Common Malfunctions and Notes for Infrared Thermometers
Influence of Ambient and Background RadiationDuring infrared inspection of outdoor power equipment, the infrared radiation received by the detector includes not only the self-emitted radiation from the measured parts of the equipment, but also reflections from other equipment components and the background, as well as direct solar radiation. Such radiation interferes with the temperature measurement of target areas and causes errors in fault detection.
Attenuation of Equipment Radiant Energy TransmissionThe transmittance of radiation emitted by the tested equipment decreases with the distance between the infrared thermometer and the measured object, and the attenuation increases as the distance grows. This reduces the radiation contrast between faulty and normal areas. Meanwhile, the reduced target energy received by the infrared thermometer results in a displayed temperature lower than the actual temperature of the fault point, leading to missed detection or misdiagnosis. This issue is especially prominent when identifying equipment faults with a slight temperature rise.
Countermeasures against Radiation InterferenceTo mitigate the impact of solar radiation and high-temperature background radiation, proper shielding measures shall be adopted during inspection, or dedicated optical filters shall be installed on the infrared thermometer to filter out solar and other background radiation. Select instruments with appropriate parameters and a reasonable testing distance to ensure the measured area falls within the instrument's field of view, thereby minimizing background radiation interference.
Influence of Atmospheric AttenuationThe infrared radiant energy emitted by electrical equipment travels through the atmosphere to the infrared thermometer. During transmission, it suffers absorption attenuation from gas molecules such as water vapor, carbon dioxide and carbon monoxide in the air, as well as scattering attenuation caused by suspended particulate matter.
Correlation Between Detection Distance and Atmospheric ImpactThe adverse effects of atmospheric conditions become more significant as the detection distance increases. To ensure temperature measurement accuracy, inspections should be conducted in dry, clean atmospheric environments. Shorten the detection distance as much as possible on the premise of ensuring safety, and apply reasonable distance correction to measurement results to obtain accurate actual temperature values.
Influence of Meteorological ConditionsAdverse weather conditions, including rain, snow, fog and strong winds, exert negative impacts on temperature detection with infrared thermometers and often lead to false fault indications. To reduce meteorological interference, field tests are recommended on rainless, fog-free and windless nights with stable ambient temperature.
Optimization of Inspection Time and EnvironmentTo weaken ambient and background radiation interference for outdoor electrical equipment testing, use infrared thermometers preferably on cloudy days or after sunset with no direct sunlight. This avoids interference from direct, reflected and scattered solar radiation. For indoor equipment, turn off lighting lamps and keep away from other heat radiation sources.
Detection Adjustment for High-Reflective SurfacesFor equipment surfaces with high reflectivity, take targeted measures to reduce reflection from solar rays and surrounding high-temperature objects, or adjust the detection angle to the optimal position that avoids reflective interference.
