What is a fuse link?
In the 1880s, inventor Edison applied for a patent for a fuse equivalent to a safety switch in a circuit. After a long time, different types of fuses have been produced. The standards formulated by the International Electrotechnical Commission (IEC) define it as a “fuse link“.
The earliest fuse link was used to protect expensive electric lamps. In the industrial technology environment more than 100 years ago, electric lamps could only last for a short time and were very expensive. Edison made more than 1,600 heat-resistant materials and more than 600 kinds of plant fibers.
Experiment to create a carbon filament light bulb. After continuous improvement, the use of tungsten as a filament was developed as a fuse for protecting electric lamps. Its original purpose is to protect important electrical components.
When the circuit fails, the current will increase abnormally, which may damage important components in the circuit and may also cause a fire. However, a fuse link is installed in the circuit. When the current rises abnormally, the fuse link will blow and cut off the current, which can protect the safe operation of the circuit.
There are many types of fuse link, the common plug-in type, screw type, closed type, fast, self-reset, the plug-in type is commonly used in circuits of 380V and below, the screw type is used in circuits of 500V/200A and below, and the closed type is generally used. They are all square ceramic tubes filled with quartz sand for arc extinguishing.
They are used in circuits below 500V/1KA. The structure of the fast type is similar to that of the closed type, but the material of the melt is different, and silver flakes are used. of the melt. The self-recovery type uses sodium as the melt.
When the short circuit produces a high temperature, the sodium will vaporize. The gaseous sodium can limit the current of the short circuit, and the temperature drops. The metal sodium has good electrical conductivity and can be reused.
People often think that as long as the voltage and current are the same, they can be replaced, but this concept is wrong. Believe it or not, an article wrote that the motor fuse link of refrigeration equipment burned out, and it said 16a, so I found another 16a and replaced it. Just turned on the equipment and it burned out.
This is because the fuse link is protected by the protection The form can be divided into the well-known overcurrent protection and the overheating protection affected by temperature factors. The voltage and currents are the same, and the current of the refrigeration equipment is 5-7 times the rated current when it is electrically turned on, so it will burn so quickly.
What is a Fuse link can also be divided into ultra-slow, slow, medium-speed, fast, ultra-fast, etc. according to the fusing speed.
The fault current of the circuit in which the fuse link is placed must be less than the rated breaking current specified in the standard, otherwise ignition, fire and other phenomena. Choose inferior fuse link, its breaking capacity is not up to the standard, it will cause the failure to cut off the fault current and cause fire and other hazards.
Although the fuse is one-time and has a single function, its current limiting breaking capacity is high and the price is cheap.
What is a fuse link?
