Hrw 11-12 Drop Fuse

I. Overview

Dropping fuses and pulling load drop fuses are outdoor high voltage protectors. It is installed on the high-voltage side of distribution transformer or the branch line of distribution line. It is used for short-circuit, overload protection and load-sharing current of transformer and line. The drop fuse consists of an insulating bracket and a fuse pipe. The static contacts are installed at both ends of the insulating bracket and the movable contacts are installed at both ends of the fuse pipe. The fuse pipe consists of an arc extinguishing tube in the inner layer and an epoxy glass tube in the outer layer. The pull-load drop fuse adds elastic auxiliary contacts and arc extinguishing cover to divide and close the load current.

When the drop fuse is in normal operation, the fuse pipe is tightened by the fuse to form a closed position. When the system fails, the fault current causes the fuse to fuse rapidly and form an arc. The arc extinguishing tube is heated by the arc and decomposes a large amount of gas, which forms a high pressure in the tube and blows longitudinal along the pipeline. The arc is rapidly elongated and extinguished. After the fuse is fused, the lower part of the movable contact loses tension and turns down. The locking mechanism releases the fuse tube, confusing the falling of the fuse tube and forming an obvious breaking position. When the load needs to be pulled, the contact is pulled by insulating rod. At this time, the active and static contacts are still in contact. The contacts are pulled by insulating rod, and the auxiliary contacts are separated. Arc is generated between the auxiliary contacts. The arc is elongated in the slot of the arc extinguishing hood. At the same time, the arc is extinguished when the current passes zero.

2. Normal operating conditions of fuses

1: ambient temperature: - 40 ~40;

2: Relative humidity: the daily average is not more than 95%, and the monthly average is not more than 90%.

3: Installation location: not more than 1000m above sea level (not more than 3000m at high altitude);

4: Wind speed: no more than 35m/s;

5: Ice thickness: not more than 200 mm;

6: Installation site: There should be no fire, explosion, chemical corrosion and severe vibration.

7: Earthquake intensity: no more than magnitude 8;

8: It is not suitable for places with burning or explosion danger, places with violent vibration or shock, areas with conductivity, chemical gas action, and areas with serious pollution and salt fog.

3. Brief introduction of structure

The fuse is composed of base and arc extinguishing device. The lower end of the arc extinguishing tube is equipped with a spring bracket which can rotate. The fuse is always in a tense state to ensure the self-locking of the arc extinguishing tube at the closing position. In the overload or short circuit between the circuit and transformer, the fuse is fused and the fuse is quickly withdrawn from the arc extinguishing tube. The step-by-step exhaust mode solves the contradiction between breaking the large and small current on the same fuse.

4. Model Description