We all know that the development of electronic industry in China is faster and faster, we should continue to promote its development in the industry. Next, we analyze the specific content of lightning protection and maintenance of air switch of lightning protector.
You first look at the air switch in which cases it can protect the trip: over-current, under voltage, short circuit, phase loss and so on. The models and performances of air switches used for different purposes or installed in different places are different, so specific problems should be analyzed.
If lightning strike causes short circuit of line to ground, over-current or short-circuit current will appear. If the current exceeds the action current of switch, it will trip.
The protection design of general power supply lightning arrester is not to install varistor, but to install more perfect SPD. The protective elements in SPD include ZnO varistor or gas discharge tube. The method of installing a single varistor is not good, not only the structure is inconvenient, but also the selection of varistor parameters. The selection of SPD also has the problem of parameter selection.
When the air switch of PDU has a current of more than 1ms and more than 6 times the rated current of the air switch, the air switch will automatically open. Because the installation and operation of air switch is more convenient than fuse, air switch is widely used to replace fuse in China. Pay attention to the following when using air switch:
1. If the air switch is too large, it is difficult to protect itself;
2. When the current that can be cut off automatically when the air is opened and disconnected is too small, the air itself will explode or the joint will be welded automatically.
3. Less importantly, when the rated current of the open circuit main switch is not too large, the PDU can be omitted before the vacancy.