Tag Archives | November


6:00 am
November 1, 2005
Print Friendly

Get "Control" Of Your Data Trending

Time is critical when it comes to identifying degrading equipment performance.

Progress Energy’s Harris Plant is a 950 MW(e) pressurized water nuclear reactor. In November 2003, operators conducting a surveillance test on a piece of the plant’s emergency service water equipment noticed that the differential pressure (dP) was below the minimum required value. During the ensuing investigation, a review of past data showed that the dP had begun decreasing in August 2003—three months earlier—yet had gone undetected. As a result, the site management was interested in improving timeliness in identifying degrading equipment performance. The solution was to use statistical control charts.

Control charts are a statistical trending method used to determine when data variance, or a change in data, is abnormal. They have been used for many years in the manufacturing industry for product or process quality control, but personnel at Harris are now using the method to trend equipment performance and identify degradation in performance at an early stage.

Following the rules
Data varies for many reasons including the repeatability and reproducibility of instruments, differences in test conditions and dependence on other parameters (e.g. temperature). Equipment performance trending requires an understanding of data variance and when it is due to an abnormal cause. An abnormal cause is a degrading condition in the equipment. For example, a worn bearing in a pump motor or a hardening diaphragm in an air-operated valve are degrading conditions. When these degrading conditions are detected early, they can be scheduled without a need for emergent corrective maintenance. A stable work schedule helps the maintenance organization effectively maintain plant equipment and ultimately results in a more reliable facility.

Control charts help you understand when an abnormal cause is present. When data is measured, it typically has a normal distribution, as shown in Fig. 1. A typical control chart is shown in Fig. 2. It consists of the normally distributed data plotted with time. The centerline (green line) is the mean of the data points and the upper and/or lower control limits (red lines) are typically three standard deviations from the mean. The control chart rules (see Sidebar ) are applied to the data trended on the control chart to determine when an abnormal cause may be present and require further investigation.

Proving effectiveness
The effectiveness of the control chart method was first realized through trending of reactor coolant system (RCS) leakage. The Plant Technical Specifications require periodic monitoring of the system leakage every 72 hours to ensure it does not exceed 1 gpm. To comply with this requirement, the leakage is calculated every 24 hours and trended. In the past, the leakage data was subjectively evaluated against past data. This frequently required re-performance of the surveillance to validate apparent increases in leakage when the data only changed due to normal statistical variance.

Fig. 3 illustrates the application of the control chart to the calculated leakage data. On February 7, 2005, the leakage began to increase. By February 12, the data violated control rules 1 and 3 (refer to Sidebar 1). When the data exceeded the upper control limit of 0.090 gpm, Harris personnel began the process of evaluat-ing several potential leakage paths. The systematic elimination of potential sources culminated in a plant walk-down. During the plant walk-down, a two-inch isolation valve was found with a packing leak. The RCS system uses borated water. The leaking valve shown in Fig. 4 shows the boron deposits on the valve and nearby equipment. The valve packing was tightened to eliminate the leak on March 18. The data then returned to normal. The leak was 0.08 gpm. This is equivalent to approximately one cup of water each minute, illustrating the sensitivity of this trend method.

Numerous other examples have also occurred that demonstrate the effectiveness of using control charts for trending of equipment performance. In the ASME Inservice Test Program (IST), the condition of air-operated valves is monitored by trending the valve stroke time. The application of control charts has identified erratic performance of solenoid valves, hardening diaphragms and drifting air regulators. These issues were identified well in advance of exceeding an operational limit and permitted scheduling the maintenance rather than the organization responding to an emergent equipment failure.

The payoff
Implementing control charts for data trending not only improves timely identification of equipment degradation, it also standardizes the approach to data trending. Personnel typically will use everything from pencil and paper to computer software to trend data based on their years of experience and comfort with computers.

Control charts are a tool that can help them be proactive in monitoring equipment performance and avoid being reactive to equipment issues. They provide a sound basis for making decisions related to the taking of further action to understand the cause of adverse trend and avoid organizational vulnerability to the common data trending errors (refer to the Sidebar).

The initial reaction by personnel to using statistics can be negative. Many people believe they can subjectively identify abnormal trends in data based on their experience. In some cases this is true. However, experienced personnel are not always available due to vacation, sickness or organizational attrition. Their threshold for identifying and communicating degrading conditions can also vary. Controls charts provide the standard tool without a need for specific component experience to interpret them.

To be successful in implementing this change to your data trending standard, it is important to secure organizational buy-in from the top down. There are key elements to the implementation that are essential. They include:

  1. Management Training – Ensure your management team understands the basic statistics involved with control charts. If they are interested in seeing the data trends, it helps them understand what changes in data are significant. It will also help in clarifying their expectations associated with the organization’s response to the data when it violates the control rules.
  2. Expected Response to Data – Establish with the management team what the organization’s standard response should be to data that violates the control chart rules. This should be a graded approach based on the criticality of the equipment and establish the expected timeliness of reporting the issue and scheduling the maintenance.
  3. Personnel Training – Ensure that the personnel developing the control charts understand the basic statistics involved and the standard approach when data violates the control chart rules. This should include a basic understanding of what can cause data variance and how the data is expected to change from the potential equipment failure modes/mechanisms.
  4. Purchase a Software Tool – To minimize the work involved in the development of control charts, software should be provided to personnel. There are many software tools on the market, each with its pros and cons. Harris utilized a Microsoft EXCEL add-in that proved to be very effective since personnel were familiar with EXCEL.
  5. Start Small – The organization can be overwhelmed if control charts are placed on every possible parameter. Understand what the critical equipment is in the plant and what the critical performance parameters are before getting started. Pilot the method on a limited set of equipment to work through the logistics involved with the implementation. Logistics include: how and to whom potential equipment issues are to be reported: how the identified issue should be prioritized in the work scheduling process, etc.
  6. Understand the Data Pedigree – To get started, it is important to understand the pedigree of historical data used to create control charts. The data must be under statistical control to start. That means, if there were high or low values due to some equipment problem in the past, that data should be excluded or eliminated from the control chart. The data must also be independent or not subject to other influences (i.e. bearing temperatures that fluctuate with ambient temperature conditions). Additionally, if the equipment is subject to varying loads during operation, it may be necessary to establish consistent test conditions for collecting data.

Statistical control charts are a very effective method for monitoring equipment condition. It provides personnel a trending tool that is sensitive to changes in equipment performance, as well as a method that provides the earliest indication of a degrading equipment condition. Early indications of degrading performance can be investigated to determine the scope of required maintenance and the maintenance scheduled without a need for emergent work.

A stable work schedule has many benefits, including helping the maintenance organization effectively maintain plant equipment, resulting in a more reliable facility. It also improves the plant personnel’s quality of life, with less call outs from emergent equipment failures.

Daryl R. Gruver is supervisor of Component Engineering at Progress Energy’s Shearon Harris facility. He received his B.S. in Nuclear Engineering from Pennsylvania State and his M.S. in Nuclear Engineering from the University of Cincinnati. Gruver holds a Level II ASNT certification in Vibration Analysis and Thermography: telephone: (919) 362-2820; e-mail: Daryl.Gruver@pgnmail.com

Continue Reading →


6:00 am
November 1, 2005
Print Friendly

Information Management Strategies To Achieve Collaborative Asset Life Cycle Management

Raising the levels of “asset intimacy” among service providers is crucial where maintenance is concerned.

Companies typically will embrace a business trend in an effort to move ahead of the competition, achieve long-term savings and, in some cases, improve service levels. Among today’s more noteworthy trends is outsourcing of maintenance. What is often overlooked, however, is the impact that this type of outsourcing has on the quality of asset information management.

While a majority of businesses traditionally have not kept all plant maintenance operations in-house, in some sectors today, over half of equipment maintenance is outsourced. The public sectoralso is moving in this direction—even in areas such as defense operations where highly sensitive information is the norm.

Companies that outsource maintenance operations face challenging questions regarding asset information management, including:

  • How do you monitor third-party maintenance providers to ensure accuracy, safety and quality compliance?
  • How can service providers be efficiently integrated into in-house maintenance and repair operations?
  • What is the best way to manage service levels without direct control of contracted resources?
  • Does the spread of outsourcing mean that in-house maintenance, repair and overhaul (MRO) is gradually losing critical technical skills?

At the same time, the move toward outsourcing places a new burden on service providers by requiring them to now know more about their customers’ assets — in real-time — than in the past. But, without broad access to asset information, such as engineering documentation and service histories, service contractors are unlikely to be able to deliver the sophisticated maintenance strategies and cost savings that their customers demand. How will service providers achieve new levels of “asset intimacy” without a radical re-thinking of asset information management?

Can contractors effectively add value to maintenance and repair operations over the long haul, or will asset service levels decline as a result of outsourcing?

Effective management of expanding service networks and the complexities that directly result from outsourcing require a sophisticated collaborative asset management solution. Simply stated, companies need to build tight coordination between the activities of in-house maintenance workforces and outsourced service providers.

3 levels of “maturity”
The relationship between service and maintenance information systems is often poorly aligned. Both types of systems facilitate maintenance and repair services for equipment owners and operators, but they operate under different business conditions. These differences ought to have no impact on the quality of asset management, but, because of built-in limitations, they do.

While today’s service systems support many customer relationships and complex contractual arrangements, such as service-level agreements and entitlements, maintenance management systems normally support only a single customer (i.e., the enterprise) and relatively simple financial arrangements, if any. Depending on the degree of a company’s maintenance outsourcing and the complexity of its assets, enterprises fall into one of three asset management maturity categories.

  • Companies in the first category—Activity-Based Asset Management—utilize the simplest maintenance and service operations that require little more than the ability to schedule and track activities and costs.
  • At the next level—Siloed Asset Management— information management becomes more robust, but information remains siloed within organizations, addressing either the needs of service providers or in-house maintenance, but rarely both.
  • The final asset management maturity category is Collaborative Asset Life Cycle Management. At this stage, maintenance and service operations are required to increase their collaboration and information needs to converge. Increasing the size of the service network or the complexity of the assets requires an enterprise to effectively “climb” the maturity ladder or risk asset reliability and maintenance cost problems.

Collaboration is essential
There is a great difference between managing an in-house workforce and relying on a service network. For example, engineering managers will run into problems when they increase the amount of maintenance they outsource, yet they continue to manage maintenance operations as if nothing had changed. Only those companies that understand the significant differences between maintaining an internal workforce and outsourcing will be able to successfully lower overhead costs without jeopardizing safe and effective plant operations.

With outsourcing, plant engineers are forced to control service supply costs and manage a network of providers with limited visibility and control. Meanwhile, they must be equipped to guarantee acceptable asset service levels, plant safety and regulatory compliance. The result is often an increase in maintenance errors and diminished responsiveness that may endanger customer service levels.

Existing maintenance management systems, never designed to manage across extensive outsourcing, simply don’t provide a complete view of service status for the enterprise or the service provider. While outsourcing may lead to savings in the short term, it is likely that asset information gaps will gradually erode assets, causing capitalized asset costs to rise. To overcome this challenge, it is important for companies to implement a collaborative asset management solution.

The key to maintenance-service collaboration is access by all stakeholders to critical, accurate asset information , such as recent and historical service records, engineering documentation, manufacturer service bulletins, certifications and regulatory notices. To achieve new levels of collaboration between stakeholders without weakening business operations, companies are beginning to consider a new approach, the previously-referenced collaborative asset life cycle management. An effective strategy of this nature includes two core components: asset data hubs and unified applications to provide real-time information.

Uniting disparate systems
Collaborative asset life cycle management calls for service and maintenance partners to eliminate duplicate data, accommodate both structured and unstructured information and facilitate communication among disparate business systems to process the constant flow of new information from outside sources, including equipment manufacturers and regulators. To accomplish those goals, powerful asset information management data hubs are necessary.

A data hub is a real-time processing engine that automatically verifies, cleanses, de-duplicates and merges information—and then synchronizes all systems. Service and maintenance rely on their own business systems; data hubs that are online and easily interoperate across different systems help to consolidate information from all disparate sources to provide business insight about best maintenance practices and service histories.

It’s also important to note that technology must support ubiquitous computing, including spatial information for geographically dispersed assets, embedded sensor data, RFID and equipment telemetry. Much more than today’s mobile computing, ubiquitous computing can locate assets whose whereabouts are not easily known, update service supply chain status, optimize global multi-echelon spare parts inventories, and cut down the significant travel, research and waiting time associated with maintenance and service execution.

Consolidated enterprise view
Information systems designed for collaborative asset life cycle management must incorporate unified data models and computing standards even more than in the past as simple semantic transaction interfaces aren’t robust enough for the information-sharing that is required. Extensible Markup Language (XML) provides an alphabet and perhaps grammar, but it’s not yet a full-blown language that all computers share. To date, SQL and XML have provided valuable windows that we can see and walk through, but not the data highways we can drive across. Service Oriented Architecture (SOA) and Web services will pave the way for the much needed unification of applications.

In their early years, enterprise resource planning (ERP) suites were perceived as only a partial solution because, instead of eliminating information, they actually made the wealth of information bigger. Mature ERP suites enable enterprise information to be consolidated in one place and dramatically reduce or completely eliminate silos of asset information. Years ago, when banks did this with consumer credit information, they tapped into a huge opportunity to better serve their customers.

Collaborative asset life cycle management requires the same approach with manufactured product information, especially for complex equipment that has long lifecycles. Only by unifying asset information can an entire service network gain the real-time information quality, compliance and control needed for sophisticated maintenance strategies and high asset service levels.

As the move to outsourcing maintenance and service continues, so do the challenges of managing asset information effectively. IT systems that successfully enable collaborative asset lif cycle management between an organization and its service partners must accurately consolidate asset information from disparate systems and also embrace unified data models and computing standards.

Innovation —particularly in the area of collaborative asset life cycle management—has enabled information technology to be less costly and more scalable. When coupled with a defined business strategy, software solutions can facilitate the collaborative asset lifec cycle management vision at a reasonable cost.

Technology plays a critical role in maintenance and repair operations. In particular, utilizing asset data hubs and unified applications will facilitate advanced collaboration between a company and its outsourced service provider. Following this path, a company will be able to achieve the very critical stage of Asset Information Management maturity.

‘Sunny’ Hemant Gosain is senior director, applications development, at Oracle, and currently the head of development of the company’s enterprise asset management, asset tracking and supply chain cost management products. Before joining Oracle, he was a senior consultant with MCI Systemhouse, where he led and managed several IT projects and ERP implementations. Telephone: (650) 506-9284; e-mail: hemant.gosain@oracle.com

Continue Reading →


6:00 am
November 1, 2005
Print Friendly

Partnering To Improve Electric Motor Reliability

A company becomes its own customer with outstanding results. In the process, a new motor repair shop certification program is born.

Electric motors, whether AC or DC, will vary considerably in construction, operation, and performance. All share a distinction, though, in usually rating high on reliability incident reports.

The “bad news” is that this was the case at an SKF plant in Hanover, PA. The “good news” is that solutions were found, valuable lessons were learned and a new program was launched by SKF to provide others in the industry with the tools and expertise to help keep electric motors performing with minimal problems and downtime.

Regardless of type, electric motors experiencing failure will usually be subject to one of three common failure modes (although the root causes for each mode may differ):

  • Failure to start when required;
  • Gradual performance degradation in service; or
  • Catastrophic in-service failure.

Any and all of these modes will drive unwanted downtime and unanticipated costs, which was the situation in the SKF plant in Hanover. Here, it was liquid-cooled motors to power grinding machines that were under-performing. Many were failing regularly and most were vibrating above normal levels, based on periodic vibration analysis conducted at the facility. In an effort to avert catastrophic failure and attempt to preserve uptime, motors were replaced (and rebuilt) immediately when changes in their vibration spectrum were charted. Unfortunately, this chain of events had become routine, expensive and time-consuming, especially since many of the motors were being replaced every few months. A short-term approach, it further failed to identify root causes of the problems that could have pointed the way to remedial actions.

Expediting a solution
A catalyst to expedite a solution came with an internal SKF program (the “PRE-FORM Project”) launched with the goal to establish ever-higher quality and precision standards for all SKF facilities worldwide. In Hanover, the program, in part, required that overall vibration levels of the grinding machines would have to be reduced and that the performance of the electric motors would have to be enhanced to help contribute to improved plant output and quality.

Striving to meet these goals, Hanover turned for outsourced expertise and ultimately commissioned one of its own for the task: SKF Reliability Systems of San Diego, CA. The SKF factory, in fact, became an SKF customer. In the process, new standards and specifications were implemented with strong results. Moreover, an even stronger partnership was forged among all parties, including motor repair shop and plant maintenance personnel.

Unearthing the root cause
Experience tells us that most in-service electric motor failures result from mechanical problems. Possible non-bearing causes abound. These can include windings, wiring, grease or seal failures that, in turn, may result in bearing failures (although bearings are not the root cause).

There often can be additional bearing-related issues involving lubrication (too much, too little, or contamination), misalignment, unbalance, looseness or vibration, among other known influences. Improper motor use and inadequate maintenance can add to potential problems and premature bearing failure.

The initial quest to find answers for the prevailing motor failures in Hanover proved especially vexing as documented in a maintenance-log timeline for one of the motors:

  • 2/20: Motor identified as “going bad.”
  • 2/28: The motor failed (locked up) within days. Shaft end bearing showed excessive heat from locking up, making it difficult to determine exact cause of failure. Independent motor repair shop rebuilt motor and repaired shaft. Motor was re-installed.
  • 4/17: Motor began showing early signs of same conditions encountered in previous failure. This time the motor was pulled earlier for inspection. It was determined that the bearing clearance (internal) appeared to have been reduced, causing 360° ball tracking and increasing internal temperature (which would lead to premature failure). The shaft end bearing was replaced and the motor was re-installed.
  • 6/08: The motor showed trend toward failure for a third time and was sent to the repair shop for complete rebuild and precision G.4 balance. Motor was re-installed.

The search for solutions can be difficult without the proper “tools.” Thus, in tackling the many symptoms and causes of in-service failures of the motors at Hanover, the team adopted a comprehensive Root Cause Failure Analysis (RCFA) approach.

RCFA serves as a structured investigation seeking to identify the true cause of a problem, the cause-and-effect relationships and the actions necessary to prevent repetition. Improvement activities resulting from RCFA studies may suggest machine design improvements, targeted training for operations or maintenance staff and/or provision of specialist equipment for monitoring and maintenance of machinery. In short, RCFA actions can help remove the “guesswork” factor.

Partners in progress
Specialists from SKF Reliability were engaged to conduct a wide range of RCFA services. These included vibration analysis when mechanical problems were encountered; balancing of electric motor pulleys for machine tools and auxiliary equipment, shafts and couplings; and alignment of machine-tool components with digital laser equipment.

As a result, several factors were found to contribute to the repeated motor failures. They included inappropriate bearings (these were replaced with types more suited for the motor application); contamination (remedied by upgrading the sealing function in the motor); misaligned shaft and housing fits (corrected by rewriting specifications for fits and follow-through documentation); and rotor unbalance, on both new and old motors (prompting new requirements to promote balanced systems).

Among the improvement activities recommended in the RCFA, SKF also took an unusual step in training, equipping and certifying the independent electric motor repair shop. This helped strengthen the relationship between customer and service provider and forge a true partnership. The shop was trained to trace root causes of motor failures; mount and install bearings correctly using state-of-the-art tools and techniques; and perform precision maintenance. Both parties jointly developed a specification/process as an established guide to service the motors.

Certification program for shops
The outcome in Hanover (in concert with the global SKF Trouble-Free Operation Program) led to the creation and industry-wide rollout of a unique training and certification program. The “SKF Certified Electric Motor Service” program is available for leading electric motor service shops seeking to gain value-added competence and a competitive edge in the crowded marketplace.

This certification focuses on the four key factors that influence bearing life: product quality, environment, installation, and maintenance. Providers completing this extensive training program earn recognition as “SKF Certified” and are equipped to help improve plant productivity by virtually eliminating premature failure of electric motor bearings.

For end-users, certified shops offer unprecedented access to advanced technologies and expertise, improved quality and increased uptime. The shops are fully supported with specialized bearing tools and lubricants specifically designed for SKF bearings; sophisticated bearing dismounting and mounting equipment; SKF engineering support and technical services (including failure analysis); and high-quality bearings and components.

In Hanover, electric motor reliability at the grinding machines is no longer an issue and measurable savings have been realized. The plant has reduced the total cost of motor maintenance by almost 40 percent and technicians now can spend more time implementing focused procedures instead of puzzling over problems.

Fredrik Franding is Project Manager, Industrial Electrical Market Segment, SKF USA Inc., Kulpsville, PA; telephone: (215) 513-4759; e-mail fredrik.franding@skf.com

Continue Reading →


6:00 am
November 1, 2005
Print Friendly

Extending The Operating Life Of Your Electric Motors

This article is adapted from the U.S. Department of Energy’s tip sheet “Extend the Operating Life of Your Motor,” originally prepared by the Washington State University Energy Program and Lawrence Berkeley National Laboratory.

When it comes to the operation of industrial processes, life cycle cost (LCC) analysis is an often-ignored methodology that can lead to significantly reduced facility operating costs. This is not a new concept—it has been standard practice in the development and procurement of complex military systems for many years. Federal government guidelines require life cycle analysis for federal agencies considering energy and water conservation projects and renewable energy projects in all federal buildings. Even the Hydraulic Institute (a manufacturers’ trade association) has published a handbook on the subject, to help lead facilities personnel through the analysis for pumping systems.

LCC analysis need not always be a time-consuming and expensive en-deavor, however. Such analysis is essentially a methodology for calculating and comparing the installation and operating costs of alternative proposed projects over the life of the equipment, process or facility. Experience has shown that for motor-driven systems in general, energy and maintenance costs tend to dominate operating costs. Thus, quantifying these costs over the life of the system goes a long way in identifying opportunities for savings.

While many organizations do not regularly conduct LCC analyses, most do have some form of an asset management program. Understanding and maximizing the life of electric motors should be a part of asset management for any organization with significant quantities of electric motors.

The Industrial Technologies Program within the U.S. Department of Energy (DOE) has a variety of materials addressing potential opportunities to reduce energy and maintenance costs in industrial process systems. This includes software tools, a series of guidebooks, case studies, tip sheets and other materials. Many of these materials relate to motors and motor systems, including a specific series of tip sheets on energy and maintenance opportunities. The following information comes from the tip sheet on how to extend motor operating life.

Why care about motors?
Over 1.2 million integral horsepower motors are sold each year in the United States, and about 3 million motors are repaired annually.

On average, motors account for almost 70 percent of the total electricity consumption for manufacturing facilities, and 23 percent of total U.S. electricity consumption—equal to about 680 billion kWh/year.

Even small improvements in motor operating life or efficiencies can result in significant cost savings at energy-intensive facilities.

Why do motors fail?
Certain components of motors degrade with time and operating stress.

  • Electrical insulation weakens over time with exposure to voltage unbalance, over and under-voltage, voltage disturbances and temperature.
  • Contact between moving surfaces causes wear. Wear is affected by dirt, moisture and corrosive fumes, and is greatly accelerated when lubricant is misapplied, becomes overheated or contaminated, or is not replaced at regular intervals.
  • When any components are degraded beyond the point of economical repair, the motor’s economic life is ended.

For the smallest and least expensive motors, the motor is put out of service when a component such as a bearing fails. Depending upon type and replacement cost, larger motors—up to 20 or 50 horsepower (hp)—may be refurbished and get new bearings, but are usually scrapped after a winding burnout. Still larger and more expensive motors may be refurbished and rewound to extend life indefinitely.

An economic analysis should always be completed prior to a motor’s failure so as to ensure that the appropriate repair/replace decision is made.

How long do motors last?
Answers vary, with some manufacturers stating 30,000 hours, others 40,000 hours, and still others saying “It depends.” The useful answer is “probably a lot longer with a conscientious motor systems maintenance plan than without one.”

Motor life can range from less than two years to several decades under varying circumstances. In the best circumstances, degradation still proceeds, and a failure can occur if it is not detected. Much of this progressive deterioration can be detected by modern predictive maintenance techniques in time for life-extending intervention.

Even with excellent selection and care, motors still can suffer short lifetimes in unavoidably severe environments. In some industries, motors are exposed to contaminants that are severely corrosive, abrasive and/or electrically conductive. In such cases, motor life can be extended by purchasing special motors, such as those conforming to the Institute of Electrical and Electronic Engineers (IEEE) 841 specifications, or other severe-duty or corrosion-resistant models.

The operating environment, conditions of use (or misuse) and quality of preventive maintenance determine how quickly motor parts degrade. Higher temperatures shorten motor life. For every 10 ¡ C rise in operating temperature, the insulation life is cut in half. This can mislead one into thinking that purchasing new motors with higher insulation temperature ratings will significantly increase motor life. This is not always true, because new motors designed with higher insulation thermal ratings may actually operate at higher internal temperatures (as permitted by the higher thermal rating). Increasing the thermal rating during rewinding, for example, from Class B (130¡ C) to Class H (180¡ C), does increase the winding life.

Maximizing motor life
The best safeguard against thermal damage is avoiding conditions that contribute to overheating. These include dirt, under and over-voltage, voltage unbalance, harmonics, high ambient temperature, poor ventilation and overload operation (even within the service factor).

Bearing failures account for nearly one-half of all motor failures. If not detected in time, the failing bearing can cause overheating and damage insulation, or can fail drastically and do irreparable mechanical damage to the motor. Vibration trending is a good way to detect bearing problems in time to intervene.

With bearings often implicated in motor failures, the L10 rating of a bearing may be cause for concern. The L10 rating is the number of shaft revolutions until 10 percent of a large batch of bearings fails under a very specific test regimen. It does not follow that simply having a large L10 rating will significantly extend motor bearing life. Wrong replacement bearings, incorrect lubricant, excessive lubricant, incorrect lubrication interval, contaminated lubricant, excessive vibration, misaligned couplings, excessive belt tension and even power-quality problems can all destroy a bearing. Always follow the manufacturer’s lubrication instructions and intervals.

Make sure that motors are not exposed to loading or operating conditions in excess of limitations defined in manufacturer specifications and the National Electrical Manufacturers Association (NEMA) standard MG-1-2003. This NEMA standard defines limits for ambient temperature, voltage variation, voltage unbalance and frequency of starts.

Motor couplings should not be ignored, either. For direct drive applications, correct shaft alignment ensures the smooth, efficient transmission of power from the motor to the driven equipment and to protect the operating life of the equipment. Incorrect alignment occurs when the centerlines of the motor and the driven equipment shafts are not in line with each other.

Misalignment produces excessive vibration, noise, coupling and bearing temperatures, leading to premature bearing or coupling failure.

Motor management
When an electric motor does fail, you must decide whether to repair or replace. DOE’s resources include tips on developing a repair vs. replace policy, a “Guidelines to a Good Motor Repair” document and other related materials.

When the decision is made to repair, use a respected service center and be prepared to ask questions to ensure quality repair. A good motor service center can often pinpoint failure modes and indicate optional features or rebuild methods to strengthen new and rewound motors against critical stresses. DOE’s “Service Center Evaluation Guide” offers guidance in selecting a quality service center. The Electrical Apparatus Service Association (www.easa.org) is another good source of guidance on motor repair.

Developing a repair vs. replace policy for various sizes and applications is the first step in establishing a Motor Management Program. Other motor management strategies can include purchasing policies (considering premium efficiency motors), establishing a motor inventory, tracking motor life, creating a spares inventory, and scheduled maintenance. The U.S. Department of Energy’s MotorMaster+ software program is a free, straightforward tool used by many organizations to implement motor management programs. Putting such a program in place can be part of a larger plant operations asset management program.

1. “Extend the Operating Life of Your Motor,” U.S. Department of Energy, September 2005.
2. NEMA Standard MG-1-2003, “Motors and Generators.”

Vestal Tutterow is a senior program manager for the Alliance to Save Energy, promoting improved energy efficiency within the industrial sector and providing support to the Department of Energy’s Industrial Technologies Program; telephone: (202) 530-2241; e-mail: vtutterow@ase.org; Internet: www.ase.org

Continue Reading →


6:00 am
November 1, 2005
Print Friendly

Multi-Technology Approach To Motor Diagnostics

No magic bullets here. One instrument can’t possibly provide all the information you need to evaluate the health of an electric motor system.

There is a persistent misconception that a “magic bullet,” in the form of a condition-based monitoring (CBM) instrument, will provide all of the information one needs to evaluate the health of an electric motor system. Often, this misconception is reinforced through commercial presentations made by the manufacturers of such instruments or their sales representatives. In reality, though, there is no “Holy Grail” of CBM and reliability when it comes to electric motors. No single instrument will provide you with every piece of information that you need.

But, through a better understanding of your electric motor system(s) and the capabilities of CBM technologies, you can have a complete view of your system and its health, and gain confidence in estimating time to failure in order to make good recommendations to management.

Electric motor systems
An electric motor system involves far more than just the motor. In fact, it is made up of six distinct sections, all with their different failure modes. The sections are:

  • The facility power distribution system, which includes wiring and transformers.
  • The motor control, which may include starters, soft starts, variable frequency drives and other starting systems.
  • The electric motor – a three phase induction motor for the purpose of this article.
  • The mechanical coupling, which may be direct, gearbox, belts or some other coupling method. For the purpose of this paper, we will focus on direct coupling and belts.
  • The load refers to the driven equipment such as a fan, pump, compressor or other driven equipment.
  • The process, such as wastewater pumping, mixing, aeration, etc.

Most will view individual components of the system when troubleshooting, trending, commissioning or performing some other reliability-based function related to the system. What components are focused on depends upon several factors, which include:

  • What is the experience and background of the personnel and managers involved. For instance, you will most often see a strong vibration program when the maintenance staff is primarily mechanical, or an infrared program when the staff is primarily electrical.
  • Perceived areas of failure. This can be a serious issue depending upon how the motor system is perceived and will deserve more attention to follow.
  • Understanding of the various CBM technologies.
  • Training (but when is training ever NOT an issue?).

The perceived areas of failure present an especially serious problem when viewing the history of your motor system. Often, when records are produced, the only summary might state something like, “fan failure, repaired,” or “pump failure, repaired.” The end result is that the perceived failure has to do with the pump or fan component of the motor system. This especially becomes more of an issue when relying upon memory to provide the answers to the most serious problems to be addressed in a plant, based upon history. For instance, when looking to determine what part of a plant has been causing the most problems, the answer might be, “Waste water pump 1.” The immediate perception is that the pump has a consistent problem and, as a pump is a mechanical system, a mechanical monitoring solution might be selected for trending the pump’s health. If a root-cause had been recorded on each failure, it might have been determined to be the motor winding, bearings, cable, controls, process or a combination of issues.

In a recent meeting, while discussing the selection of CBM equipment, the attendees were asked for modes of failure from their locations. The answers were fans, compressors and pumps. When discussed further, the fans were found to have bearing and motor winding faults being most common, pump seals and motor bearings for pumps, and, seals and motor windings for compressors. When viewed even closer, the winding faults were found to be asso-ciated with control and cable problems, improper re-pairs and power quality. The bearing issues had to do with improper lubrication practices.

In effect, when trying to determine the best way to implement CBM on your electric motor system, you need to take a system view, not a component view. The result is simple: improved reliability, fewer headaches and an improved bottom line.

Condition-based monitoring test instruments
Following are some of the more common CBM technologies in use. More detail on the technologies can be found in “Motor Circuit Analysis”[1]. Details as to the components of the system tested and capabilities can be found in Tables 1-4.

De-energized testing:

  • By applying a voltage of twice the motor rated voltage plus 1,000 volts for AC and an additional 1.7 times that value for DC high potential (usually with a multiplier to reduce the stress on the insulation system), the insulation system between the motor windings and ground (ground- wall insulation) is evaluated. The test is widely considered potentially destructive[2]. Surge comparison testing: Using pulses of voltage at values calculated the same as high potential testing, the impedance of each phase of a motor are compared graphically. The purpose of the test is to detect shorted turns within the first few turns of each phase. The test is normally performed in manufacturing and rewinding applications as it is best performed without a rotor in the stator. This test is widely considered potentially destructive, and is primarily used as a go/no-go test.
  • Insulation tester: This test places a DC voltage between the windings and ground. Low current leakage is measured and converted to a measurement of meg, gig or tera-Ohms.
  • Polarization Index testing: Using an insulation tester, the 10 minute to 1 minute values are viewed and a ratio produced. According to the IEEE 43-2000, insulation values over 5,000 MegOhms need not be evaluated using PI. The test is used to detect severe winding contamination or overheated insulation systems.
  • Ohm, Milli-Ohm testing: Using an Ohm or Milli-Ohm meter, values are measured and compared between windings of an electric motor. These measurements are normally taken to detect loose connections, broken connections and very late stage winding faults.
  • Motor Circuit Analysis (MCA) testing: Instruments using combinations of values for resistance, impedance, inductance, phase angle, current frequency response, capacitance and insulation testing can be used to troubleshoot, commission and evaluate control, connection, cable, stator, rotor, air gap and insulation to ground health. Using a low voltage output, readings are read through a series of bridges and evaluated. Non-destructive and trendable readings collected, often months in advance of electrical failure. Note: Different manufacturers of this technology use different combinations of test values.

Energized testing:

  • Vibration Analysis: Mechanical vibration is measured through a transducer providing overall vibration values and FFT analysis. These values provide indicators of mechanical faults and degree of faults, can be trended and will provide information on some electrical and rotor problems that vary based upon the loading of the motor. Minimum load requirements for electric motors to detect faults in the rotor. Requires a working knowledge of the system being tested.
  • Infrared analysis provides information on the temperature difference between objects. Faults are detected and trended based upon degree of fault. Excellent for detecting loose connections and other electrical faults with some ability to detect mechanical faults. Readings will vary with load. Requires a working knowledge of the system being tested.
  • Ultrasonic instruments measure low and high frequency noise. Will detect a variety of electrical and mechanical issues towards the late stages of fault. Readings will vary with load. Requires a working knowledge of the system being tested.
  • Voltage and current measurements will provide limited information on the condition of the motor system. Readings will vary with load.
  • Electrical Signature Analysis (ESA) uses the electric motor as a transducer to detect electrical and mechanical faults through a significant portion of the motor system. Usually used as a go/no go test, ESA does have some trending capabilities, but will normally only detect winding faults and mechanical problems in their late stages. Some manufacturers are sensitive to load variations and readings will vary based upon the load. Requires nameplate information and many systems require the number of rotor bars, stator slots and manual input of operating speed.

Major components and failure modes

To provide an understanding of the types of faults and technologies used to detect them, some of the major issues from the various components of the motor system are reviewed below. As an overview, however, this may not encompass all of the modes of failure that you may experience.


Incoming power. Starting from the incoming power to the load, the first area that would have to be addressed is the incoming power and distribution system. The first area of issue is power quality, then transformers.

Power quality issues associated with electric motor systems include:

  • Voltage and current harmonics: With voltage limited to 5% THD (Total Harmonic Distortion) and current limited to 3% THD. Current harmonics carry the greatest potential for harm to the electric motor system.
  • Over and under voltage conditions: Electric motors are designed to operate no more than +/- 10% of the nameplate voltage.
  • Voltage unbalance: Is the difference between phases. The relationship between voltage and current unbalance varies from a few time to many times current unbalance as related to voltage unbalance based upon motor design (Can be as high as 20 times).
  • Power factor: The lower the power factor from unity, the more current the system must use to perform work. Signs of poor power factor also include dimming of lights when heavy equipment starts.
  • Overloaded system. Based upon the capabilities of the transformer, cabling and motor. Detected with current measurements, normally, as well as heat.

The primary tools used to detect problems with incoming power are power quality meters, ESA and voltage and current meters. Knowing the condition of your power quality can help to identify a great many “phantom” problems.

Transformers are one of the first critical components of the motor system. In general, transformers have fewer issues than other components in the system. However, each transformer usually takes care of multiple systems-in the electric motor, as well as other systems.

Common transformer problems (oil-filled or dry-type models) include:

  • Insulation to ground faults
  • Shorted windings
  • Loose connections, and,
  • Electrical vibration/mechanical looseness

Test equipment used for monitoring the health of transformers (within the selection of instruments in this article) include:

  • MCA for grounds, loose/broken connections and shorts
  • ESA for power quality and late stage faults
  • Infrared analysis for loose connections
  • Ultrasonics for looseness and severe faults
  • Insulation testers for insulation to ground faults

MCCs, controls and disconnects. The motor control or disconnect is responsible for some of the primary issues with electric motor systems. The most common for both low- and medium-voltage systems are:

  • Loose connections
  • Bad contacts including pitted, damaged, burned or worn
  • Bad starter coils on the contactor
  • Bad power factor correction capacitors which normally results in a significant current unbalance.

The test methods for evaluating controls include infrared, ultrasonics, volt/amp meters, ohm meters and visual inspections. MCA, ESA and infrared provide the most accurate systems for fault detection and trending.

Cables – Before and after the controls. Cabling problems are rarely considered and, as a result, they provide some of the biggest headaches. Common cable problems include:

  • Thermal breakdown due to overloads or age
  • Contamination that can be even more serious in cables that pass underground through conduit
  • Phase shorts, as well as grounds These can be caused by ‘treeing’ or physical damage.
  • Opens due to physical damage or other causes.
  • Physical damage. often in combination with other cable problems. Test and trending is performed with MCA, infrared, insulation testing and ESA.

Motor supply side summary. On the supply side to the motor, the problems can be broken down as follows:

  • Poor power factor – 39%
  • Poor connections – 36%
  • Undersized conductors – 10%
  • Voltage unbalance – 7%
  • Under or over voltage conditions – 8%

The most common equipment that covers these areas includes MCA, infrared and ESA.

Electric motors. Electric motors include mechanical and electrical components. In fact, an electric motor is a converter of electrical energy to mechanical torque. Primary mechanical problems include:

  • Bearings – general wear, misapplication, loading or contamination.
  • Bad or worn shaft or bearing housings
  • General mechanical unbalance and resonance

Vibration analysis is the primary method for detection of mechanical problems in electric motors. ESA will detect late-stage mechanical problems as will infrared and ultrasonics. Primary electrical problems include:

  • Winding shorts between conductors or coils
  • Winding contamination
  • Insulation to ground faults
  • Air gap faults, including eccentric rotors
  • Rotor faults, including casting voids and broken rotor bars

MCA will detect all of the faults early in development. ESA will detect late-stage stator faults and early rotor faults. Vibration will detect late-stage faults, insulation to ground will only detect ground faults, which make up less than 1% of motor system faults. Surge testing will only detect shallow winding shorts and all other testiing will only detect late stage faults.

Coupling (direct and belted). The coupling between the motor and load provides opportunities for problems due to wear and the application.

  • Belt or direct drive misalignment
  • Belt or insert wear
  • Belt tension issues (that are more common than most think and which usually result in bearing failure)
  • Sheave wear

The most accurate system for coupling fault detection is vibration analysis. ESA and infrared analysis will normally detect severe or late-stage faults. Load (fans, pumps, compressors, gearboxes, etc.) The load can have numerous types of faults depending on the type of load. The most common are worn parts, broken components and bearings.

Test instruments capable of detecting load problems include ESA, vibration, infrared analysis and ultrasonics.

Common approaches
There already are several common approaches to multi-technology within industry, as well as several new ones (See Table 3). The best use a combination of energized and de-energized testing. It is important to note that energized testing is usually best under constant load conditions and trended in the same operating conditions each time.

One of the most common approaches has been the use of insulation resistance and/or polarization index. These will only identify insulation to ground faults in both the motor and cable, which represents less than 1% of the overall motor system faults (÷5% of motor faults).

Infrared and vibration are normally used in conjunction with each other with great success. However, they miss a few common problems or will only detect them in the late stages of failure.

Surge testing and high potential testing will only detect some winding faults and insulation to ground faults, with the potential to take the motor out of action should any insulation contamination or weakness exist.

MCA and ESA support each other and detect virtually all of the problems in the motor system. This accuracy requires MCA systems that use resistance, impedance, phase angle, I/F and insulation to ground and ESA systems that include voltage and current demodulation.

The newest and most effective approach has been vibration, infrared and MCA and/or ESA. The strength of this approach is that there is a combination of electrical and mechanical disciplines involved in evaluation and troubleshooting.

As found in a recent “Motor Diagnostic and Motor Health Study,”[3], 38% of motor system testing involving only vibration and/or infrared saw a significant return on investment (ROI). This number jumped to 100% in systems that used a combination of MCA/ESA along with vibration and/or infrared. In one case, a combined application of infrared and vibration saw an ROI of $30k. When the company added MCA to its toolbox, the ROI increased to $307,000-ten times the original-by using a combination of instruments.

Application opportunities
There are three common opportunities for electric motor system testing. These include:

  • Commissioning components or the complete system as it is newly installed or repaired. This can provide a very immediate payback for the technologies involved and will help you avoid infant mortality disasters.
  • Troubleshooting the system through the application of multiple technologies will assist you in identifying problems much more rapidly and with greater confidence.
  • Trending of test results for system reliability, again using the proper application of multiple technologies. Using tests such as MCA, vibration and infrared, potential faults can be trended over the long term, detecting many faults months in advance.

This article provides a brief overview of how multiple technologies can work together to provide you with a good view of your electric motor systems.

Through a good understanding of this approach, and proper application of it, you can realize significant returns in your maintenance program.



Table 1: Motor System Diagnostic Technology Comparison
PQ Cntrl Conn Cable Stator Rotor Air Gap Brgs Ins Vibe Align Load VFD
Off-Line Testing
High Potential Testing X
Surge Test X
Insulation Tester X
Ohm Meter L L
PI Testing X
MCA Test X X X X X X X
On-Line Testing
Vibration Analysis L L L X X X X
Infrared X X X L L L L L
Ultrasonics L L X L
Volt/Amp L L L L L

Continue Reading →


6:00 am
November 1, 2005
Print Friendly

Can Core Competencies Be Outsourced?

In last month’s column, we presented evidence that if a company uses assets to provide a product or service, maintenance is, indeed, a core competency. Still, there exists a school of thought that you should only outsource non-core business functions. Does this apply to maintenance/asset management?

Consider the following reasons to outsource maintenance.

The first reason has been a given since maintenance organizations have been in existence. Outsourcing maintenance is typically done in organizations that perform many projects or schedule outages or shutdowns. In these situations, there is a fixed amount of work that needs to be performed in a given time period.

If the work exceeds in-house resources, outside resources are brought into the equation. Also, if specialty tasks need to be performed, outside resources that specialize in performing these tasks can be brought in and perform the tasks at a higher level of efficiency and effectiveness.

The second reason for outsourcing maintenance is to provide specialty skills. In some organizations, certain types of maintenance on control, automation or HVAC systems is outsourced. This is a cost-benefit decision. In many cases, the work generated by these systems is insufficient to justify staffing a full-time employee. Thus, it becomes more cost-effective to outsource the maintenance function, provided certain performance guarantees are negotiated.

The third reason for outsourcing is beginning to grow among financial officers in companies. As CFOs continue to look for ways to increase shareholder value, they are examining every possible cost-saving avenue. Outsourcing companies now are directly approaching CFOs with the business proposition to replace the in-house maintenance function with an outsourced organization. The advantage? Reduced maintenance expendituresÐand any reduction in expenses is an increase in profit. No matter how you slice it, this can be an immensely compelling proposition for a CFO.

In-house maintenance/asset managers may try to refute these claims, but consider some statistics. What if 1/3rd of all maintenance resources really are wasted due to ineffective and inefficient management techniques and it does take three to five years (internally) to transform a reactive maintenance culture into a ÒBest PracticeÓ organization? Can a professionally-managed outsourced maintenance more rapidly reduce maintenance expenses while increasing equipment availability and efficiency?

What can maintenance/realiability managers do if they want to keep their maintenance/asset management as an internal business function? The key is to become professional maintenance managers. To do so, they must learn to translate their technical language into the language other company managers speak—financial… dollars and cents. If not, an increasing number of maintenance organizations will fail to show value. And, they will be outsourced.

Today’s maintenance/ reliability managers must accelerate (their improvement programs lowering maintenance expenses), innovate (find better practices that improve asset reliability and efficiency) or evaporate (be prepared to be outsourced).

The responsibility of any CFO (or COO and CEO, for that matter) is to improve profitability. Unless their internal maintenance function is optimized, outsourcing will always be an attractive option.

Continue Reading →


6:00 am
November 1, 2005
Print Friendly

Make Sure Your Message Is Understood

Bonjour! Bongiorno! Buenos dias! Salut! Hola! No matter what language you speak, it all translates to the same thing, right? Well, you might want to rethink that belief.

A common challenge across many industries, when it comes to corporate growth, is how to successfully communicate a specific message in another language. While English is the accepted language of world finance and corporate operations, when your business takes you to another country, you must be willing and able to adapt. This is especially true in the case of manufacturing and maintenance, where a majority of employees are local men and women just trying to make a living.

There is no question that everyone prefers to be trained, lectured, facilitated, coached and otherwise communicated with in his or her native tongue. We Americans are probably more demanding of this than any group of people.

It is not unusual to see, for example, an American on business or vacation abroad who becomes indignant because a local shop owner doesn’t do business in English. Could it be that we simply don’t make the connection that over there WE are the foreigners!? The truth of the matter is that regardless of which country we may visit, it should be incumbent upon us to at least attempt the local language. This simple—sometimes embarrassing—act will allow you to garner an immense amount of respect with the local population. And, it will provide a great measure of credibility with your client in a foreign country.

Remember that if your work takes you out of the United States, you generally can’t make the transition without some local help from within the country you are visiting. Presentations and training materials must be translated—and should be done by someone who “speaks the lingo” of your profession.

Take a look at any English-to-“X” dictionary and see just how many engineering, maintenance or manufacturing-unique words it contains. Unfortunately, there are very few. Yet, it is utterly impossible to communicate any principles or theories to a plant, maintenance, materials, reliability or other professional without using these technical words.

If you can’t find a dictionary of technical or engineering terms for your language requirements, you have no option but to find a local resource—or give up the client. It’s your choice.

Most maintenance professionals in the U.S. understand the theory, process and application of the Responsibility, Accountability, Support and Information (RASI) model. In every process, each step requires someone who is “Responsible” for getting it done (the Doer) and someone who is ultimately “Accountable” for this step in the process (the Buck Stops Here). I was embarking on a coaching session at a client site in Quebec, in the beginning stages of RASI development, when several members of our client focus team noted (in French), “But there is no difference between Responsibility and Accountability.” As it turned out, they were correct. If you look up the word “accountable” in your French Quebec-American dictionary, you will find that the primary definition is, indeed, “responsible.”

We were able to overcome this dilemma in Quebec by re-defining the “R”and the “A” in the classic RASI model. We decided that the “R” would represent the “Accountable” person and the “A” would represent the “Actor” (the Doer), or “Responsible” person in the model. In this way, we were able to retain the RASI title for the model while still accurately representing each of the letters in the acronym. This same approach should work well with many other languages as a company may continue expanding its business into the global market.

Many language scholars would agree that, while most Americans struggle with any foreign language, English—and American English, in particular—is, in fact the hardest language to master. We have many words that are spelled the same, but which have several different meanings, as well as many different words with the same root meaning.

The message here is that if you have designs on expanding your business or service outside of the U.S., don’t get caught with your Funk & Wagnalls down!

Bob Call is a Senior Consultant with Life Cycle Engineering. He has over 20 years experience in maintenance and reliability, specializing in project management, process improvement and supervisory skills training. E-mail bcall@LCE.com4360

Continue Reading →


6:00 am
October 1, 2005
Print Friendly

Precision Alignment Implementation

Arizona Chemical (Arizona) operates 14 manufacturing locations worldwide. In the “good old days,” each plant was relatively well assured of a production basis each year. As markets matured, distribution improved and customer requirements tightened, however, Arizona had to change to remain competitive. The sites now compete with sister plants for production capacity, as well as for capital funding. Production is assigned (scheduled) based on many factors. One of these is equipment reliability.

The site referenced in this article is in Savannah, GA. It was once part of a paper mill operation. Chemicals produced at the time of this writing were actually a side benefit of the paper-making process in that they extracted valuable products from the pine oils released in processing wood for paper making. Most of the mechanics had come from the paper side of the plant, as had their maintenance practices.

The paper industry is notable for its early adoption of precision alignment techniques. Starting with dial indicators, this segment was among the first to employ the rim-and-face technique. Later on, the reverse-rim method gained acceptance. When laser alignment systems were developed almost 20 years ago, the paper industry was among the first to embrace the new technology.

Regardless of how good they are, though, technology and tools alone are not enough. There is a need for a cultural change. People have to believe that there is a better way. They have to believe that “doing things differently” actually will make a difference in their plant’s operation, its competitiveness and their own livelihoods. This cultural change is what made the difference at the Savannah plant.

Getting an edge
Project Advantage is a corporate-wide initiative that International Paper (IP) has made available to its operating units. The key to its success is local “buy in.” Without the commitment of a plant’s management, the program is not started. But, it also is not a top-down type of mandate. Rather it offers a “better way” that plant management can embrace. In return for their commitment and support, IP provides training and guidance to make the initiative work. Further, Project Advantage doesn’t just cover maintenance. Instead, it touches all aspects of a unit’s operation (e.g., production, engineering, shipping and receiving, customer support, etc.).

The management of Arizona’s Savannah plant decided in 1999 to adopt key elements of Project Advantage to improve their operations. Besides the maintenance function, efforts also were undertaken in production and administrative areas.

Several years later, the plant’s maintenance superintendent began identifying key failures, pump work and other failures. Uptime was good, but significant resources still were being dedicated to repairs and equipment rebuilds. Almost all pumping capacity was backed up with spares, so the impact of failures could be minimized. In February of 2003, an introductory meeting was held at the plant. This meeting was conducted by IP corporate personnel who were champions of Project Advantage.

Based on the initial presentation, plant management elected to participate in the program. This meant committing resources to improving several key areas of the plant. Project Advantage encompassed about 30 different operational areas. The four on which the plant chose to focus were precision maintenance, operator-based reliability (ODR), work systems and root cause failure analysis (RCFA). In the maintenance arena, this meant adopting a precision process. Methods and tools would have to change in order that maintenance could be performed in a precision fashion.

The chemical plant cooperated with the paper mill on precision training as a way of leveraging scarce resources. At the time, there were approximately 35 mechanics, instrumentation technicians, pipe fitters, electricians and millwrights. All of these people were trained. They learned that installing precision would prevent rework and enhance the reliability of their operations. Management approached this as a solid investment that would yield returns, and backed it up with budgets for tools and training. A recap of the type of training provided is described below.

Precision maintenance/alignment
Keeping in mind that precision alignment is a subset of precision maintenance, several related topics were addressed in the training. It was natural at a chemical plant for mechanical seal and pump training to be provided. This training improved the knowledge and skill level regarding seal installation, maintenance and performance during operation, which, in turn, increased availability and reliability.

Among the leading causes of machinery failures are installation/assembly errors. Within the scope of Project Advantage, significant time was devoted to teaching how to avoid those types of errors. Personnel were taught how to determine the proper shaft fit for common applications (e.g., bearings, sheaves, impellers, etc.). They also learned how to reduce and prevent fit errors with precision measurement tools, such as depth, inside and outside micrometers, telescoping gauges, dial indicators, radius gauges, torque wrenches and digital “Vernier” style calipers.

The basics
Precision alignment was approached from the basics. First of all, a clear understanding of the objective of precision alignment was taught and demonstratedÐto measure and position two or more machines such that their rotational centerlines are within tolerance when the machines are at operating temperatures and conditions. It was found that there had been several different definitions “floating around” the plant. Thus, by obtaining buy-in to one common definition, it was easier to work to a common goalÐsomething that seemed quite obvious, but was not always achievable!

Part of the basics training included learning how to graphically plot alignment conditions and results. Before the acquisition of any (laser) alignment systems, however, dial indicator methods were taught. This reinforced the fundamentals of alignment and ensured that the plant did not rely on the availability of laser technology to secure the benefits of precision alignment. Some fundamental concepts clearly had to be learned and understood before an effective precision alignment program could be implemented. The plant determined that those responsible for the alignment of machinery would, at a minimum, need to understand:

  • Basic math functions (addition, subtraction, adding & subtracting positive/negative numbers, multiplication and division)
  • How a dial indicator works
  • Rotational centerlines
  • Pre-alignment checks
  • Offset
  • Offset misalignment
  • Angularity
  • Power planes
  • Correction planes
  • Horizontal
  • Vertical

A process was taught, starting with a prescribed set of pre-alignment steps and stages to better secure a precise alignment. Participants were taught how to understand and be able to prove relative shaft centerline-to-centerline position. The focus on coupling condition was de-emphasized.

A key to the precision alignment process is addressing the critical pre-alignment checks, such as runout, correcting pipe strain, soft foot, rough alignment and establishing a torquing sequence. Skipping any of these steps can lead to a frustrating and unsuccessful alignment. By emphasizing these preparatory steps, and demonstrating their importance, mechanics would learn to take the time to prepare before aligning. This means that at times it takes longer to perform an alignment, but overall many more alignments are accomplished successfully.

Dial indicator methods
The rim-face and reverse-rim dial indicator methods were practiced. Technicians were taught to choose the right method for the job, as well as to how to check for bar sagÐand how to correct it. Gaining an understanding of what to do when machinery becomes base-bound or bolt-bound was especially useful. The graphical solution method has proven very useful for solving base-bound situations. By learning the “old way,” alignment fundamentals were reinforced and this paved the way for successful adoption of laser alignment tools.

Alignment tolerances
Alignment tolerances were also explored during the Project Advantage training initiative. When the program began, there was some confusion about how to interpret an alignment tolerance chart and then how to properly apply these tolerances. An effective aligner must know how to use alignment tolerances. Simply relying on an instrument’s “idiot light” to tell one when machinery is aligned is not a substitute for understanding the application of alignment tolerances. For the novice, it can lead to costly errors. The aligners needed to understand why tolerances are important. They were also taught how to take a set of tolerances from an OEM and convert them into useable parameters for the particular alignment instrumentation being used.

Dynamic movement
Realizing that all machinery moves as it goes from a state of rest to its operating temperature and conditions, time was spent discussing dynamic movements. Although most of the machinery that is routinely aligned only moves slightly, there are many machines that require offsets to account for dynamic movements. Unfortunately this concept had previously been neglected as part of the alignment process. The usual excuses included:

  • Because it doesn?t matter…
  • We always leave the motor 5 mils low…
  • We can calculate the growth…
  • We don’t have targets from the OEM…
  • It is too difficult and expensive to measure…

Dynamic movement does indeed matter. It can cause machinery to significantly deviate from an aligned condition as it goes from off-line to running. One can make an effort at calculating the thermal growth, but this is only part of the total dynamic movement. Keep in mind that there are reaction forces (such as dowels, piping, etc) that cannot be accounted for with thermal growth measurements. In addition, the horizontal movement (and machines don’t grow symmetrically!) cannot be calculated.

OEM-provided targets (if available) should be taken with a grain of salt. It has been found that they almost always provide for equal growth at the front and rear of machinery. Moreover, they almost never provide any guidance about horizontal movement. The only answer is to measure the true dynamic movement of the specific critical machinery. To meet this goal, the plant acquired special fixturing (OL2R Fixtures) and a laser system for measuring the dynamic movement on the specific machinery.

Finally, the value of documentation was emphasized to the participant. Documentation plays an important part in improving reliability. Forms have been created for the physical inspection, as well as for the installation and alignment process. Now, at the Savannah plant, all maintenance procedures are recorded on equipment-specific sheets and kept with the respective equipment’s file. This allows a mechanic to evaluate the history of a piece of equipment while preparing to perform a replacement or alignment. Documentation has been a key part of the process, as it also helps in communicating “wins” to other plant personnel and serves to maintain focus and momentum.

Selecting a laser alignment tool
From the precision maintenance training, the mechanics at this Arizona plant realized that most of the precision alignments could be accomplished with dial indicators. But. they also knew that a properly selected laser system offered too many compelling advantages to not be the standard for all precision alignments. The mechanics did not want an overly complicated (and feature-laden) laser alignment system, although they did tend to be somewhat gadget-oriented, to the point of always wanting more power, more options.

Next, the millwrights were involved in the evaluation and selection of a laser alignment tool. They knew that while many features from the various vendors were nice, when it came time to do a precision alignment, they probably only needed a small fraction of those features. They did not want to become bogged down and confused by all the bells and whistles that had seemed so necessary when they first looked at the laser systems. Such features can waste time and effectiveness if people operate the system with a trial-and-error approach, don’t ever become proficient or abandon the tool altogether. This ends up costing time and money with each and every alignment they perform. After the millwrights had their say as to which system they wanted, an easy-to-use laser alignment tool was selected.

A culture change
At Arizona Chemical in Savannah, there has been a marked change in people’s attitudes about precision alignment. They now see it as part of an overall effort that is improving the reliability of the site’s equipment. With management backing, there has been a consistent effort to move forward. There has been no back sliding; people have stopped taking short cuts with machinery alignments. Precision is now standard—and expected. Personal job satisfaction runs high at this plant, with the millwrights feeling as though they’re working in a professional manner. The following list outlines some of the benefits to date:

  • Prior to precision maintenance, the mode of operation was to simply replace parts; many pieces of equipment were spared, with quick change-outs allowing for continuous processes to remain operational. Now, however, failures have been reduced and the spared equipment is scheduled for regular operation, rather than being held for emergencies.
  • The plant initially started out having root cause meetings every week. Because of improvements, though, these meetings were rescheduled on a monthly basis.
  • Training on structured problem-solving was provided to some of the mechanics. This allowed them to take charge in resolving most equipment issues.
  • Additional training was planned, including precision alignment follow-up training. Even welders have gone through the precision maintenance class, gaining better appreciation of what millwrights do/need.
  • Plans were put in place for a pump shop designed specifically for rebuilds; providing a clean environment with all the necessary tools and fixturing for proper pump overhauls.

The mechanics at this plant have identified and outlined key factors they believe can make a precision alignment program more effective. There are many resources available (especially online) that anyone beginning a precision alignment program can tap into to explore how to leverage these key areas:

  • Securing management commitment
  • Gaining essential stakeholder “buy-in”
  • Developing training strategies (it needs to be thorough and on-going)
  • Obtaining agreement for a precision alignment objective
  • Teaching the basics of alignmentÐover and over again!
  • Always working to some agreed-upon alignment tolerances
  • Using documentation to build a complete machine history and to communicate “wins”
  • Taking dynamic movement into account—it will make a difference!
  • Fostering a culture change to one of “precision”
  • Carefully selecting laser alignment systemÐget what you need (forget about what you “want”)

EDITOR’S NOTE: This article is based on a presentation in Norfolk, VA, at the 12th Annual SMRP Conference, in October 2004.

Mark Garza is a reliability engineer at Arizona Chemical. His responsibilities include managing the predictive and preventive maintenance of plant equipment, managing a mechanical integrity program and providing technical support for the maintenance department.

Ron Sullivan has served as president of VibrAlign, Inc. since 1996. He joined this organization in 1989 as field service manager, responsible for supporting industrial customers with predictive maintenance consulting services, including: vibration analysis, training, field balancing, and laser alignment services; telephone: (800) 379-2250 ext. 103; e-mail: ron.sullivan@vibralign.com

Continue Reading →