Types of fuses: purpose, description, marking

Fuses are used everywhere and everywhere - they are in technology, in a variety of electrical devices, cars, industrial equipment. There are many kinds of these elements. What are they for and what are their features? Let's consider the main types of fuses.

Characteristic

A fuse is a general term that is used fairly steadily in the field of electrical engineering. This part involves protection for wires, equipment and electrical networks. A fuse is a switching product. What is its purpose? The fuse is designed to protect the electrical network from high currents and short circuits. The principle of operation of the part is very simple - in the case of overcurrents, a specially designed element is destroyed. Often this is a fuse-link. So all kinds of glass fuses are arranged.

These inserts are an indispensable element, without which no type of safety elements is possible. Inside it there is also a special arcing device. The inserts in the fuses are made of porcelain or fibrous bodies and fixed in special parts that conduct electric current. Elements designed for small currents may not have a body at all.

Melting

These are the most common types of fuses for use in everyday life. Probably, this is the only element that is easiest to diagnose for health. To do this, you just need to look at the detail on the skylight - it will be seen if the insertion fuse is intact or not. These details are manufactured in a glass case.

Fused tubular ceramic

This element is practically no different from the glass product. The only difference in the material from which the body is made. But in operation these parts are not so comfortable - it will not be possible to diagnose "the light". For testing, you need to use testers or multimeters.

Fusible link LDPE

These types of fuses operate on the basis of the same principle. But here the design is modified in such a way as to see the state of the part. So, if the item is blown, a special flag will appear at the back of the product.

Elements with quartz sand

These fuses are characterized by high arc suppression characteristics. They are produced in two versions: in a casing made of ceramic materials or in glass cases. Often, the product is designed to work with high currents. There are even more advanced models. The device of the fuse provides one more detail, similar in construction to the LDPE. It is necessary that you can find out which of the fuses is blown.

Fast-acting fuses

These products are nothing special from the rest. The only difference is that when a short circuit occurs, the fusible part burns very quickly.

SMD

These products can be found in electronic devices. They are very tiny. The principle of operation and designation of fuses is to protect the equipment from high currents, which they can do very well.

Self-healing

These are quite interesting solutions. A self-healing fuse is a part inside which is a special plastic. While the plastic insert is cold, it can conduct electricity. As soon as the insert is heated to a certain temperature, its conductive properties are lost by increasing the resistance. After cooling, the current can again pass through the product. The plus of these details is that after a burnout there is no need to replace the element. The industry produces these products in various forms. They are suitable for soldering using surface mounted or surface mounted technology. In general, these types of fuses are used in low-power circuits.

Explosive

If all of the above items are known to everyone, then an explosive fuse is a rare group. The process of the part burning out is provided with a rather effective sound. A special explosive device, which is attached to a conductive part, explodes. Special sensors are responsible for this. The latter follow the current in the electrical circuit. These are very accurate fuses, since they are practically independent of the characteristics of the metal on the conductive part. This element depends on the accuracy of the current sensor.

Other types of fuses

For working in high voltage circuits, special autogas, gas products, as well as liquid-type elements are used. There are even shooting fuses. In everyday life they can not be seen - this is a professional powerful equipment.

Marking and symbols

Each manufacturer makes fuses under a certain code or article. The fuse number allows you to find and refine the specifications in the catalogs. Often, these codes can be found on the cases of products. Also, the code can be applied to the metal part. In addition to the codes, the main data can also be indicated on the housing - this is the nominal current in A, the rated voltage in V, which disconnects the characteristics or features of the design. From these data it is possible to determine the purpose of the fuses.

So, the value of the rated current is the maximum permissible value at which the part can function normally for a long time.

Nominal voltages are the maximum permissible voltage at which the part safely breaks the circuit in the event of a short circuit or during an overload in the network.

The breaking capacity is called the maximum currents. With them, the fuse will work, but its casing will not be destroyed.

The characteristic is the time dependence, in which the fuse element is destroyed by the current that flows through the part. Different types of fuses according to the characteristics are grouped according to the application and speed of response. Usually these characteristics indicate the power components. For the designation letters of the Latin alphabet are used. The first is the breaking capacity. So, G is the full range, the part is able to protect the circuit from both overload and short circuit. A - the range is partial, and such types of fuses protect only against short circuits.

The second letter denotes the types of chains:

• G is a chain of general purpose.
• L - protection of cables, as well as distribution systems.
• M - protection of circuits in electric motors.
• Tr is a fuse capable of protecting a transformer network.

Elements with the letter R are used together with power semiconductor equipment. And PV can provide protection of solar batteries.

So, we examined what kinds of fuses there are and what they are labeled.