Drop-out fuse cutout and load switching fuse cutout are of outdoor used high voltage protective device, Tobe connecte with incomin-g feeder of distribution transformer or distribution lines, it mainly protect transformeror lines from short circuit andoverload, and on/off loading, current, Drop-out fuse cutout is composed of insulat insulator supports and fuse tube, static contacts is fixed on two sides of insulator support and moving contact is installed on two ends of fuse tube, Fuse tube is composed of inside arcexting tube. Outer phenolic compound paper tube or epoxy glasstube, Load switching fuse cutout provides enfored elastic auxiliry contacts and arc-extinguishing exclosure for switching on-off loading current.
At normally working via fuselink tightened the fuse tube is fixfed to form up of close position, In case system occure faults, fault current result in fuse melt immediately and take piece electric are, which let arc-extinguishing tube being heated and fexplode a lotofgas, Th-os will produce high pressure and below of the are along with tube, After fuselink melt moving contact has no tightened strength again, mecganismis locked and fuse tube drop out, Cutoutnow is in open position, When itneeds toswitch off during cutout loading, operat-or shall via insulating operating bar pull the moving contact, atits beginning main contact and auxiliary static contactis contactedst-ill, Whiling pulling the auxiliary contact is separated between auxiliary contacts there occur electric arc and the arc will be lengthene-d in arc-extinguishing enclosure gap and meanwhile arc-exting explode gas to blow off the arc during current passing zero