跌落式 熔断器及负荷跌落式熔断器是户外高压保护电器。它装置 在配电变压器高压侧或配电线支干线路上，作变压 器和线路的短路，过载保护及分，合负荷电流。跌落式 熔断器由绝缘支架和熔丝管二部分组成，静触头 安装在绝缘支架两端，动触头 安装在熔丝管两端，熔丝管 由内层的消弧管和外层环氧玻璃管组成。拉负荷 跌落式熔断器增加弹性辅助触头及灭弧罩，用以分， 合负荷电流。跌落式 熔断器在正常运行时，熔丝管 借助熔丝张紧后形成闭合位。当系统发生故障时，故障电 流使熔丝迅速熔断， 并形成电弧，消弧管受电弧炽热，分解出大量的气体，使管内形成很高压力，并沿管道形成纵吹，电弧被 迅速拉长而熄灭。熔断丝断后，下部动 触头失去张力而下翻，锁紧机械释放熔断丝，熔断丝跌落，形成明显的开断位置，当需要位负荷时，用绝缘杆开动触头，此时主动，静助触头仍然接触，继续用 绝缘杆拉动触头, 辅助触头也分离，在辅助 触头之间产生电弧，电弧在 灭弧罩狭缝中被拉长，同时灭弧罩产生气体，在电流过领时，将电流熄灭。
Drop-out fuse cutout and load switching fuse cutout are outdoor high voltage protective device. To be connected with incoming feeder of distribution, transformer or distribution lines. It mainly protect transformer or lines from short circuit and overload and ON/OFF loading current. Dropout fuse cutout is composed of insulator supports and fuse tube. Static contacts is fixed on two sides of insulator support, moving contacts is installed on tow ends of fuse tube. Fuse tube is composed of inside arc extinguishing tube. Outlineer phenolic compound paper tube or epoxy glass tube. Load switching fuse cutout provides enforced elastic auxiliary contacts and arc shield for switching on-off loading current. At normally working condition, fuse link tightened the fuse tube is fixed to form up of close position. In case system occur fault, fault current will let the fuse melt immediately and electric arc will be brought, which let arc extinguishing tube being heated and resolved a lot of gas. This will produce high pressure in the tub, and blow along with the tube, and then the arc will be extended and extinguished. After fuse link melt, moving contacts has no tightened strength, locking device release the fuse, fuse tube drop out, cutout now is in open position. When it needs to switch off during cutout loading, use the insulating operating ball pull the moving contact, now main contact and auxiliary static contacts is still in contacting. Whiling pulling, the auxiliary contacts is separated, and then electric arc occurred between auxiliary contacts, arc is extended in the arc shield, at the same time the arc shield explode gas, when the current overload, let it extinguished.