0001.2707.22 Circuit Protection

Fuses are an important type of safety device that prevents electrical circuits from being overloaded. In applications that require protection from overcurrent, fuses are typically used. The fuse essentially \'trips\' or \'opens\' the circuit when the current passing through it exceeds a certain limit. In this article, the application field and working principle of fuses will be discussed.Fuses can be found in a variety of applications. They are commonly used in residential, commercial, automotive and industrial applications. Fuses are used in domestic appliances such as toasters, ovens, microwaves and washing machines; and in electrical equipment such as TV’s, computers and DVD players. In automotive applications, fuses are used to control the current to electrical components such as batteries and alternators. In industrial applications, fuses are used to protect high-powered motors, generators and switchgear.The working principle of a fuse is simple. It is composed of a metal strip (or wire) that has a specified resistance. When the current flowing through the fuse exceeds the specified limit, the fuse \'blows\' or the metal strip melts, interrupting the flow of electricity. This prevents further build-up of current, thus protecting the electrical circuit from overheating and potential damage. Fuses come in a variety of sizes and types, which are dependent on the application they are used in and the amount of protection they require.The selection of a fuse is very important and depends on the required current protection. A fuse which is not of the correct rating or type could result in the fuse \'blowing\' frequently or not tripping when required. Thus it is important to always select the correct fuse for the application in order to ensure optimal protection. The maximum amount of current which a fuse can safely carry is referred to as its rating. This rating is typically a number that represents the maximum amount of amperes that the fuse can safely carry without tripping. Generally, the lower the rating of the fuse, the lower the current which can pass through it before it trips.Fuses also vary in terms of their construction and time-response curves. Common types of fuses include slow-blow, fast-blow, non-rewirable and ceramic. Each of these types have different time-response curves, determined by an appromixation of how long it takes for the current passing through a given fuse to be reduced by a certain percentage. It is important to select the correct type of fuse for the application as different types provide different levels of protection.In summary, fuses are an important type of safety device that protect electrical circuits from overload. They are commonly found in a variety of applications and are available in a variety of ratings and types. The selection of the correct fuse for the application is essential in order to ensure optimal protection.