With the latest developments and the advent of low cost spot thermal cameras, thermography is now accessible to all for the fast troubleshooting of electrical and mechanical installations.
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It’s now possible to purchase entry level spot thermal cameras for as little as £200 to £300. At this level, the benefits of being able to identify faulty installations and equipment early and prevent serious disruption to production processes and systems, easily justify the costs. The latest designs combine real time thermal imaging with spot infrared temperature measurement and come packaged in rugged pistol shaped designs, ideal for electricians and maintenance teams needing fast on-site diagnostics. The cameras show hot and cold spots at a glance and accurately measure spot temperatures of hot and hard to reach surfaces.
The question is what do you need to know to get started? The latest entry level products are point and shoot in nature, so they are easy to use and it’s fast to get up and running. To get the most out of the cameras and understand where they can be used for troubleshooting, it’s important to understand some basics about how they work and what to look out for.
Troubleshooting with thermography relies on that most components in a system show an increase in temperature when malfunctioning. The increase in temperature in an electrical circuit could be due to loose connections causing increased resistance or in the case of mechanical equipment it could be the result of a worn bearing. By observing the infrared heat maps of components in working systems and equipment, faults can be located and their significance and root causes evaluated. As contact with the system is not required, inspections can be made under full operational conditions resulting in no loss of production or downtime.
Heated objects radiate infrared energy, which can’t be seen by the human eye, but can be detected by a thermal camera and displayed as a series of colour gradients or heat map on the screen of the camera. The heat map shown by spot thermal cameras can be used to show relative surface temperature and identify hot spots. The temperature of the hot spots is measured at the same time with the built-in infrared thermometer. Thermal imagers that measure and record the temperature of each pixel on the screen are also available but come with a hefty price tag and many features that are not needed for initial troubleshooting. As with conventional cameras, thermal cameras cannot see through the surface of the component and can only see line of sight.
What to look out for when using thermal cameras ?
Beware of reflections. Just as with a normal camera, thermal cameras are susceptible to reflections, but of course you can’t see infrared with the naked eye. For example when measuring the temperature of a window you may see a hotspot which is in fact purely a reflection of heat from the camera operator
Surface Emissivity makes a difference. Emissivity is the capacity of a surface to emit heat. It is a relative quantity between 0 and 1 and expressed in terms of an ε value. Thermal and electrical insulators are excellent emitters, but metals are unlikely to have emissivity above 0.25 unless they are heavily oxidised. If you are inspecting different material surfaces and making quantitative temperature measurements, you’ll get the best results with a camera on which you can easily adjust the emissivity for the application. For purely qualitative inspections it’s less important.
Easy selection of colour pallet & emissivity for enhanced analysis
Choosing the right feature set
Generally spot thermal cameras avoid the need for complicated menus to be setup before getting started, but there are a range of features available on different model to choose from.
Here are some key considerations to ensure the right tool for the job:
- Blended images. A blended thermal and optical image makes it easier to identify components
- Rugged design. Tough enough to survive a toolbox for on-site use
- Fixed or adjustable emissivity for a wide range of surfaces
- Laser pointers and built-in torches for easy targeting in low light environments
- Selectable colour palettes for enhanced analysis
- Screen capture or image storage and download for reporting
Built-in LED torch and laser pointer make targeting easy in all environments
With the new generation of point and shoot spot cameras and a basic understanding of the dos and don’ts, it’s fast, easy and affordable to add thermal imaging to your troubleshooting toolkit. The range of applications is extensive from non-contact electrical and mechanical fault finding through to identifying sources of heat loss and checking the correct functioning of heating and ventilation systems. The latest cameras provide an affordable solution for busy electricians and maintenance teams to troubleshoot problems quickly and identify potential maintenance issues early.
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