电气设备是故障多发装置。利用红外测温仪或红外热像仪能够检测出设备发热异常部位并确定其表面温度，再结合红外诊断标准便可对异常设备的故障严重程度进行判别，从而实现对电气设备的故障诊断。针对电气设备控制箱电气元件的发热缺陷，利用ST80+红外测温仪与FLIR E320红外热像仪进行了温度监测，并通过运用表面温度法和相对温差法进行故障严重程度诊断，对两种设备监测诊断的差异进行了分析。结果表明，利用红外热像仪能较准确地监测诊断出电气元件的过热缺陷，利用红外测温仪能检测出多数控制箱电气元件过热缺陷，但对部分缺陷的严重程度等级判别低于热像仪的判别结果。

Electrical equipment is the device in which failures often happen. An infrared thermometer or infrared thermal imager can be used to detect the abnormal overheated part in electrical equipment and determine its surface temperature. At this time, if the infrared diagnostic criterion is incorporated, the fault severity of the abnormal equipment can be determined. Thus, the failure diagnosis of electrical equipment can be implemented. Aiming at the overheated components in electrical control boxes, both an ST80+ infrared thermometer and a FLIR E320 infrared thermal imager are used to measure the temperature of an electrical control box. Through the determination of the fault severity of the component by both the surface temperature difference and the relative temperature difference, the diagnostic difference between the infrared thermometer and the infrared thermal imager is analyzed. The results show that the infrared thermal imager can monitor and diagnose the overheating defects of electrical elements while the infrared thermometer can detect the overheating defects of most electrical elements in electrical control boxes. However, the infrared thermometer is not as good as the infrared thermal imager in the diagnosis of failure severity of electrical components.