Drop-out fuses and pull-down fuses are outdoor high-voltage protection appliances. It is installed on the high voltage side of the distribution transformer or on the branch line of the distribution line. It is used as short circuit, overload protection and split and combined load current of the transformer and line. The Drop-out fuse consists of two parts: an insulating bracket and a fuse tube.The static contact is installed at both ends of the insulating bracket, the movable contact is installed at both ends of the fuse tube, and the fuse tube is composed of the arc extinguishing tube of the inner layer and the phenolic paper tube or the epoxy glass tube of the outer Iayer. Control load Drop-out fuse enhanced auxiliary contact and arc extinguishing cover, which is used to split and combined load current.
When the drop out fuse is in normal operation, the fuse tube is tensioned by the fuse to form a closed position.When the system fails, the fault current causes the fuse to melt quickly and form an arc. The arc extinguishing tube is heated by the arc, decomposing a large amount of gas, forming a high pressure inside the tube, forming a longitudinal blow along the pipe, and the arc is rapidly elongated and extinguished.After the fuse being blown, the lower moving contact loses tension and turns down, locking the initial machine, releasing the fuse tube, and the fuse tube falling, forming an obvious breaking position.When the load needs to be pulled, use the insulation rod to pull the movable contact.At this time, the active and static contacts are still in contact, and the active and auxiliary contact is continued by the insulating rod, and an arc is generated between the auxiliary contacts, the arc elongated in the slit of the shield, and the arc extinguishing cover being generated the gas, which extinguishes the arc when the current crosses zero.
Fuse Link …“KB、KU、KS” type
Types and Applications “KB, KU, KS”type belong to”K”and”T”type fuse links. According to I EC-282 standard, there are three types: common type, universal type and threaded type. The fuse 24 is suitable for 11~33kV voltage class drop-out fuse.