Views:128 Author:Site Editor Publish Time: 2020-12-23 Origin:Site
Pluggable terminal blocks are a kind of key parts used to protect grounding. From system software, subsystems, server cabinets, components, circuit boards to each removable individual module, it is responsible for the electromagnetic energy of the automatic control system transmission and data signal manipulation. Therefore, this determines the use of wiring terminals everywhere, especially in areas that must be wired, there are pluggable terminal strips.
The plug-in terminal is used to realize electrical connection and terminal connection. It is made up of two parts plug-in connection, one part presses the line tightly, and then plugged into the other part, and this part is soldered to the PCB board. The plug-in terminal uses a combination of easy-to-operate pluggable connection and a firm and universal screw method to connect various parts.
Panel mount pluggable terminal block is commonly used pitches are 3.50mm, 3.81mm, 5.00mm, 5.08mm, 7.50mm, 7.62mm.
This standard is equivalent to adopting the international standard IEC455 (1988) "General Rules for the Identification and Application of Alphanumeric System of Equipment Terminals and Specific Wire Ends."
1. Subject content and scope of application
This standard specifies various methods for identifying electrical equipment (hereinafter referred to as equipment) terminals, and formulates general rules for identifying equipment terminals and specific wire ends with an alphanumeric system. This standard applies to equipment (such as resistors, fuses, relays, contactors, transformers, rotating electrical machines, etc.) and the identification markings of the terminals of the combination of these equipment, as well as the identification of specific wire ends. When necessary, the detailed application of these general rules to certain products and the necessary auxiliary identification methods can be given in the relevant standards.
2. Reference standards
GB 4728 Graphical symbols for electrical diagrams GB5465 Graphical symbols for electrical equipment.
3. Identification method
One or more of the following methods can be used to identify equipment terminals and specific wire ends.
(1) Use the marking system of related products to determine and identify the actual or relative position of the equipment terminal or specific wire end.
(2) Use the marking system of related products to determine and identify the color markings of the equipment terminals and specific wire ends.
Various problems often occur during the use of pluggable terminal block.
1. Causes the problem of burning black
If the pluggable terminal block connector is black, one of the possibilities is not necessarily burnt black, oxidation may also be black. So how to verify whether it is burnt black? The method we take is to wipe it off with a finger. If it can be wiped off, like soot, it is a black substance formed by oxidation, which can only be wiped off with sandpaper or a file.
Problems that cause high temperatures
There are two possibilities: the pluggable terminal block is loose and the contact resistance is too large, resulting in overheating. The pluggable terminal block connector is not loose, but the circuit has overcurrent heating due to some unknown reason, such as the power supply voltage is too high, or the load is short-circuited.
1）The voltage is too high. You can check from the source, the secondary voltage of the transformer-the voltage in the distribution box-the voltage of the electrical equipment.
2）Ground fault. You can also find it from the transformer, and then ground it to the distribution box. The grounding should be grounded, and the normal phase line should be removed from the ground fault. You can use an insulation meter or a shaking meter to measure when the power is cut off, and measure in sections. Try to measure only the power supply and distribution lines such as cables, wires, circuit breakers, and switches. If it is really difficult to section, unplug the weak current equipment, the fuse of the sensing device.
The key to grounding is that the grounding resistance should be low and the contact area should be large. The former can ensure that the grounding point has a "zero potential" as low as possible close to the ground potential, which can avoid the possibility of lightning back from the grounding wire and entering the power supply loop after lightning strikes. The latter can ensure that there is enough capacity to provide a fault current channel, including lightning or short-circuit faults. Because the actual construction process in theory has always been changed according to the changes of contemporary technology and technology, so whether this grounding method works, whether it is good or not, depends on how the new standard specifications are stipulated.