In electric motors and other equipment, fuses are used with the purpose of limiting the current of a circuit, providing the interruption when we have a short circuit or overload. Short circuit is an intentional or accidental connection between two points of a system, electrical equipment or a component. Under these conditions the current assumes a value many times higher than the operating current, thus causing the equipment and part of the plant to undergo excessive thermal or electrodynamic stress.
Its performance is due to the casting of an element by the Joule effect, caused by the elevation of current in a given circuit. The fuse has properties where its melting point is less than the melting point of copper, which is the material most commonly used in general purpose conductors.
They are composed of a conductor of reduced section, mounted on a base of insulating material and when overload occurs the fusible link fuses, ceasing the passage of electric current, avoiding damages to the installation and equipment.
In motor fuses, the rated current is the current value that the fuse must withstand and the breaking current is the maximum value it will break.