To judge the quality of an HMI filter, it is necessary to understand the performance indicators of the HMI filter. The main parameters of the HMI filter are rated voltage, rated current, leakage current, insulation resistance, withstand voltage, operating temperature, insertion loss, etc. The most important one is the insertion loss. Insertion loss is often expressed as "IL", sometimes also called insertion attenuation. This indicator is the main indicator of the performance of the power supply filter, usually expressed in decibels or frequency characteristic curves. It refers to the power ratio or terminal voltage ratio of the test signal transmitted from the power terminal to the load terminal before and after the filter is connected to the line. The larger the decibel, the stronger the ability to suppress interference.
Therefore, when purchasing an HMI filter, you must fully consider the number of phases, rated voltage, rated current, leakage current, certification, volume and shape, insertion loss, etc. The rated voltage/current must meet the requirements of the product, and the leakage current cannot be too large. Choose an HMI filter with a relevant certification system. The volume and shape are determined according to actual conditions.
In addition to these, it needs to be based on actual needs. For example, some HMI filters are military-grade, some are industrial-grade, some are dedicated to household equipment, some are dedicated to inverters, and some are dedicated to medical equipment. Only by determining the target of use can you choose the HMI filter that suits you. In fact, as long as the basic conditions are met, the price and cost are often considered.