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Hot topic: Preventative maintenance

Power Control Ltd outlines the advantages of preventative UPS maintenance via thermal imaging and how to get the most out of your analysis.

Thermal imaging records the concentration of radiation in the infrared part of the electromagnetic spectrum and converts it into a visible image. Today, thermal imaging is often the first choice in preventative maintenance and is one of the most non-intrusive, non–invasive and non-destructive diagnostic tools for predictive maintenance of a UPS.

The use of thermal imaging helps to quickly identify problems, allowing for safe, controlled shutdown. This helps eliminate any unplanned disturbances, prevents untimely failure and with regular diagnostics, can extend equipment life. Significant commercial and operational efficiencies can also be recognised with the correct and frequent use of thermal imaging.

Thermal imaging for preventative maintenance

As most electrical components raise in temperature when there is fault, thermal imaging has become the essential diagnostic tool for easily identifying any ‘hot spots’ in electrical systems. Heat patterns captured through thermal imagery can help to pinpoint the origin of any problem areas and be used to identify and prevent any future causes of equipment failure.

Whilst UPS systems are designed to deliver power protection, they can still breakdown. UPS failure can be due to a number of factors such as batteries, capacitors, filters and operating conditions. Planned preventative maintenance of these critical elements can not only improve performance and reliability but also extend the lifespan of equipment and avoid any unplanned downtime. 

Thermal imaging is often the first choice in preventative maintenance and is one of the most non-intrusive, non–invasive and non-destructive diagnostic tools for predictive maintenance of a UPS. By detecting anomalies, that are often unnoticed by the naked eye, corrective action can be taken promptly to ensure costly system failures do not occur – giving total piece of mind.

A thermal imaging camera is used to detect hot and cold spots using an image. Used to scan a UPS system, thermal imaging can help detect faulty connections or components that are running at a higher temperature than normal or safe.

Most UPS systems and their components will normally give off heat but an increase in heat may confirm a fault is emerging. This way of periodic testing can also highlight changes and the potential demise of an internal component. It is also a way to ensure maintenance can be budgeted for and downtime can be planned in advance if used regularly.

With the promotion of preventative and predictive maintenance, thermal imaging is an integral part of a solid and regular maintenance programme and will almost certainly enable long lasting confidence in equipment.

A typical thermal imaging service will involve the inspection if all electrical components of an installation. In analysing the temperature, preventative failure evaluations can be achieved for all electrical items including UPS, switchboards, power factor correction systems, distribution cables, batteries and transformers.

A more detailed analysis used for UPS systems and associated equipment can improve reliability and contribute to enhanced its MTBF (mean time between failures) and reducing MTTR (mean time to repair). Thermal imaging diagnostics can be undertaken in live operating environments and can very quickly identify any critical areas that need addressing. These can include loose connections, corrosion, harmonic interferences and load fluctuations.

Thermal imaging best practice

Thermography can be influenced by different situations and it is therefore important to consider the following for thermal imaging best practice recommendations.

  • The load: Anomalies in performance can be more easily detected when equipment is running as close to full load as possible and thermal imaging should be done at no less than 40% load.
  • Temperature: Extreme temperature environments (hot or cold) must be indicated on the analysis to show a true representation of thermal imaging results.
  • Consistency: Thermal imaging will be undertaken on several occasions throughout the lifecycle of a preventative maintenance programme so equipment settings, load and conditions ideally need to be the same to achieve an accurate view.
  • Photo image: To support any thermal imagery captured it is also advised to take a photo image of the equipment to be used as a reference point to identify key components.
  • General observations: The condition of the equipment and environment in which it is operating should be documented as this can be used in the final analysis and towards identifying key failure signals and pinpoint areas that need further inspection/maintenance.
Optimising thermal imaging analysis

When analysing a thermal image and for a true interpretation of the image to give best overall analysis, the following factors need to be considered.

Measurement conversion

For true analysis, the settings on the thermal imager should be in line with the temperature limits that it is being compared with. If this is not possible then accurate temperature conversion must be undertaken. The universal conversion formulas to use are:

[°C] = ([°F] – 32) × 5/9
[°F] = [°C] × 9/5 + 32 °F to °C (or vice versa)

Colour grades

Analysers of thermal images need to have a good understanding of the colour scale of their testing equipment. Differing colour scale settings will give a skewed view of hot-spots/problem areas. As part of a preventative maintenance programme, these settings must remain consistent throughout to gain good trend analysis.

Discharged energy

The equipment’s emitted energy plays an important part in the thermal imaging process as it is a prime indicator of the overall equipment temperature. This consideration looks largely to reflective heat. It is important to include discharge energy values in any analysis.

Physical compound makeup

Staying on the topic of temperature, all equipment will have varying thermal properties with different abilities to retain and release heat. Understanding specific thermal conductivity is essential to avoid distorted results.

Whilst thermal imaging can be a principle preventative maintenance tool for identifying any potential faults, risks and failures, it should not be carried out in isolation. Other preventative maintenance practices should also be adopted and analysis of each collated to form reasonable conclusions.


Thermography can increase the reliability and efficiency of equipment and generally prevents breakdowns and stoppages, which overall can reduce maintenance costs and production losses.

Preventative and predictive maintenance should form part of all business power protection strategies. Thermal imaging forms an integral part of these solid and regular maintenance programmes and will almost certainly deliver long lasting confidence in equipment.

At Power Control, we understand how important it is to have minimal downtime. Thermal imaging provides a solution to detect faults with no direct contact with the UPS. There is no interference with the load or power supply. This analysis determines problems without the necessity to isolate the mains supply and prevents costly situations for customers.

Expertly trained engineers operate the thermal imaging equipment with ease as part of standard preventative maintenance programmes and during regular maintenance checks if required to detect electrical unbalance, electrical overload, lose or corroded connections or electrical faults within the UPS. The imaging is done at a safe distance at a time suitable to the client with minimal safety risk and may spot problems that normally go unnoticed.

For more information please visit, email or call the office on 01246 431431

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