Archive | February

380

1:21 am
February 2, 2002
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Maintenance Success Depends on Three Elements of Productivity

bob_williamson

Robert M. Williamson, Strategic Work Systems, Inc.

Too often, we see maintenance managers and supervisors trying to improve maintenance by focusing on a narrow solution to a bigger problem. They may be focusing on only one of the three productivity elements: people, equipment, and work processes. Here are some familiar examples:

  • It is often assumed that if we train people in a critical skill or if new people with the “right skill sets” are hired or brought in under a maintenance contract, we will improve the way we do maintenance. Widespread training shows only narrow improvements. Or hidden costs associated with new people will override the return.
  • Many facilities and plants have spent hundreds, if not thousands, of hours developing new preventive maintenance (PM) programs and procedures hoping they will lead to improved equipment performance and reliability. Or they have implemented a computerized maintenance management system (CMMS) to manage work orders, parts usage, maintenance labor hours, etc. While the intentions are admirable, unfortunately the results are not always what they hoped for.
  • Efforts are often undertaken to upgrade major equipment components to new ones that last longer and require little or no maintenance but are most likely more expensive. Time and expense are dedicated to an equipment improvement that does not get the promised results.

One of our clients encountered a considerable maintenance problem with a large centrifugal pump. Impellers, vanes, and sometimes shafts would break during normal operations. Maintenance leadership first focused on ensuring mechanics were properly installing and maintaining the pump. With no real improvements, they then focused on training operators about proper pump operation. That led to no change either. Then an operator discovered the pump was being started with the discharge valve closed. They realized that when the old manual operations procedures were automated the year before, they had introduced a programming error into the startup sequence: The valve should have been throttled open when the pump was started. They eventually solved the problem, but look at the lengthy back-door approach.

Now, let’s look at improving maintenance by focusing on all three elements of productivity: people, work processes, and equipment. Here are seven steps for using these three elements to improve maintenance efficiency and effectiveness (efficiency: doing things right, effectiveness: doing the right things).

  1. Do not just do something in the hopes that it will improve maintenance. Focus on results—some specific improvement target such as better equipment performance or reduced planned and unplanned downtime on critical equipment. Focus on the equipment element of productivity.
  2. Identify the people who make decisions, develop plans and schedules, manage the work, buy the parts and supplies used, maintain the equipment information, develop procedures, or actually perform the work on or for the targeted equipment. Focus on the people element of productivity.
  3. Gather all the procedures, work methods, guidelines, and documentation used to operate and maintain the equipment. Focus on the work process element of productivity.
  4. Determine what the equipment is telling you about its performance problems. Look at the data: availability, performance efficiency, and rates of quality. Look at maintenance hours, parts and supply costs, etc. Look for equipment root causes.
  5. Begin looking for inconsistencies across the three elements of productivity. Do the people truly have the right skill sets to address the equipment problems? Are they working in concert with each other? Look for people root causes.
  6. Do the people use the right work processes? Are they documented? How much trial-and-error methods are used? Does everybody do things the best way possible? Or do they do things their own (not always the best) way? Do some of the procedures have errors in them? Look for work process root causes.
  7. Address only one problem at a time. Consider improving all three elements simultaneously. Apply the changes, and measure the results. You should see an improvement; it may be small or it may be huge.

Focus on results—tangible and sustainable results—by focusing on all three elements of productivity simultaneously to quickly improve your maintenance efficiency and effectiveness in a sustainable manner. MT
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218

1:13 am
February 2, 2002
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Is the Maintenance Organization Here to Serve?

Moving from customer/supplier relationships to partnerships

During the 1980s and 1990s many organizations embraced Total Quality Management (TQM) as a means to improve product quality and ultimately overall business performance. Some of these organizations had success, but many failed for a number of reasons. The reasons they failed are beyond the scope of this article, but almost all the organizations that adopted TQM or continuous improvement practices went through the exercise of identifying their customers, suppliers, and major products, processes, and services. Many adopted the horizontal or “systems” view of work known as process management. Baseline measurements were established, improvement tools were introduced, and the improvement process was launched.

Typically the improvement effort begins at the corporate level and then cascades to the plant floor. Teams are one tool that many organizations use to increase employee involvement. Some businesses implemented empowered work teams to move the organization to participative management where the teams are actually responsible for managing a process.

As stated earlier, one of the hallmarks of the TQM process is the identification of key customers and suppliers for the organization’s products and services. These are called external customers and suppliers. TQM dictates that this effort be taken a step further as each business unit defines what its core products and services are and then identifies its processes along with the customers and suppliers for those products and services. These are called internal customers and suppliers.

Many organizations that implemented TQM strategies have retained the practice of identifying their internal downstream customers and upstream suppliers within their business processes. This includes the maintenance service organization that supports most businesses and industries at the plant and facility level.

Typically operations has been identified as a customer of the maintenance organization. Operations usually relishes this role as a customer and without much prompting takes on the assumption, although misguided, that the customer is always right. Maintenance assumes that because operations is the customer it must do everything in its power to “satisfy the customer” because TQM and continuous improvement teaches that if you satisfy your customer you will produce a higher quality product which will result in lower costs. This is true in some respects but there can be a downside to this approach if not undertaken properly.

Why go through this exercise of identifying customers and suppliers? The reasons are:

  1. Customers can provide the suppliers, whose services they use, with the precise requirements needed to optimize their process.
  2. Customers can provide suppliers feedback when the suppliers’ services are not meeting the customers’ specifications.
  3. Suppliers can provide feedback to the customers on how the customers can help the suppliers succeed. This is very seldom practiced and will be discussed later.

Sets up dialogue
During my consulting visits to various organizations, I have worked with maintenance groups who have adopted the practice of calling the operations teams they support as their customers. As someone who has studied and practiced quality management tools and techniques, I usually applaud this effort. It starts the dialogue between operations and maintenance. Communication is usually a problem between these two functions. In many instances, an adversarial relationship has developed between operations and maintenance. Any tool that assists maintenance in improving communication with operations and understanding what their requirements are should be promoted. Unfortunately, when this customer/supplier relationship is developed between operations and maintenance it is sometimes carried to an extreme.

In a true customer/supplier relationship the customer has the ability to fire the supplier when the supplier fails to deliver or meet the customer’s requirements. This happens quite frequently in the business world and I am sure all of us as homeowners (customers) have experienced this. For example, a homeowner hires a gardener and, after a few months of shoddy service and repeated feedback sessions, decides to fire the gardener and hire someone new.

Internal customers do not have this prerogative. I have experienced instances where the operations group decides to use services for maintenance other than its own maintenance organization. This can be a very subtle rejection of the services its maintenance organization provides. For example, internal PLC repairs and software configurations are not made rapidly enough or perhaps the service does not quite satisfy those who operate the equipment so operations decides to hire a contractor to perform this service. The contractor will report directly to the operations group. Operations will feel more in control and think that it is receiving better service and lower cost when in reality this may be far from the truth.

Systems thinking
To understand what is really happening it is necessary to discuss systems. A system can be defined as a collection of parts that interact with each other to function as a whole. The parts of a system are often viewed of limited value when taken separately but when combined and arranged correctly they become very valuable. In other words, the parts or elements work together to achieve a common purpose. In fact, many times the sum of the parts is greater than the whole. This is defined as synergy.

With systems there is usually a certain interdependency between the parts. When a system is functioning correctly there is usually high interdependency between parts. When the system is functioning incorrectly there is low interdependency between parts. Some examples of systems would include biological organisms (such as plants, animals, and the human body), the atmosphere, chemical reactions, industries, factories, teams, and all organizations.

Many times, when the parts or elements of a system are not aligned properly, the system becomes dysfunctional or suboptimized. It can no longer achieve its intended aim. The parts, with competing agendas and improper alignment, actually become very inefficient and incur tremendous waste. This can happen even though some of the elements or parts of the system appear to be optimized and performing at a high level. Optimization of only some of the parts results in suboptimization of the system.

An example would be a manufacturing business that creates a product. Within that manufacturing business or process are many subprocesses. Each of the subprocesses contributes to the manufacturing of the final product. One of the subprocesses, which is responsible for a small piece of the final product, could have lower costs than the other subprocesses and appear to be operating more efficiently than the others. But in reality it could be shipping a product to its downstream internal customer that requires a lot of rework to make it usable for that downstream process. Usually this occurs because the upstream supplier fails to properly identify his downstream customer’s requirements. As a result, the product he ships or transfers to his downstream customer is “out of spec” or “fails to meet the requirements” required by the customer.

This of course begs the question: why do we worry about what the product looks like after it leaves one subprocess to go to another? Because many unnecessary costs and waste in the form of out-of-spec products and services can be transferred to the downstream customer. In some cases, these costs are double or triple what they would be if handled right the first time in the process where they were designed to be eliminated. In a system each process is designed to create a product or service and transfer it to its customer in the most efficient manner possible for the system and not that individual process.

That is why, in TQM parlance, we must go through the process of identifying what our customers’ specifications are for each downstream process. Customers sometimes are proactive and identify these before hand and share them with their suppliers. This is usually done in the form of surveys, questionnaires, and product specification forms. Unfortunately, in many instances, the customer will set such high requirements for its suppliers that many costs are transferred to the supplier that might be more appropriately handled by the customer.

This is not a significant problem when we are talking about external suppliers. Typically we go through a bidding process with several different external suppliers. Usually the external supplier offering the highest quality at the lowest cost is selected. In this situation, companies let the competitive nature of enterprise control the costs of the service they are receiving from their external supplier. On the other hand, if some of the costs and process wastes are transferred to an internal supplier then the costs are merely transferred to another process within that business. Process owners who transfer these costs think they have done something clever and are at times quite proud of themselves, when in reality the supplier or process to whom these costs were transferred may not be as capable of managing and reducing the waste and costs as the customer is.

Customer/supplier relationships
How does this phenomena apply to customer/supplier relationships between operations and maintenance? As stated earlier, many maintenance organizations today have taken the approach that operations is their customer. Their purpose in life, however noble, is to meet or exceed their customer’s expectations. Unfortunately, this type of relationship between internal customers and suppliers can actually drive costs up, lower the quality of services, and create an antagonistic relationship between maintenance and operations. Once the organizations become antagonistic, maintenance will isolate itself and adopt a “you operate, we fix” mentality with very little communication and cooperation. See accompanying section “How to Know When Relationships Need Fixing.”

In this dysfunctional relationship, the system is not optimized but suboptimized. The subprocesses, although operating efficiently in the eyes of the process owners, actually are allowing waste to occur and driving costs up. In this case, the maintenance organization, suboptimized by a poor relationship with its customer, will incur unnecessary costs, inefficiencies, and waste which will manifest themselves ultimately as poor equipment reliability. Poor equipment reliability is the antithesis of a partner’s goals and objectives.

That raises the question of how maintenance and operations avoid creating an environment of non-cooperation and competitiveness. The key is the practice of identifying customers and suppliers and their respective requirements and specifications. Customers can help their suppliers succeed by conducting ongoing dialogue with them to improve their processes as a team. Identifying the customers’ requirements is not enough. In any business organization internal customers must go beyond merely passing on their specifications and requirements to their suppliers.

Partnerships
One way to achieve this is to move beyond thinking customer and supplier to developing a partnership. A partnership between internal customer and supplier, in my estimation, would represent an evolvement from the relationship that many organizations practice today. The customer and supplier, in the context we are discussing now, are operations and maintenance.

Rather than operations dictating to the maintenance organization how it works with them, operations and maintenance should develop a partnership. In his book “Stewardship,” Peter Block describes what partnership means: “Partnership means to be connected to another in a way that the power between us is roughly balanced& When we talk of supplier-customer partnerships&what we are seeking is to recognize the interdependence of the parties and replace control with cooperation.”

What we are trying to achieve is a level of cooperation that is attained when both customer and supplier feel accountable and responsible for the system as a whole. They are more than just customer and supplier; they are stakeholders who feel a sense of ownership from their processes that can be achieved only by partnering rather than one serving another blindly without any voice in how to best manage and care for the process or equipment. So how do we build a partnership between operations and maintenance? See accompanying section “What You Need to Build a Partnership” for the six requirements.

When a partnership is developed between operations and maintenance, finger pointing and the blame game will slowly disappear. Processes will function at a higher capability, ownership will increase, and communications will improve. When equipment is needed for a PM, all options and alternatives can be voiced and heard by both operations and maintenance. As a result, better decisions will be made that reflect the best interests of the system rather than a subprocess. Systems will be optimized and equipment reliability will improve. Organizations will develop greater speed, flexibility, and capacity to change direction. Ultimately the stakeholders, operations and maintenance, will have greater ownership of the system.

Organizations today are faced with more challenges than ever before. Business as usual will not be good enough; in fact incremental improvement may not be enough. The challenge for today is to not only improve but improve at a rate faster than ever imagined. Taking years to develop the behaviors and culture necessary for a thorough implementation of a process improvement initiative will be intolerable if not fatal.

Today’s organization must move from a customer/supplier relationship to a partnership to succeed in the 21st century. The partnership model described here not only will provide the platform needed to succeed but will foster an environment where greater cooperation exists, and will seed the organization with the behaviors and cultural norms necessary to sustain long-term business improvement. At the end of the day an organization where customers and suppliers have created a partnership will experience greater productivity and business results and be positioned to be a front runner in today’s new economy. MT


Tracy T. Strawn is a senior consultant, maintenance and reliability, at the Marshall Institute, Inc., 1800-1 Tillery Pl., Raleigh, NC 27604; telephone (800) 637-0120

How To Know When Relationships Need Fixing

  • Operations writes the majority of work orders as urgent or emergency. There is little to distinguish emergency work from nonemergency work. If all work orders are urgent or high priority, the priority system becomes ineffective as a tool to ensure crews are working on the most important work first.
  • Operations refuses to write work orders for some types of work. Because the mechanic is already out at the machine on another work order, he is expected to respond to a “shoulder tap” and fix another unrelated job. Once this behavior becomes acceptable it is hard to eliminate.
  • Operations refuses to stick to the schedule. Work scheduled is bumped for other non-urgent work at the last minute, not due to changes in the production schedule but because it is convenient. Maintenance is expected to make adjustments as necessary because the customer comes first. Weekly schedules become meaningless and ineffective as a tool to maximize craft productivity.
  • Operations delays in turning over equipment. Operations, for whatever reasons, delays in isolating the equipment for maintenance to make its repairs. It’s the old “dollar waiting on a dime” syndrome. Maintenance personnel must stand around the equipment waiting for it to be released and isolated or they are sent to another job by the maintenance supervisor.
  • Work orders created by the operations group are not filled out properly. Maintenance is expected to fill in the gaps. Operations has either never received the training or never been held accountable for work order data quality. This results in significant rework by the maintenance group trying to find the data; this ultimately leads to poor analysis.
  • Operations can’t find time to meet with the maintenance group to discuss problems and opportunities or to build schedules. Because operations does not own the maintenance process its priorities lie elsewhere. Production problems will always take precedent over maintenance concerns.
  • “We own it, you fix it”. This is the attitude adopted by many operations groups. The operations group operates the equipment and pays the bills and therefore the maintenance group is reduced to a necessary evil. This type of relationship is definitely not conducive to promoting cooperation between the two organizations.
  • Maintenance develops a superiority attitude where operations is reduced to a bunch of fools operating and destroying equipment. This is usually the end of the evolution or de-evolution I should say. At this point communication has broken down or is minimal, and cooperation is a foreign word. Operations and maintenance play the blame game, pointing fingers at one another, and the production process suffers which is often fatal.

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What You Need To Build A Partnership
  1. Systems thinking. Operations and maintenance must view their processes as part of a larger system. It must be understood that actions or lack of action affects the downstream and upstream processes. These subprocesses make up a larger system and their poor performance can affect the system as a whole and ultimately business profits. One way to develop a systems thinking mentality is to map your business’s major processes. This allows you to see the interdependencies between business groups.
  2. Dialogue between stakeholders. Communication must be two way under a partnership. That implies trust and integrity when dealing with each other. This can best be accomplished in a team environment. Some tools or activities that are useful in achieving this are team surveys and joint vision and mission building between operations and maintenance.
  3. Interdependence and cooperation. Relationships must be developed that foster openness and a balancing of power. Accountability, process requirements, and demands must flow in both directions. One of the most effective ways to accomplish this is the development of cross functional teams. A cross functional team would be comprised of operations, maintenance, purchasing, engineering, and, if necessary, contractors. The objective would be to create a forum that would promote interdependency and cooperation.4. Partnership contract. A contract should be drawn up between operations and maintenance that describes the behaviors each should exhibit that will make the partnership manifest to the organization.
  4. Partnership contract. A contract should be drawn up between operations and maintenance that describes the behaviors each should exhibit that will make the partnership manifest to the organization.
  5. Clear roles and responsibilities. Each stakeholder that is a member of a subprocess of a system should have clear roles, responsibilities, and expectations written up for his position. This is best done in a team setting where input from stakeholders can be gathered and discussed so that expectations are clear.
  6. Management support, commitment, and buy-in. For the partnership to work effectively, management or leadership also must be committed to fostering this type of relationship. The partnership behaviors should be modeled by management and expectations cascaded to the rest of the organization. One way to gain management buy-in is for management to create or at least participate in the development of a maintenance and reliability policy.

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182

12:59 am
February 2, 2002
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Reliability Goes Nonfat With Lean Maintenance

It drove Henry Ford crazy! The automobile-manufacturing pioneer focused on eliminating waste on his automotive assembly lines because he was well aware of the cost associated with waste. Wasted material, wasted motion, and wasted time drastically affected bottom line profitability.

Maintenance operations focus on avoiding equipment malfunction and fixing things that have failed to function as intended or required. Most maintenance departments do not consider their activities in terms of eliminating waste. In reality, the move from a reactive to a proactive maintenance strategy (RCM, TPM, etc.) is made easier when a preliminary focus is applied to eliminating waste in the maintenance delivery and management system. This is especially true for companies that already run under a lean manufacturing system.

Lean manufacturing
Toyota engineers who studied Henry Ford’s work in waste elimination developed lean manufacturing. This effective system defines the seven common forms of waste and includes a process for continuous improvement. You may already be working in a lean manufacturing company, even though maintenance operations are often overlooked in terms of training and other lean resources that are applied to operations or production.

Lean maintenance
Lean maintenance is a term used by many companies that are beginning to blend the techniques of lean manufacturing with maintenance experience. Unfortunately, many lean experts rarely combine the resident knowledge of the maintenance operation and their own. Without a maintenance background, an operations consultant finds it difficult to analyze waste in a maintenance operation, as a maintenance consultant would find operational waste difficult to spot.

Lean philosophy defines waste as “anything that does not add value to the product, process, or service.” In a lean maintenance system, sources of waste usually consist of outdated procedures and overstocked and underused inventory of equipment, material, and parts, as well as wasted labor, time, and transportation. (See accompanying section Simple Steps to Lean.”)

According to Greg Folts, director of operations for the Marshall Institute, Raleigh, NC, maintenance operations may be wasting up to 25 percent of available labor. Some plants find that up to 60 percent of wasted maintenance labor results from activities that add no value to the output factors or overall performance measurements of the plant.

One tool that Folts uses at the beginning of a lean maintenance implementation is value stream or process mapping. This procedure pinpoints sources of waste and is used to develop a more efficient and effective process or task. A group of stakeholders, people who are directly affected by the process being studied, are selected for that part of the mapping. A typical group may include members of the operations staff, maintenance staff, supervisors, engineers, and maybe purchasing or accounting. Each person who performs a function in the process explains his activity and it is noted on a large sheet of paper tacked to the wall. Wasteful areas like delay and waiting are identified. The entire process becomes visible as the sheet fills with each individual’s tasks.

Processes or tasks are mapped in sequence, which can be enlightening for someone who performs only one part of the process and does not know what occurs prior or subsequent to his individual activity. A thorough and analytical understanding of a process makes waste easy to spot.

When all the players involved in process mapping map out a “what is” scenario, everyone usually agrees that the current methods are not the best way to get things done. Several obvious improvements can be mapped right away. This is especially true when the process crosses multiple disciplines such as purchasing, maintenance, production, and engineering. The team then can develop the “to be” map as well as create an implementation strategy to eliminate the waste. In order to become effective at identifying sources of waste, it is useful to fully understand the forms of waste as they exist in the maintenance operation (see accompanying section “Seven Forms of Waste in Maintenance“).

Reasons for waste
The primary goal of any company should be to maximize the output that brings money in the door and minimize expenses that carry money out the door. Metrics that are department specific without regard to overall business goals will suboptimize the entire system and allow waste to creep into the system. People who perform functions in a process or task are often isolated and only know or understand their activities without regard to how they fit into the system. It is possible that finance, production, and maintenance may all meet or exceed their measurement criteria while suboptimizing the rest of the company. This eventually can cause the business to fail.

Process mapping allows people to see the larger picture and to work as a team to optimize the overall business result. What is the best way to run this process from a business perspective is the question that sets the tone in a process mapping session.

Record keeping
Good records are key to maintaining a waste-free environment. A good computerized maintenance management system (CMMS) is essential, although many companies use Kanban, a Japanese system that uses visual triggers, as well.

Visual workplace
Laminated bar-coded work order cards can be generated from a CMMS and placed near each machine. If there was an unplanned shutdown on a machine, an operator could scan the proper failure bar code on the laminated card and it would start a work order request from maintenance for “machine down” or “machine will not cycle” or some other failure code. The card then could be placed in a rack that is visible to operations and maintenance supervisors.

The code would signal that an electrician is required on that machine because it will not start. The system automatically prints a work order in the maintenance department. This avoids the operators having to look for a supervisor only to find the supervisor is not available, then searching for an engineer to approve the work order request.

The visual part of the system allows everyone to see the Kanban card in the rack. Supervisors could quickly scan the rack to see the status of any required maintenance work orders.

Lean maintenance as a process
Lean maintenance is a journey, not a destination. It is about continuous improvement as an ongoing process. A lean system requires that priorities be set for delivering value and eliminating waste. When a lean process includes all functioning members of the process combined with open, honest, and blame-free communication, huge gains in productivity and profitability can be achieved. MT


Seven Forms of Waste in Maintenance

A core concept of lean manufacturing is eliminating the seven forms of waste. This concept can be helpful for maintenance as well as production. Knowing what to look for can be useful when pinpointing areas of waste, which often overlap in many tasks and processes.

1. Overproduction

A key waste in manufacturing facilities is the waste of overproduction. Activities often are performed that add no value or for which the customer is not willing to pay. In maintenance, this waste translates to performing preventive and predictive maintenance tasks at intervals more often than optimal and results in the overproduction of maintenance work. Unnecessary preventive maintenance (PM) is 100 percent wasteful.

2. Waiting

Maintenance-related waiting includes the production department waiting for maintenance personnel to perform a service. Waiting for tools, parts documentation, transportation, and other items also is wasteful. Waiting is not a value-added activity and must be eliminated or greatly reduced. Plan and schedule jobs in coordination with production, move the parts and documents closer to the job, and buy extra tools and store them near the job location where they will be used.

3. Transportation

Ask anyone in the plant what he sees maintenance people doing and the answer often will be “walking around.” Tools that are stored a long way from the job, commonly used repetitive parts that have not been preassembled or kitted, documentation that must be hunted down, and work orders for machines that are not available all cause excess transportation. Maintenance people do spend a lot of time walking; most of it does not add value to the process. Transportation also can refer to running, driving, and flying.

4. Process waste

In reactive or breakdown maintenance, repairs are typically conducted to achieve operation as soon as possible, sometimes eliminating an opportunity to perform a longer term or higher quality repair. Planning and scheduling for maintenance is like setup for production. They are the keys to eliminating process waste.

5. Inventory

A typical maintenance inventory storeroom contains 65 percent needed material and 35 percent obsolete or rarely used material. In addition, secret inventories may be kept informally to ensure availability when needed. Organizing an effective lean spares strategy will eliminate the waste caused by obsolete and secret inventories. Inventory for a maintenance operation also includes the work order backlog. Like physical inventory, too much maintenance work inventory means slow response, unexpected breakdowns, and a high reactive labor percentage. Too little backlog of maintenance work inventory means inefficient planning and scheduling.

6. Motion

Wasted motion/unnecessary process in the maintenance operation usually revolves around PM tasks that do not add value to the output. For example, a monthly PM inspection on a pump that has not changed status in three years should be extended to a longer frequency such as quarterly, semi-annually, or annually depending upon the criticality of that piece of equipment.

7. Defects

Job recurrence because of improperly performed repair work is a huge source of waste. How many times does the job need to be repeated before it is performed correctly? Using tools such as root cause analysis can ensure that the proper action is taken to eliminate the source of the defect. Proper training and detailed procedures can assist in ensuring defect elimination.

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Simple Steps to Lean

  • Improve tool storage using strong visual cues such as painted outlines or foam cut outs to show where tools should be stored.
  • Improve documentation storage. Make sure it is neat, organized, and accessible by those who need it. Have a system that clearly shows when a file is out or missing.
  • Use visual cues to show how things should be (normal state).
  • Use visual cues to indicate status, next inspection due date, etc.
  • Create a simple and uniform work request system that provides visual cues for operators, maintenance, and supervisors.
  • Use root cause analysis techniques to solve problems permanently.

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227

9:26 pm
February 1, 2002
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VFDs Can Cut Costs

Variable-frequency drives are beneficial, but you must avoid voltage spikes that can cause winding failure.

When you want to control motor speed, you usually choose a clutch or a variable-frequency drive (VFD)—also called an inverter. In most cases, the advantages of VFDs make them the better choice, so much so that industry installs 10,000 to 15,000 VFDs each week. But VFDs have their limitations; for example, they cannot multiply torque. Misapplication can be expensive and frustrating. But correctly applied, VFDs can reduce costs while increasing success with production goals.

How VFDs work
The primary purpose of a VFD is to enable constant-speed ac induction motors to run at variable speeds. Two factors determine the speed of an ac induction motor: the frequency of the supplied power and the number of magnetic poles per phase. For example, at 60 Hz the synchronous speed of a four-pole motor is 1800 rpm (120 x 60 cycles/sec divided by 4 poles = 1800 rpm). Unless one of these factors changes, the speed remains constant. But a VFD can change the utility’s sinusoidal ac power to variable-frequency dc current, making it possible to adjust (reduce) the speed of ac induction motors almost infinitely.

The most common method VFDs use to accomplish this is pulse width modulation. By sending the motor pulses of dc voltage in varied widths, an inverter mimics the increasing and decreasing amplitude of an ac sine wave. The pulse at the center of each wave is the widest (longest duration), while those on either side of it are progressively narrower (shorter duration). When VFDs modulate the width of pulses in this way, they are referred to as pulse-width modulation inverters (PWMs).

The amplitude or peak voltage of each pulse is, in theory, about the same as the maximum amplitude of the sinusoidal voltage supplied by the utility. The polarity of the pulses changes from positive to negative during the second half of each cycle, replicating the polarity shift that occurs with ac power during each complete cycle.

With the VFD, you can adjust the motor speed by simply changing the frequency of the simulated sine wave. Decreasing the frequency slows the motor, while increasing it (within limits) causes the motor to speed up. Although VFD technology works well in most situations, serious problems may arise with some applications and motor-drive systems.

Switching frequency and cable length problems
Because a VFD sends out several thousand pulses each second, the switching frequency can become a problem. This is true especially if the cable between the drive and motor is more than 50 ft long. In such cases, a reflected and an incident pulse can meet at the motor terminals, effectively doubling the voltage that surges into the motor winding.

Similar to a wave striking a beach, a pulse’s amplitude can increase as it reflects back and crosses other incoming waves. Extensive testing by motor manufacturers and others shows that cables longer than 50 ft contribute to the higher voltage spikes that cause motor winding failures.

Extensive testing shows you can expect voltage spikes of 1500-2000 V or more at the terminals of a motor rated for 460 V operation. Unfortunately, standard insulation systems will not handle this kind of overvoltage. IEEE Standard 43 specifies proof-testing the insulation system integrity of new 460 V windings only once at 2000 V. The standard does not account for the voltage stress a VFD may impose several times each second throughout the life of a motor.

Some motor manufacturers have developed VFD-duty motors by upgrading winding voltage-withstand capability and reducing the core and winding losses. Likewise, several drive manufacturers have improved the quality of output power from the drive. Faster rise times may be desirable from a control perspective, but a slower rise time is gentler to the motor. The relationships between cable length, motor insulation, and VFD rise time are complex. Each variable plays a part in determining the corona inception voltage, which is the threshold at which high voltages partially discharge, ionizing trapped air and deteriorating insulation. If a particular combination (motor, VFD, and cable length/type) works well, changing any one variable can change everything.

Some end users employ line filters to protect their motors. Such filters dissipate the energy increase caused by long cables. Filters are not particularly expensive (about 10 to 20 percent of the cost of the drive), but they do add more components to the system. When possible, it is preferable to avoid cable runs longer than 50 ft.

Increased heating
Even where cable length is not a problem, motors can run 10-20 C hotter on a simulated 60 Hz PWM waveform than on real sinusoidal power. Excess heat is a major cause of insulation deterioration and failure. Insulation life drops by half with each 10 C increase in temperature. That means the insulation system of a motor that runs 20 C hotter than its rated temperature would last only one-fourth of its normal life.

Adding to the problem, VFD-driven motors generally operate at lower speeds. The fan therefore will dissipate less heat, leading to an even hotter motor and more heat in the windings.

Fortunately, most VFD applications today involve motors driving fans or pumps. These are centrifugal loads, so the power required to drive them increases as the cube of the speed increase. Conversely, driving the pump impeller at a lower speed reduces power requirements significantly. That means less current, so heating due to the current density of the winding also decreases. These factors do not necessarily offset each other, however, so predicting the winding temperature is difficult.

Final tips
VFDs offer many benefits, not the least of which is the ability to directly drive variable-speed loads using ac induction motors. If you elect to install one, try to avoid long cable runs. You also should consider using a line filter or reactor to reduce or eliminate harmful voltage spikes.

Another option might be to buy an inverter duty replacement motor. If the motor is large and expensive, a cost-effective alternative may be to have a local service center rewind it using inverter-duty wire and special insulation. You also should specify additional varnish treatments to fill spaces between wires, increasing the corona inception voltage (the threshold at which the corona effect occurs). The additional varnish also improves heat conduction from the wire to the laminations, helping to cool the motor. These steps should prolong the life of the motor when operating with a VFD. MT


Chuck Yung is a technical support specialist with the Electrical Apparatus Service Association (EASA), 1331 Baur Blvd., St. Louis, MO 63132; (314) 993-2220.EASA is an international trade organization that keeps members up to date on materials, equipment, and state-of-the-art technology related to the sale, service, and maintenance of motors, generators, drives, controls, and other electromechanical equipment through its engineering and education programs.

 

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223

8:07 pm
February 1, 2002
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The Secret To Life

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Robert C. Baldwin, CMRP, Editor

While surfing down the cable channels the other day, I clicked on the movie “City Slickers” and stayed long enough to enjoy the “secret to life” scene. That is where city slicker Mitch Robins (Billy Crystal) and tough trail boss Curly (Jack Palance) get to know each other while driving strays back to the herd.

Curly shares his philosophy with Mitch, noting that city slickers spend 50 weeks a year getting knots in their rope and think 2 weeks of playing cowboy will untie them. The conversation continues something like this:

Curly: Do you know what the secret to life is?

Mitch: No, what?

Curly: This (holds up one finger).

Mitch: Your finger?

Curly: One thing, just one thing. You stick to that and everything else don’t mean nothin’.

Mitch: That’s great, but what’s the one thing?

Curly: That’s what you got to figure out.

And that got me to thinking. What is the most important thing happening today in the plant equipment maintenance, reliability, and asset management profession? I couldn’t come up with just one thing, but I did come up with two: MIMOSA and SMRPCO. One is in the technical sector and one is in the management sector.

The Machinery Information Management Open Systems Alliance (MIMOSA) advocates the open exchange of equipment condition related information between condition assessment, process control, and maintenance information systems.

The association is working to untie the knots in the plant information network by developing a common XML vocabulary to facilitate plug and play connectivity.

The SMRP Certifying Organization (SMRPCO), an independent division of the Society for Maintenance & Reliability Professionals (SMRP), has developed a certifying process for maintenance and reliability leadership.

Perhaps its most significant achievement is the work process model it developed to describe the capabilities it believes are required to achieve certification. That model covers work processes for business and management, people skills, equipment reliability, manufacturing process reliability, and work management. It helps to untie the blinders that keep business leaders from realizing there is more to equipment asset management than just knowing how to fix things.

We are participating members of both organizations and proudly display their badges on our masthead. Their progress signals that the profession is reaching a new level of maturity. That’s good. But we can’t slack off or we’ll surely get more knots in our rope. MT

rcb

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316

7:30 pm
February 1, 2002
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Digital Telemetry Monitors Motor Health

0202flanders

The system consists of three physical elements: the rotor collar—a split ring clamped around the motor output shaft, a copper pickup loop surrounding the rotor collar, and a receiver unit.

There is a scene in the movie “Hunt for Red October” to which maintenance personnel can relate. In it, the skipper of a Russian attack submarine tells his Executive Officer: “Inquire of engineering whether it is possible to go to 105 percent on the reactor.” A few moments later, the visibly shaken Executive Officer reports, “Engineering says 105 percent is possible but not advisable.”

Sound familiar? It should; throughout industry, those in charge of corporate finances are pushing harder than ever to squeeze every last erg of performance from the money they have invested in equipment. That translates to pushing the equipment harder. In the world of large dc motors, the desire to “do more with what we’ve got” can have disastrous consequences including unplanned outages and expensive repair bills.

Not long ago, a metals-producing company had a 6000 hp dc motor on a rolling mill, and wanted to know if it could “over-load” the motor to get more work out of it. Our answer was guarded: “Maybe, provided you don’t overheat the armature and thermally fail the insulation.”

Monitor armature temperature
In deciding if over-loading is feasible, you need to monitor the temperature of the armature conductor. That is where the greatest current density is, about 4500 A/sq in. The key to monitoring the temperature of the armature conductor is to find a way to transmit the data from the resistance temperature detectors (RTDs) over the air gap from the rotating armature to a stationary receiver.

Some people think they can get information about the temperature of the armature indirectly by putting RTDs on the motor frame. This does not work very well because the frame tends to be thermally insulated from the armature, and the current density on the stator is typically much lower than on the armature. We have seen several examples of armatures that have been “cooked” with no warning from the RTDs on the frame. The bottom line: if you want to do health monitoring on an armature, you have to get the data direct.

In addition, it is not good enough to simply do spot checks on a motor. If something goes wrong, it does not take long for the insulation to thermally fail. All it takes is a blockage of air flow to cause an expensive repair. For dc motors of 1000 hp and more, a rebuild can range from $100,000 to $800,000, and a new motor can cost from $250,000 to $2 million. So if the motor is running continuously, there are serious economic reasons for continuous monitoring of the armature temperature, particularly if you are running at or near the recommended limits of the motor.

One system for getting data safely and accurately from the RTDs on the armature to a stationary receiver is the Motor Monitor from Accumetrics Associates, Schenectady, NY. It allows continuous monitoring of up to eight temperature sensors on the armature windings of dc industrial drive motors. The temperature data is transmitted off the rotor by digital wireless means to a stationary receiver that displays the temperature and alerts operators if preset limits are exceeded.

Avoid data contamination
We suggested to the rolling mill that the prudent course would be to instrument the armature and use the Motor Monitor to continuously keep an eye on the temperature. It is a maintenance-free device that can withstand corrosive environments, important in a rolling mill. In addition, because it uses digital telemetry to transmit data, the device is immune to the data contamination that could be caused by the high levels of electrical noise and magnetic fields found in the mill.

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BLOCK DIAGRAM OF MOTOR MONITOR: Fig. 1. The monitor employs a digital telemetry technique to insure high data accuracy and noise immunity.

Fig. 1 presents a block diagram of the Motor Monitor. Unlike other techniques that have been used in the past to get sensor signals off the rotor, the monitor does not use sliprings and does not rely on older wireless techniques such as analog FM telemetry. The system consists of three physical elements: a rotor collar, a pickup loop, and a receiver unit.

The rotor collar is a split ring customized to clamp around the motor’s 18-in. diameter output shaft. The collar is made from a high-strength epoxy glass composite and contains electronics that accept inputs from RTD sensors mounted on the armature windings.

The pickup loop is rigid copper mounted on the motor housing so that it surrounds the rotor collar with about a 3/8 in. gap. A fine wire is embedded in the outside of the collar on the rotor. The pickup loop works in conjunction with this embedded wire to form a rotary transformer, allowing transfer of signals between the rotor and stator. A radio frequency power signal, generated in the receiver unit, is transferred across this transformer to the rotor where it is rectified to provide dc power for the electronics mounted on the rotor.

The telemetry system provides 2 mA constant dc excitation to the eight RTD inputs (the armature actually had only six RTDs so fixed resistors across the two unused inputs provided a means to verify the accuracy of the system). The voltage measured across each of these sensor inputs provides an indication of temperature. The eight input voltages are multiplexed, amplified, and digitized by the rotor electronics. The resulting digital data stream is modulated on an RF carrier and transferred off the rotor through the same transformer windings that transfer the power. The transfer of data through these inductive coils provides a secure data transfer that is not subject to interference from other radio sources that might exist in the environment.

The data is recovered in the receiver and is displayed in degrees C on the front panel of the control cabinet that contains the receiver unit. Alarm and trip temperatures are preset for each RTD and relay outputs are provided to the rolling mill users.

Results were clear
The Motor Monitor was set up on the 6000 hp motor and the temperature was watched carefully as the current was varied. The results of the test were clear: increasing the current by 10 percent was extremely likely to cause the motor to fail very quickly. The rolling mill was left to decide whether the revenue from increased production would offset the cost of an annual motor rebuild.

The system now continuously monitors the temperature of the armature, giving the rolling mill operators a valuable tool for monitoring the health of their motors. Maintenance personnel have bottom-line-oriented information to present to their finance people. That Russian submarine Captain would be envious of hard data like that.

We have reached the inescapable conclusion that all large dc and ac motors should be monitored continuously for rotor temperatures. When warranted, a Motor Monitor also may be configured to provide monitoring of strain, load, pressure, acceleration, and vibration. It seems a good bargain: the cost of a system to provide continuous health monitoring on a large electric motor is a tiny fraction of the capital investment that is at risk. MT


Information supplied by Allen Patterson, electrical engineer at Flanders Electric Motor Service, 10334 Hedden Rd., Evansville, IN 47711; (812) 867-4014 . For more information about motor monitoring and rotor telemetry, contact John Reschovsky at Accumetrics Associates, Schenectady, NY; (518) 393-2200.

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270

7:15 pm
February 1, 2002
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I'll Meet You On The Web

Numerologists report that 2002 is the year of partnership and collaboration. As you begin new initiatives and improvement programs, you may want to ask yourself how you can approach these goals as part of a team rather than alone.

There may be many resources available locally; however, there is a world full of useful information and you may need to draw on the knowledge and experience of people in distant locations. As travel has become more difficult in recent months, it may be time to consider other methods of sharing expertise and experience.

The Internet provides a host of tools for collaboration ranging from simple instant messaging (IM) and e-mail based discussion groups to more advanced virtual conference services where slide presentations, software applications, and web tours may be presented.

E-mail
With all the talk about broadband, video-conferencing, and other high-tech collaboration tools, e-mail is still the killer application for collaboration. You may want to consider using a public e-mail address such as Hotmail or Yahoo! for privacy protection and to avoid letting your company e-mail address end up on spam or “junk” e-mail lists.

Instant messaging
IM is simple to use, but often is overlooked as a powerful business communication mechanism. With IM, you can quickly see if any of the people on your list are online. If so, you can quickly send them a text message that will pop up on top of whatever application they are working in. They can respond quickly without having to stop working on the program they have open at that moment.

Free IM software is offered by MSN, AOL, and Yahoo!. Unfortunately, they do not interface with each other so you may have to download all three. A better method would be to simply ask your key advisers if they already use an IM service and sign up for that one.

E-mail discussion lists
These are group discussions that take place via e-mail. You can send a question to the entire list and anyone on the list can answer. Often you will receive several answers from various experts around the world. Usually the answers are offered within a few hours.

When the issues are not clear-cut or the group’s opinions diverge, ongoing and interesting e-mail discussions often follow. These lists are noncommercial and vendors should be forewarned to keep the sales pitch down to a minimum or r.isk alienating the list members.

Virtual meetings
PlaceWare
, WebEx, and Centra offer virtual meeting centers (and free trials) on the web. They are easy to set up and do not require the involvement of your IT department. The services are used for delivering presentations, demonstrating software, and allowing anyone in a meeting to view, annotate, and edit any document electronically. Workgroups can collaborate on projects, any time, from anywhere.

All you need to attend or conduct a meeting is a telephone and an Internet browser. The use of a standard telephone for two people or telephone conference call for multiple attendees is recommended.

Don’t overlook the people in your workplace, especially the ones directly involved with the operation, maintenance, or repair of equipment. They have a wealth of information and experience that is often overlooked while management searches for the next “silver bullet” improvement program.

Feedback
We hope you continue to find this column useful and that you provide feedback on what you want us to cover in the future including any web sites or special areas that would be of benefit to our readers. MT

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207

2:09 pm
February 1, 2002
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Process Improvement and Integration

Increasingly, organizations are required to do more with less to stay afloat in today’s difficult economy. This places a heavy burden on maintenance personnel. It is imperative that you implement world-class processes that ensure your assets perform efficiently, and that you implement the appropriate computerized maintenance management system (CMMS) or enterprise asset management (EAM) technologies to facilitate those processes. This implementation faces three major challenges:

  • Islands and applications. Traditional CMMS/EAM solutions were implemented over long periods of time because of complex data building and architectural requirements. These factors led to multi-year implementations, resulting in many sites having different versions of the same software and leaving people scrambling to meet release dates. Add to that the load required to integrate financials and other systems, and it is no wonder many companies have implemented automated processes but are in no position to take advantage of them across multiple sites.
  • Best of breed vs. point solutions. The CMMS/EAM vendors’ “features war” of the 1990s led to exciting breakthroughs in technology, but some vendors lost focus with the process. Most software companies jumped a little early on the Internet bandwagon, offering browser-based front ends to their legacy products. While providing a better end user experience, this battle for mind share actually delayed some new projects from getting started, resulting in today’s many Web-enabled applications, but few pure Internet applications that can tangibly provide the benefits.
  • Mergers and acquisitions. On top of all this, we experienced a merger-mania that seemed to cross all industries. The epidemic of mergers and acquisitions resulted in many companies having multiple systems from competing vendors trying to work together. The situation is so extreme that one large utility has a team of specialists that spend all their time tackling this issue. The recent mergers and attempted takeovers in the CMMS/EAM space provide additional complications. Many companies find themselves yoked to an organization that they did not want or choose. What are they to do?

In order to compete in this environment and maximize your return on assets, you must not only improve your processes but integrate them with other processes throughout your organization. Following are some key guidelines to help you effectively implement process improvement and integration.

Process improvement
The first step in process improvement, as in any complex problem, is to measure. Where are you now? Can you get accurate data across areas of your responsibility for comparison? If not, look at the ways your data is collected and processed and see where the differences are. Simply changing how work is recorded (and at what level) may bridge the gaps between some systems and locations. If that is not possible, look at your corporate financial system for costs, since most CMMS/EAM systems consolidate transactions there.

Once you have your eye on the key metrics related to costs and performance, chart them. Look at the trends that emerge. Now you can plot trouble areas and build key performance indicators (KPI). These indicators will differ based on what you do and what you track. You will start to see the difference between simple numbers (e.g., how many stock issues were transacted) and the truly valuable ones such as cost of failures and the related downtime.

It is important to be aware of a trend, but can you do anything about it? One of the problems historically with financial reports is that once you get them, it is too late to do anything (the money is spent). Aside from costs, look at your assets and capital equipment. Have you established goals for failures and time to repair? Does your system allow you to record the goal and then track and show you the result? If not, some ad-hoc reporting is in order. This is one area where maintenance can be proactive and respond quickly to emerging trends as they arise.

Regardless of your specialty, most maintenance professionals possess a vast amount of insight. Even before the CMMS/EAM revolution, planners and maintenance personnel knew from experience what equipment would create problems in certain conditions. This experience was acquired over the years and was crucial for successful turnarounds and outages. New systems can link failures to corrective work packages and even schedule work automatically, but fall far short of the kind of knowledge you possess. Moving that information beyond the department, and even the facility, to benefit the entire corporation is vital to true collaboration.

Making information available to people when they need it is the area where technology can help the most. This is also where a pure Internet solution becomes important. Imagine you just received a message asking for some help with a troublesome pump. After looking at the configuration and history, you may be able to point out a few suggestions. With the latest technology, the fact that the request for assistance came from another plant, perhaps half way around the world and in a different language, was transparent to you. You simply responded in your native language and let the system take care of the rest. Languages, local customs, and distances hinder collaboration because of the time required to manage such obstacles. Time is the great equalizer. It is the same the world over, and it is the currency in which we trade.

Process integration
How tasks and information are routed in any system dictates the amount of effort required to maintain it. Older systems require many, many hours of unproductive time manually routing work and information just to keep the system working. Companies do not have the resources today to feed data manually into CMMS/EAM systems to get reports. This data must be transformed automatically into useful information as part of the work execution process.

Much like the way enterprise resource planning (ERP) changed the way buyers work with suppliers, new CMMS/EAM systems will change the way maintenance interacts with the rest of the organization. In the early 1990s, buyers went from local procurement activities to a commodity or a line-of-business approach. By expanding these areas of responsibility, huge savings were generated by leveraging relationships, not transactions. We are poised to make a similar transformation and take our experiences beyond our own organization to benefit the rest of the larger corporation. To make this happen, barriers to this true collaboration must be removed. Technology can play a part, but people will make it happen.

How will this come about? It is simple—evolution.
As we move forward, we evolve. For example, the first preventive maintenance system I ever saw was in the Navy, as a ballistic missile technician in the submarine force. We had one real constant: time. Everything revolved around “time in service” and was replaced on schedule. While I understood the importance of the mission (not to mention keeping the water out of the “people tank”), I always wondered how many good components were thrown out with the bad. This curiosity led many to sample along the way and created the predictive model.

Those philosophies are now simple elements of the reliability centered maintenance (RCM) model, one that looks beyond failures. Looking at an asset’s role in the process, and understanding why it fails, is key to the RCM approach. There are new initiatives underway with on-line analytics that will further change how we look at maintenance, but it will always be up to us to understand what planned vs. actual really means, in more than time and money. This constant state of change has a name: continuous improvement.

Commit to continuous improvement
The evolution of maintenance philosophy demands change. As the maintenance business evolves, we are constantly tuning our resources, both internal and external, to meet the challenge. As we move into the 21st century, new partnerships will be forged among manufacturers, suppliers, and users, who will require new collaborative tools that use the Internet to communicate. Just as portals have consolidated access to corporate applications, new CMMS/EAM systems must bring together all the involved parties into the maintenance lifecycle. The Internet is the only way to bring it all together, but without the right processes in place, it is just glorified e-mail. Your next system must have a way to promote best practices and be able to change as it evolves with your experiences.

The true gift of continuous improvement and the application of best practices is understanding. Knowing failure modes, their root causes, and how to respond will give you insight into the asset you never thought possible. Taking that information out your door to help the broader corporation will be much more valuable, and justify the time and money invested in the tools you use. MT


Information supplied by Kevin Kling, director of sales support, Indus International, 3301 Windy Ridge Pky., Atlanta, GA 30339; (770) 952-8444

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