Interlocking Protection Response Of Fuses

When an unacceptable overload or short-circuit current occurs in a circuit, the lattice structure inside the fuse wire begins to disintegrate, initiating a series of sophisticated physical processes designed to safely disconnect the circuit. The molten material (usually made of metals such as silver or copper) heats up rapidly due to Joule heating, intensifying atomic thermal motion and distorting its ordered lattice arrangement. This micro-change is the starting point for drop out fuse to perform its protection function.

As heat continues to accumulate, the molten material rapidly reaches and exceeds its melting point, undergoing a phase transition from solid to liquid. At designed weak points such as the neck, the molten metal breaks first. In some high-energy faults, the molten material may even be directly heated and vaporized, expanding tens of thousands of times in volume instantaneously. At this point, the air ionized by the metal vapor forms a high-temperature electric arc at the break point, which, if left uncontrolled, will continue to conduct electricity and pose a danger.