How to do anti-static ground wire detection in electronic factories
The electrostatic protection work in the electronic production workshop is well-known, but some factories may have anti-static products in use due to management neglect, but there is no detailed inspection on a regular basis. Now it is recommended to install in enterprises with high electrostatic requirements. When the electrostatic grounding is good, the instrument should be used for testing, or professional personnel can be used for measurement.
All anti-static ground wires use 6 m㎡ multi-strand copper-core insulated wires, and each floor or appropriate section uses copper bars or switches above 401, and the knife is connected to the main line to facilitate inspection and maintenance.
The anti-static ground cable should be well insulated with the equipment shell, workbench iron frame, work light frame, etc., to prevent short circuit, overlap or broken skin connection. At the "trunk end" of the sectional copper bar or switch, another inspection line (1.5~2m² is enough) is laid. Each workshop has 2~3 inspection points, which are fixed and clearly marked. Use a grounding resistance tester (also called a shake meter). 1) The resistance between each anti-static test point and the anti-static ground wire is 5-15Ω, ideally 0Ω. However, the actual measurement is that the resistance of the wire from the test point to the summary point + 6 m ㎡, and the sum of the resistance of the wire from the summary point to the measured point, which is about 5-15Ω and basically unchanged. If the measurement result tends to infinity, It is for anti-static ground wire or a broken wire in the measuring wire, which should be repaired in time.
The resistance value between the electrostatic grounding wire and the equipment grounding wire is composed of the wire resistance of the anti-static ground wire itself, the wire resistance of the equipment ground wire itself, and the ground resistance between the two ground wires. However, due to the degree of ground dryness and wetness between the two grounding wires, the influence of ground current is very complicated, especially the ground current, the size, direction, frequency, etc. change every moment, and it mainly determines the measurement result, so it can only be measured with a pointer meter. Values ranging from more than ten ohms to hundreds of K are considered normal, only indicating that there is no short circuit or open circuit between the two places.
Based on the above detection data, it can be judged whether the current workshop anti-static ground wire is working normally.