What is Fuse : Different Types and Its Applications

In the former days of telegraphy, the scientist who became more popular because of his efforts is the French person “Breguet”. He was the person who suggested the utilization of reduced part of conductors to guard telegraph stations against the hits of lighting with liquefying, the slighter wires would guard equipment along with wiring in the building. In the year 1864, lighting installations and telegraph cables can be protected by employing a variety of foil fusible essentials and wires. At the end, Thomas Alva Edison earned rights for a fuse which is an element of his electric distribution system in the year 1890. And now, this article discusses fuse, types of fuses, and its applications in various fields.

What is Fuse?

In the field of electronics or electrical, a fuse is considered as the most crucial device which is employed in various electrical circuits that give protection from the overcurrent conditions. The device is included with a metal strip where it gets dissolved when there is a flow of an extended range of current values. Because of the metal dissolving, the circuit becomes an open circuit and disconnects the flow of power supply through the device.

It is also termed as an automatic disconnection of supply that is frequently shortened to ADS.  This is the cheaply available device that is implemented for protecting the electrical circuits in the conditions of either circuit short or high range of current magnitudes.

Why Do We Require Fuse?

These are used to prevent the home appliances from the high current or overload damage. If we use a fuse in the homes, the electrical faults cannot happen in the wiring and it doesn’t damage the appliances from the fire of wire burning. When the fuse gets break or damage, then an abrupt sparkle happens which may direct damage your home appliances. That is the major reason we require different types of fuses to guard our home-appliances against damage. There are many types of fuses used for circuit protection.

Fuses are generally rated in Amperes. Even though their functionality is based on the self-production of the heat in the scenarios of additional current through their own developed electrical resistance. This can be generally achieved by making the fuse wire length to be as short as possible. As the wire length is not dependent on current rating values, the minimal length of wire imposes the minimal value of resistance.

Characteristics of Fuses

There are few characteristics for the fuses in the electric domain and those are explained as below:

• Current rating value – The frequent conduction of the maximum amount of current which holds the device without making it as molten is termed as current rating value. The measurement value is in amperes and has thermal characteristics.
• Voltage rating value – Here, voltage is in series connection with the fuse which does not augment the voltage rating value.
• Temperature – Here, the functional temperature of the fuse is more so that the current rating drops down. This makes the fuse to get molted.
• Voltage drop – When there is additional current flow through the device, the fuse gets molted and makes it as an open circuit. As because of this, there will be a change in resistance and the voltage drop becomes minimal.

Working Principle of Fuse

The working principle of the fuse is “heating consequence of the current”. It is fabricated with a lean strip or thread of metallic wire. The connection of the Fuse in an electrical circuit is always in series. When there is the production of a high level of current electrical circuits, the fuse gets soften and it makes the circuit be in an open condition. The extreme flow of current may direct to the collapse of the wire and prevents the supply.

The working scenario of this device is mainly dependent on the heating condition of the current. In the general functioning of the current, there will be a normal flow of the current through the fuse. Because of the current flow, heat will be developed in the fuse element and the generated heat will be dissipated into the atmosphere. Due to this, the temperature level of the heat is maintained less than the melting point values.

Whereas in the fault conditions, there will be a flow of short-circuited current through the device. The magnitude of this current value is more when compared with that of normal current magnitude levels. This causes the development of a high range of temperature in the fuse. So, the device starts to melts and breaks down. In this case, the fuse stands as a protective element from overload or short circuit.

As the fuse element is constructed of a highly chosen metal conductor, it holds the fuse. So, the essential operation of this device is to permit only limited current values through the device. If not, it breaks the electric circuit and has overvoltage suppression ability. The basic construction of the fuse is shown as follows:

A fuse in the electric circuit can be changed by placing a new fuse which has similar power rating levels. It can be designed with elements like Cu (copper), Zn (zinc), Al (aluminum), and Ag (silver). They also perform like a circuit breaker for breaking the circuit while the abrupt fault happens in the circuit. This works like a safety measure or protector for humans from risks. Like this, the fuse works.

Fuse rating = (power (watts)/voltage (volts)) x 1.25

The selection of a fuse can be done by calculating the fuse rating by using the above formula.

• Choose the fuse.
• Write down the voltage (volts) and power (watts) of the appliance.
• Calculate the fuse rating.

After the result, use the maximum fuse rating. For instance, if the calculated fuse rating is the maximum fuse rating. It means that when the calculated fuse rating is 7.689 amps, then a fuse with 8 amps has to be fitted in the electrical circuit.

Different Types of Fuses

Fuses are essentially classified into several types which are based on the application namely AC type fuse and DC type fuse. And again these are further classified into various kinds based on the voltage levels. The following diagram clearly depicts the electrical fuse types chart depending on the AC fuse and DC fuse.

DC fuses are available superior in size, and they have a constant value over ‘0’ volts, and because of this, it is somewhat complicated to remove and deactivate the circuit. Also, there may be the chance of developing an electric are in between the molten wires. To get rid of this, few electrodes are positioned at more distances and due to this, DC fuses appear is huge size, and construction of this becomes complicated. A basic DC fuse is shown as:

AC Types of Fuses

The AC fuse is slighter in size when compared with DC fuses and they have an oscillation of nearly 50 to 60 times in each and every sec from least to highest. As a result, there is no chance of an electric arc generation between the molten wires. For this reason, they can be crammed in small sizes. Further, AC fuses are classified into two parts namely HV fuses and LV fuses. Here LV& HV indicates the low voltage and high voltage.

LV Fuses

The low voltage fuses are divided into five types and those are of the rewirable, cartridge, drop out, striker, and switch fuses.

Rewirable Types of Fuses

Rewirable fuses come under the classification of LV fuses, and those are almost used in small applications such as wiring in the house, small-scale industries, and other tiny current applications. These types of fuses include two essential parts where those are a fuse base, which has two terminals like in and out. In general, this element is fabricated with Porcelain. Another part of this fuse is a fuse carrier, which grips the fuse element.

This element is fabricated with aluminum, tinned copper, and lead. The main advantage of a fuse carrier is that we can simply plug and remove from the base of the fuse without the risk of shock. As the fuse is damaged due to heavy current, then we can simply eliminate the Fuse Carrier as well as put back the fuse wire.

Cartridge Types of Fuses

The cartridge type of fuses has entirely closed containers and metal contact as well. The applications of this fuse mainly include low voltage (LV), high voltage (HV), and small fuses. Again, these types of fuses are classified into two types, they are D-type and Link-type fuses.

• D-type Cartridge Fuse

This type of fuse is composed of the cartridge, base of the fuse, adapter ring, and cap. The base of the fuse consists of a fuse cap, which is packed with the fuse ingredient by cartridge using an adapter ring.

It is composed of the cartridge, fuse base, cap & adapter ring. The fuse base has the fuse cap, which is fitted with the fuse element with a cartridge through the adapter ring. The connection of the circuit is finished when the tilt of the cartridge builds contact through the conductor.

• Link Type Fuse

The link type fuse is also known as high rupturing capacity (HRC) or BS type fuse. In this sort of fuse, the current flow with the fuse element is specified under standard conditions.

In this BS type fuse, the flow of current by fuse element is given under normal condition. The arc which is generated by the fuse blown is controlled is fabricated with porcelain, ceramic, and silver. The container of the fuse element is packed with silica sand. This type of fuse is again categorized into two parts includes a blade type and bolted type.

• Blade and Bolted Types of Fuses

The knife type fuse or plug-in type of fuses is designed with plastic. This type of fuse can be simply changeable in the electric circuit exclusive of any load.

In bolted type fuse, plates of this fuse are conducting are set to the base of the fuse.

Striker Types of Fuses

The striker type of fuse is employed for tripping and closing the electrical circuit. These fuses are having plenty of force as well as displacement.

Switch Type Fuse

Basically, the switch type fuse is enclosed with a metal switch and also a fuse. These fuses are mainly used in low and intermediate voltage levels.

Dropout Types of Fuses

In this fuse type, fuse melting creates the element to drop down below gravity regarding to its minimal assistance. These kinds of fuses are employed for safeguarding external transformers.

These are the main types of LV Fuses.

HV (High Voltage) Types of Fuses

Generally, HV fuses are used to protect the transformers like instrument transformers, small power transformer and also used in power systems. These fuses are normally charged for voltages over 1500V to 138000V.

The fused part in HV fuses is fabricated with either copper, silver or in some cases Tin is used, in order to offer consistent and steady performance. These fuses are classified into three types which include the following.

Cartridge Type HRC Fuse

The fuse component of the HRC is cut in the helix form which evades the effect of the corona at the upper voltages. It includes two fused elements namely low resistance and high resistance, and that are located parallel by each other. The low-resistance wires take the usual current which is blown-out as well as decreases the short-circuit current throughout the fault state.

Liquid Type HRC Fuse

This type of fuse is packed with carbon tetrachloride also preserved at both the tops of the caps. Once the error occurs when the flowing current surpasses away from the allowable limit, and the element of the fuse is blown-out. The fluid of the fuse performs as an arc extinguishing standard for the HRC fuse types. They may be used to protect the transformer as well as the support protection to the breaker circuit.

Expulsion HV Types of Fuses

These types of fuses are extensively used to protect the feeders as well as transformer due to they’re low-priced. It is designed for 11kV; also their cracking capability is up to 250 MVA. This type of fuse includes an unfilled open-finished cylinder designed with synthetic resin-bonded paper.

The elements of the fuse are positioned in the cylinder, and the tops of the tubes are linked to appropriate equipment at every finish. The arc generating is blown off in the inside covering of the cylinder, and the gases thus shaped destroys the arc.

Based on the specifications, requirements, and applications, there exist multiple types of fuses. People can find multiple types of fuses in the electrical engineering domain, types of fuses used for circuit protection, types of fuses in power system, types of mv fuses, am type fuse, ferrule type cartridge fuse, mcb fuse types, gg type fuse, box type fuse, and many other kinds.

The other crucial type of fuse that is most in implementation is the glass fuse. Glass fuses have the benefit of the fuse component visible which is so easy to detect whether it is working or not. Also, these glass fuses have a minimal braking ability that normally limits the usage of applications to 15 amps. few of the different types of glass fuses are:

• AGC series having 3 inches sized glass body
• AGU series having 5 inches sized glass body
• AGW series having 7 inches sized glass body
• AGX series having 3 inches sized glass body
• SFE type of glass fuse

What Types of Fuses are Used for Motor Protection?

Mostly, time delay types of fuses are implemented in the applications of motor branch systems. This kind of fuse can be easily sized as that of the motor entire load current so that it prevents circuit conditions and short-circuiting for the electrical network.

Advantages and Disadvantages of Electric Fuse

Few of the advantages and disadvantages of electric fuse are mentioned as follows:

Advantages

The advantages of electric fuse are

• It is non-expensive and it does not any kind of additional care and maintenance
• The devices are completely automotive fuses and need minimal time when compared to that of circuit breakers
• As fuses are available in less size, they induce current restricting impact in abnormal conditions
• The features of reversible time-current permit the device to be employed for overload safeguarding

Disadvantages

The disadvantages of electric fuse are:

• It requires some time at the time of fuse replacement
• The time-current feature will not be every time-synchronized with that of the safeguarding element

Applications of Different Types of Fuses

The different types of fuses and their uses have discussed are essential components in all the electrical circuits. Some of the main applications of fuses in the Electrical and Electronics field include the following.

• Power Transformers
• Electrical Appliances, like ACs (Air Conditioners), TV, Washing Machines, Music Systems, and
• many more.
• Electrical Cabling in Home
• Mobile Phones
• Motor starters
• Laptops
• Power Chargers
• Cameras, Scanners, Printers, and Photocopiers
• Automobiles, electronic devices and Gaming’s

From the above information, finally, we can conclude that fuse and their types explained. The main function of the fuse is to protect the electrical circuits from the overflow of current. In a real-time situation, the flow of current during the wires may not be consistent all the time. In those situations, the device may get damaged from overheat. While the equipment has highly developed with the handling of a circuit breaker, these types of fuses are still employed in various places like fundamental electrical components. Here is a question for you, what are called semiconductor fuses?

Photo Credits : CircuitDigest