Fuses are also known as current fuses, which are primarily 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 the rising current may damage some important devices in the circuit or expensive devices, it is possible to burn the circuit or even cause a fire. If the circuit is properly placed in the fuse, then the fuse will be abnormal in the current rise to a certain height and heat when the fuse itself cut off the current, so as to protect the safe operation of the circuit.
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 of fuse with the same specifications, the same material, geometric dimensions to the same, resistance The fuse is made of lead and antimony alloy; the second part of the electrode, usually two, it is an important part of the melt and circuit connection, it must have Good 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 to install, use , It must have good mechanical strength, insulation, heat resistance and flame resistance, in use should not produce fracture, deformation, combustion and short circuit and so on.
Power circuits and high-power equipment used by the fuse, not only the general three parts of the fuse, but also the arc device, because the protection of such a fuse circuit is not only a large current, and when the melt occurs when the two The end of the voltage is also high, often the melt has melted (blow) or even vaporized, but the current is not cut off, the reason is that the moment in the fuse under the action of voltage and current, the fuse between the two electrodes Arc phenomenon. The arc extinguishing device must have a strong insulation and good thermal conductivity, and was negative. Quartz sand is commonly used arc extinguishing materials.