How to choose a fuse?

When it comes to fuses, I firmly believe that most of my good friends will not find it weird. As a very common component and equipment, fuses are used very frequently. However, do you really have to master the function of fuses?
The fuse is actually connected in series in the circuit, and the basic principle of thermal fuse is used to ensure the reliable operation of the circuit. In general, when the circuit has a common fault or abnormality, along with the current increase, it is likely to destroy various types of circuits in the circuit. Machinery and equipment are also likely to damage the circuit and even cause a terrifying fire accident. If a fuse is installed, the situation will be completely different. When the current is too large, the fuse will cut off the current to maintain the reliable operation of the circuit.
Therefore, fuses are equivalent to commercial insurance to ensure circuit safety, and its significance is obvious, so what are the selection criteria for fuses?
1
According to different application scenario design and technical parameters to clarify.
When the protection objects of fuses are different, the selection of fuse types is also different. For example, for the maintenance of small-volume lighting fixtures or motors with small output power, RC1A series plug-in fuses should be selected. Due to the small melting index of the melt, it is beneficial to the overcurrent protection of the circuit. Conversely, for the maintenance of large-space circuits or high-power electrical appliances, other overcurrent protection devices should be installed basically where the fuse is installed.
If you encounter a circuit or combustible gas with a relatively large estimated short-circuit fault current, you can consider choosing the RL series product screw disconnect switch or the RT series product high disconnect switch, otherwise you can choose the RM10 series product disconnect switch.
2
Should be consistent with the load characteristics of the target being maintained.
Most electrical equipment has a certain load capacity. Under certain circumstances, it is OK to overrun in the short term. For example, when high-power appliances such as central air conditioners operate, the current will double. The fuse should incorporate this feature, otherwise it is very easy to fuse and it is also a very cumbersome thing.
3
Cross-level fusing should be avoided.
There should be good harmony among the various fuses. Generally speaking, the rated current of the upper-level fuse is about 2-3 times the rated current of the next-level fuse. When a problem occurs, the next fuse should be the first to fuse. Meanwhile, fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse fuse
4
Attention should be paid to the hazard of motor starting current.
Fully considering the hazards of the motor starting current, the fuse is generally only used as the overcurrent protection of the motor, and the thermal relay should be used for overvoltage protection.
5
Properly pair maximum power and melt rated current.
The maximum power cannot be lower than the rated current of the melt, and the rated breaking capacity should exceed the larger short-circuit fault current that will be generated in the circuit.
According to the above content, everyone needs to further master the fuse. The safety mentioned is not a trivial matter. When choosing a fuse, or give full play to the spirit of 120, contact the actual situation, think more and compare more, so as to prevent unnecessary inconvenience.