The use of power terminal block in electronic devices has become a trend. Power terminal blocks are gradually increasing in size and can carry more power. As the size of the terminal blocks increases, their importance in the functionality of the equipment becomes more prominent, and they play an increasingly important role in ensuring the product’s distinctive features.
Continuously improved circuit board technology has significantly increased the current that terminal blocks mounted on panels can carry. It has already broken through the 110A limit, far exceeding the level of previous products. This makes the question of which power terminal block to use in the design process to meet system requirements more complex. In addition, various regions employ distinct methods to measure performance parameters, resulting in a considerable difference in the nominal parameters they provide for the same product. Therefore, understanding these differences is very important to ensure long-term reliability and guarantee low cost.
Engineers must also actively consider marketing considerations, a factor that is often overlooked. Usually, power terminal blocks are visible to users, so the marketing department often hopes that the product will match the color and style of the entire system in appearance.
In the following, the LCSC supplier Kangnex will introduce the important factors affecting the selection of power terminal blocks.
Power Handling Factor
One of the first factors to consider is the power handling capability of the device. Simply reading the datasheet does not guarantee accurate comparative data. Engineers must actively understand and determine the testing methods behind the product performance data listed in the manual.
Currently, there is no unified standard for determining the power and performance specifications of terminal block products by organizations such as UL, IEC, CSA, and DIN. Users need to understand the difference between UL and IEC specifications. The specifications of terminal block products manufactured in Europe use IEC standards, while those manufactured in the United States use UL standards.
The difference between these two standards is very large. Engineers who do not understand the method of determining product specifications will take a considerable risk. Because the selected device may not meet the required power level or the specifications of the selected device may far exceed the design requirements. In Europe, engineers determine the current rating of the device by actively 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 measuring personnel take this current as the rated current value (or current value) of the device.
Another item in the IEC specification is the allowable current value, which is 80% of the 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 device’s current nominal value. One can observe that engineers actively consider the temperature of the metal conductor part as a very important factor in all applications. This is even more important for industrial equipment. Because industrial equipment often needs to work in an environment with a temperature of up to 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. Depending on the nominal value type and insulation material used in the selected device, the product must operate at a current lower than the rated value to ensure that they can work reliably within the desired temperature range. Sometimes, materials suitable for compact packaging devices may not meet heat dissipation requirements well, so the current used by such terminal block devices must be much lower than the rated value.
As enterprises become more globalized, system designers increasingly use power terminal products produced in other countries. Since Europe employs the nominal value measurement method, it is common for engineers in Europe to use devices below their nominal values. However, many American designers are not familiar with this concept, and if they do not understand the differences between the standards, they will encounter many difficulties in the design process.
When selecting devices, engineers often overlook the terminal connection technology. To address this, engineers must actively consider the terminal connection technology as an important factor in their selection process. Most power terminal block products still use through-hole connections. This method can provide the necessary mechanical support and ensure solid electrical contact with the power layer embedded in the multi-layer circuit board. Engineers use various types of pins to connect the terminal blocks to the circuit board. Some companies only provide single-pin models, while others offer multi-pin products. The advantage of multi-pin products is that they can distribute the current more evenly to the circuit board traces, providing more reliable mechanical stability and improving the solidity of soldering.
Appearance Factor
Although the name “power terminal block” does not sound pretty, many companies believe that it plays an important role in product appearance and user affinity. Power terminal block connectors must be convenient for on-site installation because they are often installed at the front of easily visible product panels. As a result, marketers often want to have a say in the appearance of power terminal block products. However, engineers frequently encounter situations where they must change products that meet all mechanical and electrical parameter requirements. This necessity arises because the products do not meet sales requirements. If this happens at the end of the design cycle (often when the marketing department sees the prototype), then a fierce debate is hard to avoid, which can lead to increased costs and delivery delays. In many industrial control systems, terminal connectors are often one of the few components that technicians need to pay special attention to. Although its user interface is relatively simple (mainly screws), it is very important for the normal operation of the equipment.
In general, as the current increases, the wires become thicker, and the torque required to tighten these thick wires to the terminal blocks also needs to increase. Therefore, power terminal blocks require larger screws and stronger insulating shells. Sometimes small screws are used to save space. This is often the case in very compact terminal products. With wires that are more than 1/4 inch in diameter, these small screws are difficult to work with. When technicians and maintenance personnel need to install multiple wires, using screws of an adequate size to simplify the wiring process can save a lot of time. This is why it is so important for engineers to listen to the marketing department early in the design process. If the terminal must be properly polished or the right color, it is much easier to state these parameters as an original product requirement than to adjust them at the end of the development cycle.
When terminal blocks are used in consumer products (such as high-end stereo products), appearance becomes increasingly important. In fact, some designers often specify that terminal block devices used for audio equipment should be gold-plated, which, although it increases costs and does not significantly improve performance, gold plating does improve the appearance of the product.
Conclusion
Understanding the measurement methods of power terminal block parameters is a key part of system design. Confirming that the selected power terminal blocks meet the temperature range, current, and voltage requirements of the power equipment helps to ensure the long-term reliability of the system. In addition, if the selected power terminal block devices adopt wiring technology that can meet market requirements and ensure user operation convenience in the design, it can greatly improve the success rate of the final product.
Kangnex is a supplier of connector solutions. The company’s main products include pluggable terminal blocks, screw terminal blocks, and fence terminal blocks. Kangnex also has strong customization capabilities and can provide professional customized solutions and additional services based on the personalized needs of global customers.
Visit Kangnex’s brand page on LCSC.
Source: Kangnex
