Plug-in fuse: It is often used at the end of the line with a voltage level of 380V and below as a short-circuit protection for distribution branch lines or electrical equipment.
Spiral fuse: There is a fuse indicator on the upper end cover of the melt. Once the melt is blown, the indicator will pop up immediately, which can be observed through the glass hole on the porcelain cap. It is often used in the electrical control equipment of machine tools. Spiral fuse. The breaking current is large and can be used for short-circuit protection in circuits with a voltage level of 500V and below and a current level of 200A or below.
Enclosed fuses: Enclosed fuses are divided into two types: filled fuses and unfilled fuses, as shown in Figure 3 and Figure 4. Filled fuses generally use square porcelain tubes, which are filled with quartz sand and melt, and have strong breaking capacity. They are used in circuits with voltage levels below 500V and current levels below 1KA. The non-packing closed fuse packs the melt into a closed cylinder, with a slightly smaller breaking capacity, and is used in power grids or power distribution equipment below 500V and 600A.
Fast fuse: Fast fuse is mainly used for short circuit protection of semiconductor rectifier components or rectifier devices. Due to the low overload capacity of semiconductor components. It can only withstand a large overload current in a very short period of time, so the short-circuit protection is required to have the ability to quickly fuse. The structure of the fast fuse is basically the same as that of the enclosed fuse with filler, but the melt material and shape are different. It is a variable-section melt with a V-shaped deep groove punched by a silver sheet. The fast fuse is usually referred to as "fast fuse", which is characterized by fast fusing speed, large rated current, strong breaking capacity, stable current limiting characteristics and small size.
Self-resetting fuse: Using sodium metal as melt, it has high conductivity at room temperature. When a short-circuit fault occurs in the circuit, the high temperature generated by the short-circuit current causes the sodium to vaporize rapidly, and the vaporized sodium exhibits a high resistance state, thereby limiting the short-circuit current. When the short-circuit current disappears, the temperature drops, and the metal sodium restores its original good electrical conductivity. The resettable fuse can only limit the short-circuit current and cannot really break the circuit. The advantage is that there is no need to replace the melt and it can be reused.
