By EECTECH | 12 May 2020 | 0 Comments
How to choose a fuse?
Speaking of fuses, I believe that the majority of electrician friends will not feel unfamiliar. As a very common component device, the frequency of use of fuses is very high, but do you really understand the function of fuses? EECTECH will tell you how to choose a fuse.
Introduction:
The fuse is actually connected in series in the circuit. The electrical components that use the thermal fuse principle to ensure the safe operation of the circuit. To be more specific, when the circuit fails or is abnormal, as the current continues to increase, it may cause various The damage caused by the device may also burn the circuit or even cause a terrible fire. If a fuse is installed, the situation will be completely different. When the current is too large, the fuse will fuse its own components to cut off the current and operate safely from the protection circuit.
In this way, the fuse is equivalent to an insurance to ensure the safety of the circuit. Its importance is obvious, so what are the principles for selecting the fuse?
1. Determined according to different usage scenarios and parameters
When the protection object of the fuse is different, the type selection of the fuse is also different. For example, for the protection of the lighting circuit with a small capacity or the small power motor, the RC1A series plug-in fuse should be used, because the melting coefficient of the melt is Small is conducive to the overcurrent protection of the circuit. On the contrary, for the protection of large-capacity circuits or high-power electrical appliances, it is necessary to install other overcurrent protection devices on the basis of installing fuses.
If you encounter a circuit or a flammable gas that is expected to have a large short-circuit current, you can consider choosing RL series spiral fuses or RT series high breaking fuses with high breaking capacity. Otherwise, you can use RM10 series fuses.
2. There should be a good coordination with the overload characteristics of the protected object
Most electrical equipment has a certain overload capacity. Under certain conditions, a small amount of short-term excessive operation is no problem. For example, when a high-power appliance such as an air conditioner starts, the current will double, and the fuse will To adapt to this characteristic, otherwise it is also a very troublesome thing to easily blow.
3. Should prevent overstepping fuse
There should be good coordination between the fuses at all levels. Generally, the rated current of the upper-level melt is about 2 to 3 times greater than the rated current of the lower-level melt. When a fault occurs, the lower-level fuse blows first. At the same time, after the fuse is blown, the upper-level fuse can be automatically restored, otherwise, once the over-step fuse occurs, a small wire short circuit may cause a large-scale power outage.
4. Pay attention to the influence of motor starting current
Considering the influence of the starting current of the motor, the fuse is generally only used as the short-circuit protection of the motor, and the thermal relay should be used for overload protection.
5. The correct matching of the rated power and the rated current of the melt
The rated power should not be less than the rated current of the melt, and the rated breaking capacity should be greater than the large short-circuit current that may occur in the circuit
Through the above content, everyone must have a further understanding of the fuse. The so-called "safety is no small matter". When choosing the fuse, it is still necessary to fight the spirit of 120. Combining with the actual situation, think more and think more Contrast, so as not to cause unnecessary trouble.
The above is that EECTECH brings you the sharing of fuse, I hope to help you.
Leave a Reply
Your email address will not be published.Required fields are marked. *