The Application of Infrared Thermal Imager in Equipment Precision Inspection
Heating is often an early sign of electrical equipment damage or functional failure, making it a critical parameter to monitor during precision inspections of electrical equipment. Technical personnel conducting precise infrared thermal imaging inspections regularly check the temperature of key equipment, which can quickly detect abnormal temperature rise for further inspection and reduce the possibility of unplanned shutdown due to equipment failures.
Introduction to Principles
The principle of infrared temperature measurement
Infrared is an electromagnetic wave. Any object with a temperature above absolute zero (-273.15 degrees Celsius) will continuously emit infrared radiation. The infrared radiation characteristics of an object are closely related to its surface temperature. Therefore, by measuring the infrared energy emitted by the object itself, its surface temperature can be accurately determined.
Principles of Infrared Thermal Imager
Infrared thermal imaging instruments use infrared detectors, optical imaging objective lenses, and optical scanning systems to receive the infrared radiation energy distribution pattern of the measured target, which is reflected on the photosensitive components of the infrared detector. The detector converts infrared radiation energy into electrical signals, which are amplified, processed, and converted into standard video signals. The infrared thermal image is displayed on a television screen or monitor. This thermal image corresponds to the thermal distribution field on the surface of the object, which is essentially the thermal image distribution of infrared radiation in various parts of the target object being measured.
The advantages of infrared thermal imagers
(1) By measuring the surface temperature distribution of the device, the position and distribution of the object's heating area can be intuitively seen, and the internal heat loss area and properties of the device can be analyzed, thereby determining the health status of the device. Visual display of hot spot temperature, clear thermal images, and the ability to store and print.
(2) It has dual functions of qualitative imaging and quantitative measurement, and can distinguish small temperature differences. Real time thermal images can be clearly displayed on the screen, providing conditions for establishing a thermal image database and achieving the function of image acquisition, storage, and analysis in one.
(3) Using an infrared thermal imager to detect equipment belongs to long-distance non-contact scanning inspection, which can ensure personal safety and the normal operation of the equipment without affecting the normal production on site.
Precautions for precision equipment inspection
(1) Use an infrared thermal imager to measure the temperature of the abnormally hot area. When measuring temperature, the surface emissivity of the object being measured should be correctly selected first, appropriate reference materials should be selected to determine the ambient temperature, compensation parameters such as ambient temperature, relative humidity, and measurement distance should be entered, and an appropriate temperature range should be selected. It is particularly important to choose the appropriate surface emissivity for the tested object, as it can seriously affect the accuracy of the measured temperature.
(2) The same measurement object should be measured from different directions to find the temperature value of the highest heating point. When measuring different measurement objects, the distance and orientation should be consistent.
The application of infrared thermal imager in the field
Precision inspection of on-site transformers
When using an infrared thermal imager for precise point inspection of a triple split transformer, attention should be paid to observing the temperature distribution of the coil, iron core, and wiring on each side of the transformer. During normal operation of transformers, the temperature of the iron core is generally the highest and there is a large temperature difference between the iron core and the coil. The obtained infrared image should have a clear color boundary between the iron core and the coil.
Precision inspection of high-power high-voltage synchronous machines on site
When using an infrared thermal imager to inspect on-site high-voltage synchronous motors, not only can the outer surface be directly observed to determine the stator temperature distribution, but the temperature distribution at the connection between the excitation coil ends and the shaft collector ring can also be observed through observation holes. The connection between the excitation coil and the shaft collector ring of the high-voltage synchronous motor we use is a hard connection fixed by bolts. By using an infrared thermal imager through the observation hole of the large motor, these connecting pieces can be scanned and detected at low speeds, which can intuitively reflect their temperature distribution and heating situation and effectively avoid the occurrence of the above problems.
Precision inspection of on-site electrical control cabinets
Due to the large number of electrical components inside the on-site electrical control cabinet, many electrical connectors are required to connect them to each other. If the joint connection is poor, the bolts and washers are not tightened or too tight. Corrosion caused by dust; The actual cross-sectional area of the conductor is reduced due to various reasons such as poor component materials and mechanical vibrations. Due to the above factors, the contact resistance is abnormal, and the heating power increases when the current passes through. Moreover, the longer the power on time and the greater the current, the abnormal heating will occur, resulting in an abnormal increase in temperature rise. After each inspection, the distribution and temperature of hot spots should be recorded, and compared with previous pictures. If any abnormalities are found, they should be checked and tightened as soon as possible using maintenance time. Prevent equipment accidents caused by loose wiring.
Conclusion
Using an infrared thermal imager for precise inspection enables some equipment that cannot or is difficult to perform inspection under normal production to be easily and comprehensively inspected. By using specialized inspection forms and implementing inspection systems, as well as archiving corresponding inspection records, the operation status of on-site equipment can be well tracked, and various equipment accident hazards can be predicted and discovered. So as to prevent accidents and provide strong guarantees for the stable operation of equipment.