Fuses: how they work and where they are used, the advantages and disadvantages of devices

A fuse is a protective element that helps to prevent the development of any accident. There are several options for this device: electromechanical, electronic, self-healing and fusible. The latter are one of the most common options. To understand what fuses are used for, it is necessary to study their properties and features of use.

General characteristics

The fuse is a disposable component that protects the power supply from overload, being the weakest link in the network. Elements of this type are used in almost all power grids.

To understand how a fuse works, its structure and functions should be studied.

This small device consists of a piece of wire that is designed to carry no more than a certain current. If the current increases, then the special fuse link begins to melt or even evaporate. Thus, an open circuit occurs.

Fusible components are a reliable and cheap way to protect your equipment. The design of such a protective element includes a housing - a basic part that provides connection of the fuse to the electrical circuit. It is usually made from special types of ceramics or glass. The base of the fuse is a special fusible link, a conductive element that consists of an alloy of metals such as zinc, copper, lead and iron.

In addition to the fusible section, the body also contains a device for controlling the fusible element, a trigger sensor, a small plate indicating the model and type. Among other things, the housing has the function of an arc extinguishing chamber.

Any safety element has a special markingwhich indicates:

1. Degree or range of protection. For example, a - short circuit protection, g - overload protection.
2. Type and device and main areas of its application. For example, G is a general-purpose device, B is for protecting mining equipment, Tr is for transformers, and so on.

Varieties of devices

Fuses are used successfully as protective equipment in power supply systems. Most often they are used in the houses of the old housing stock, as well as in production.

The main advantage of this device is its low cost and ease of maintenance. There are a lot of classifications and there is no single system.

But still fusible safety elements differ:

1. By type of execution - collapsible and non-collapsible.
2. By filling: filled and unfilled. Quartz sand is most often used for filling, since it extinguishes the arc well.
3. By performance: semiconductor, low voltage, medium or high voltage. Semiconductors or high-speed ones have very fast response times and are therefore very popular. Low voltage models are used to monitor circuits with voltages up to 1 kV. Low voltage types are used to protect transformers, motors and batteries from excessive loads up to 30 kV. As for industrial facilities, they practice the operation of fuses that are designed for high voltage.
4. By sight: fork, cork, knife, quartz, etc. The type of device is mainly determined by the scope of use. For example, forklifts are used in cars, cork - for lighting devices and low-power engines.

Advantages and disadvantages

Fuses, like all devices used in our life, have advantages and disadvantages. The positive characteristics of this small but such an important element include:

1. Simple design that prevents damage to the mechanism.
2. Weak speed of action, therefore, fuse-links are used for selectivity.
3. Preservation of properties after replacing the fuse, while burnt-out contacts of the machine significantly change the protection characteristics.
4. Cutting off the current in only one phase - emergency (if there are 3 phases in the asymmetric circuit). In other phases, power will remain.

As for the disadvantages, then they are also available. For example:

1. One-time use without the possibility of repair.
2. A fuse design that allows unscrupulous craftsmen to make shunting, which increases the likelihood of a wiring fire.
3. Phase imbalance at significant currents.
4. Possibility of illegal installation of a fuse for an increased current value.

Despite all the flaws in these elements, fuses are an indispensable part of many electrical devices. With the right choice, the element will protect the equipment not only from short circuit and damage, but also from fire and fire.