简体中文
When facing the selection of terminal blocks, the first thing that comes to mind is the wire diameter, current, wiring direction, application situation, wiring method, etc. The wire diameter and current are also the wire diameter and rated current. In addition, the wiring direction generally has front and side outgoing lines. This design mainly facilitates the operation of technical personnel, thereby improving work efficiency and application. The application range of wiring terminals is wide. For example, if the purchased wiring terminals are welded to the PCB circuit board, it is impossible to choose the wiring method for the wiring terminals used on the guide rail. Generally, there are docking, hanging, fixing, and other methods. The basic composition of a universal wiring terminal is composed of an insulating base, insulation partition, and wire components, and the insulation base is integrated.
There are certain rules that can be found in the correct selection and use of wiring terminals under different environmental conditions. Although there is no clear usage system in the industry, specific terminals can be selected based on specific usage environments and conditions. There are four basic principles that can serve as a reference.
Firstly, before setting the terminal, you need to understand what type of terminal you want. According to the functional classification of the terminal, there are: ordinary terminal, safety terminal, test terminal, grounding terminal, double-layer terminal, double-layer conduction terminal, three-layer terminal, three-layer conduction terminal, one in and two out terminal, one in and three out terminal, double in and two out terminal, knife switch terminal, overvoltage protection terminal, marking terminal, etc. According to current classification, it can be divided into ordinary terminals (low current terminals) and high current terminals (over 100A or 25MM wires). Classified by appearance. It can be divided into rail type terminal fixed terminal circuit board terminal (PCB terminal), etc.
Secondly, the size of the wiring needs to be considered. For different wiring terminals, their size and wiring range are different. Usually, when using terminals, it is better to choose a slightly larger wiring range than the actual wire diameter. Because the current market standards are quite chaotic, if you choose a wiring aperture of the same size as the wire diameter, it is possible that the wiring range will become smaller due to terminals produced in the market that do not meet the standards, and the wire cannot be inserted into the crimping box.
Once again, there are current regulations in the industry for rail terminals, which have been in the market for decades. Different models have specific current specifications, and products must meet or exceed this standard.
Finally, the amount of space used. Different terminals can be selected for different space sizes. For example, in narrow spaces, you can choose double-layer terminal blocks or three-layer terminal blocks.
In addition, when selecting wiring terminals, the following points should also be noted:
1、 Appearance
Good wiring terminals should first have good workmanship, and those that cannot pass visual inspection basically do not need to waste time conducting electrical testing. So, what kind of wiring terminal is considered good workmanship? It is widely believed in the industry that qualified terminal plastic parts should have an overall intangible change, a flat surface, no scratches, no burrs at the edges and corners, and a uniform wall thickness; More importantly, the fit between the plug and the needle seat is high, and there is no phenomenon of high or low insertion and extraction force.
2、 Material
Firstly, plastic parts should have good flame retardancy, i.e. UL94V-0 flame retardant grade; A simple test method is to ignite an open flame, and when the plastic part leaves the open flame and goes out, it indicates that the wiring terminal has good flame retardant performance; Then there is the crimping frame, and many customers often refer to the crimping frame as the copper material of the wiring terminal. Upon careful identification from the appearance, copper frames have a more angular texture than iron ore. Of course, the safest way is to open the plastic parts and take out the wire pressing frame for further testing, without listening to the salesperson's one-sided words.
3、 Torque
90% of the poor contact of wiring terminals in the market is due to screw torque not meeting the requirements, so the screw torque of wiring terminals is particularly important. Therefore, it is best to personally feel whether the screw can press the wire tightly with a screwdriver.
