Look at the fuse fusing condition and analyze the

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Look at the fuse fusing condition and analyze the cause of the fault

Abstract: in many electrical equipment, fuses are inseparable. This paper analyzes the cause of the fault from the fuse fusing condition of the commonly used hK2 series knife switches

key words: fuse fusing condition fault Untitled Document in many electrical equipment, fuse is indispensable. This paper analyzes the cause of the fault from the fixture on the commonly used hK2 series knife switch fuse condition experimental machine. (1) The fuse is broken in the middle: the screw of the knife switch presses the fuse tightly, and its fusing point is in the middle of the fuse length. If the fusing point is very small, it can be judged that the load is overloaded and fused, or the connected fuse is too small. Because the fuse generates heat when passing a large current, with the increase of time, heat ① in the process of adjusting the speed range, 1 must cut off the power supply. The more the power is accumulated, the higher the temperature is. When the melting point of the fuse is reached, it will fuse in the middle, which is a normal protective fuse. (2) There is no need to wait for the concrete solidification wire head to break: the screw pressing the two ends of the fuse is broken near the screw, which is the screw of the knife switch fuse is not tightened, it is loose and oxidized for a long time, the contact resistance increases, heat is generated, and a vicious cycle makes the fuse fuse fuse fuse near the screws at both ends. (3) The middle of the fuse is seriously burnt out: during the switching of the three-phase knife switch, one fuse is seriously blown, which is generally a single-phase grounding fault, and the three fuses are seriously blown at the same time, which is a serious overload. All fuses are melted, and the arc chamber of the knife switch is blackened, indicating that the overload current is very large. The reason must be found out before replacing the fuse for trial closing. (4) The knife switch is severely burned: after the failure occurs, all the fuses are vaporized. In serious cases, the porcelain chassis of the knife switch is burned to pieces, and burned from white to red. The failure is accompanied by an explosion. This situation is serious. The reason is serious overload or short circuit, and the instantaneous overload current in the fuse is much larger than the normal working current. At the moment when several fuses fuse at the same time, the generated arc is large and isolated without a gate cover. The arcs are connected together, resulting in serious short-circuit current. In order to prevent the occurrence of the above faults, the following measures should be taken: ① analyze the circuit completely, select the appropriate fuse according to the load, and do not use too large fuse to limit the fusing current. ② When pressing the fuse on the knife switch, the complex part in the middle of the fuse should be recessed to the middle and lower part of the arc chute of the porcelain chassis. At this time, the fire arc generated is not easy to fly out and cause harm. ③ Be sure to cover the brake cover, so that the live part will not be exposed, which can reduce unsafe factors. ④ Keep the knife switch clean and free of dust to avoid the reduction of insulation and contributing to the occurrence of fire arc short circuit

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