Fuse links are automatic, selectively acting medium voltage switching devices which will protect your transformers, cables, condensors and installations safely from the thermal and dynamic effects of short circuits within the voltage range of 3-36 kV. High breaking capacity fuses are used for the short circuit protection of m.v. installations. When they are placed in front of transformers, capacitors, motors, cable outlets or voltage transformers, they protect against the heat or other bad effects of short circuit by quick circuit breaking capabilities.
Fuses are the most effective and economic way of protection against short circuits. Fuses are not suitable devices for protection against overload. They work safely only over the Imin value. Namely it does not operate safely within the range of In (rated current value) and Imin value, and in some cases the fuses may be damaged. Depending on the quality of the current line used and the construction of the fuse, Imin is around 3 In or more. Naturally the expansion of the safe operating area for a fuse is a great advantage. For this reason Imin should be as small as possible. For ourfuses Imin is around 4 In. This result is due to the construction and the quality of the material.If loading between In rated current and Imin is a must and cannot be prevented, then it is recommended to use load break switches with thermal protective fuses. In that case, before the extreme heat produced in the fuse reaches the tolerance level of the electro porcelain tube of the fuse, the thermic system works to loosen the striker pin which in turn switches off the loadbreak switch in three phases, thus minimizing the risk area.