Inspection items of fuse

Fuse is a kind of over-current protection appliance, which is mainly composed of melt, shell and support. The melt is the key element to control the fusing characteristics. The daily inspection and maintenance of fuse mainly include the following aspects.

1. Whether the fuse signal indicator is normal.

2. Check whether the contact points of the fuse are in good condition, closely contacted and free from overheating.

3. Check whether the rated value of fuse and melt matches with the protected equipment.

4. Check whether the fuse appearance is damaged or deformed, and whether the porcelain insulation part has flicker discharge traces.

1. When fusing the melt, carefully analyze the causes of fusing. The possible causes are:

(1) Normal fusing due to short circuit fault or overload operation

(2) There is mechanical damage during the installation of the melt, which makes its sectional area smaller and causes false fracture during operation.

(3) If the melt has been used for too long, the melt will be broken by mistake due to oxidation or high temperature during operation, which will change the melt characteristics.

2. When replacing the melt, it is required to:

(1) Before installing a new melt, find out the cause of melt fusing. If the cause is not determined, do not replace the melt for test delivery.

(2) When replacing a new melt, check whether the rated value of the melt matches the protected equipment.

(3) When replacing a new melt, check the internal burn of the fuse tube. If there is serious burn, replace the fuse tube at the same time. When the porcelain melting pipe is damaged, it is not allowed to use other materials to replace it. When replacing the melt of the packed fuse, pay attention to the packing.

3. The fuse shall be maintained simultaneously with the power distribution device:

(1) Clean the dust and check the contact condition of the contact point.

(2) Check the appearance of the fuse (remove the fuse tube) for damage and deformation, and check the porcelain parts for discharge flicker marks.

(3) Check whether the fuse, melt and the protected circuit or equipment are matched, and timely investigate if there is any problem.

(4) Pay attention to check the N line in the grounding system and the grounding protection line of the equipment. It is not allowed to use fuses.

(5) During the maintenance and inspection of the fuse, the power supply shall be cut off according to the requirements of the safety regulations. It is not allowed to take off the fuse tube with electricity.

Fuses are widely used in low-voltage distribution systems, control systems and electrical equipment. As short circuit and overcurrent protection, they are one of the most widely used protective devices.