The reason for the temperature rise of the thermal fuse
The temperature rise of the fuse refers to the temperature rise value of the fuse when the rated current flows in the fuse, that is, the actual measured temperature minus the ambient temperature. The UL standard sets its upper limit at 75°C, because the melt of the fuse is more sensitive to temperature. If it is used for a long time at a certain temperature, its melting point and impedance will change. This change will affect the accuracy of the fuse. If the temperature of the fuse rises to a certain level in normal current, it will blow out. The fuse is not suitable for overload protection.
Generally, the temperature of the circuit rises soon after the fuse is installed and the current is connected. The reasons for this situation are: 1. The circuit voltage is unstable 2. The rated current of the fuse is too small 3. The fuse is aging
Unstable voltage will cause the current to increase. If the selected fuse type and parameters are not wrong, then the fuse will not have much impact in this case. If the rated current of the fuse is too small, the normal operation of the circuit will also cause the fuse to blow. The fuse needs to be replaced. The aging of the fuse is very dangerous to use in the circuit. At this time, the internal resistance of the fuse is very unstable. At this time, the fuse needs to be replaced to ensure the normal operation of the circuit. Therefore, we need to watch out when the temperature rises.
Nowadays, some circuits also have temperature rises during operation. Then, in order to prevent circuit damage or fuse easy to blow, there are thermal fuses and ceramic fuses that can protect these special circuits from over-temperature and overload. If the temperature of the fuse rises in the circuit, find out the problem in time and solve the problem to ensure the safety of the circuit.
