2022-09-28
2022-09-28
High-voltage fuses are made of copper, silver, zinc, lead, lead-tin alloy, etc. The melting points of these materials are also different, so different currents need to use different materials, and their fusing temperatures correspond to 1080 ℃, 960 °C, 420 °C, 327 °C, 200 °C. Instructions for use of these different materials are as follows:
1. The melting point of zinc, lead, lead-tin alloy and other metals is relatively low, but the resistivity is relatively large. Therefore, the cross-sectional area of the fuse to be used is large, and a large amount of metal vapor is generated when the fuse is blown, which is not conducive to arc extinguishing, and is mainly used in circuits below 1kV.
2. Copper and silver have high melting points, but low resistivity and good electrical and thermal conductivity. Therefore, the cross-sectional area of the fuse to be used is small, and the metal vapor generated when fusing is also small, which is easy to extinguish the arc, and can be used in high-voltage and high-current circuits. However, if the passing current is too large and the temperature is too high for a long time, it is easy to cause damage to other components in the fuse. To make the melt fuse quickly, a large current must flow, otherwise the fuse time will be prolonged, which is not good for the protection equipment. In order to eliminate this shortcoming, a tin or lead ball is often welded on the copper or silver melt to reduce the melting temperature of the melt and improve the protection performance of the melt.