Archive | 1999

257

1:12 am
April 2, 1999
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Where Do We Go From Here?

bob_baldwin

Bob Baldwin, Editor

I spent several days last month participating in the Plant Engineering and Management sector of the National Manufacturing Week conference and trade show in Chicago. I liked the new show layout with enterprise resource planning software, automation software and systems, enterprise asset management software, and plant equipment and systems in the same hall. However, I didn’t get to see much because developers of maintenance information systems were much more aggressive and successful this year in their bids for my attention. Most of their discussion revolved around features associated with the Internet or Web.

A common theme was the Web browser interface that benefits ordinary users by providing an interface similar to what they use at home to surf the Web. They can easily enter a work request or access information without training. Power users such as planners would continue to use the standard interface with a full range of features. Also new was the online approach to CMMS in which the software resides on the supplier’s server and the user operates the system via the Internet.

As far as the conference was concerned, attendance seemed low, at least in the sessions I attended. Good information was presented on managing equipment reliability and maintenance, but few people were there to receive it–a situation that makes a good case for business-to-business publications such as Maintenance Technology.

Perhaps the most significant event was an ad hoc meeting that included several professional societies: The Society for Maintenance & Reliability Professionals, the Association of Facilities Engineers, the Institute of Industrial Engineers, and the Plant Engineering and Maintenance division of the American Society of Mechanical Engineers. Represented officially by officers or staff, or unofficially by regular members, they met to discuss the common objective of boosting the image of the equipment reliability, maintenance, and asset management profession.

The consensus: the profession’s image needs bolstering to bring it up to the level of its contribution to the bottom line. The resolution: the image can be improved, and the group wants to meet again in the fall to develop an agenda to that end. The next step: better communications among the constituents. The need: input from practitioners about what is needed.

Where do we go from here? Is the committee’s goal worth pursuing? MT

rcb

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1331

12:10 am
April 2, 1999
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Study Shows Shaft Misalignment Reduces Bearing Life

Relatively small amounts of shaft misalignment can have a significant impact on the operational life of bearings. Summary of Maintenance and Reliability Center research notes that a 5-mil offset misalignment can reduce expected bearing life by as much as 50 percent in some cases.

American industry invests significant time and money performing precision alignment of rotating machinery. The basis for this expenditure is two assumptions: misalignment causes a decrease in motor efficiency, and misaligned machinery is more prone to failure due to increased loads on bearings, seals, and couplings. The Maintenance and Reliability Center, University of Tennessee Knoxville, has investigated both assumptions. Phase one of this research determined that there is no measurable decrease in motor efficiency correlated to motor misalignment when the tested couplings are operated within the manufacturer’s recommended range. Phase two, reported in this article, determined the relationship between motor alignment, roller element bearing load, and predicted bearing life.

It is generally agreed that proper alignment is critical to the life of the machine, and coupling wear or failure, bearing failures, bent rotors or crankshafts, plus bearing housing damage are all common results of poor alignment. We also know that loads on mechanical parts, such as bearings, seals, and couplings, decrease with improved alignment. These reduced loads result in decreased noise and vibration, decreased operating temperatures, decreased wear on mechanical systems, and decreased downtime due to breakage. All of these result in a longer and more reliable operating life span of equipment.

Clearly, there is cost associated with a precision alignment maintenance program. Alignment equipment, personnel training, labor associated with alignment, and machinery downtime are all expenses associated with a program to assure proper alignment. All of these costs need to be weighed against any expected benefits. Thus, it is necessary to predict in real terms, and in a systematic and scientific manner, what these benefits will be. This research experimentally determined the reduction in bearing life for different alignment conditions.

These numbers can be used in a more sophisticated model to estimate financial losses due to machinery misalignment.

Coupling Type Maximum offset
misalignment
Maximum angular
misalignment
Grid 12 mils 11 mils/in
Elastomer (tire) 70 mils 40 mils/in
Link pack 26 mils 8 mils/in
Gear 50 mils 15 mils/in

Methodology
Shaft misalignment can be divided into two components: offset misalignment and angular misalignment. Offset (or parallel) misalignment occurs when the centerlines of two shafts are parallel but do not meet at the power transfer point, and angular misalignment occurs when the centerlines of two shafts intersect at the power transfer point but are not parallel. Often misalignment in actual machinery exhibits a combination of both types of misalignment.

Testing was performed at The University of Tennessee’s Mechanical Engineering Engine Laboratory using a fully loaded 60 hp ac induction motor running at about 3562 rpm and driving a dynamometer. Load sensors were positioned at both the inboard and outboard bearing locations. The load was measured at a rate of 6000 Hz for 5 sec from seven load-sensing locations. A tachometer signal was measured at the same rate on the eighth channel. This resulted in recording approximately 100 data points per revolution for about 300 revolutions for each channel for each misalignment condition.

The electric motor was bolted to a steel plate with ground and polished pads. The smooth and flat contact surfaces between the midplate and the base plate facilitated accurate movement of the motor during changes of alignment and also eliminated soft foot.

The vertical alignment of the motor was held constant at less than 1 mil offset and 0.1 mil/in. angular misalignment, and all changes in alignment during testing took place in the horizontal plane. Changes in alignment were made while the motor was fully loaded; both dial indicators and laser alignment systems were used to monitor the alignment condition.

 

force-rate-balance-equation

Fig. 4 Force (rate) balance equation was used to determine the force and moment rates (spring constants) of the flexible couplings. Pure offset case is illustrated.

Four different coupling types that were identified as being the most commonly used were selected for the alignment testing (Table 1).

Bearing load measurement
Several load-measuring device designs were considered, including measuring strain in the rotating shaft, refitting the motor with load-sensing end bells, finding actual bearings with load-sensing capabilities built into them, and trying to measure loads at the motor feet and extrapolating these measurements to forces at the bearings. None of these options appeared to satisfactorily fulfill the experimental design requirements.

A final design concept was chosen in which a sensing interface (sensor ring) was placed in the motor between the shaft bearings and the supporting structure of the motor. However, this configuration required that some space be created between the outside of the bearing and the inside of its housing. This was provided by replacing the original motor bearings with ones having a smaller outer diameter.

bearing-load

Fig. 5. Three Dimensional plots of observed and calculated data show relationship between misalignment and bearing load (left) and bearing life (right).

A finite elements analysis was used to design the sensor rings and balance strength against load sensitivity. Force induced strain in the sensor rings was converted to voltage signals by strain gages located at several locations around the sensor rings. The strain gages were assembled in temperature compensating, full bridge configurations located in each quadrant of the sensor ring. The voltages from the strain gages on both inboard and outboard bearings were recorded with a data acquisition board at 6000 Hz for 5 sec giving 100 samples per revolution. The load sensors were experimentally calibrated over a range of loads from 0 to about 300 lb and had a sensitivity of 1.5 lb, giving more than acceptable performance.

Experimental procedure
All changes in alignment were made to the horizontal plane with the motor operating under full speed and full load conditions. The system was run 1 to 2 hr so that constant operating temperatures were attained. For each of the four coupling types, misalignment conditions were varied in the following order:

  1. Pure positive offset misalignment up to maximum
  2. Combination of positive offset and positive angularity
  3. Pure angular misalignment up to maximum positive
  4. Combination of negative offset and positive angularity
  5. Pure offset misalignment up to maximum negative

For each of these cases, data was taken at four or five evenly spaced interim alignment conditions between the aligned and maximum misaligned conditions.

bearing-life-expectancy

Fig. 6. Contour plot of bearing life expectancy for a given misalignment condition (same data as the bearing life plot in FIg. 5.)

Summary of results
Data was collected for the misalignment experiments for all four coupling types. The data then was analyzed to determine the change in the expected coupling life with respect to the misalignment condition.

The measured forces show that the couplings can be accurately modeled as a combination of several linear and torsional springs. This means that any misalignment between two coupled shafts can be considered to be either a linear or angular displacement, and the coupling is a spring, which generates a force and moment proportional to this displacement. The ratio of the force or moment induced by the coupling to the displacement is the spring rate k for the coupling:

k-coupling

Both offset and angular misalignment are shown to result in the generation of a combination of a transverse force and a moment at the coupled end of the shaft. Therefore, there are four spring rates needed to describe the functioning of a given coupling:

ko,f – spring rate relating force to offset misalignment, lbf/mil
ko,m – spring rate relating moment to offset misalignment, lbf-in./mil
ka,f – spring rate relating force to angular misalignment, lbf/(mil/10 in.)
ka,m – spring rate relating moment to angular misalignment, lbf-in./(mil/10 in.)

If these four constants are known for a specific coupling, the bearing loads induced by misalignment can be calculated for any size motor and for any given misalignment condition.

The force rates for the inboard and the outboard bearings were experimentally determined and a simple force (rate) balance equation for the system was used to determine the force and moment rates (spring constants) of the flexible coupling. A diagram of this force balance for the case of pure offset is shown in Fig. 1. The same approach is used for determining the two spring rates for angular misalignments. In this case, the equations would be changed so that ko,m and ko,f would be replaced by ka,m and ka,f.

Roller element bearing life
The information presented to this point has related shaft misalignment to bearing load. A further relationship can be developed to determine bearing life for roller element bearings as a function of the additional load caused by shaft misalignment. Bearing manufacturers provide load capacity ratings C which can be used to estimate bearing life H for a specific bearing operating under a specific load L and rotational speed V (rpm). The equation relating capacity, load, and life is:

99-04p15

More complicated bearing life expectancy equations that utilize vibrations and masses can be found but are not needed for this problem. A ratio between the estimated life of a bearing in a perfectly aligned case (with load La) and a misaligned case (with load La + Lo) can give a description of the reduction of useful life of a bearing operating in misaligned conditions:
remaining-life-factor

This factor will be a positive value that is less than or equal to 1. The product of this factor and the maximum estimated life of the bearing (under perfectly aligned conditions) will give a new estimate on the life of the bearing under a misaligned condition. For instance, if the remaining life factor was calculated to be 0.6, then one could expect that the bearing would last only 60 percent as long as a bearing in an aligned condition. In such a case, 40 percent of the operating life of the bearing was lost due to misalignment. This factor accurately shows the impact that improper alignment can have on bearing life and thus on the intended operating life of machinery.

link-coupling

Link Coupling
elastomeric-coupling

Elastomeric Coupling
grid-coupling

Grid Coupling
gear-coupling

Gear Coupling
Fig. 7. Contour plots reflected about the zero offset line show alignment operating regions for a given bearing life expectancy for the four coupling types tested.

Using this equation, the measured loads, and an initial load of 500 lb, we can plot the remaining life factor versus the different alignment conditions. Since the alignment condition is defined by two variables, offset and angular, this is a three dimensional plot. Fig. 2a is a plot of the load measurements for the link coupling. The angular and offset misalignments are varied over the horizontal axes, and the vertical axis plots the bearing load at a given misalignment. Only about 100 of the data points shown in this graph were measured directly; the remainder were generated via spline interpolation between the known points. The remaining life factor equation was used then with the data from Fig. 2a to determine what percentage of inboard bearing life can be expected for a given misalignment condition and plotted in Fig. 2b.

Fig. 3 is a contour plot of the information in Fig. 2b. The contours trace lines of constant percent life expectancy. One striking feature of this plot is that there are no closed regions specifying a finite range of operation enclosing a specific life expectancy range. This map, for instance, predicts the same life expectancy (100 percent) for a bearing operating in a perfectly aligned case as one operating with an offset of +5 mils and an angularity of +80 mils/10 in. This means that for a specific bearing and coupling there exist certain combinations of angular and offset misalignment which cause bearing loads induced by angular misalignment to cancel those caused by offset misalignment.

It may be somewhat impractical to use the data in Fig. 2 to establish standards for machine alignment. A simple way to use that data is to take a reflection of the data around the zero offset misalignment point. This serves to create clear suggested operating regions for machinery for a given desired level of bearing reliability. Fig. 4 shows these operating regions for the four different types of couplings used in this research.

Note that in the plot for gear coupling in Fig. 4, the regions are not as linear as those of the other couplings. This is probably due to the gear coupling having two planes of force transfer. Because of this the gear coupling also gave the least repeatable results.

Consideration of misalignment in the vertical plane
All of the results in this study were determined exclusively by examining the effects of misalignment in the horizontal plane. But, by exploiting the radial symmetry in rotating machinery, these results can easily be extended to encompass misalignments in the vertical direction as well as combined horizontal/vertical components. This is performed by simple vector addition as shown in the following equations:

99-04p16b

The values for the combined offset and angular misalignments from these calculations can be used in all of the bearing load and life calculations presented. In order for the above equation to be used properly, the angular misalignment must be given in units of length/length (for instance mils/10 in.) and not in radial units such as degrees or radians.

Conclusions
The results from this research show that, for the couplings used in this testing, moderate shaft misalignments induce bearing loads that are large enough to have a significant impact on the life of the bearings. These increased loads are apparent in increased vibration and increased bearing and coupling temperatures.

The addition of load-measuring bearings to commercial motors may be useful as an on-line measuring system to detect rotational imbalance and misalignment. This could assist in moving from periodic maintenance strategies to condition based maintenance strategies and also could assist in the diagnosis of problematic equipment.

This research shows that angular misalignment has a much smaller impact on bearing life than offset misalignment. Angular misalignment may, in fact, play a more significant role in reducing bearing and coupling life than this study suggests. This is due to two points: (1) axial forces that were not measured may reduce bearing life, and (2) angular misalignment may be a major factor in reducing coupling life. Neither of these two assumptions was studied in this research.

It is a commonly held belief that a flexible coupling operating in an angular misaligned state will induce an oscillatory axial load on the coupled shafts. This belief is substantiated by practical experience–angular misalignment in rotating machinery is commonly diagnosed by detecting excessive axial vibration. The bearing load sensors used in this research project could not detect this axial loading (only transaxial bearing loads were measured in this research), and, therefore, could not be used to measure the oscillatory thrust loads on the bearings.

It is suspected that the transaxial load measurements alone do not fully describe the degrading impact that angular misalignment has on bearings. It is likely that angular misalignment can decrease bearing life further by inducing an additional load in the axial direction. The results in this project which estimate the adverse impact that angular misalignment has on bearing life should be considered a minimum estimate.

The effect of angular misalignment on the couplings would be to increase forces in the coupling. These forces are oscillatory in nature due to the successive compression and expansion of the coupling materials. These oscillatory forces grow with increased angular misalignment, accelerating fatigue failure of the coupling components. Therefore, we suggest that offset misalignment unnecessarily loads and degrades the bearings while angular misalignment primarily degrades the coupling.

TABLE 2. RULES FOR OFFSET MISALIGNMENT AND INBOARD BEARING LIFE
Maximum offset (direct measurament and percent of maximum for three expected bearing life)
Maximum coupling
offset recommended
by manufacturer
Coupling Type 90% life expectancy 80% life expectancy 50% life expectancy
Link 3 mils
(12% max)
5 mils
(19% max)
20 mils
(77% max)
26 mils
Elastomeric 8 mils
(11% max)
21 mils
(30 % max)
70 mils
(100% max)
70 mils
Grid 1 mil
(8% max)
2 mils
(17% max)
5 mils
(42% max)
12 mils
Gear 5 mils
(10% max)
10 mils
(20% max)
35 mils
(70% max)
50 mils

Using average offset values for various life expectancies, it can then be broadly stated for the couplings used in this study that: 1. If the motor is offset misaligned by 10 percent of the coupling manufacturer’s allowable offset, then one can expect a 10 percent reduction in inboard bearing life. 2. If the motor is offset misaligned by 20 percent of the coupling manufacturer’s allowable offset, then one can expect a 20 percent reduction in inboard bearing life. 3. If the motor is offset misaligned by 70 percent of the coupling manufacturer’s allowable offset, then one can expect a 50 percent reduction in inboard bearing life.

General rules
The results from this study can be further condensed and generalized into a convenient set of rules. Table 2 shows the amount of offset misalignment that can be tolerated in order to remain within certain regions of maximum possible life expectancy. These tolerable offset magnitudes then are normalized by the coupling manufacturer’s specified maximum offset. MT


The results presented in this article are part of a research project conducted for the Maintenance and Reliability Center at the University of Tennessee, Knoxville. This research was funded by Computational Systems, Inc. and Duke Power Corp.

J. Wesley Hines, Stephen Jesse, and Andrew Edmondson are all on the staff of Maintenance and Reliability Center, College of Engineering, University of Tennessee, Knoxville, TN 37996. Dan Nower is product champion with Computational Systems, Inc., 835 Innovation Dr., Knoxville, TN 37932. The authors can be contacted by email: Hines, hines@utkux.utcc.utk.edu; Jesse, sjesse@utk.edu; Edmondson, edmondso@ utkuxl.utk.edu; and Nower, nowerd@smtpg.compsys.com

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257

12:58 am
February 2, 1999
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The Last Stupid Customer

bob_baldwin

Bob Baldwin, Editor

I just returned from a trip on the Internet to research some topics for this and future issues. As usual, I came back both delighted and frustrated: Delighted by some of my finds and frustrated by roadblocks put up by well-meaning webmasters.

Here are a couple of business finds. As a starter, you can’t beat www.ceoexpress.com. It has all the best news and business links arranged compactly by categories on one page. It can also be personalized to include some special categories to which you can add your favorite sites, which I hope includes ours: www.mt-online.com.

My Web browser is now set to automatically bring up the ceoexpress page when it opens. One of the sites linked to that page is www.findspot.com, which provides some valuable help for using search engines to track down information.

One of my maintenance finds was MotorMaster+, the electric motor management software and database developed by the Washington State University Energy Program for the U.S. Department of Energy.

The software, which can be operated from the Motor Challenge site www.motor.doe.gov/mmplus, or downloaded, allows the user to peruse a 17,500 record database of electric motors in various sizes and configurations from a variety of manufacturers. Data includes efficiency and other parameters including retail price.

When I saw the field for motor price, I was reminded of how the Internet is changing the way people buy things. It has certainly revolutionized automobile purchasing. I can remember the feeling of power I had a decade or so ago when I walked into the dealership armed with “secret” dealer invoice information from our company’s friendly leasing agent. Today, that power is available freely on the Web at a number of sites. Just check auto links in the “tools, travel, and fun” section at the bottom of the ceoexpress page to get started.

I am also reminded of a quip by a marketing and sales strategist at an automobile company: “Online car-buyers are a savvy bunch and are privy to information never before available to them. In a very short period of time, the last stupid customer is going to walk through our dealership doors.” Although we are not there yet with electric motors and most other goods for industry, we are headed in the right direction. And what else should we expect to see someday on the Internet? Check out the thoughts of Blaine Pardoe, our newest Viewpoint columnist. MT

rcb

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187

12:55 am
February 2, 1999
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The Impact of the Internet on Maintenance Departments

“So, should I be on the Internet?” This is becoming a more common question to those of us involved with consulting on maintenance operations. People tend to look at us as if we have crystal balls and can predict the future, when in reality we are only now starting to see the impact of this technology on maintenance organizations. Given the technology, the trends, and the direction of CMMS and other software, there are a few areas where the Internet may start to have some impact on how work is done.

The Internet, to most people, is a combination of a graffiti-painted wall and the Yellow Pages. There’s a lot of talk about the Internet and how it’s going to change our lives, but as maintenance professionals, everyone is curious about what that really means. And, while consultants are often vague about those answers, I’m going to lay it on the line.

From a realistic standpoint, here’s where the impact of the Internet is going to be on maintenance operations in the next few years. My pundits and peers will most likely take shots at this list, but I’ve tried to stay away from “pie in the sky” thoughts and keep this realistic. I’ve listed them in order of their immediate impact on maintenance departments .

Ordering of parts and materials
This exists already with a number of vendors having on-line ordering capability. The days of the shelf of catalogs and long minutes on the phone to order a part are disappearing. Already with some of the maintenance vendors that are out there you can check the availability of stock, shipping times, etc. You can even track shipments with various freight companies to ensure that the motor is on the way and when it will arrive. The biggest hurdle is interfacing your purchasing department with the vendors so that approvals can happen quickly.

Availability of manuals and maintenance procedures
Some equipment manufacturers are already starting to put their manuals online as well as the recommended maintenance procedures, and the trend is likely to increase. These are much easier to deal with than attempting to update them by hand in a binder that is also used to prop up the coffeepot.

E-mail and discussion forums with peers
Most people are shocked that e-mail would appear so far down on this list, but in terms of actual changes in a maintenance worker’s or manager’s everyday life, contact with peers in the outside world is limited. Where it will start is for getting technical support from a vendor. Soon, services like www.dejanews.com will start hosting forums for maintenance managers so that they can share tips, techniques, etc., with each other.

Online diagnosis, troubleshooting
Vendors web sites often have an e-mail address for getting help with their equipment that you have installed. What is coming for our industry sometime in the near future is that you are going to be able to plug in your symptoms when the equipment is broken and get a list of procedures online for fixing it. Chances are you will be able to get access to an engineer to walk you through it as you go. These services are going to cost money, but they will be faster than waiting for “Repairguy Bob” to show up and most likely they will be much less expensive.

Web-based CMMS
Given the cost of database systems, servers, and the people needed to support them, it’s really just a matter of time before your work orders will have a Web interface. You will most likely not even have to store your own data on-site, and they will be accessible from any PC that has a Web browser. While to some this is a step back to the earlier era of centralized systems, in reality, it’s a global solution that is just around the corner.

So what does all of this mean to maintenance professionals? One: there are major training implications for this influx of technology. It’s one thing to know that the information is out there, it’s another teaching Dave from the fourth-shift HVAC crew how to use a mouse to double-click. Two: managers are going to have to change how they get to the information and distribute it to the workers. MT


Blaine Pardoe is a principle in Enterprise Management Systems and a highly regarded expert in the field of technology learning, CMMS implementation, and the maintenance industry. He is the author of the best-selling book, Cubicle Warfare, and numerous novels and is a frequent contributor to Maintenance Technology. Continue Reading →

222

12:53 am
February 2, 1999
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Applying Wear Particle Analysis to Rotating Machinery

Used oil analysis determines the condition of the lubricant; ferrography determines the condition of the machine.

You have a sound preventive maintenance program in place. You have even added some predictive maintenance elements to it, but you are still getting unplanned catastrophic failures. Adding ferrography to the mix can give adequate warning of possible failures so repairs can be planned.

Ferrography is a microscopic examination process developed in 1971. Initially, it looked only at ferrous wear particles in lubricating oils. Advances in technology now allow ferrographers to classify wear particles from many substances, both magnetic and nonmagnetic. The process is not limited to ferrous metal or oils-greases also can be analyzed.

Don’t confuse a used oil analysis program with ferrography. Used oil analysis determines the condition of the lubricant; ferrography determines the condition of the machine.

The spectrographic component of oil analysis provides an incomplete profile of the wear metal in the system. Because laboratory instruments can sense only particles smaller than 8 microns and the onset of abnormal wear initially is revealed by an increased concentration of particles greater than 8 microns, the ability of spectrographic oil analysis to provide useful information on your machines is limited.

A comprehensive lubricant analysis program will contain elements of both techniques. It is important to know the condition of the lubricant and its ability to perform as designed, as well as the presence of contaminants and wear particles.

Conducting wear particle analysis
Typically on a monthly basis, lubricant samples are taken from a machine and sent to a laboratory specializing in ferrography and lubricant analysis. Used oil tests, such as viscosity, and spectrographic and chemical analyses are conducted. Additionally, in the first phase of ferrography, wear particle concentrations are routinely monitored and compared to detect wear trends. This establishes a baseline for the earliest possible detection of abnormal wear onset. The second phase begins when the onset of abnormal wear is detected.

Trained analysts with a thorough knowledge of the equipment being monitored and the metallurgy of its components analyze the deposited particles through a microscope up to 1000X. Detailed microscopic analysis identifies the wear mechanisms that are causing the particle generation, identifies the probable source of the particles, and determines which components are experiencing the wear. Fig. 1 illustrates normal machine wear when viewed at 500X. The strings of particles in the image are made up of many flat platelets of less than 15 microns that are lined up on the magnetic lines of flux as the microscope slide is prepared. Fig. 2 illustrates larger laminar platelets viewed at 1000X that indicate rolling contact failure of a bearing. Through heat treatment and chemical reactions on the slide, the actual metallurgy of the particles can be determined.

Recently, a large chemical plant was able to avoid a catastrophic failure and save $100,000 by effectively using a combination of used oil analysis tests and ferrography. The machine, a General Electric turbogenerator, had been operating normally. A lubricant condition report, based on chemical and spectrographic analysis, showed normal degradation; continued use of the lubricant was recommended. However, an equipment condition report rated the machine condition CRITICAL. This evaluation was based on an increasing wear particle concentration and the presence of lead/tin babbitt particles ranging up to 90 microns (see Fig. 3). It was recommended that the machine’s bearings be inspected at the earliest opportunity.

Examination of orbit plots and vibration time waveforms indicated possible journal impacting. The machine was shut down and the subsequent inspection revealed that the babbitt lining had been wiped and there was minor scoring on the shaft which could be polished out. This fault could have gone undetected until vibration alarms signaled an impending failure, and the subsequent additional damage to the shaft may have required removal and repair or replacement. Ferrography provided the early warning necessary to prevent a potentially catastrophic failure. MT


Information supplied by Predict/DLI, Cleveland, OH; telephone (216) 642-3223.

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201

11:59 pm
February 1, 1999
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Eat an Elephant-Implement a CMMS

Insight on why companies may not reach their goals when implementing computerized maintenance management systems.

How do you eat an elephant? “One bite at a time.”

How do you implement a maintenance management system? “One step at a time.”

An elephant is a large animal and it is doubtful anyone would want to eat one. But the old proverb, with a little twist, has a similar paradox to implementing a computerized maintenance management system (CMMS). Not developing the proper steps to implementation may lead a company to failure.

The first and most important step in the implementation process is for plant management to decide how the maintenance department should function. This will depend somewhat on the size and scope of plant operations. Some key matters to be resolved are listed in the section “Questions to Ask About Maintenance Department Functions.” How the maintenance function is handled will dictate staffing and policy needs and can help in the CMMS selection process.

Plant commitment
Once it is decided how plant maintenance will function, the next step is to gain plant commitment to the process. Without this commitment, the system will never be fully functional. Lack of total plant commitment is the most common reason why companies who have purchased maintenance management systems do not reach their expectations.

After determining the maintenance function and gaining total plant commitment, a company needs to select and purchase a CMMS that meets its needs. Consideration must be given to data collection and data entry. How and by whom will the data be collected and entered? Unless the company is converting from one CMMS to another where some of the data can be electronically transferred, considerable data entry will be required.

What kinds of equipment records are available? Is preventive maintenance and spare part information available? Who will perform an equipment survey if it is necessary? This survey will require dedicated personnel and must be performed by someone who knows the plant equipment. Even if a survey is not necessary, forms may need to be developed to match the system requirements.

Manual data entry takes time and should be performed by someone trained in system requirements. Experience has shown that these duties are often assigned to personnel who are very capable in their own capacity but have little or no keyboarding or computer training.

The maintenance storeroom
Maintenance planning includes determining both the labor and materials required to perform a job. In order to calculate accurately the costs for a work order, material costs as well as labor costs need to be tracked.

Before inventory can be added to the system, the storeroom has to be organized to provide proper storage and parts location. Inventory control procedures have to be in place and a plan has to be developed for requisitioning maintenance supplies from the storeroom.

Implementation schedule
The next step should be developing an implementation schedule. This schedule will let plant management know where they are in the implementation process.

  • How long will it take to survey the equipment and enter the data?
  • When will PM requirements be entered?
  • When can work order planning and scheduling be kicked off?
  • When will the maintenance storeroom be sufficiently functional to identify spare parts for cross reference to equipment, to reserve parts against work orders, and to be used for issuing and automatic reordering of supplies?

Many CMMS contain add-ons including bar coding options, the ability to display drawing images, etc. Management will have to decide on the value of these functions to their organization, then take the necessary steps to make the system functional before adding them. In one manager’s words, “We have to crawl before we can walk.”

Taking ownership
A final step is having key personnel take ownership of the system. A CMMS vendor or a maintenance management consulting company may be requested to assist in the implementation process. Even though an outside consultant’s advice may not coincide with what company employees would like to hear, company personnel must be willing to work through the difficulties and differences in philosophy in order for the CMMS implementation to succeed. MT


Ronald Hemming is president and managing partner of Maintenance Technologies International, LLC, a plant maintenance management consulting and engineering firm located in Milford, CT, with affiliated offices in Niagara Falls, NY. Daniel Davis is a senior maintenance management consultant. Hemming may be contacted at (203) 877-3217; Davis may be contacted at (716) 284-4705.

Questions To Ask About Maintenance Departments

  • Is all maintenance work to be planned and scheduled as much as possible?
  • Generally, a CMMS will track maintenance labor and material costs. Will all maintenance labor and material be logged to the system? This will require every job to have a work order for requisitioning material and entering craft hours.
  • Who is going to plan and schedule maintenance work? Does the scope of maintenance work require dedicated maintenance planners, or can maintenance supervisors plan, schedule, and supervise maintenance work?
  • Is production going to be involved in maintenance scheduling? If so, how will this be coordinated? Weekly meetings? Daily meetings? A phone call?
  • If production is not involved in maintenance scheduling, what priority will be assigned to the preventive maintenance work and how will it be scheduled?
  • What reports will be necessary to carry out the scheduling function? A simple list of unscheduled work? Backlog by production foreman?
  • Is a maintenance clerk necessary to support the maintenance group? If not, how will management reports, daily schedules, and work order entry and close out be handled?

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774

9:14 pm
February 1, 1999
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Using Incentive-Based Contract Maintenance

Incentive clauses in maintenance service agreements benefit both owner and contractor when they focus on important goals. Here are some issues to consider.

When you buy a service, what do you believe is the contractor’s primary goal? A. Pride; B. To employ people; C. To make you happy; or D. To maximize the difference between his receipts and his cost? While A, B, and C are noble goals, the reason the contractor is in business is D: to make money.

 

completed-pm-work-orders

PM work orders completed in scheduled time was part of the original maintenance agreement at a paper mill in the mid-South. Kellogg Brown & Root has been providing total maintenance services at this mill since the early 1990s.

 

In a similar vein, service providers should ask that question about you. As the owner, what is your primary objective? A. To employ the contractor’s people; B. To build the contractor’s resume; C. To be a good citizen; or D. To maximize the value you receive for each dollar spent? Obviously, your primary objective is D: to maximize value received.

Pros And Cons Of An Incentive Plan

Advantages

  • Creates greater ownership and commitment by the contractor
  • Motivates the generation of new ideas
  • Encourages closer cooperation between owner and contractor
  • Influences key personnel assignments to the project
  • Creates potential for greater management attention to the project
  • Stimulates a more disciplined approach to using information and control systems
Disadvantages
  • Additional administrative costs
  • Extra negotiations
  • Changes in priorities require renegotiations
  • Increased number of disputes
  • Difficulty in establishing fair and equitable targets for performance measures

Is it easy to see that these two goals might not be in alignment? In fact they could end up being 180 degrees out of alignment. Then, what can you do to motivate the behavior of the contractor to be consistent with your goals and objectives?

The answer to this question can be found in the behavioral sciences. Expectancy theory argues that the motivational force to perform or expend effort is a multiplicative function of the expectances concerning future outcomes and the value of those outcomes.

This concept of expectancy then has two specific components:
1. Expectancy or probability of success associated with each behavior, and 2. Association of certain outcomes with every behavior.
If we apply these concepts, we find that motivation will be greatest when:

  • Participants believe that performance at a particular level is possible.
  • Participants believe that performance will lead to certain positive outcomes.
  • The outcomes are found to be attractive.

The behavior of a contractor is linked to certain attractive outcomes (increased receipts) which are tied to obtainable performance measurements. These performance measures gauge the contribution of the contractor to those drivers, which maximize the value received by the owner.
Kellogg Brown & Root has been working with incentives in our contact maintenance business for over 15 years. We have had successful incentive plans, and some plans which were not so successful. Advantages and disadvantages of incentive plans we have observed are outlined in the accompanying section “Pros and Cons of an Incentive Plan.”

reliability

Reliability: Monthly Machine Failure Rates. Machine failure rate is part of the maintenance agreement at a major chemical plant located east of Houston. Kellogg Brown & Root provides total maintenance services at this location, where there has been an incentive plan in place for 5 years.
reliability-index

Reliability Index: Machines Requiring Rework During “Warranty” Period. Count of machines requiring rework is part of the maintenance agreement at another major chemical plant in Texas. Kellogg Brown & Root provides total maintenance at this plant. There has been an incentive plan in place at this location for 4 years.
Making Incentive Clauses Work

The success of incentive clauses in maintenance contracts is a product of a variety of factors. The following observations are offered as suggestions for consideration during the development of a maintenance service agreement:

  • An integrated approach to design and implementation has been found to be the most successful. Contractors should be involved in plan design. Owners must remain an active member of the team and not abdicate this accountability during implementation.
  • Owner’s commitment to success is paramount for plan success. You must want your contractor to earn the bonus.
  • Performance measures must be obtainable, within the contractor’s control, comprehended, and valid.
  • Bilateral determination of results creates a collaborative environment between the owner and contractor.
  • Goals and status must be communicated to all employees.
  • A high level of trust between owner and contractor must be established and sustained.
  • Positive incentives encourage positive actions, behaviors, and relationships. Negative incentives encourage behaviors and actions that are defensive.
  • Effective incentive plans are designed carefully to respond to specific requirements and particularities of application.
  • A contractor’s degree of risk aversion increases with his inability to absorb the potential loss.
  • Two-way communication is essential at all levels of both the owner’s and contractor’s organizations.
  • Incentive plans take time.
  • You can’t incent capabilities into a relationship which neither owner nor contractor is capable of providing.
  • Incentive plan design should be flexible. Don’t be afraid to change the design if it is not yielding results. Review the plan at least annually.

The incentive clauses in the service agreement must be designed around the plant’s overall maintenance and asset management goals. Generally, clauses will have a minimum performance figure above which a bonus award will be paid. There will also be a maximum goal figure above which the incentive bonus will cease to increase with performance. Some of the clauses we have worked with include the following:

­ Safety work orders completed within scheduled time.
­ PM work orders completed within scheduled time.
­ Emergency workload.
­ Overtime worked by maintenance core group.
­ Absenteeism.
­ Asset maintenance downtime.
­ Skills inventory-work time devoted to developing multiskilled crafts.
­ Reliability-monthly machine failure rate.
­ Productivity-man-hours per completed base work order.
­ Training-percent of training man-hours to goal.
­ Contractor’s man-hour performance-over or under budget.
­ Contractor’s overall maintenance performance-over or under budget.
­ Safety-recordable incident rate.

The accompanying performance charts illustrate incentive clause measurements from three different contract maintenance agreements.
Incentives can be useful for motivating performance when the owner-contractor relationship is long term, focused on business goals, and with shared control.
Strive for these features in your maintenance projects. The accompanying section “Making Incentive Clauses Work” offers observations for consideration as you develop your incentive plan. MT


Wayne A. Crew, P.E., is vice president of maintenance at Kellogg Brown & Root, a Halliburton Company, 4100 Clinton Dr., Houston, TX 77001-0003; telephone (713) 676-3368; e-mail wayne.crew@halliburton.com. Continue Reading →

214

12:50 am
January 2, 1999
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Embracing Asset Management

bob_baldwin

Bob Baldwin

Last year was not the best for some of us. Many maintenance and reliability organizations were under increased pressure to conform to the dictum: “Do more with fewer people and less money.” Expect no let up in demands this year. Pressure will continue to rise unless demand is vented or capacity is increased.

Our capacity to deal with the demands of the job is a function of the amount of information available to us, as well as our organization’s approach to the work. With the low-level repair approach to plant equipment, the organization is under extra pressure because it is operating in the dark, operating with little information on equipment condition and thus controlled by equipment breakdown.

As an organization elevates its approach to include preventive and predictive maintenance, the outlook becomes brighter. The organization now has more information about the equipment and increased capacity to manage it. The pressure of breakdown maintenance has been reduced. Embracing the higher-level principles of reliability-centered maintenance and modern business processes again increases capacity of the organization.

The outlook is expected to become even brighter at the next higher level: asset management. Although the asset management function is still being defined, its major characteristics are coming into focus. It views equipment reliability, capacity, availability, and maintenance as elements of an asset utilization strategy supporting plant objectives. Asset management is a strategic peer at the plant operations table, not a vassal for providing maintenance services.

We believe in asset management and we have made it a part of our tag line—The magazine of plant equipment reliaiblity, maintenance, and asset management. This issue has several articles that deal with asset management:

  • Brad Peterson, in “Defining Asset Management,” explores some of the characteristics of asset management and describes an asset management model being installed in a progressive plant of a major industrial company.
  • Gino Palarchio, in “The Physical Asset Management Profession in 2010,” presents the thoughts of the leadership of the Society for Maintenance & Reliability Professionals on where we should direct our efforts.
  • The article “Exchanging Enterprise Asset Information” reviews the progress of the Machinery Information Management Open Systems Alliance in enabling an information network to serve the asset management function.

I hope you will join us in one of our resolutions for the new year—To facilitate the growth of the equipment asset management profession. MT

rcb

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