Different Types of Electrical Fuses and Their Applications
An electrical fuse is a device which is used to counter current overload in a circuit by interrupting the current flow and creating an open circuit condition. It essentially acts as a self-sacrificial disruptor to stop the flow of excessive current and the damage it may cause, such as overheating and sparking.
When an electric fuse component intercepts too much heat, it melts, thereby causing an interruption in the smooth flow of current. This preemptively stalls any potential damage to the whole circuit and all the appliances attached to it. To gain further understanding of electric fuses and their various types, we will discuss more about them in further detail below.
How an Electrical Fuse Works
These devices are typically designed for one-time use (except for resettable fuses, which can be used multiple times). To put it simply, once a fuse breaks and shuts a device’s current down, its job is over. Fuses are one of the most cost-effective ways to provide automatic high-voltage current protection against instances of current overload.
However, protection from an overflow of current can be obtained from many other devices, such as switches, relays, and circuit breakers. Additionally, the costs, service requirements, and optimum efficiency ratings of each type of device can vary.
Fuses are used in the utility industry to protect cables, capacitor banks, distribution transformers, and other electrical equipment from the harmful effects of excessive current. They are installed strategically to break the connection before a sudden surge of current can reach the network equipment in high voltage electrical networks.
Different Types of Electrical Fuses
Every type of fuse is designed as a unique remedy to single or multiple instances of extreme electrical events. However, the working principle of all fuses is the same regardless of type: to combine both intercepting and interrupting elements in a single, self-contained device.
Let us now look into some of the most commercially used electrical fuses:
- High Rupture Current (HRC) Fuses: Used in extreme high-fault current overload crises, these fuses are designed with a transparent casing made of magnesium silicate, a.k.a steatite. This casing contains quartz powder or a non-conducting fluid, such as mineral oil, in liquid-filled HRC fuses. They are largely used to act as a defense mechanism for motor circuits which are often prone to short circuits and short-term overloads.
- Semiconductor Fuses: These are used to protect power semiconductors and are rated at 1250, 1000, or 650V AC, but other voltage ratings are available as well. Although their dimensions are shorter than fuse-links used in industrial applications, their square-ceramic-body designs are extremely popular.
- Spark Gap Surge Arresters: A spark gap arrester is made of two electrodes separated by a gap containing air or an inert gas, all enclosed within an insulated chamber. A temporary electrical surge of a considerable magnitude breaks down the air insulation between the electrodes, establishing a quick connection between them. This transient connection is exceptionally conductive, and it shunts the surging electrical energies to the ground.
- Blade Fuses: Largely used in automobiles, blade fuses are also known as plug-in or spade fuses, and they contain two prongs (encased within a plastic body) that can be plugged into sockets. These fuses have been used in the automotive industry since 1981. Today, they are available in three standard sizes: large maxis (APX), mid-sized regular (ATC/ATO), and small minis (ATM). The APS is also a low-profile version of the mini (ATM), using the Amp color-coding system.
- Resettable Fuses: These are made of a particular type of polymer and contain carbon black particles. The fuse has two states: low resistance (wherein the heat generated by the current makes no change to the crystal structure of the polymer) and high resistance (a state reached when heat from an excessive current overflow disrupts the circuit). These find typical application in DC motors, where overloading can damage the sensitive coils of motors.
Applications Of Electrical Fuses
In any circuit/power system, electric fuses resist the flow of current beyond a certain threshold. Based on this working principle, they are suitable for the following broad applications:
- Fuses find use as a protective component in household electronic devices such as air conditioners, refrigerators, television sets, etc.
- They are used in industrial equipment such as transformers, capacitors, and heavy-duty industrial electric motor control systems.
- They are useful in heating and lighting protection systems from extreme thermal overstress.
- In the complex electric circuitry of airplanes, a collection of fuses–a fuse box–is installed between all electrical devices and a power source. These fuses have a pre-defined voltage rating, which signifies the threshold of the maximum voltage that the fuse box can withstand. However, most airplanes use circuit breakers for primary electric devices.
It cannot be emphasized enough that circuit breakers and electric fuses are essential to maintain the safety and efficiency of high voltage circuit systems, such as those used in the aviation industry. However, inferior-quality fuses that compromise the circuit's safety and all connected appliances are not even an option worth considering. This is why only trusted names such as Cogent Sourcing should be relied upon. We at Cogent Sourcing take immense pride in delivering only the best in class, quality-tested circuit-protection solutions in the aerospace sector. Contact us today to avail the best aircraft circuit systems for your procurement needs.
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