1. Whether it is AC or DC, first switch the multimeter to the corresponding voltage position, first check the voltage of the pile heads on the two fuses, if normal, it means there is no problem with the power supply, and then check the voltage of the pile heads on the two fuses. If the voltage is the same as the upper pile head, there is no problem with the fuse. If the lower pile head detects no voltage, it can be concluded that one fuse is burned or both fuses are burned.
2. If there is no voltage at the lower pile head, put one multimeter pen on the lower pile head of the fuse and one on the upper pile head of the fuse. If there is voltage, it means which fuse of the pile head is good. If there is no voltage, put the test pen on the pile head. Which fuse is bad. Change the test leads and use the same method to check the quality of another fuse or other fuses.
3. The method of measuring resistance cannot be used for live inspection. Pull out the fuse, use the ohm crotch or buzzer setting of the multimeter, and touch the test leads to both ends of the fuse. If the resistance is zero or the buzzer will sound, it means it is good. Otherwise it is bad.
Simply connect the resistance end of a multimeter to both ends of the fuse.
If the resistance is large, it means it is broken; if the resistance is zero or very small, it means it is good.
After the current in the fuse exceeds the specified value for a period of time, the heat generated by itself causes the melt to melt, thereby disconnecting the circuit.
Fuse use and maintenance
Fuses are an electrical appliance that plays a safety protection role in low-voltage power distribution systems. Fuses are widely used in power grid protection and electrical equipment protection. When a short-circuit fault or overload occurs in the power grid or electrical equipment, the fuse can automatically cut off the circuit to prevent electrical appliances from being damaged. damage to prevent the accident from spreading.
The fuse is composed of an insulating base (or support), contacts, melt, etc. The melt is the main working part of the fuse. The melt is equivalent to a special wire connected in series in the circuit. When the circuit is short-circuited or overloaded, , the current is too large and the melt melts due to overheating, thus cutting off the circuit. The melt is often made into filaments, grids or sheets.
The melt material has the characteristics of relatively low melting point, stable characteristics, and easy fusing. It generally uses lead-tin alloy, silver-plated copper sheet, zinc, silver and other metals. During the process of melt fusing and cutting off the circuit, an arc will be generated. In order to safely and effectively To extinguish the arc, the melt is generally installed in the fuse housing and measures are taken to quickly extinguish the arc.