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Friday, 6 March 2020

Types of Fuses and Classification



  • In Electrical or Electronic Engineering the fuse is used for safety of the devices. The fuse is usually an electronic device, which is used to protect circuit from over current, overload and make sure the protection of the circuit.
  • Is composed of an alloy which has a low melting point. The strip of this fuse is placed in series with circuit.
  • The fuse is mainly classified into two types. And depending on the input supply voltage they are classified in AC fuses and DC fuses. AC and DC fuses are again classified are following. 
Classification of Fuse
Classification of Fuse


AC Fuses

  • In AC system, there is easy to extinguish the arc produced due to the over current because in AC system the voltage is with 50 to 60 Hz frequency and it changes its amplitude from 0 to 60 in one second. 
  • Because of this AC fuses are little small than DC fuses. AC fuses are again classified in Other types.


DC Fuses

  • In DC system, because of over heating when the metallic wire melts and arc produces and it is very difficult to extinguish this arc due to the DC constant value.
  • In order to minimize the fuse arcing the DC fuses are bigger than the AC fuses.  


Rewirable Fuse


Rewirable Fuse

Rewirable Fuse

  • This kind of fuse is most commonly used in the case of domestic wiring and small scale usage. Another name of this type of fuses is kit-kat type fuse. 
  • The main composition is of a porcelain base which holds the wires. The fuse element is located inside a carrier that is also made out of porcelain. It is possible to remove the fuse carrier without any risk of electric shock. 
  • The main advantage of this type of fuse is that it is easy to install and also replace without risking any electrical injury. 

Cartridge Fuse


Cartridge Fuse
Cartridge Fuse
   
  • Cartridge fuses to protect many of the electrical appliances such as motors air-conditions, Pumps, Refrigerators, etc. It was developed to overcome the disadvantages of the former. 
  • The fuse wire is enclosed in a glass tube, with two metal caps at both ends. So the fuse element does not deteriorate. Replacement is expensive. This fuses are available 600A and 600 V AC and has used for Industries, Commercial Area.
  • This fuses are of two types 
                                         1.D- type cartridge fuse and 
                                         2. Link type cartridge fuse


1. D- Type cartridge Fuse
  • This can not be interchanged and comes with the fuse base and cap, adapter ring, and the cartridge. The main feature of this fuse is its reliability. 
2. Link type cartridge fuse or HRC High Rupturing Capacity Fuse


HRC Fuse
HRC Fuse


  • The link type cartridge fuse is also called the HRC fuse means High Rupturing Capacity fuse. The fuse wire or element can carry short circuit heavy current for a known time period. 
  • During this time if the fault is removed, then it does not blown off otherwise it blow off and melt. The enclosure of fuse is either of glass or some other chemical compound. 
  • The Operation of HRC fuse is that when the over rated current flow through the fuse element of HRC fuse the element is melted and vaporized. 
  • The filling powder is of such a quantity that the chemical reaction between the silver vapor and filling powder forms a high resistance substance which very much helps in quenching the arc.

High Voltage Fuse
  • All fuses used in power system from 1.5kV up to 138 kV are categorized as high voltage fuse. High voltage fuse are classified to protect instrument transformer used for electricity material, or for small power transformer where the expense of a circuit breaker is not warranted. 
  • When the fuse blow, heat from the arc causes the boric acid to evolve large volume of gases. The associated high pressure and cooling gases rapidly quench the arc. High voltage fuses rated for more than 1500V and up to 13kV.

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