Overheated electrical components can lead to failed equipment and expensive repairs. One way to combat this situation is to conduct preventive electrical maintenance. Detecting problems before they become serious issues makes good sense. Thermal imaging technology is one tool used to pinpoint electrical inefficiencies and worn components before they reach the point of failure.

How does thermal imaging work?

Before addressing the benefits and application of thermal imaging to electrical maintenance efforts, it’s important to have a basic understanding of the science behind the technology. Thermal energy makes up one part of the electromagnetic spectrum. The naked eye cannot see thermal energy, because it is emitted from objects as heat, not reflected as light. The hotter an object, the more thermal energy it emits. All objects — even inanimate ones, such as electronic components — emit some form of thermal energy.

Infrared thermal imaging cameras are detectors and precision optics platforms that provide a visual representation of infrared energy emissions. A thermal imaging camera transforms thermal energy into visible light and processes that information through these basic steps:

1. A specialized camera lens focuses infrared radiation that is given off from all objects.

2. Infrared detectors detect and measure this focused radiation to create a thermogram, also known as a temperature map.

3. The camera then translates the thermogram into electric impulses.

4. The electric impulses are sent to a signal processing unit where they are translated into usable data.

5. Once translated, the signal processing unit sends the data to a display where thermal emissions are visible to a viewer.

6. Where quantitative information is required, the thermal camera can also provide accurate temperature values of the surface being viewed.

7. Images can be saved for later analysis and report generation.

Benefits in electrical maintenance

Thermal imaging cameras have transformed the conventional approach to correcting electrical inefficiencies and failures. Their ability to scan and quickly reveal when equipment is running hot or cold is extremely important for evaluating costs, safety, and compliance. For example, thermal imaging can help electric maintenance professionals:

• Check for loose/overly tight connections

• Identify overloaded components

• Evaluate uneven voltage distribution

• Recognize failed/fatigued components

• Identify faulty fuses

• Classify imbalanced circuits

• Monitor damaged switches

When used for preventive maintenance, thermal imaging cameras can monitor equipment for low and high voltages at safe distances. Additional benefits of thermal imaging cameras include:

• Ease of use and affordability — In the past, many companies hired thermographers (experts who used their understanding of heat transfers and thermal imaging cameras) to evaluate the condition of any object, including electrical machinery, in order to conduct on-site inspections. Today, thermal imaging cameras are easier to use and more affordable than ever. Many companies own the cameras and use maintenance staff to perform routine checks more frequently.

• Accuracy — A key component of preventive electrical maintenance is checking the integrity of electrical installations to identify overheating connections and faulty components. Thermal imaging sensors monitor temperature fluctuations. Therefore, the cameras only identify problems that need repair. Temperature changes can also identify the priority of a problem in a large-scale environment. Thermal imaging cameras can also rescan repaired equipment to guarantee it is functioning properly.

• No downtime — Thermal imaging cameras allow for inspections to be conducted while components are running without loss to production, which has a significant effect on the bottom line.

• Prevention of premature failure and extension of equipment life — Most electrical systems emit some type of heat before they are on the verge of failure, usually a sign of resistance or excessive friction. Thermal imaging cameras can quickly identify temperature fluctuations before the component fails, which prevents costly system interruptions, fires, or arc flashes.

• Saved images — Often, the person conducting the inspection is not necessarily doing the repair. Some cameras save images, which enables the person handling the repair to know exactly where issues are and what needs to be done.

• Image fusion — Many cameras use image fusion — the process of overlaying a picture from a thermal imaging camera on top of a visible light image — to help electrical staff understand the extent to which component is damaged. This process helps to make the image easier to interpret and aids in pinpointing problems.

Today, thermal imaging cameras are established tools in electrical preventive maintenance programs. The financial, safety, and compliance benefits are undeniable, while their ease of use and low cost make them invaluable to maintenance professionals.