Five Minute Facts  

Important Aspects about Condition Monitoring

Dr. Thierry Erbessd | President and Chief Innovation Officer, Erbessd Instruments

Technology in predictive maintenance is growing fast, and so is Condition Monitoring which is one of the its most important activities. In particular, the wireless sensors in Condition Monitoring came to change completely the way we used to see machinery reliability.

What is Condition Monitoring? What do we need to learn about modern technologies applied in it? Well, I am a Vibration Analysis technology developer and I invite you to take some time to read this few tips I have written for you.

What is Condition Monitoring?

Condition monitoring is the process of periodically measuring one or more parameters in machinery to identify significant changes that usually indicate failures in process. It is an essential part of predictive maintenance, thus, allowing to plan maintenance actions focused on avoiding failures and their consequences.

Therefore, condition monitoring provides enough information to address actions towards components that require attention.

Continuous condition monitoring is usually applied to rotating machinery such as fans, compressors, pumps and combustion engines, etc.

Main benefits of condition monitoring

Analyze machinery performance

You can get tendency graphs of vibration monitoring, current consumption, changes in temperature, pressure, from your machinery. In this way, you will know what the behavior trend is in each period. Thanks to this you will prioritize the order of maintenance. As a result, you will be able to reduce downtime and make better decisions about production plans

Reduce Maintenance cost

Some parts, such as gearboxes or bearings can be very expensive to replace, which is why a correct condition monitoring can offer the benefit of a longer life span for the components. Remember, condition monitoring is an investment that can pay off in the short term.

Increasing production capacity

Maximize production capacity with reliable operation machines. You will accurately plan the maintenance schedule. Therefore, you will create more efficient production plans and you will meet delivery times that satisfy your customers.

Monitoring anywhere your are

You can stay away from the company, some Conditioning monitoring systems are easy to use just as plug & play. In other words, wireless sensors measures the condition indicator and transmit it to your own database. Now it is possible to have apps and web sites to display monitoring results not only in a period but also in real time. This can be done from a mobile device, tablet or computer, anywhere you are.

Technologies applied in condition monitoring: Who is it for?

There are several techniques applied in condition monitoring but in importance we can enumerate the following:

  • Vibration analysis
  • Temperature monitoring
  • Current measurement and analysis
  • Speed ​​Measurement
  • Thermography
  • Ultrasound
  • Lubricant analysis
  • Acoustic analysis

Criticality of a system

The criticality index of a system is often used to determine the type of condition monitoring that needs to be applied to a system. Hence, critical Index takes in account the following factors:

  • Economic impact due to an unexpected strike
  • Cost of repair
  • Environmental impact due to a strike
  • Impact on security for staff
  • Among others

Criticality index, therefore, divide the machines into 3 categories:

  1. Critical machinery: This type of machinery has the highest hierarchical level within the productive chain. It includes equipment such as power plants and steam turbines which are the heart of the company. This machinery is vital and therefore requires a very close condition monitoring system.
  2. Essential Machinery: These machines are an integral part of the production chain, however, in case of an unexpected failure, production will not be affected. Because of their cost being more accessible, companies allow to have replacement systems placed parallelly to avoid production downtimes in case of failure. As the process continues, monitoring the condition of these machines is vital to implement alternate plans at the right moment.
  3. Non-critical machinery: These systems have a minor impact on production and do not usually represent an economic risk for the production chain.

Economic aspects of Condition Monitoring

Savings due to production downtime reduction: The most significant savings arising from predictive maintenance are due to the significant reduction in production downtime.

The savings arising from downtime reduction can be calculated through the number of hours of downtime multiplied by the added value per hour for the process.

Cost of downtime = Downtime X $ Value per hour of process

Savings in maintenance costs: Additionally, Savings in maintenance are due to the reduction in man-hours to carry out repairs + savings due to the reduction of unnecessary replacements. This is calculated as follows:

$ Savings in Hours = (Man Hours invested in Major Maintenance – Man Hours for minor maintenance) X $ weighted Hour / Man

Condition Monitoring Costs: The costs of condition monitoring systems depend on the chosen system which can be Permanent or Portable. Of course, Permanent systems require more investment if the number of machines is large. On the contrary, Portable systems are cheaper, although, they require a specialist to measure each machine periodically.

Impact of condition monitoring on the environment and safety

The main goal of machinery condition monitoring is to reduce its wear and tear by extending the lifetime of all its components. Either through the reduction of vibration or by improving its temperature conditions, the machine will have a lighter work and therefore several benefits.

Electric power consumption: Making a mathematical correlation between vibration and energy is very difficult. Even more because of the wide variety of machines that exist in a company. However, a study conducted by The Journal of Industrial Technology* proved that a given machine can consume twice as much current only because of its vibration. Of course, this study was made in motor that can increase its vibration in proportions that a big machine is unable to do. Nevertheless, the study does prove a realistic relationship between power consumption and vibration.

Safety and health: The reduction of vibration is closely related to the reduction of noise from a machine and therefore reduces the impact on the health of the staff in charge. Prevalence of conditions such as retinal detachment and hearing loss induced by noise can be reduced by applying a correct condition monitoring.

Environmental and Economic Impact. The ecological footprint left by predictive maintenance is considerably greater than that of predictive maintenance, because in the first one, the idea is to replace critical parts as well as lubricating whether it is needed or not. These actions are intended to avoid stoppages, although they are not always necessary.

Implementing good Predictive maintenance actions will not only reduce the environmental impact by avoiding all these wastes but will also have a much lower productive cost.

Key Aspects to successfully implement Condition Monitoring

The condition monitoring process has key aspects to achieve some of the goals in a short period of time. No one knows everything before starting and therefore it is important to take into account the following advices:

Know what you want to measure: It is very important to decide what parameters you want to measure in a machine, as well as what machines you desire to monitor. The most important parameters for condition monitoring are vibration, temperature and current.

Establish a starting point: You probably are not an expert analyst and you don’t need to, either. The first is to establish a starting point. For all you know, your machine is working fine right now, and you want to know when that changes. The starting point will let you know when your machine exceeds the current values. Over time and with the help of information and experience, you will know what are the real limits ​​ for each machine.

Periodic verification: None of this will work by itself unless you create a routine of checking the status of your machinery and alarms.

Set Alarms: At some point you will see that your vibration or any other parameter changes. Verify your trend graph, evaluate and adjust your alarm values ​​to know how soon they will be overcome again.

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About the Author

Dr. Thierry Erbessd President and Chief Innovation Officer, Erbessd Instruments

Thierry Erbessd, Mexican entrepreneur who has revolutionized the field of Vibration Analysis and Dynamic Balancing worldwide.

Dr. Erbessd is a graduate of the National Polytechnic Institute of Mexico and is also a passionate programmer, he is the creator of DigivibeMX software that competes among the best systems for vibration analysis. He is currently the President and Chief Innovation Officer of the Erbessd Instruments, a leading company in solutions for industrial maintenance.