Precautions for infrared thermometer in equipment fault diagnosis
The impact of atmospheric attenuation: The infrared radiation energy on the surface of the tested electrical equipment is transmitted to the infrared detection instrument through the atmosphere, which is affected by the absorption and attenuation of gas molecules such as water vapor, carbon dioxide, and carbon monoxide in the atmospheric combination, as well as the scattering and attenuation of suspended particles in the air. The attenuation of equipment radiation energy transmission decreases with the distance between the detection instrument and the tested equipment, so its attenuation increases with the increase of distance. Reducing the radiation contrast between the faulty and normal parts of the tested equipment can also reduce the target energy received by the infrared instrument, causing the displayed temperature of the instrument to be lower than the actual temperature value of the tested fault point, resulting in missed detection or misdiagnosis, especially for detecting equipment faults with low temperature rise. As the detection distance increases, the impact of atmospheric combination will become increasingly significant. In order to obtain the accuracy of the target temperature, it is necessary to choose a dry and clean environment for testing as much as possible; Shorten the detection distance as much as possible without affecting * *, and make reasonable distance corrections to the temperature measurement results in order to obtain the actual temperature value.
The impact of meteorological conditions: Adverse weather conditions (such as rain, snow, fog, and strong winds) can have adverse effects on equipment temperature detection, often giving false fault phenomena. In order to reduce the impact of meteorological conditions, testing should be carried out as much as possible on nights without rain, fog, wind, and stable environmental temperatures.
The impact of environmental and background radiation: When conducting infrared detection of outdoor power equipment, the infrared radiation received by the detection instrument not only includes the radiation emitted by the corresponding parts of the tested equipment itself, but also includes reflections from other parts of the equipment and the background, as well as direct sunlight radiation. These radiations will cause interference with the temperature of the tested part of the equipment and bring errors to fault detection. In order to reduce the impact of environmental and background radiation, when conducting on-site infrared testing of outdoor electrical equipment, it is best to choose to conduct it on cloudy days or when there is no light at sunset. This can prevent the impact of direct incident, reflected, and scattered solar radiation; For indoor equipment, it is possible to turn off the lighting and avoid the impact of other radiation. For highly reflective equipment surfaces, appropriate measures should be taken to reduce the impact of solar radiation and surrounding high-temperature object radiation, or to change the detection angle and find a best angle to avoid reflection for detection. In order to reduce the impact of solar radiation and surrounding high-temperature background radiation, appropriate shielding measures should be taken during detection, or appropriate infrared filters should be installed on infrared measuring instruments to filter out solar and other background radiation. Select instruments with appropriate parameters and detection distances for testing, so that the tested equipment is within the field of view of the instrument, thereby reducing interference from background radiation.
