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Home / Technical Articles / Maintenance Management Of Electrical Equipment (Condition Monitoring Based) – 5

Preliminary preparation phase for CDM in the working industry

In case of new industry, it would be easy to implement Condition Monitoring based Maintenance Management (CDM) as apart of respective equipment or system itself after evaluating various factors discussed in previous part 4 of article. The new industry may also take into account various technical and financial aspects of CDM discussed in this paper.

Maintenance Management Of Electrical Equipment - Condition Monitoring Based, Part 5
Maintenance Management Of Electrical Equipment – Condition Monitoring Based, Part 5 (photo credit:

Read previous parts of this series – Part 1 | Part 2 | Part 3 | Part 4

Considering the difficulties in introducing CDM in the working plant as discussed in previous part 4, it is appropriate to discuss issues relevant to incorporation of CDM program in the working plant.

One of the very attractive aspects of CDM is the fact that it can be implemented in a relatively inexpensive, step-by-step approach without much difficulty. Because CBM is based on the equipment oriented concepts of PDM, it can be applied gradually – one system at a time. Eventually the entire power system is included in the program and cost savings would begin to multiply thereafter.

Whenever any major revision in the maintenance management is made, it is essential to include review the safety procedures relevant to that specific electrical equipment or system for consequences of CDM.

Data Collection and Storage Procedures

Possible Preventive Maintenance schedule for Electrical Apparatus in a Petrochemical Process Plant
Possible Preventive Maintenance schedule for Electrical Apparatus in a Petrochemical Process Plant

The major difference between PMM/PDM and modern CDM is the use of maintenance data collected. In the past, maintenance data obtained at fixed interval under the maintenance program was reviewed and filed in most of the industries. Hardly any attention was paid to comparison of data or plotting of trend of results obtained.

As described in this paper, trend plotting and statistical analysis are the fundamental building blocks of CDM.

Comparison of absolute values, and perhaps more importantly, comparing data deviations via statistical analysis provide information never before available. Obviously, a statistically relevant database is required to be maintained for getting advantages of CDM.

As mentioned, many industries have at least maintained good records of operating data, maintenance data and test results over the years for the equipments and systems. This data is to be converted to a computerized database, which one may find time consuming, but simple.

The table structure for database should be as general as possible and it can be developed as per suitability of the maintenance organization created in the industry. The structure should allow create database for various types of electrical equipment as well as incorporate future modifications.

Each maintenance and testing result record should be correctly dated to allow identifying the specific test interval.

Along with maintenance database, it is necessary todevelop the equipment database. If desired, the equipment database may be linked to the master maintenance database. It may also be incorporated in the master maintenance database; however, more flexibility is realized if they are kept separate.

Equipment failure and outage information

A compilation of equipment’s unscheduled outage data is a must to help assessment of risk of failure under CDM program.

This information may include such data items as type of outage, cause of failure, outage duration with dates, work carried out in brief, spares used (if any), cost incurred and other such data.

Damage to inside of coil winding stack of oil-filled transformer
Damage to inside of coil winding stack of oil-filled transformer (photo credit:

Outage information can be used to prioritize the implementation sequence of the CDM program. Obviously, the equipment or system with a high failure rate and/or a high value to the production should be enrolled in the program first.

Preliminary budget and plan

The final and most important step of preliminary preparation is the estimation of preliminary plan and a budget for implementing CDM program.

It may be noted that as the plan for implementing CDM would be preliminary, one should expect modifications as the actual program implementation begins and consequently the actual cost may also revise.

For example, the equipment such as low and medium voltage circuit breakers are not as readily predicted as the transformers, the concept of detailed statistical analysis may be dropped in favor of a less rigorous approach.

Practical implementation phase of CDM program in the working industry

Once preliminary strategy and budget costing for the proposed program is approved, the database and other information gathered in preliminary phase will be put to work as an active Condition Monitoring Based Maintenance Management Program.

Development of detailed evaluation criteria and methods

Based on the database gathered in preliminary phase, the maintenance management team should decide the statistical evaluation techniques to be used as an analytical tool and control strategies. The exact nature of strategies, to be used, may become known with passage of time.

If desired, the services of qualified and experienced CDM consultant can be engaged to assist the selection and implementation of appropriate strategies.

Finalisation of recommended maintenance procedures and intervals

Initial source of normal maintenance and trouble shooting is the O&M Manual supplied by the equipment manufacturer. As the details provided in the manual would be general, the maintenance procedures can be added as needed based on the opinions and observations of the engineers and skilled technicians.

The ambient environmental conditions are also extremely important in the overall evaluation.

CDM Report Formats

Since long, the printed formats or handwritten registers have been around in almost all the industries to record the maintenance work carried out and test results. The major limitation of printed formats is the need for modification and manual transfer of handwritten data into the various computer databases.

With the advent of computers, specifically laptops, the data for all the activities can be directly entered into the computer at the site of maintenance. The information can then be downloaded into the main maintenance PC and/or acompany local area network. As another option, if the testing equipment has in-built memory to store the test results, the data so stored may be transferred into the maintenance PC from the test equipment.

This approach is especially effective when the testis actually performed under computer control.


Large numbers of industries have sincerely implemented CDM programs, however all the industries have not been able to generate measurable benefits. Technology limitation is not the principle cause of these failures, but it is their failure to make the necessary changes in the workplace that would permit maximum utilization of these predictive tools.

Some of the proactive steps, which can eliminate these restrictions, are narrated hereunder to help gain maximum benefits from CDM program.

Organisation culture change

There is a perception in the minds of corporate-level managers that CDM technologies are exclusively a maintenance management or breakdown prevention tool, which must be drastically changed at the corporate level and permeate throughout the plant organisation.

Though sound simple, it is daunting task to change this corporate attitude toward perception of CDM, as most of the corporate-level managers have rather limited or no knowledge or understanding of maintenance – or even the need for maintenance-convincing them that a broader use of CDM technologies is extremely difficult. In their view, the maintenance group is solely responsible for the breakdowns and unscheduled delays. They cannot understand that most of these failures are the result of issues not related to maintenance.

If the data regarding equipment reliability in various industries are judiciously reviewed, the maintenance relevant production interruptions and quality problems would be found to the tune of around 15 – 20%. Remaining 80 – 85% problems would be found totally out of purview of the traditional maintenance function’s responsibility.

Industrial processes often involve expensive equipment for producing expensive products
Industrial processes often involve expensive equipment for producing expensive products (photo credit:

Other nonmaintenance causes are incorrect design of equipment/system, inappropriate operating practices, sub-standard spare parts and numbers of other non-maintenance causes are the major contributors to production and product-quality problems, not maintenance.

CDM program should be used as a plant or process optimization tool to detect, isolate, and provide solutions for the deviations from desired performance, which may result in lost capacity, poor product quality, increased costs, or a threat to employee safety.

CDM program has the capability to perform this critical role, but that is simply not being used to optimum. To accomplish this task either of following approaches can be considered.

First approach

The first approach would be to select engineers having knowledge of one or more of these requirements. For example, the group might consist of the best operations, maintenance, and technical personnel available from the current workforce. Care must be taken to ensure that each group member has some real knowledge of his specialty area. This group may be made accountable for total plant optimisation.

This group must have the authority to cross all functional boundaries and to implement changes under CDM to correct the problems observed with analysis.

Second approach

The second approach is to hire services of professional reliability consultants. This approach may be found easier at first glance, but not so because there are very few qualified and experienced reliability professionals available at very high cost. Most of these professionals would prefer to offer their services as short-term consultants.

Hence, extreme caution is required to be exercised in selecting the consultant.

This new group must have a thorough knowledge of machine and process design, and be able to implement best practices in both operation and maintenance of all critical production systems in the plant. In addition, they must fully understand procurement and plant engineering methods that would provide best life-cycle cost for these systems.

Finally, the group must understand the proper use of CDM program. Few plants have existing employees who have knowledge of these fundamental requirements.

After formation of new team, necessary training forthe reliability team must be the first priority. The team member having maximum knowledge and skills to carry out the assigned function may impart training especially regarding application of CDM based on concept of reliability. Sufficient training is a must to ensure maximum return on the investment made for the new team and system.

This training should focus on process or operating dynamics for each of the critical production systems in the plant.

All the plants have few superstars who do not have a real, in-depth knowledge of their perceived specialty. In other words, the best operator may in fact be the worst contributor to reliability or performance problems. Although he may get more capacity through the unit than anyone else, the practices followed by him may be the root-cause of chronic problems experienced in the plant.

As the suggested approach is a radical departure from the traditional organisation culture found in most industries, the resistance would be met to change from all levels of the organisation. With few exceptional employeeswho understand the absolute need for a change for betterment of plant, most of the workforce would not voluntarily accept this new functional group; however, the formation of a dedicated group of professionals that is absolutely and solely responsible for reliability function and production optimisation of total plant operation is essential.

It is the only way any industry can achieve and sustain optimum performance.

Will be continued very soon…

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Ashok Parikh

Working as Electrical Engineering Consultant located at Vadodara, India providing System Design & Engineering services to various industries, possessing 40 years of experience in diversified industries and consultancy.


  1. Sarel May
    Dec 19, 2019

    I really like to get information so that i may develop a tool and check manually how can i develop preventative mantenance plan and schedules

    • Ashok Parikh
      Dec 20, 2019

      You may please go through the O&M Manuals supplied by the respective manufacturer of electrical equipment, i.e. transformers, motors, cables, HV/LV switchgear, etc. and prepare periodic preventive maintenance plan in accordance with schedule of maintenance and maintenance check points given for the equipment. For example, checks may be specified by the manufacturer of the transformer would be weekly, monthly, six monthly, yearly and so on. You can use either PC pr laptop for PM records.

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