Types and characteristic of HRC fuse

Types and characteristic of HRC fuse

Fuse is a current interrupting device which used for protection from over current. It is used for short circuit protection in medium voltage (up to 33KV) and low voltage (up to 400V)..  In modern this type fuse (HRC) provides reliable discrimination and accurate characteristics. In some point of view HRC fuse is better than circuit breaker.
Types of HRC fuse

1. Semi- enclosed or rewireble type.

This type of fuse we can see in our houses. The fuse carrier can be pulled out and the blown out fuse element (which wire melts) can be fill-up by a new one and carrier is replaced in the fuse base.

2. Totally enclosed or cartridge type.  

The fuse link element (the wire which melts) is enclosed in a totally enclosed container and is provided with metal contacts on both sides.

This type of fuse also divided in two types
1. D type      2. Bolted type

3. Current limiting fuse link. 

A fuse –link which control current to a considerable lower value than the prospective current.

4. Drop-out fuse.

 In this fuse after the operation of fuse –carrier drop out.  There by providing isolation between the terminals. 

5.. explosion fuse 

6. Striker fuse 

A device which incorporates a fuse and a mechanical device, the operation of fuse release the striker with certain pressure and displacement.

7.Switch fuse  

A mixed unit comprising, switch and fuse .

Characteristic of HRC fuse 

Operation of fuse link. 

Process of arcing and  pre-arcing resulting in blowing of fuse-link.
Cut-of. The melting of fuse-element before the current reaches the required peak. The value of current at which the cut-off occurs is called cut-off value.

Pre-arcing time. 

Time between commencement of the cut-of and the  current loop .

Arcing time 

It is that time when final current become zero. Or it is time between cut-of and final current zero time

Total operating time 

It is Pr-arcing time plus acting time.

Fuse

  Fuse is current interrupting device which opens the circuit ( in which it is inserted) by using  the element when the current in the circuit exceeds  a certain value .
Fuse element. The part of the fuse which is designed to melt when the fuse operates.
Fuse link. The part of the fuse which needs replacement when the fuse blows out.

Application of HRC fuse 

• protection of radial lines
• transformer protection

• It is also used of capacitor protection
• it is also provide Protection of underground distribution system
• It is used in meter board in residential application.

• It is also protected different electrical device as like that.
•  Transformer
• Generator 
• Motor  
• Circuit-breaker 
• Protective rely