Drop Out Fuse

Intrioduciton

A Brief Overview

Drop type fuses and pull load drop type 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 wire, and is used as the short circuit and overload protection of the transformer and the line and the division and combination of load current. The drop-out fuse is composed of two parts: an insulating support and a fuse tube. The static contact is installed at both ends of the insulating support, and the moving contact is installed at both ends of the fuse tube. The fuse tube consists of an inner arc absorbing tube and an outer phenolic paper tube or epoxy glass cloth tube. The pull load drop type fuse enhances the elastic auxiliary contact and the arc extinguishing cover, which is used to divide and combine the load current.

In normal operation, the fuse tube forms a closed position after being tensioned with the fuse. When the system fails, the fault current makes the fuse quickly fuse, and the arc arc extinguishing tube is formed by the arc burning, decomposes a large amount of gas, so that the tube forms a high pressure, and the longitudinal blowing along the pipeline, the arc is rapidly stretched and extinguished. After the fuse is blown , the lower moving contact loses tension and turns down, locks the machinery, releases the fuse tube, and the fuse tube falls, forming an obvious breaking position. When it is necessary to pull the load, use the insulation rod to pull the moving contact, at this time the active and static auxiliary contacts are still in contact, continue to use the insulation rod to pull the contact, the auxiliary contact is also separated, and an arc is generated between the auxiliary contacts, the arc is stretched in the mask narrow gap, and the arc extinguish the arc when the current exceeds zero.

Small model and meaning

This product model is prepared according to the provisions of JB/T8321-1996 “AC

High voltage Fuse type preparation Method”, as follows

Small use and implementation standards

This product is used in 10~35kV distribution line branch line and distribution transformer primary side, for overload and short circuit protection, split rated load current.

The product model is prepared according to the provisions of JB/T8321-1996 “AC High Voltage Fuse type preparation method”, and the product parameters are implemented according to the GB15166.3-1994 “AC High voltage fuse injection fuse” standard. For the important parameters and configuration methods not clearly defined in the standard, according to JB/DQ2139-1986 “10~35KV outdoor AC high voltage drop melting.

The requirements of the interim Technical Conditions of the breaker shall be amended and implemented.

Normal service condition

◆ Ambient temperature: not higher than +40℃, not lower than -30℃;

◆ Altitude: no more than 1000m; (More than 1000m can be amended according to GB31.1-1997);

◆ Power frequency: 50±2Hz;

◆ Seismic intensity: 7 degrees and below;

◆ Maximum wind speed: 35m/s.

Drop out fuse