Howard W Penrose, Ph.D.
VP Electrical Reliability Programs
T-Solutions, Inc.
hpenrose@tsoln-inc.com
Selecting Vendor-Partners and Parts Storage
One of the keys to the success of any motor management program is the selection and relationship with vendors.
A common challenge to the development of a program is that there will be a reduction in the demand for large cost repair and parts. This can have a negative impact on the security of a vendor, unless changes also occur within the vendor and the relationship of the vendor and the company.
The vendor can survive changes within their customers by changing the way they do business. For instance, by offering PdM and CBM services, troubleshooting and RCFA support, the vendor can provide value in new areas that have higher profitability than standard repair. Additional services can include parts storage and maintenance and field manpower support.
Within the company, the selection of the vendor becomes very important. As the company’s program expands, the proper vendor selection and relationship can make the difference whether the program succeeds or fails. Proper selection should include an agreed method of communication, specifications and evaluation/grading of the vendor on a regular basis.
In many motor management programs, the electric motor repair shop or distributor, may be involved in storing spare motors. Even in this case, monitoring how the motors are stored is vital. In the first place, the motors should be stored in an area that is maintained above the dew point or a space heater installed to avoid potential winding and bearing failures. The motor shaft must also be turned periodically and the storage area must be away from heavy traffic or machines which will cause vibration damage to the motor bearings.
Howard W Penrose, Ph.D.
VP Electrical Reliability Programs
T-Solutions, Inc.
hpenrose@tsoln-inc.com
Selection of CBM Tools and Maintenance Practices To Meet Requirements
This part of the equation is often seen by the maintenance or reliability professional as the development of the program, itself. One of the most common approaches has been the purchase of tools, such as vibration, MCA, ESA or other technology, then looking for where to apply the instrument(s) as the program.
The most successful approach has been the methodical approach that we have been covering in this lecture series. Having reviewed the RCM requirements of the equipment at your facility will help you identify which technologies, techniques and procedures will have the greatest impact.
Condition Based Monitoring
This can be significant if, for example, a plant attempts to build a program around just a vibration analysis instrument. While the technology will assist in a large number of areas, in the mechanical arena, it will require a larger amount of experience and time when dealing with electrical issues. For instance, identifying bearing issues is fairly straight-forward with a fair amount of detection to failure time being possible. However, rotor bar problems are not as easy to identify and can be mis-diagnosed as other electrically-related issues. The key issue here is time. If time is being spent in areas where the technology is weaker and requires more time to analyze with a lesser chance of detecting a fault early enough, then the program will be ineffective and associated personnel inefficient.
This is not the failure of the personnel, or a demonstration that a program will not be successful, it is a failure of the process. Even in the worst cases, re-grouping and applying a backfit approach can turn the program around. Herein occurs one of the biggest challenges: The ability to realize that an error was made and move forward.
The next stage of failure that I have seen in a program is when an incorrect technology has been selected for the specific type of application needs. While virtually any technique or technology, worth its salt, can have a simple payback measured in days, when properly applied, people become the issue. We are, all of us, unwilling to put ourselves in a position where we may have to identify that we have made an error and will continue to operate ineffectively in order to protect our perceived reputation.
The sign of a true leader or champion is someone who is willing to admit that the direction that has been taken is incorrect, is able to learn from the error and makes the changes necessary to move forward. When leadership does not occur, the program fails, frustration results and the company loses money. Worse, once management realizes that the program is ineffective, it can be shut down or involved management and employees reassigned or laid off.
However, by identifying the issues using a process, such as a backfit continuous improvement-type process, you can document and present the results with a plan to move forward early enough to save money. Then the issue becomes a management decision. Depending on the management style, you will have a greater chance of being identified, positively, as someone who is concerned about the company, its mission (see previous lecture) and the success of the program.
Maintenance Practices
There is a tremendous amount of misinformation, in training programs, articles, books, etc., related to proper maintenance practices. A majority of the information is not deliberately misleading, just a matter of perspective.
For instance, I have listened to statements within classes, and sales presentations, about how some new coupling technologies eliminate or reduce critical alignment tolerances. The fun part of this is that while the coupling may be able to withstand the torsional forces of misalignment, it does not mean that other components, such as bearings, of the system can withstand the forces resulting from misalignment.
In the case of greasing, there are multiple schools of thought. One is that the grease should be purged from a housing each time the motor is greased, ie: quarterly. Another is that a finite amount of grease based upon the bearing size. Lately, another school recommends the use of ultrasonics for adding grease with a grease gun. This area is of great enough interest that I am going to handle it in a lecture series of its own!
Now, getting away from the tasks, themselves, there is another area of weakness in may maintenance practices: No written practices. If you request that a maintenance or reliability technician go grease a bearing, how will s/he do it? Now ask another technician. Will the task be performed in the same way? Unless the practice has been identified and put together as a written procedure, you cannot expect the task to be performed the same way. If it is one technician, and that technician leaves, now what?
One of the key opportunities through the RCM-Based approach is the agreement and application of written practices to ensure that tasks are performed in a repeatable manner.
Howard W Penrose, Ph.D.
VP Electrical Reliability Programs
T-Solutions, Inc.
hpenrose@tsoln-inc.com
The Concept of RCM-Based Motor Management – Part 3
Step 4: Determine Functionally Significant Items of the System
There may be certain components of the selected system that require their own special focus of functional components and fault analysis. Adding this step allows for this analysis without having to split the system up even more.
Step 5: Perform a Failure Modes and Effects Analysis
In this step, you will identify the failure modes and effects on the system. For instance, if a failure mode is a seized bearing, then the effect will be that the shaft stops turning. In this stage, all of the failure modes and effects are identified. The final step is to determine which failure modes and effects are likely and move them to the next step.
Step 6: Logic Tree Review
This stage first poses a series of questions related to evident and hidden failures and sets a classification A – D related to the type of task that results. The types of tasks include:
Class A: Required maintenance for safety and environment
Class B: Mission/Production Related
Class C: Economically required
Class D: Required when hidden failures will generate an unsatisfactory condition when required.
At this point, this second level of screening assists in the logical selection of design changes, condition based maintenance, preventive maintenance or no maintenance performed.
Stage 7: Determine Servicing and Lubrication
This provides the practitioner the opportunity to determine what periodicity and types of lubricants are to be used. The periodicity is based either on service recommendations or over/under - greasing history.
Stage 8 – 10: Paperwork for Documenting Procedures and Tasks
As described.
Stage 11: Determine Tasks for Inactive Equipment
Procedures are developed for maintaining spares and other inactive equipment.
Stage 12: Develop Corrective Maintenance Processes and Specifications
Procedures are developed for performing corrective maintenance and specifications for vendor repairs are developed. Best practices are developed or organized.
Stage 13: All procedures, tasks, best practices and specifications are approved.
Stage 14: Backfit Process
This process involves the continuous improvement stage of the program. Periodically, a maintenance effectiveness review is performed using a logical process to ensure that the program is working.
Through all stages, it is very important to document the reasons for all decisions. This allows the effectiveness review or other auditing to understand the logic behind the decisions. If there is little or no documentation, significant time will be lost in future second-guessing.