What we need to pay attention to is when the high-voltage fuse will break. Knowing the reason of the fuse will be of great help for us to install and use the high-voltage fuse later.
High voltage fuses generally fuse under the following circumstances:
1, high pressure fuse specification is small, improper installation, mechanical strength is not enough and fuse, generally only break a phase. In most cases there is no obvious arc. Power supply can be restored by replacing the high voltage fuse.
2, the transformer due to internal failure caused by high voltage fuse fuse, mostly two-phase fuse fuse. In this case, the cause should be determined before resuming power transmission. When the transformer is faulty inside, it often causes oil injection from the large cover joint of the tank, the oil filling hole, etc., open the cover of the oil filling hole and smell whether there is lampblack smell. According to the lampblack smell, the transformer is burned out and whether it can be continued to be used. If there is no obvious sign, the cause should be identified before being put into operation.
3. High voltage fuse is broken due to short circuit or overload in the distance. Due to the long fusing time and the combination of high and low pressure fuses, high and low pressure fuses can be fused at the same time. In this case, arc marks and melting points of the fuse are left on the fuse tube and porcelain support. During processing, the transformer high and low voltage to ground and insulation resistance between them are measured with a dial meter, and the conduction of high and low voltage winding and its DC resistance balance are measured with an ohmmeter. If no different, disconnect the low-voltage side fuse, replace the high-voltage fuse for power supply, listen to the transformer sound is normal, and measure whether the secondary voltage is balanced. If there is no problem, restore power to the low voltage.
