How Does A Drop-out Fuse Cut Off The Current?

drop out fuse cut out operates under normal conditions with its internal fuse in a conductive state. When an abnormal fault current occurs in the system, the fuse melts rapidly, triggering an electric arc. Simultaneously, the filling material inside the fuse tube is heated by the arc, generating a large amount of gas. The gas pressure pushes the fuse tube down the guide rail, causing the moving and stationary contacts to disengage. After the fuse melts, the contacts lose their tension, and the fuse tube falls to a clearly open position under its own weight and the push of the spring, resulting in circuit interruption. At the same time, the electric arc is longitudinally blown or stretched, cooled, and extinguished inside the arc extinguishing device (such as an arc-blowing tube or arc-extinguishing hood). Thus, drop out fuse element completes the current interruption.