The fuse is actually a short-circuit protection device, which is widely used in distribution systems and is mainly used for short-circuit protection or severe overload protection. The fuse is a simple and efficient protective electrical appliance, which mainly plays a role of short-circuit protection for the circuit.
The fuse mainly includes a melt and an insulating tube (insulating seat) installed with the melt. When used, the melt is stringed into the protected circuit. When a short-circuit fault occurs in the circuit, the melt is instantly blown off the circuit to provide protection.
Ordinary fuze: 1. Insert type fuze. It is often used in line terminals with voltage levels of 380V and below, and used for short-circuit protection of power distribution branches or electrical equipment.
2. Screw fuse. There is a fuse indicator on the upper end cover of the melt. Take it out of the glass hole on the porcelain sleeve immediately after fusion, and you can see it. It is often used in electronic control devices of machine tools. The screw fuse has a high breaking current and can be used for short-circuit protection in circuits with a voltage level of less than 500V. The current level is 200A.
3. Close the fuse. Closed fuses are divided into two categories: filled type and non-filled type. The filling type fuse generally adopts the inner quartz sand and melting square porcelain tube, which has a strong breaking capacity and is suitable for circuits with a voltage level of less than 500V and a current level of 1KA.
4. Fast fuse. It is suitable for short-circuit protection of semiconductor rectifier components or rectifiers. Because the semiconductor component overload is small. The short-circuit protection can withstand a large overload current in a very short time, and the short-circuit protection requires a fast fuse capability.
5. Self-recovery fuse. The device has a high electrical conductivity at room temperature. When a short-circuit fault occurs in the circuit, the high temperature generated will quickly evaporate the sodium, and the vapor sodium has a high resistance state, thereby limiting the short-circuit current. The overcurrent disappears, the temperature drops, and the sodium restores the original good conductivity.
In fact, the fuse is connected in series in the protection circuit. When the circuit is short-circuited or severely overloaded, the fuse will automatically blow and play a protective role. Therefore, the important role of the fuse in our daily production and life is self-evident.
