The working principle of fuses
- Release on :2018-09-12
The fuses invented by Edison more than a hundred years ago were used to protect the expensive incandescent lamps at that time. With the development of the times, the fuses protect the electronic/electrical equipment from overcurrent/overheating and avoid serious damage caused by internal faults. .
When a current flows through the conductor, the conductor will heat up due to a certain resistance of the conductor. And the calorific value follows this formula: Q=0.24I2RT; where Q is the calorific value, 0.24 is a constant, I is the current flowing through the conductor, R is the resistance of the conductor, and T is the time at which the current flows through the conductor; We can easily see the simple working principle of the fuse.
When the material from which the fuse is made and its shape are determined, its resistance R is relatively determined (if its temperature coefficient of resistance is not considered). When current flows through it, it heats up and its heat is increasing over time. The magnitude of the current and the resistance determine the rate at which the heat is generated. The configuration of the fuse and its installed condition determine the rate at which the heat is dissipated. If the rate at which heat is generated is less than the rate at which the heat is dissipated, the fuse will not blow. If the rate at which heat is generated is equal to the rate at which heat is dissipated, it will not blow for a considerable period of time. If the rate of heat generation is greater than the rate at which heat is dissipated, then more and more heat is generated. And because it has a certain specific heat and quality, its heat increase is reflected in the temperature rise, when the temperature rises above the melting point of the fuse, the fuse will be blown. This is how the fuse works.
We should know from this principle that you must carefully study the physical properties of the materials you select and ensure that they have a consistent geometry when designing and manufacturing fuses. Because these factors play an important role in the normal operation of the fuse. Again, you must install it correctly when you use it.