What is the reason why the fuse always burns out?

When the current exceeds the specified value, the melt is blown with the heat generated by itself, and the circuit is disconnected.

Fuse. Working principle: The metal conductor is used as a melt in series in the circuit, and when the overload or short-circuit current passes through the melt, it heats up by itself.

And fuse, thus breaking the circuit of an electrical appliance. The fuse has a simple structure and is easy to use, and is widely used in power systems.

It is used as a protective device in various electrical equipment and household appliances.

The fuse has a resistor, so it consumes a certain amount of energy w = irr, which is basically completely converted into heat energy. When the two ends of the fuse are in poor contact (the contact area is too small or the connection is virtual), the contact resistance will increase greatly, the energy consumed on the resistance will increase faster, and the temperature of the fuse will increase rapidly. The conductive resistance of the metal generally increases with the increase of temperature, which further increases the temperature of the fuse.

When the heat generated by the fuse is balanced with its heat dissipation, the temperature no longer rises. Generally, this temperature does not cause the fuse to blow, so the fuse will operate at this temperature for a long time. In this way, it is easy to burn out the shell and keep the safety inside.

Fuses are usually installed in a circuit fuse, and when the current flowing through the line is too large, the fuse blows. For example, the general circuit current limit of daily household appliances is 5A, when the current accommodated by the fuse is lower than this value, it is easy to be burned short, or the current in the line increases instantaneously when the user uses high-power electrical appliances, the fuse in the fuse will also be blown out, so as to play a role in insurance and avoid burning out the instrument.

The resistance of the fuse is too old, and the heat emitted is too old, which burns out the shell.

Too many electrical appliances are used or the rated current of the energy meter is too small. Or if the quality of the fuse is not good, you can try Wenzhou Enrong. Earnestly look.

Too many electrical appliances are used or the rated current of the energy meter is too small.

There is a problem with the specification, it is big, and you have to check whether there is a problem with the line!

I believe that everyone will encounter a sudden power failure, in fact, this is because of the sudden problem of the circuit, the fuse is one of the reasons, what is the reason for the fuse blowing?

1. Short circuit: There is a short circuit fault on the line side, and the fuse is quickly broken;

2. Overload: The load current exceeds the rated current of the fuse, and the air and land grip fuse is heated and fused for a long time (generally about 1 hour of the rated current).

3. Pulse: When the circuit is started or the power supply is unstable, an instantaneous high current causes the fuse to be disconnected; In addition, if the fuse is not tightened during installation, or the fuse is damaged, the fuse will also be blown off.

4. There is a difference between current short circuit and current overload: current short circuit is a direct connection between the live wire and the neutral wire, without passing through the electrical appliance, and quickly produces an almost unobstructed current loop, and the extra-large current passes through the fuse, and the resistance of the fuse suddenly becomes larger and the heat energy is blown instantly;

Current overload is the total power of the electrical appliances used is too large, that is, the current consumed is too large, when increasing the opening of the electrical appliances, the current through the fuse continues to increase, the resistance of the fuse also gradually increases and the heat energy of the bucket is blown off.

When the current exceeds the specified value, the melt is blown with the heat generated by itself, and the circuit is disconnected by the difference.

The working principle of the fuse generator: an electrical appliance that uses a metal conductor as a melt in series in the circuit, and when the overload or short-circuit current passes through the melt, it is blown because of its own heating, so as to break the circuit. The fuse has a simple structure and is easy to use, and is widely used as a protective device in power systems, various electrical equipment and household appliances.

Summary. Pro-fuse is an electronic component used to protect the circuit, if the current in the circuit exceeds the rated current of the fuse, the fuse will automatically blow off to protect the safety of the circuit. Common causes of fuse blowing include:

1.Circuit load is too high: The fuse has a specific current rating, and if the current in the circuit exceeds the rated current of the fuse, it will cause the fuse to blow.

2.Short circuit: A short-circuit fault in a circuit can cause a sudden increase in current instantaneously, exceeding the rated current of the fuse, resulting in the fuse blowing out.

If the current in the circuit exceeds the rated current of the cracker fuse, the fuse will automatically blow out to protect the safety of the circuit. Common causes of fuse blowing include:1

Circuit load is too high: The fuse has a specific current rating, and if the current in the circuit exceeds the rated current of the fuse, it will cause the fuse to blow. 2.

Short-circuit bend: A short-circuit fault in a circuit causes a sudden increase in current to exceed the rated current of the fuse, resulting in the fuse blowing out.

3.Overload: An overload fault in the circuit will cause the current to exceed the rated current of the fuse for a period of time, and the overload will use the fuse for a long time to heat up, and eventually the fuse will blow out.

4.Fuse aging: Long-term use of the fuse will age, resulting in the reduction of the conductivity of the fuse, and the burning of the rent.

5.Installation error: The installation process of the fuse is also relatively complicated, and if the installation is not in place, poor contact and other problems, it may also lead to the fuse burning.

In general, the reasons for the fuse to burn are different, and it is necessary to pay attention to the relevant factors in the actual use process, so as to avoid or reduce the fuse of the stove god air fuse as much as possible, and improve the safety and reliability of the circuit.

The fuse can always be burned and deformed, which may be the deformation of the shell of the fuse caused by the high temperature, so in order to control and solve this problem, it is necessary to strictly control the temperature and control the temperature, so that the temperature control is within a reasonable range of the silver family, in addition to the possibility of the problem of the fired material.

A fuse is a current protector that melts the melt with the heat generated by itself when the current exceeds the specified value for a period of time, so that the circuit is disconnected. Fuses are widely used in high and low voltage power distribution systems and control systems, as well as electrical equipment, as a protector for short circuit and overcurrent.

Classification of fuses.

Plug-in fuse: It is often used at the end of the line at the voltage level of 380V and below, as a distribution branch line or electrical equipment for short circuit protection.

Spiral fuse: The upper end of the melt is covered with a fuse indicator, once the melt is blown, the indicator will pop out immediately, which can be observed through the glass hole on the porcelain cap, it is often used in the electrical control equipment of machine tools. Spiral fuse.

The breaking current is large, and it can be used for short-circuit protection in circuits with voltage level 500V and below and current level below 200A.

Enclosed fuse: enclosed fuse is divided into two types: packing fuse and non-packing fuse, the packing fuse is generally used square porcelain tube, filled with quartz sand and melt, strong breaking capacity, used in the circuit below the voltage level of 500V and the current level of 1KA below. The fillerless closed fuse loads the melt into a closed cylinder with a slightly smaller breaking capacity, and is used in power grids or power distribution equipment below 500V and below 600A.

Fast fuse: Fast fuse is mainly used for short-circuit protection of semiconductor rectifier components or rectifier devices. The structure of the fast fuse is basically the same as that of the packed closed fuse, but the melt material and shape are different, and it is a V-shaped deep groove variable cross-section melt made of silver sheets.

Self-resetting fuse: Sodium metal is used as the melt, which has high conductivity at room temperature. When a short-circuit fault occurs in the circuit, the short-circuit current generates a high temperature that causes the sodium to vaporize rapidly, and the vapor sodium presents a high-resistance state, thus limiting the short-circuit current.

When the short-circuit current disappears, the temperature drops, and the sodium metal regains its original good conductivity.

The resettable fuse can only limit the short-circuit current, but cannot really break the circuit. The advantage is that the melt does not have to be replaced, and it can be reused.

Hello, the problem of this land belt is caused by a short circuit in the line, internal damage to the electrical appliances and the poor quality of Zheng Xingdu's insurance itself. When the line current is too large or the current borne by the insurance itself is too small, it will lead to frequent fusing of the insurance, in this case, you can first check the quality of the insurance with a shout, or whether the insurance is falsely connected, you can replace the insurance to try it, or not, you need to check the problem caused by the short circuit of the line and the internal damage of the appliance itself. The wiring harness at the firewall location is prone to breakage, so focus on checking this location.