Introduction of power fuse

The principle of power fuse

A power fuse is one of the fuses, which refers to an electrical appliance that fuses the melt with the heat generated by itself and disconnects the circuit when the current exceeds a specified value. The fuse is a current protector made by using the heat generated by itself to melt the melt after the current exceeds the specified value for a period of time, thereby disconnecting the circuit.

The working principle of a fuse is a simple I2R versus time. The higher the current, the shorter the fusing or opening time. The power dissipation of a fuse is proportional to the square of the current through the fuse. When the power consumption is too high, the fuse blows. This feature also applies to fuse-protected harnesses. If the heat generated exceeds the heat dissipated, the temperature of the fuse will increase. When the temperature rises to the melting point of the fuse of the fuse, the fuse will be blown, that is, the circuit will be disconnected for protection.

Fuses are widely used in high and low voltage power distribution systems and control systems as well as electrical equipment. As a short circuit and overcurrent protector, it is one of the most commonly used protection devices.

Classification of power fuses

Power fuses are part of fuses (fuses), they can be divided into semiconductor protection fuses, DC fuses, special fuses, general-purpose fuses and fuse disconnectors.

Structural characteristics of power fuse

The structure of a power fuse is roughly the same as that of a fuse. It is mainly composed of melt, shell and support, among which the melt is the key element to control the fusing characteristics. The material, size and shape of the melt determine the fusing characteristics. Melt materials are divided into two categories: low melting point and high melting point. Low melting point materials such as lead and lead alloys have a low melting point and are easy to fuse. Due to their large resistivity, the cross-sectional size of the melt is large, and more metal vapor is generated during fusing. It is only suitable for fusing with low breaking capacity. device. High melting point materials such as copper and silver have a high melting point and are not easy to fuse, but due to their low resistivity, they can be made into smaller cross-sectional dimensions than low melting point melts, and generate less metal vapor when fused, which is suitable for high breaking points. capable fuse. The shape of the melt is divided into two types: filament and ribbon. Changing the shape of the variable section can significantly change the fusing characteristics of the fuse.