Application

The dropout (swing out) fuse is an expulsion type and its main function is to protect Transformers on rural distribution network. It is also particularly useful for inaccessible Sub-stations where indication of fusing is of advantage.

Construction

The Drop out fuse set has single pole construction and shall be suitable for Vertical mounting. Each pole consist of galvanized steel base, insulators of reputed make, copper alloy DO Top & Bottom contacts and fuse carrier’s top & bottom contacts, epoxy extruded fiber fuse carrier. DO fuse bottom contact and rotateable latch is specially designed in such a way that it hangs the fuse carrier on blowing of fuse element. Top and bottom contacts are provided with overtravel limit. Ferrous parts are hot dip galvanized and non-ferrous parts are heavily tinned to withstand weather. Fuse element is of EC grade copper of appropriate size to complete the current path from top post to bottom post.

Features

• Low Contact resistance through the life of switch.

• Sturdy design of current carrying parts.

• Robust design and construction.

• Smooth and trouble free operation.

Operation

On blowing of fuse element, the latch will release from top contact and the fuse carrier hangs down vertically on the bottom contact. This is advantageous for locating the fault as hanging fuse carrier is noticeable from distance and this save times which otherwise would be taken in investigation. Lift out the fuse carrier by means of the insulated operating rod from ground level, first rewire the fuse element at the bottom contact of fiber barrel, pass through the fuse element from fiber barrel, put the latch in on position, tied the fuse element on top contact of fiber barrel tightly and screw the wing nut. Put the barrel in bottom contact of DO unit with the help of insulated operating rod & swing up the carrier and thus remake the circuit.

Installation

It can be mounted vertically on 1 or 2 nos. channels based on two-pole structure. Install three phases of DO Fuse on structure.

TECHNICAL PERTICULARS :

Sr. No.	PART NAME	QTY.
1	SYSTEM VOLTAGE	33 KV
2	RATED VOLTAGE	36 KV
3	RATED CURRENT	200 AMP.
4	IMPULSE WITHSTAND VOLTAGE TO EATH	145 KV
	ACROSS THE TERMINALS	170 KV
5	POWER FREQ. WITH STAND VOLT TO EARTH	70 KV
	ACROSS THE TERMINALS	80 KV
6	WEIGHT OF FUSE SET (APX.)	93 KG.
7	GOVERNING SPECIFICATION	IS 9385/1983