Temperature can significantly affect the performance of fuses: Firstly, we need to understand the working principle of fuses. When current flows through a conductor, due to the conductor's inherent resistance, it heats up. Greater current results in more heat generation. Once the heat reaches the melting point of the conductor, it will melt. Fuses are designed based on this principle, with the conductor being the fuse element.
The fuse's operation is determined by the balance between the heat it generates internally and the heat dissipated by its surrounding environment, thus the ambient temperature significantly affects the fuse's performance. Here, the ambient temperature refers not only to the indoor or outdoor temperature surrounding the electronic and electrical equipment but more importantly to the temperature of the small environment surrounding the fuse within the machine during operation. This is because it will have a more direct impact on the fuse's performance. Generally, atmospheric temperatures do not exceed 50°C, but the internal small environment temperature may even exceed 100°C, which can have a substantial impact on the fuse's performance.
As the ambient temperature increases, the fuse (circuit breaker) melts faster, which means its specifications are actually reduced. Since the performance of the fuse is affected by the working environment temperature, we must consider its actual operating temperature when selecting a fuse. Fuse manufacturers should provide a derating curve for their products under high-temperature conditions, which can inform customers at what temperature the rated current of the fuse will be derated to a certain percentage. This derating curve data is an important parameter of the fuse, especially for precision electronic devices and applications in special fields, which should be a key consideration during design.
Now we understand why it's crucial to consider the impact of temperature when selecting fuse models, so we must be cautious in fuse selection, as the devil is in the details.
