Fuses are also known as current fuses, and the IEC127 standard defines it as a "fuse-link". It is mainly due to overload protection. Circuit in the correct placement of the fuse, the fuse will be in the current abnormal rise to a certain height and heat when the fuse itself cut off the current to protect the circuit safe operation
More than a hundred years ago by Edison invented the fuse used to protect the then expensive incandescent, with the development of the times, the fuse protection of electrical equipment from overheating damage, to avoid electronic equipment due to internal damage caused by serious injury. When the circuit fails or abnormal, accompanied by rising current and rising
High current may damage some important devices in the circuit, it is possible to burn the circuit or even cause a fire. If the circuit is correctly placed in the fuse, then the fuse will rise in the current to a certain height and heat, when the fuse itself cut off the current, so as to protect the safe operation of the circuit.
When the current flows through the conductor, because the conductor there is a certain resistance, so the conductor will heat. Q is the heat, 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 that the current flows through the conductor. In this way, the heat is equal to that of the conductor. We can easily see the simple working principle of the fuse. When the material and shape of the fuse are determined, the resistance R is relatively constant (if its resistance temperature coefficient is not taken into account). When the current flows through it, it will heat up, with the increase of time its heat is also increasing. The size of the current and the resistance determines the rate at which the heat is generated. The structure of the fuse and the condition of its installation determine the rate of heat dissipation. If the heat is generated at a rate less than the heat dissipation, the fuse will not blow. If the velocity of heat is equal to the rate of heat dissipation, it will not blow for a long period of time. If the heat generated by the speed is greater than the speed of heat dissipation, then the heat will be more and more. And because it has a certain heat and quality, the increase in heat is reflected in the temperature rise, when the temperature rose to the fuse above the melting point when the fuse occurred in the fuse. This is the working principle of the fuse. We should know from this principle that you must carefully study the physical properties of the materials you choose when designing and manufacturing fuses and ensure that they have consistent geometric dimensions. Because these factors on the fuse can work properly played a vital role. Likewise, when you use it, be sure to install it correctly.
Basic components: the general fuse consists of three parts: First, the melt part, it is the core of the fuse, when the fuse to cut off the role of current, the same type, the same size fuse fuse, the same material, geometric size to be the same , The resistance value as small as possible and consistent, the most important thing is to fuse the same characteristics, household fuses commonly used lead antimony alloy; second part of the electrode, usually two, it is an important part of the melt and circuit connection, It must have a good electrical conductivity, should not produce a significant installation of contact resistance; Third, the bracket part of the fuse melt are generally slender and soft, the role of the bracket is to melt the three parts and become rigid as a whole easy Installation, use, it must have good mechanical strength, insulation, heat resistance and flame retardant, in use should not produce fracture, deformation, combustion and short circuit and so on.