The composition of the fuse

Usually, the fuse is composed of three parts: one is the fuse part, which is the core of the fuse. When the fuse blows, this part will cut off the current. The fuse of the same type and specification must be made of the same material, the same geometric size, and the material with the smallest and consistent resistance value. The most important thing is to have the same fixed characteristics. Household fuses are usually made of lead-antimony alloy.
The second is the electrode part, usually two. This is an important part of the connection between the melt and the circuit. It must have good electrical conductivity, which will lead to greater installation contact resistance.
The third is the bracket part. The melt of a fuse is usually slender and soft. The function of the bracket is to fix the melt and make the three parts strong and easy to install and use. It must have good mechanical strength, insulation and heat resistance. It is flame retardant and should not be broken, deformed, burned or short-circuited during use.
Arc extinguishing device
The fuse used in the power circuit and high-power equipment not only has the three parts of the ordinary fuse, but also has an arc extinguishing device, because the circuit protected by the fuse not only has a larger operating current, but also has a larger voltage at both ends of the fuse Burn out. Very high. It usually seems that the melt has melted (melted) or even evaporated, but the current has not been cut off. The reason is that when fusing, under the action of voltage and current, tension will be generated between the two electrodes of the fuse. Arc phenomenon. The arc extinguishing device must have strong insulation and good thermal conductivity, and must have a negative polarity. Quartz sand is a commonly used arc extinguishing material.
fuse
In addition, some fuses have a fuse indicator device. Their function is to change the appearance of the fuse after it is activated (blown), which is convenient for maintenance personnel to find, such as light-emitting, discolored and firmly placed indicators.