Forklift Fuse - A fuse comprises either a wire fuse element or a metal strip in a small cross-section that are connected to circuit conductors. These units are usually mounted between two electrical terminals and usually the fuse is cased within a non-combustible and non-conducting housing. The fuse is arranged in series capable of carrying all the current passing all through the protected circuit. The resistance of the element produces heat because of the current flow. The size and the construction of the element is empirically determined to make sure that the heat produced for a normal current does not cause the element to reach a high temperature. In instances where too high of a current flows, the element either melts directly or it rises to a higher temperature and melts a soldered joint within the fuse which opens the circuit.
Whenever the metal conductor parts, an electric arc is formed between un-melted ends of the fuse. The arc starts to grow until the required voltage to be able to sustain the arc is in fact greater compared to the circuits available voltage. This is what causes the current flow to become terminated. When it comes to alternating current circuits, the current naturally reverses direction on every cycle. This process significantly improves the fuse interruption speed. Where current-limiting fuses are concerned, the voltage needed in order to sustain the arc builds up fast enough to really stop the fault current before the first peak of the AC waveform. This particular effect tremendously limits damage to downstream protected devices.
Generally, the fuse element is made up of aluminum, zinc, copper, alloys or silver that would provide stable and predictable characteristics. Ideally, the fuse will carry its rated current indefinitely and melt rapidly on a small excess. It is important that the element should not become damaged by minor harmless surges of current, and should not oxidize or change its behavior after potentially years of service.
So as to increase heating effect, the fuse elements can be shaped. In big fuses, currents could be separated between multiple metal strips. A dual-element fuse may included a metal strip which melts immediately on a short circuit. This particular type of fuse could also contain a low-melting solder joint that responds to long-term overload of low values as opposed to a short circuit. Fuse elements may be supported by steel or nichrome wires. This would make certain that no strain is placed on the element but a spring may be integrated in order to increase the speed of parting the element fragments.
It is common for the fuse element to be surrounded by materials that are meant to speed the quenching of the arc. Silica sand, air and non-conducting liquids are some examples.
Click to Download the pdf