The abbreviation for HRC Backup is a cartridge fuse with high rupture resistance. It is one of the simplest types of backup used for distribution. HRC Backup consists of a fuse wire that carries short circuit current for a limited time. During the short circuit period, the fuse wire will not melt if the fault is corrected immediately.
If the error occurs persistently, the fuse element will melt and disconnect the circuits from the power supply. The low and unsafe breaking capacity of semi-closed fuses is overcome with HRC fuses. Generally the material used for HRC fuses is glass, but this is not always the case. In addition to glass, HRC fuses are made up of some chemical compounds and depend on a design based on several factors. HRC backup can be divided into three types and they are
- NH fuse,
- DIN fuse and
- Flat contact fuse.
Building an HRC backup
The body of this fuse is made of high heat resistance ceramic with metal caps on both ends welded by bright silver elements and are cylindrical. The security element is usually made of silver and is placed between the fixed elements. The space around the fuse body is filled with quartz sand, gypsum or marble dust.
How HRC backup works
The HRC fuse element will melt and evaporate when the current flowing through the fuse is greater than the rated current. The powder filler material is selected so that its chemical reaction with silver vapor forms a very high strength substance that helps extinguish the arc in the fuse. The high resistance is converted into an insulator like glass beads when the power is turned off. The electrical phenomenon of the HRC fuse includes the rise in temperature and the creation of high internal pressure when the fault current is interrupted.
Types of fuses
NH type fuses
These types of fuses are compact and lightweight. Protect against overloads and short circuits at low and medium voltage. Generally they are used as backup protection for motor starters and other devices to protect against short circuits and overloads.
DIN type fuses
This type of fuse is generally used in air and gas insulated switchgear, mining, transformers and feeder insulation. DIN fuses are used for different purposes depending on their characteristics and temperature conditions. They are available in various voltage ratings to protect transformers without backup protection or secondary fuses. They have exceptional extinguishing capability with low overcurrent and short circuit performance.
Flat contact fuse
It consists of a plastic case and two metal caps installed at the ends of the socket. This type of fuse is used in vehicle wiring to protect against short circuits. It has a low power cut. It is available in various sizes and shapes with different current ratings depending on the application.
Advantages and Disadvantages of HRC Backups
Benefits of HRC Backup
- It separates high and low current supply in case of failure.
- The operating speed is high, without noise and smoke
- Provides reliable discrimination
- No maintenance is required
- Does not deteriorate with age
- Costs are low
Disadvantages of HRC backup
- If the fuse element is blown, replacement will be necessary.
- Affects associated switches when heat is generated by an arc.
Application
- Protects low voltage distribution systems against overload and short circuit.
- It provides backup protection for circuit breakers.
- Protects loop feeds under constant load.
Conclusion
In summary, the HRC (High Burst Capacity) fuse and its various types represent a crucial aspect of electrical safety and protection. These fuses are designed to efficiently interrupt high fault currents, prevent damage to electrical equipment and ensure the safety of people and property. The different types of HRC backups such as: Some types of fuses such as blade fuses, screw fuses and cartridge fuses are suitable for different applications and offer flexibility and adaptability in different electrical systems. Their reliability, high performance and ability to handle high currents make them essential components in modern power distribution networks and industrial environments. Engineers and technicians must carefully select and install the appropriate HRC fuse type to optimize electrical protection and maintain the reliability of electrical installations.
