At present, it has become a trend for terminal manufacturers to apply power terminal The importance of functions has become more prominent, and it has also played an increasingly important role Wholesale Screwless Terminal Blocks in ensuring product features. The continuous improvement of the circuit board technology has increased the current that the terminal installed on the panel can carry. It has broken through the 110A limit and far exceeded the level of the previous product. This makes it possible to use the power wiring in the design process. The problem that the terminal can meet the system requirements becomes more complicated. In addition, the methods of measuring performance parameters are different in different regions, and even the nominal parameters given for the same product are quite different.
Therefore, in order to obtain long-term reliability and ensure low cost, it is very important to understand these differences. Engineers must also consider another factor that is often overlooked, namely marketing considerations.
Usually, the terminal blocks are visible to the user, so the marketing department often hopes that the appearance of the product can match the color and style of the entire system. The following specifically introduces the important factors that affect the selection of wiring terminals.
One of the first considerations for plug-in terminal power handling factors is the power handling capability of the device. Simply reading the data sheet does not guarantee accurate comparison data. Engineers must understand how the product performance data listed in the manual is tested and determined. Currently, UL, IEC, CSA, DIN and other organizations do not have a unified standard when determining the power and performance specifications of terminal products. Users need to understand the difference between UL and IEC specifications. The specifications of the terminal block products manufactured in Europe adopt the IEC standard, while the products manufactured in the United States adopt the UL standard.
The difference between these two standards is very large. Engineers who do not understand the method of determining product specifications will take considerable risks, because the selected components may not reach the required power level, or the specifications of the selected components far exceed the design requirements. In Europe, the current rating of the device is determined by monitoring the temperature of the metal conductor as the current increases. When the temperature of the metal pin is 45°C higher than the ambient temperature, the measurement personnel will use the current at this time as the rated current value (or maximum current value) of the device. Another item of the IEC specification is the allowable current value, which is 80% of the maximum current.
In contrast, the UL standard uses 90% of the current value when the metal conductor temperature is 30°C higher than the ambient temperature as the nominal current value of the device. It can be seen that the temperature of the metal conductor part is a very important factor in all applications. This is even more important for industrial equipment.
Because industrial equipment usually needs to work in an environment with a temperature as high as 80°C. If the temperature of the terminal is 30°C or 45°C higher than this temperature, the temperature of the terminal will exceed 100°C. According to the nominal value type and insulating material of the selected device, the products must work at a current lower than the rated value, so as to ensure that they can work reliably within the desired temperature range. Sometimes, materials suitable for compact packaging devices may not meet the heat dissipation requirements well, so the current when using such terminal devices must be much lower than the rated value.