Fuse cutout failure analysis and maintenance

1. When the melt is blown, carefully analyze the cause of the fuse. Possible reasons are:

(1) Short circuit fault or overload normal fuse;
(2) The melt has been used for too long, and the melt was accidentally interrupted due to oxidation or high temperature during operation;
(3) There is mechanical damage when the melt is installed, so that the cross-sectional area becomes smaller, resulting in a false break during operation.

2. When dismantling the melt, it is required to do:

(1) Before installing the new melt, find out the cause of the melt blown, if you are not sure about the cause of the melt, do not replace the melt for trial operation;
(2) When replacing the new melt, check whether the rated value of the melt matches the protected equipment;
(3) When replacing the 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 fusion tube is damaged, it is not allowed to replace it with another material tube. When replacing the packing fuse, care should be taken to fill the packing.

3. The maintenance work when the fuse fails is as follows:

(1) Remove dust and check the contact condition of the contact point;
(2) Check whether the appearance of the fuse (remove the fuse tube) is damaged and deformed, and whether the porcelain parts have discharge flickering traces;
(3) Check whether the fuse and melt match the protected circuit or equipment, and investigate in time if there is any problem;
(4) Pay attention to check the N line in the TN grounding system and the grounding protection line of the equipment, and fuses are not allowed;
(5) When maintaining and inspecting the fuse, the power supply should be cut off according to the requirements of safety regulations, and the fuse tube should not be taken out with electricity.