drop fuse
Summary Summary
Drop-out fuses and load-drop fuses are outdoor high-voltage protection appliances. It is installed on the high-voltage side of the distribution transformer or the branch line of the distribution line, and is used for short-circuit and overload protection of the transformer and lines, as well as for dividing and combining the load current. The drop-out fuse is composed of an insulating bracket and a fuse tube. The static contacts are installed on the three-blade ends on both sides of the insulating bracket, and the moving contacts are installed on the fuse tube. It is composed of an inner arc-extinguishing tube and an outer epoxy glass tube. The load drop fuse has an elastic auxiliary contact and an arc extinguishing cover, which are used to divide and close the load current.
When a 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 rapidly and form an arc. The arc-extinguishing tube is heated by the arc and decomposes a large amount of gas, causing a high pressure in the tube and a longitudinal blow along the pipe. The arc is quickly stretched and extinguished. After the fuse is blown, the lower movable contact loses tension and turns downward. The pin tightening mechanism releases the fuse tube, and the fuse tube falls, forming an obvious breaking position. When the load needs to be pulled, use the insulating rod to pull the contact. At this time, the active and static auxiliary contacts are still in contact. Continue to use the insulating rod to pull the contact, and the auxiliary contacts are also separated. An arc is generated between the auxiliary contacts. The arc is elongated in the slit of the arc extinguishing cover. At the same time, the arc extinguishing cover generates gas, which extinguishes the arc when the current crosses zero.
