & redesign cost -Decrease warranty costs. -Decrease wastes •Contribute to continuous improvement. Advanced Maintenance Management 113
  97. 97. Advanced Maintenance Management 114 • System FMEA focuses on global system functions. • Design FMEA focuses on components and subsystems. • Process FMEA focuses on manufacturing and assembly processes. • Service FMEA focuses on service functions. Apply to: System, Process, Design, Service Service engineers use FMEA to improve the lifecycle of the product and lower its service costs by developing a proper maintenance program. FMEA helps manufacturing engineers control the process and eliminate errors during production, thus decreasing warranty costs and wastes.
  98. 98. Potential Applications: •Equipment components & parts. •Component proving process. •Outsourcing/resourcing of product. •Develop suppliers to achieve quality. •Major process/ Equipment / Technology. •Changes. •Cost Reductions. •New Product/ Design Analysis •Assist in analysis in a flat Pareto chart. Advanced Maintenance Management 115
  99. 99. Failure Modes: •Any event which causes a functional failure. Example failure modes: •Bearing Seized •Motor burned out •Coupling broken •Impeller jammed Compressors Failure Modes : •Discharge pressure low -Air leakage -leaking valves -Defect gauge Engines Failures Mode: •Knocking -Pistons hitting the head -Crankshaft plays -Oil pump not function Advanced Maintenance Management 116 •Ways in which product or process can fail are called failure modes. The FMEA is a way to identify the failures, effects, and risks within a process or product, and then eliminate or reduce them.
  100. 100. Even the simple products have many opportunities for failure. For example, a drip coffee maker. A relativity simple household appliance-could have several things fail that would render the coffeemaker inoperable. Here are some ways the coffee make can fail: • The heating element doesn’t heat water to sufficient temperature to brew coffee. • The pump doesn’t pump water into the filter basket. • The coffee maker doesn’t turn on automatically by the clock • The clock stops working or running too fast or too slow. • There is a short in the electrical cord. • There is either not enough or too much coffee used. Advanced Maintenance Management 117
  101. 101. Advanced Maintenance Management 118
  102. 102. Advanced Maintenance Management 119 Failures are not limited to problems with the product. Because failures also can occur when the user makes a mistake. Those types of failures should be included in the FMEA. Anything can be done to ensure the product works correctly, regardless of how the user operates it, will move the product closer to 100 percent total customer satisfaction. The use of mistake-proofing techniques, also known by its Japanese term poka-yoke, can be a good tool for preventing failures related to user mistakes. The goal is
  103. 103. The failure effect as it applies to the item under analysis. Ex. Water pump stop The failure effect as it applies at the next higher indenture level. Ex. Water system pressure drop down. The failure effect at the highest indenture level or total system. Ex. System stop. Local Effect Next Higher Effect End-Effect Failure Effects Description Advanced Maintenance Management 120
  104. 104. The team size should be between 4 to 6 persons. But the number of people is dedicated by the number of areas affected by the FMEA for example (manufacturing, maintenance, design, engineering, material, technical service…etc). The customer add another unique perspective and should be considered for team membership. Team Leader: The team leader is responsible for coordinating the FMEA process as follow: 1. Setting up and facilitate meeting. 2. Ensuring the team has the necessary resources available. Advanced Maintenance Management 121
  105. 105. Advanced Maintenance Management 122 3. Making sure the team is progressing toward the completion of the FMEA process. 4. The team leader role is more like of a facilitator rather than decision maker.
  106. 106. Advanced Maintenance Management 123  Determine the boundaries of freedom  Define the scope of the project
  107. 107. Advanced Maintenance Management 124 Select a high-risk process, then follow these steps. 1. Review the process: this step usually involves a carefully selected team that includes people with various job responsibilities and levels of experiences. The purpose of an FMEA team is to bring a variety of perspectives and experiences to the project. 2. Breakdown the system into components and sub-components. 3. Brainstorm potential failure modes. 4. List potential effects of each failure mode. 5. Assign a severity ranking for each effect. 6. Assign an occurrence ranking for each failure mode. 7. Assign a detection ranking for each failure mode. 8. Calculate the risk priority number (RPN) for each effect. 9. Prioritize the failure modes for action using RPN. 10. Take action to eliminate or reduce the high-risk failure modes. 11. Calculate the Resulting RPN as the failure modes are reduced or eliminated. Steps of FMEA Process :
  108. 108. Advanced Maintenance Management 125 FMEA Working Sheet Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN Component/Item Name: Function :
  109. 109. Step.1 Review the Process or Product Advanced Maintenance Management 126 If the team is considering a product, they should review the engineering drawing of the product. If the team considering a process, they should review the operation flowchart. This is to ensue that everyone has the same understanding about the process or product. For a product, they should physically see the product and operate it. For a process, they should physically walk through the process exactly as the process flows.
  110. 110. Advanced Maintenance Management 127 Step.2 Breakdown the system into components and sub-components If the system is a large system, like a water system that supplies an industrial process, the pump can be a critical component inside the system. A motor pump is a critical subcomponent because its failure can break down the entire process. The motor pump should be broken down into more subcomponents that are likely to fail and will affect the system, such as the motor’s bearings and the rotor shaft. The FMEA will be used to prevent the probability of failure for each component or subcomponent.
  111. 111. Step.3 Brain Storm Potential Failure Modes Advanced Maintenance Management 128 Once everyone in the team has an understanding about the product or the process, team members should begin thinking about the potential failure modes that could affect the manufacturing process or the product quality. Focusing should be on the different elements (people, material, equipment, method,…etc). Once the brainstorming is completed, the ideas should be organized by grouping them into like categories. There are many ways to group failure modes, they can be grouped by type of failure (electrical, mechanical, user created). Where on the product or process the failure occurs.
  112. 112. Advanced Maintenance Management 129 Main Rules of Brainstorm: 1. Do not comment on, judge or critique ideas at the time they are offered. 2. Encourage creative and offbeat ideas. 3. The goal is to end up with a large number of ideas; and evaluate ideas later. 4. Each idea should be listed and numbered exactly as offered, on a flip chart. 5. Expect to generate at least 50 to 60 concepts in a 30-minute brainstorming session.
  113. 113. Failure Mode & Effect Analysis FMEA -How can this sub system fail to perform its function? -The Way the failure occurred -What will the operator see? Advanced Maintenance Management 130 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  114. 114. Step.4 List Potential Effects for Each Failure Mode Advanced Maintenance Management 131 For some of the failure modes, there may be one effect, while for other modes, there may be several effects. This information must be through because it will feed into the assignment of the risk ranking for each of the failure. Tips: 1. One failure mode could have several effects. For example, an electrical cutoff in the home could stop the refrigerator and damage food or prevent you from doing work on the computer. 2. Several failure modes could have one effect. A dead car battery or tire failure has the same effect on your vehicle – it will be difficult to make it to work on time with such a failure early in the morning. 3. The team must determine the end-effect each failure mode has on the system or the process. This means examining how each failure affects the entire system, the facility or the other connected processes.
  115. 115. Failure Mode & Effect Analysis FMEA -What happen when failure mode occurs? -Immediate consequences of a failure on operation, function or functionality, or status of some item. Advanced Maintenance Management 132 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  116. 116. Steps 5-7 Assign Severity, Occurrence, and Detection Rankings Advanced Maintenance Management 133 Each of these three rankings is based on 10-point scale, with 1 being the lowest ranking, and 10 the highest.
  117. 117. Failure Mode & Effect Analysis FMEA Effect of failure is determined by the worst case outcome with respect to safety and environment impact, production availability and direct economic cost and all that in numerical measure which are identified from ranking criteria Advanced Maintenance Management 134 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  118. 118. Failure Mode & Effect Analysis FMEA Safety and Environment severity degree Impact degree on availability of Production Impact degree on Cost Advanced Maintenance Management 135 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  119. 119. Description of Failure Effect Effect Ranking No reason to expect failure to have any effect on Safety, Health, Environment or Mission. None 1 Minor disruption of production. Repair of failure can be accomplished during trouble call. Very Low 2 Minor disruption of production. Repair of failure may be longer than trouble call but does not delay Mission. Low 3 Moderate disruption of production. Some portion too of the production process may be delayed. Low to Moderate 4 Moderate disruption of production. The production process will be delayed. Moderate 5 Moderate disruption of production. Some portion of production function is lost. Moderate delay in to High restoring function. Moderate to High 6 High disruption of production. Some portion of production function is lost. Significant delay in restoring function. High 7 High disruption of production. All of production function is lost. Significant delay in restoring High function. Very High 8 Potential Safety, Health or Environmental issue. Failure will occur with warning. Hazard 9 Potential Safety, Health or Environmental issue. Failure will occur without warning. Hazard 10 Severity Ranking Criteria Advanced Maintenance Management 136
  120. 120. Advanced Maintenance Management 137 Step.6 Assign an occurrence ranking for each failure mode The best method for determining the occurrence ranking is to use actual data from the process. This may be in the form of failure logs. When actual failure data are not available, the team must estimate how often a failure mode may occur, The team can make better estimate on how likely a failure mode is to occur and at what frequency by knowing the potential cause of failure. Once the potential causes have been identified for all of the failure modes, an occurrence ranking can be assigned even if the failure data are not exist.
  121. 121. Failure Mode & Effect Analysis FMEA For each failure mode there may be several failure causes. Assign a Cause for each failure mode. Select only potential failure to get failure causes. Use Why Why Technique to get the root causes. Identifying the failure cause can be the second option to determine the occurrence if no data is available in the form of failure logs. Advanced Maintenance Management 138 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  122. 122. Failure Mode & Effect Analysis FMEA The probability of failure Occurrence during the expected life of the system “potential occurrence” Advanced Maintenance Management 139 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  123. 123. Rank Freq Description 1 1/10,000 Remote probability of occurrence; unreasonable to expect failure to occur 2 1/5,000 Low failure rate; similar to past design that has, in the past, had low failure rates for given volume or load 3 1/2,000 Low failure rate; similar to past design that has, in the past, had low failure rates for given volume or load 4 1/1000 Occasional failure rate; similar to past design that has, in the past, had similar failure rates for given volume or load 5 1/500 Moderate failure rate; similar to past design that has, in the past, had moderate failure rates for given volume or load 6 1/200 Moderate failure rate; similar to past design that has, in the past, had moderate failure rates for given volume or load 7 1/100 High failure rate; similar to past design that has, in the past, had high failure rates that have caused problems 8 1/50 High failure rate; similar to past design that has, in the past, had high failure rates that have caused problems 9 1/20 Very High failure rate; almost certain to cause Problems 10 1/10 Very High failure rate; almost certain to cause Problems Occurrence Ranking Criteria Operating hours based on the automotive industry benchmark. Ranking can be determined based on historical data or similar system benchmarking Advanced Maintenance Management 140
  124. 124. Advanced Maintenance Management 141 Step.7 Assign a detection ranking for each failure mode and/or effect First, the current control should be listed for all of the failure modes, or effects , and then the detection rankings assigned. *If one failure mode or effect has several causes, detection and occurrence rankings should be assigned based on these causes. When potential causes are eliminated, the risk of failure is lowered.
  125. 125. Current control/fault detection methods applied to detect this failure. This will help assign the detection ranking. Each detection method should be assigned for each failure mode or effect. Advanced Maintenance Management 142 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  126. 126. Failure Mode & Effect Analysis FMEA Probability that a failure of mode will be Detected using the control methods that are in place. Advanced Maintenance Management 143 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  127. 127. Rank Description 1-2 Very high probability of detection 3-4 High probability of detection 5-7 Moderate probability of detection 8-9 Low probability of detection 10 Very low probability of detection Detection Ranking Criteria Advanced Maintenance Management 144
  128. 128. Step.8 Calculate the Risk Priority Number RPN Advanced Maintenance Management 145 Risk Priority number= Severity x Occurrence x Detection This number alone is meaningless because each FMEA has a different number of failure modes and effects. However, it can serve as a gauge to compare the revised RPN once the recommended actions has been instituted.
  129. 129. Failure Mode & Effect Analysis FMEA Risk Priority Number Calculation Occurrence X Severity X Detection RPN= O x S x D Advanced Maintenance Management 146 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  130. 130. RPN Calculation Benefits: •Contribute in Risk Assessment. •Compare components to determine priority for corrective action. What is RPN? The Risk Priority Number (RPN) methodology is a technique for analyzing the risk associated with potential problems identified during a Failure Mode and Effects Analysis (FMEA) Advanced Maintenance Management 147
  131. 131. Assessing the risk priority number. Each potential failure mode or effect is rated in each of these three factors on a scale ranging from 1 to 10. By multiplying the ranking a risk priority number RPN can be determined for each potential failure mode and effect. The RPN will range from 1 to 1000 for each failure mode. It is used to rank the need for corrective action. Those failure modes with the highest RPN number should be attended first. Although the special attention should be given when the severity ranking is high from (9 to 10) regardless of the RPN. Once a corrective action is takes, a new RPN is determined . This new RPN is called the resulting RPN. Advanced Maintenance Management 148
  132. 132. Step.9 Prioritize the Failure Modes for Action Advanced Maintenance Management 149 Failure modes should be prioritized by ranking them in order, from the highest risk priority number to the lowest. Chances are that you will find that the rule 80/20 rule applied with the RPNs. The team must now decided which item to work for. Usually it helps to set a cutoff RPN (cutoff point), where any failure modes with an RPN above that point are attended to. Those below the cutoff are left alone for the time being. Tip: High-risk numbers should be given attention first; then you can pay attention to the severity rankings. Thus, if several failure modes have the same risk priority number, that failure mode with the highest severity should be given more priority.
  133. 133. Failure Mode & Effect Analysis FMEA Appropriate maintenance action, appropriate maintenance task Corrective actions may include: reduce the severity of occurrence ,or increase the detection probability Advanced Maintenance Management 150 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN
  134. 134. Step.10 Take Actions to eliminate or Reduce the High-Risk Failure Modes Advanced Maintenance Management 151 This is organized using the problems-solving approaches and implement actions to reduce or eliminate the high risk failure modes. Often the easiest way to make an improvement to the product or process is to increase the detectability of the failure, thus lowering the detection rate. Increase the detection rate can be done though assigning a schedule PM action, use a proper condition monitoring program or consider a mistake proofing method in the design. For example, ac computer software will automatically warn incase of low disk space.
  135. 135. Advanced Maintenance Management 152 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN Appropriate actions taken to reduce the risk of failure
  136. 136. Advanced Maintenance Management 153 Step.11 Calculate the Risk Priority Number RPN as the High Risk is Removed Once actions have been taken to reduce the risk priority number, a new ranking for the severity, occurrence, and detection should be calculated. And a resulting RPN is calculated. Expectation is at least 50 percentage reduction in RPN with the FMEA approach. There will always be a potential for failure modes to occur. The question the company must ask is how much relative risk the team is willing to take. That answer might depend o the industry and the seriousness of the failure. For example, in the nuclear industry, there is a little margin for errors,; they can’t risk a disaster occurring. In other industries, it may be acceptable to take the high risk.
  137. 137. Advanced Maintenance Management 154 Item Function Failure Mode Failure effect Severity Failure Cause occurrence Current Controls Detection RPN Recommendation Take action Resulted S O D RPN NEW RPN based on the new Severity, Occurrence, and Detection rankings
  138. 138. Advanced Maintenance Management 155 Failure mode Failure Effect Failure Effect (System) Failure Effect (End) Failure cause Level 1 Root cause Fan operate with high vibration level Equipment damage/breakdown Unexpected plant shutdown Major production losses Bearing fails Poor Maint Equipment damage/breakdown Unexpected plant shutdown Major production losses Housing wear Poor Maint Equipment damage/breakdown Unexpected plant shutdown Major production losses Unbalance fan blade Poor Maint Equipment damage/breakdown Unexpected plant shutdown Major production losses Looseness in foundation Poor Maint Equipment damage/breakdown Unexpected plant shutdown Major production losses Shaft wear Poor Maint
  139. 139. Item name Failure mode Failure Effect (local) Failure Effect (System) Failure cause Failure Cause Root cause Oil 1.Short circuit in transformer Functional stop Production losses Particles in the oil Overheated Bad Maintenance Functional stop Production losses Water in the oil Overheated Bad Maintenance Aging Tap Changes 2-Can’t change voltage level Functional stop Production losses Mechanical damage Wear Life time/ maintenance Ex.2 Transformer Advanced Maintenance Management 156
  140. 140. Ex.3 Water System Function Functional failure/failure modes Causes Provide water to the industrial process Total loss of pressure, volume & flow Pump failed Motor failed Valve out of position Electric Motor Function Functional failure/failure modes Causes Drive the water pump Burn out Circuit Breaker tripped Bearing seized Insulation Rotor Insulation Stator Failure mode Failure Cause Sources of failure/causes Causes Bearing seized, this include bearing, seals, lubrication Lubrication Contamination Supply dirty Sealing failed Wrong type Procedure wrong Supply information wrong Tool little Human error Procedure error Too much Human error Procedure error Motor Bearing Advanced Maintenance Management 157
  141. 141. Failure effect Severity Causes Root Cause Occurrence Current fault detection methods Detection RPN Actions Local sys end S A C Seal failed Seal failed Motor shutdown System shutdown TPL Procedure wrong Lack of trainingHuman error Human error Final Table Advanced Maintenance Management 158
  142. 142. Consequence or Severity Probability or frequency (1) Low (2) Medium (3) High (1) Low (2) Medium (3) High 1 L 2 L 3 M 6 H 4 M 2 L 9 H 6 H 3 M It’s important to design your own matrix Risk=Probability x Severity Advanced Maintenance Management 159
  143. 143. Advanced Maintenance Management 160 Read the publication here URL: http://www.iienet2.org/details.aspx?id=37883
  144. 144. Advanced Maintenance Management 161
  145. 145. Electric Distribution Transformer Equipment Information Equipment Type : Distribution Transformer Technical Specs : 11KV, 2.5KV Function : Transform electric voltage from 11KV to 400V System : Electric station- Supply Glass Furnaces Availability of standby system: Generators Working intervals : 1-2 seconds Effectiveness : Avoid furnace damage, but medium productivity Advanced Maintenance Management 162
  146. 146. Advanced Maintenance Management 163 The electric transformer is considered critical because a failure causes high production losses – $5,000 an hour. A standby generator could keep the furnace running if the transformer failed. The standby was sufficient to avoid damaging the furnace but did not supply enough electricity to continue production.
  147. 147. RPN Reduction %=Ri-Rr/Ri Advanced Maintenance Management 164
  148. 148. Transformer Fault Tree Transformer Components Bushing Tank Core Winding Tap Changers Isolation Advanced Maintenance Management 165
  149. 149. Advanced Maintenance Management 166 Current Control/Prevention methods PM type Component/Item PM Level Visual inspection Oil level Monthly Silica gel Monthly Cooling fans Monthly Temp & gauges Monthly Cleaning External body of the transformer Monthly Tightening Cables Monthly Measurements Voltage Semi annual Ampere Semi annual Sampling Oil Annually
  150. 150. Advanced Maintenance Management 167 Failure type Frequency per year Oil heated 3 Short circuit 2 Volt regulation function error (tap changers fault) 3 Working condition= 24 hours Failure Log History
  151. 151. Component Name & Function: Bushing, supply high voltage Failure Mode Failure Effect Severity Failure Causes Failure Cause Failure Causes Failure Cause Occurrence Current control detection/pr evention methods Detection RPN Short circuit Equipmentshutdown 4 Fault in insulation material Water penetration or dirt Inelastic gasket Aging 1 Visual inspection and cleaning 6 24 Lack of maintenance 1 6 24 Damage bushing Sabotage stone, crash or Careless handling 1 4 16 Analysis Advanced Maintenance Management 168 Recommendation Take actions Result S O D RPN Increase inspection & detectability Use infrared camera & ultrasound for high detection ability 4 1 2 8 4 1 2 8
  152. 152. The function of the bushings is to isolate electrical between tank and windings and to connect the windings to the power system outside the transformer Advanced Maintenance Management 169
  153. 153. Component Name & Function: Tank , enclose oil, protect active parts Failure Mode Failure Effect Severity Failure cause Failure Cause Failure Cause Failure Cause Occurrence Current controls Detection RPM Leakage Equipmentshutdown 4 Tank Damage (Rupture) Material/ method Inelastic gasket or corrosion Aging 1 Visual inspection 5 20 Insufficient maintenance 1 5 20 Mechanica l damage High pressure due to gas generation Arcing 1 None 10 40 Careless handling 1 1 4 Advanced Maintenance Management 170 Recommendation Take actions Result S O D RPN Increase inspection & detectability Use ultrasound for detection of arcing phenomena 4 1 1 4 4 1 1 4 4 1 1 4
  154. 154. The tank is primarily the container of the oil and a physical protection for the active part of the transformer. It also serves as support structure for accessories and control equipment. The tank has to withstand environmental stresses, such as corrosive atmosphere, high humidity and sun radiation. The tank should be inspected for oil leaks, excessive corrosion, dents, and other signs of rough handling. Advanced Maintenance Management 171
  155. 155. Component Name & Function: Core, carry magnetic flux Failure Mode Failure Effect Severity Failure Cause Failure Cause Occurrence Current Control Detection RPN Loss of efficiency (reduction of transformer efficiency) Lower voltage, production disturbance 4 Mechanical failure DC magnetization 1 Basic measurements 4 16 Displacement of the core steal during construction (construction fault) 1 4 16 RPN=S x O x D=16 Advanced Maintenance Management 172 No Recommendation or actions will be taken here.
  156. 156. Advanced Maintenance Management 173
  157. 157. Failure Mode Failure Effect Severity Failure cause Failure Cause Failure Cause Occurrence Current Controls Detection RPN Short circuit Equipmentshutdown 4 Fault insulation Generation of copper sulfide 1 8 32 Hot spot Low oil quality 1 Oil sampling 1 4 Mechanical damage Movement of transformer Ageing of cellulose 1 None 5 20 Transient overvoltage Short circuit in the net 1 5 20 Connection of transformer 1 5 20 Lightning 1 5 20 Construction fault 1 5 20 Component Name & Function: Winding, carry current Advanced Maintenance Management 174
  158. 158. Advanced Maintenance Management 175 Recommendation Take actions Result S O D RPN Increase inspection & detectability Use ultrasound for detection of winding problems 4 1 2 8 4 1 2 8 4 1 2 8 4 1 2 8 4 1 2 8 4 1 2 8
  159. 159. The windings belong to the active part of a transformer, and their function is to carry current. The windings are arranged as cylindrical shells around the core limb, where each strand is wrapped with insulation paper. Copper is today the primary choice as winding material. In addition to dielectric stresses and thermal requirements the windings have to withstand mechanical forces that may cause windings replacement. Such forces can appear during short circuits, lightnings, short circuits in the net or during a movement of the transformer Advanced Maintenance Management 176
  160. 160. Failure Mode Failure Effect Severity Failure cause Failure Case Failure Cause Failure Case Occurrence Current Controls Detection RPN Oil Equipmentshutdown 4 Short circuit in transformer Particles in the oil Overheated Pump failure, Dirty particles in the oil 2 Visual monitoring of gauges and oil sampling 4 32 Water in the oil Overheated or aging Overheated Oil is not cooled Oil, circulation out of function, or Air/Water cooling is out of function Fan/Pump failure 2 4 32 Component Name & function: Oil, the oil serves as both cooling medium and part of the insulation system Advanced Maintenance Management 177
  161. 161. Advanced Maintenance Management 178 Recommendation Take actions Result S O D RPN Increase oil sampling frequency 1. Sample oil every 6 months 2. Increase detectability with infrared camera inspection 4 1 2 8 4 1 2 8
  162. 162. The transformer oil is a highly refined product from mineral crude oil and consists of hydrocarbon composition of which the most common are paraffin, naphthenic, and aromatic oils. The oil serves as both cooling medium and part of the insulation system. The quality of the oil greatly affects the insulation and cooling properties of the transformer. The major causes of oil deterioration are due to moisture and oxygen coupled with heat. Another function of the oil is to impregnate the cellulose and isolate between the different parts in the transformer. Advanced Maintenance Management 179
  163. 163. Function Failure Mode Failure Effect Severity Failure cause Failure Cause Failure Cause Occurrence Current Controls Detection RPN Regulate volt leveling Tap Changes Change of the voltage output 3 Can’t change voltage level Mechanical damage Wear 2 Voltage measuring 6 36 Component Name & Function : Tap Changers, regulate volt levelling Motorized Taps Advanced Maintenance Management 180 Recommendation Take actions Result S O D RPN Increase inspection & detectability Use infrared inspection to detect tap changers faults 4 1 2 8
  164. 164. Advanced Maintenance Management 181
  165. 165. The function of a on-load tap-changer (OLTC) is to regulate the voltage level by adding or subtracting turns from the transformer windings Advanced Maintenance Management 182
  166. 166. Component Name & Function: Solid Isolation, is cellulose based products such as press board and paper. Its function is to provide dielectric and mechanical isolation to the windings. Failure Mode Failure Effect Severity Failure cause Sources of failure Failure Cause Occurrence Current Controls Detection RPN Can’t supply insulation EquipmentShutdown 4 Mechanical damage Short circuit, Ageing of cellulose 1 None 10 40 Movement of transformer fault in insulation material Ageing of cellulose 1 10 40 Hot spot Low oil quality, or Overload 1 1 4 Generation of copper sulfide 1 10 40 Advanced Maintenance Management 183
  167. 167. Advanced Maintenance Management 184 Recommendation Take actions Result S O D RPN Increase inspection & detectability Use ultrasound for detection of winding problems 4 1 2 8 4 1 2 8 4 1 2 8
  168. 168. The solid insulation in a transformer is cellulose based products such as press board and paper. Its function is to provide dielectric and mechanical isolation to the windings. Advanced Maintenance Management 185
  169. 169. Part/Item RPN Bushing 16 16 16 Tank 20 20 40 4 Core 16 16 Winding 4 4 20 RPN Analysis for Transformer Components Advanced Maintenance Management 186 Part/Item RPN Winding 20 20 20 Oil 32 32 Tap Changers 36 Solid Insulation 40 40 4 40 Total 492 A cutoff point of RPN 16 can be set because over 50% of the failure modes are above this number.
  170. 170. Total Risk Priority Number= 492 Recommendations 1. Increase the detection probability for the following failures: -Winding insulation -Tap changers -Oil condition -Insulation breakage -Bushing insulation failure -Tank corrosion/leakage 2. Fit more generators to avoid production losses upon transformer failure (we will need more specially if the whole furnaces are working). Corrective Actions (stage 1): 1. Usage of thermal camera to monitor the winding, tap changers, oil temp, insulation, bushing and tank corrosion. 2. Increase visual inspection capability for the tank. Advanced Maintenance Management 187
  171. 171. Advanced Maintenance Management 188
  172. 172. Transformer Fins Overheating issue Advanced Maintenance Management 189
  173. 173. Expected Total Risk Priority Number after applying the corrective actions Corrective Actions (stage 2): Use the Ultrasound detection to detect winding problems & isolation. Expected Total Risk Priority Number after applying the corrective actions (stage 1 &2): Supportive for early detection RPN Reduction %=R initial – R revised/ =492-184/492 =62% R initial Increase inspection reduce the risk of failure Thermal Camera Advanced Maintenance Management 190
  174. 174. Advanced Maintenance Management 191 The improvements that yielded success included using ultrasound to detect issues, increasing the frequency of oil sampling and using infrared analysis to detect mechanical damage.
  175. 175. Detect Transformer Problems Electric Discharges: •Arcing •Corona •Tracking Advanced Maintenance Management 192
  176. 176. Remember FMEA is a Team Work Job! Team Members for FMEA: •Process Engineer •Operators •Quality •Safety •Maintenance •Product engineer •Customer •Supplier Advanced Maintenance Management 193
  177. 177. Design of FMEA Sheet Advanced Maintenance Management 194
  178. 178. Advanced Maintenance Management 195 Each step is a FMEA toward the target
  179. 179. Advanced Maintenance Management 196 An FMEA process can trigger a number of such actions to improve a product’s service or maintenance processes. They include, but are not limited to:  Increase the detection rate of high-risk failures using a proper technique to monitor conditions.  Increase the inspection rate for a specific component or part.  Modify the routine maintenance program.  Increase the frequency of replacing a specific spare part.  Modify the preventive maintenance schedule.  Change a spare part supplier.  Redesign a specific part in the system – or redesign the whole system.  Use different types of materials or spare parts.
  180. 180. Advanced Maintenance Management 197 Does FMEA Sound Like a Standalone Tool??
  181. 181. Advanced Maintenance Management 198 Failure mode and effects analysis can maximize a product’s reliability. But don’t mistake it as a standalone tool. For example, to determine occurrence ratings, FMEAs rely on the failure log history, and the documentation process also is important. Problem-solving techniques like “five whys,” brainstorming, fault-tree analysis and Pareto analysis must be engaged. These techniques will help determine potential failure modes; assign the severity, occurrence and detection rankings; and provide solutions or actions to eliminate those failures. Other Quality Tools and FMEA
  182. 182. Advanced Maintenance Management 199 Eng. Mohammed Hamed Ahmed Soliman The American University in Cairo Email: mhamed206@yahoo.com m.h.ahmed@ess.aucegypt.edu Tel: +201001309903 https://eg.linkedin.com/in/mohammedhamed References: Raymond J. Mikulak, Robin McDermott. (2008). The Basics of FMEA. Productivity Press; 2 edition Robert T. Amsden and Davida M. Amsdenand. (1998). SPC Simpliefied: Practical steps to quality. Productivity Press; 2 edition
  183. 183. What is ultrasonic? Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing, excess of 20,000 cycles (hertz) per second (20KHZ). Ultrasonic is a predictive maintenance technique and one of the non- destructive testing tools that used in the field of industry to detect early & hidden equipment failures. So by definition, ultrasound is totally undetectable by human ears unless aided by instruments capable of translating ultrasound to audible sound. In the marketplace, these instruments are commonly known as ultrasonic detectors and have been used for various maintenance related functions for over 25 years. Audible Ultrasound
  184. 184. What is the difference between Ultrasonic & Vibration?? Vibration is a low frequency method that can detect bearing failures and the reason of this failure. Ultrasonic is a high frequency vibration method (ultrasonic vibration) that can detect the degrees of bearing failures & wears, it can also detect the lubrication problems of the bearing. One of the most advantages of using ultrasonic over vibration, is that ultrasonic can reveal the lubrication problems and provide a very early warning of bearing faults.
  185. 185. Overview of the Instrument Lightweight and portable, ultrasonic translators are often used to inspect a wide variety of equipment. Some helpful accessories are supplied with the instrument too. Transducer Long range module Rubber focusing probe Stethoscope module Headphones Scanning module
  186. 186. TYPICAL APPLICATIONS PRESSURE/VACUUM LEAKS (TURBULENCE) COMPRESSED AIR OXYGEN HYDROGEN ETC. HEAT EXCHANGERS BOILERS CONDENSERS TANKS PIPES VALVES STEAM TRAPS MECHANICAL INSPECTION BEARINGS LACK OF LUBRICATION/FAILURE PUMPS MOTORS GEARS/GEAR BOXES FANS COMPRESSORS CONVEYERS
  187. 187. AUTOMOTIVE RAIL ROADS MARINE AVIATION ELECTRIC EQUIPMENT (Arcing/tracking/corona) SWITCHGEAR TRANSFORMERS INSULATORS POTHEADS JUNCTION BOXES CIRCUIT BREAKERS
  188. 188.  REASONS FOR ULTRASOUND: 1. ECONOMICS 2. ENVIRONMENTAL 3. SAFETY
  189. 189. 207  Locate the leak  Measure the Leak  Calculate costs  Calculate Greenhouse Gas emission reduction
  190. 190.  GOOD  SUSPECT  LUBRICATE  POST LUBRICATION (Approx. 10 Min.) UE SYSTEMS INC. All Rights Reserved
  191. 191. Detect Bearing Condition & Lubrication issues
  192. 192.  CORONA  TRACKING  ARCING  GOOD FOR MEDIUM and HIGH VOLTAGE 26.8 24.4 *>28.4°F *<23.0°F 23.0 24.0 25.0 26.0 27.0 28.0 UE SYSTEMS INC. All Rights Reserved
  193. 193. Detect Transformer Problems Electric Discharges: •Arcing •Corona •Tracking
  194. 194. Detect Electric Emissions( Arcing, Corona, Tracking)
  195. 195. Detect Gearboxes broken teeth
  196. 196. 1. Ultrasound emissions are directional. 2. Ultrasound tends to be highly localized. 3. Ultrasound provides early warning of impending mechanical failure 4. The instruments can be used in loud, noisy environments 5. They support and enhance other PDM technologies or can stand on their own in a maintenance program 6. Test hazard equipments from long distances. 7. Discover early failures without stopping the equipments. Advantages of Ultrasonic
  197. 197. 1. Surface to be tested must be ground smooth and clean 2. Skilled and trained operator is required. 3.Quite expensive method. Disadvantages of Ultrasonic
  198. 198. This equipment can usually store the measurements to an onboard memory chip and transmit the data to PC software.
  199. 199. Treatment and measurements of signal Ultrasonic or acoustic vibration is energy created by the friction between moving components (bearings, couplings, gear mesh, etc…). This energy is really an AC voltage or current that is at best, highly unstable and erratic. To provide useful data for acoustic vibration monitoring this energy must be made linear for repeatability purposes. A quality ultrasonic detector uses True RMS conversion techniques to accomplish this. RMS means “Root Mean Squared.” It’s a way of measuring an AC voltage by means of taking the root of mean squared samples. Basically, True RMS measurement is a technique that provides consistent theoretically valid measurements of electrical signals derived from mechanical phenomena such as strain, stress, vibration, shock, expansion, bearing noise, and acoustic vibration.
  200. 200. The electrical signals produced by these mechanical actions are often noisy, non-periodic, non-sinusoidal, superimposed on DC levels, and require True RMS for, valid, accurate, and repeatable measurements
  201. 201. Infrared monitoring and analysis has the widest range of application (from high- to low-speed equipment), and it can be effective for spotting both mechanical and electrical failures. It also requires minimum skills for analysis. Everything on this planet contains thermal energy and therefore has a specific temperature. This thermal energy is emitted from the surface of the material. This energy is called is infrared (IR) radiation. The amount of IR radiation emitted at a certain wavelength, from the surface of an object, is a function of the object's temperature. This is a very important concept, since it implies that one can calculate the temperature of an object by measuring the infrared radiation emitted from it.
  202. 202. Detectors in the infrared camera convert this incoming infrared energy from the infrared spectrum to the visual spectrum so we can see the infrared energy Infrared Thermography is the technique for producing a visible image of invisible (to our eyes) infrared energy emitted by objects
  203. 203. IR Benefits Applications Thermal & Radiation science Camera handling Inspection routines & reporting Analysis techniques
  204. 204. Applications of Thermography
  205. 205.  Measurements are:  Non-contact.  Obtained without disturbing production.  Applies to all type of equipment.  Reliable data  Quickly identifies specific location  Apply to most all conditions
  206. 206. Average downtime cost: Lost Revenues Industry Sector Revenue/Hour Chemicals $704,101 Construction & Engineering $389,601 Electronics $477,366 Energy $2,817,846 Food & Beverage $804,192 Manufacturing $1,610,654 Metals/natural resources $580,588 Pharmaceuticals $1,082,252 Utilities 643,250
  207. 207. Various Inspection Points
  208. 208. Machine Heat Sources
  209. 209. Industrial Equipment Applications
  210. 210. Electromechanical & Mechanical Systems Commonly inspected components • Pumps • Fans • Heat Exchangers • Gearboxes • Bearings • Drive belts • Motors Typical reasons for temperature hotspots or deviations • Bearing problems - lubrication, wear, etc. • Bad alignment • Bad cooling- due to reduced airflow • Friction due to wear, misalignment or inadequate lubrication
  211. 211. Bearing Temp is 108.4deg C due to overload issue and this may be a cause of unbalanc e issue Bearing Failures
  212. 212. Bearing temp is 81.2 Bearing temp is high due to greasing problem
  213. 213. Clean the surface and recheck again
  214. 214. Bearing temp is 110degC due to overload issue, this may be due to unbalance issue.
  215. 215. Loose or tight belt heats up abnormally
  216. 216. Pumps Bearing
  217. 217. Motor Bearing
  218. 218. Motor Bearing Motor bearing temperature is high due to excessive belt tension
  219. 219. Overheated Motors
  220. 220. Heat Exchanger Blocked heat exchanger section (green arrow)
  221. 221. Process installations Commonly inspected components • Refractory insulation • Tanks and vessels • Steam systems/traps • Pipes and valves • Heaters/Furnaces • Manufacturing equipment • Plastics Industry (Molding) • Metal Foundry • Boilers and Reactors
  222. 222. Furnace Refractory Thermal Isolation
  223. 223. Refractory Damage
  224. 224. Furnace tubes & Burners
  225. 225. SP01 Casing leaks such as this one can be easily identified with infrared Boiler
  226. 226. Turbine Leakage
  227. 227. Cement Rotary Kiln
  228. 228. Piping : lack of insulation
  229. 229. Piping : lack of insulation
  230. 230. Piping (missed insulation)
  231. 231. 85.5°F 144.3°F 100 120 140 75.8°F 196.2°F 80 100 120 140 160 180 SP01: 153.4°F SP02: 173.9°F 79oC 67o C Notice the temperature difference at flange Condenser Air Leakage
  232. 232. 66.5°F 396.0°F AR01: >364.3°F This leaking valve is over 177oC (350oF). Most leaking valves are less evident. Detect Valves Leakage
  233. 233. 93.7°F 488.6°F 100 200 300 400 SP01: 393.3°F 176.6°F 667.2°F 200 300 400 500 600 SP01: 533.9°F AR01: *598.0°F • All boiler, turbine, stop valve, valve chest, etc., drain lines need to be checked for leak through. • Make sure a valve is totally closed before inspecting. Leaking drain Turbine reheat steam line drain valve leaking Valves Leakage
  234. 234. Power plant : Valves leakages
  235. 235. •IR can identify leaking bypass lines and improper operation (must monitor). •One must know the trap cycle of operation. •Comparison between like equipment that is operating the same often confirms problems. •Use Ultrasonic Acoustics to confirm problems 118.6°F 361.0°F 150 200 250 300 350 SP01 80.2°F 103.2°F 85 90 95 100 SP01 Steam trap stuck open. Steam trap working normally . Steam trap by- pass leaking. Steam Traps
  236. 236. Storage Tanks Levels
  237. 237. Electrical systems •(3 phase) Power distribution •Fuse boxes •Cables & connections •Relays/Switches •Insulators •Capacitors •Circuit breakers •Controllers •Transformers •Battery banks •Motors •Substations
  238. 238. Connection problem Motor Starter Connection Problem
  239. 239. Thermal image showing a failing connection on an electrical component
  240. 240. Transformer
  241. 241. Transformer Oil Fins Overheating issue
  242. 242. Transformer cabinet terminal block connection Low Oil Level
  243. 243. Transformer Winding problem Thermo graphing Windings
  244. 244. Capacitor
  245. 245. Insulation problem
  246. 246. Infrared Analysis for Electric Panels 1. Conductors Problems 2. Starter Problems
  247. 247. 3. Circuit Breaker 4. Switches
  248. 248. 5. Terminal Connectors 6. Switch Gears
  249. 249. 7. Breaker wires & connectors 8. Conductors
  250. 250. 9. PLC (Some panels have controllers) Fig.1 Fig.2
  251. 251. 10. Fuse Boxes
  252. 252. Buildings Commonly inspected components •Walls •Roofs •Windows •Doors •HVAC •Insulation •Floor heating
  253. 253. Concrete Inspections This example shows that even though the bridge deck doesn’t generate heat it can still be analyzed with thermography.
  254. 254. Missing insulation in a residential dwelling wall costs the occupants hundreds of dollars each year in heating and cooling. House Insulation Inspection
  255. 255. Air leakage round a roof latch
  256. 256. Building –Moisture in Roof
  257. 257. Roof (trapped water)
  258. 258. Drain blockage at house
  259. 259. Heat loss in buildings
  260. 260. Aircraft Inspections Composite aircraft materials are extremely sturdy and lightweight. These materials are vital to aircraft performance and airworthiness. However, the honeycomb structure of this material presents a potentially dangerous problem: water ingress
  261. 261. Medical Thermography Race horse sustained an injury in a fall. The infrared image shows where the problem is, and monitored the process of the healing
  262. 262.  It shows a visual picture so temperatures over a large area can be compared.  It is capable of catching moving targets in real time.  It is able to find deteriorating, i.e., higher temperature components prior to their failure.  It can be used to measure or observe in areas inaccessible or hazardous for other methods.  It is a non-destructive test method.  It can be used to find defects in shafts, pipes, and other metal or plastic parts.  It can be used to detect objects in dark area. Advantages of Thermography
  263. 263.  Due to the low volume of thermal cameras, quality cameras often have a high price range (often US$6,000 or more)  Images can be difficult to interpret accurately when based upon certain  objects, specifically objects with erratic temperatures, although this problem is reduced in active thermal imaging  Accurate temperature measurements are conflicted by differing emissivity and reflections from other surfaces  Most cameras have ±2% accuracy or worse and are not as accurate as contact methods.  Only able to directly detect surface temperatures. Limitation of the Thermography:
  264. 264. Books: Machinery Vibration Analysis & Predictive Maintenance. Institutes: Mobius Institute www.Mobiusinstitute.com Vibration Institute www.vibration.org Infraspection Institute www.infraspection.com
  265. 265. Prepared by Eng.Mohammed Hamed Industrial Engineering Consultant & Lecturer Email: mhamed206@yahoo.com : m.h.ahmed@ess.aucegypt.edu Tel : +201001309903 LinkedIn: eg.linkedin.com/in/mohammedhamed/
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