3412.0122.22 Circuit Protection

3412.0122.22 Application Field and Working Principle

Fuses are indispensable components of any electrical system, providing fault protection for electrical circuits. They play an extremely important role in protecting circuits and personnel from damage caused by short-circuits,current overloads and electrical fires. 3412.0122.22 Application field and Working Principle are the two main functions of these essential components.

Application Field

The 3412.0122.22 application field covers a wide range of duties. Low voltage (600V AC and below) fuses are generally used for protecting low-voltage systems such as 120/240V single-phase and 3-phase, while medium-voltage fuses are designed to operate reliably in 600V AC to 69KV AC range systems. Generally, fuse current ratings are based on maximum continuous load current, current at fault levels, and overcurrent that the fuse must be capable of safely interrupting.

Fuses are commonly used and applied in the renewable energy sector, such as solarian PV systems, to limit the short circuit and related currents of DC/AC systems. They are also applied in electrical power distribution networks, industrial equipment, automotive equipment, IT and telecommunications equipment, maritime and aerospace applications, and mining installations.

Working Principle

The fundamental characteristics of a fuse are its ability to open the circuit by melting the element when the current passing through the element exceeds a predetermined value. This working principle is based on the Joule-Thompson effect. The heat generated by the element of the fuse enhances its current rating to the point that the fuse element melts. This interrupted the flow of current, resulting in the breaking of the circuit. In order to achieve this purpose, the fuse must be composed of two parts - a fusible element and a fuse link.

The fuse link is mainly composed of a conducting material, such as copper or aluminum, and its purpose is to provide a conductive path for current from the fuse to the external circuit. The fusible element is composed of a metal alloy, commonly made with tin and lead, and it is the part of the fuse which melts and opens the circuit during a fault. As the current passing through the fuse element increased, the temperature of its component increases. When the pre-determined current rating is reached, the alloy element of the fuse melts, thus interrupting the flow of the current.

Fuses provide a valuable safety feature for circuits. They protect the circuit from possible faults and reduce the risk of fire and injury. When choosing a fuse, it is important to consider the application as well as the current that may flow through the fuse before making a selection.