An electric fuse, typically called a fuse, is a device that protects a circuit from any imminent failure such as voltage overload. A fuse is the weakest link of a circuit, and it works on the heating effect of the electric current.
The fuse is connected in series with the circuit, and it allows a limited amount of current in the circuit. When the current exceeds the permitted limit, the material of the fuse heats up and melts, disconnecting the power flow and disrupting the circuit until it is replaced.
Types of Fuses
There are several different types of fuses available on today’s market for a range of uses. Fuses are primarily classified based on current type into AC Fuses and DC Fuses. AC fuses are further classified into high-voltage and low-voltage.
In a DC circuit, the value of the current flowing through the circuit is constant and is always more than 0. With a DC circuit, there is a chance that the wire will still facilitate an electric arc between the two ends, even an excessive current melts the material.
Hence, in comparison to the AC fuses, two electrodes are placed further apart in a DC Fuse. This reduces the likelihood of an electrical arc but adds to the size of the device. DC Fuses are bigger than the AC Fuses.
Contrary to a DC circuit, there is an oscillating current that flows through an AC circuit. This results in a minimum and maximum point in the circuit between which, for a moment, passes through 0. Thus, making it easier to snuff the arc between the electrodes. Naturally, the size of an AC Fuse is smaller.
These types of fuses are typically used in power systems where the voltage reading is between 1500 V and 1, 38,000 V. Silver, copper, or sometimes tin is used in these fuses to ensure stable performance. Expulsion type HV fuses make use of boric acid in the fuse link chamber.
Low-voltage fuses are divided into four different subtypes:
– Rewireable – This type of fuse is generally used in home wirings or smaller circuits. They have a porcelain casing that contains the wires. Once the circuit breaks due to the overload, the fuse can be rewired and put back to maintain the flow of the current.
– Cartridge – The fuse is placed inside a closed container with metal contacts on both ends. There are two types of cartridge fuses, D-type and Link type.
– Dropout – Mainly used for protecting the transformer, this type of fuse drops out of the circuit once it melts due to overload.
– Striker – A device that is normally used for closing tripping circuits.
– Switch – Used in low and medium voltage circuits. These are available as 3-pole or 4-pole units, and the fuse has a rating in the range of 30-800 amps and a 46 kA capacity.
We hope you enjoyed this quick insight into different types of fuses. Fuses play an important role in ensuring the stability and integrity of a circuit, and understanding how each element interacts is essential for safety.