Drop-out fuse cutout and load switching fuse cutout are of outdoor used high voltage protective device. To be connecte with incoming feeder of distribution transformer or distribution lines it mainly protect dansformer or lines from shod circuit and overload. and on/off loading current. Drop. out fuse cutout is composed of insulat lnsulator suppods and fuse tube.static contacts is fixed on two sides of insulator support and moving contact jS installed on two ends of fuse tube. Fuse tube iS composed of inside arc-extinguishing tube, outer phenolic compound paper tube or epox glasstube. Load switching fuse cutout provides enforedelastic auxiliary con.tacts and arcextinguishing exclosure for switching on/off loading current.Al normally working via fuselink tightened lhe fuse tube iS fixed to form up of close position. 1n case system occure faults, fault currenl result in fuse melt immediately and take place electric arc. which let arc. extin.
guishing tube being heated and explode a lot of gas. This will produce high pressure and blow off the arc along with tube. After fuselink melt moving contact has no tightened shrength again, mechanism is loched and fuse tube drop out. Cutout now is in open position. When it needs to switchn off during cutout loadin9, operator shall via insulating operating bar pull the moving contact, at its beginning main contact and auxiliary static contact is contacted still. Whiling pulling the auxiliary contact is sepa-rated between auxiliary contacts there occur electric arc and the arc will be lengthene in arcextinguishing enclosure gap and meanwhile arc-ex-tinguishing explode gas to blow off the arc during current passing zero.