What Are HRC Fuses?

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High Rupturing Capacity (HRC) Fuses come in various sizes, shapes, and electrical requirements. However, all HRC fuse types are intended to safeguard circuits in particular applications. An HRC fuse’s ability to safely stop an overcurrent in an electrical circuit—which may be significantly higher than the circuit’s normal operating current—is its primary distinguishing characteristic. Instead of the internal fuse element, which controls the fuse’s opening speed and normal current handling capacity, an HRC fuse’s ability to safely stop a high over-current is primarily a result of the materials and construction of the fuse. 

Principle of Operation of HRC Fuses

Under normal circumstances, the fuse’s current flow does not supply enough energy to soften the element. However, before the fault current reaches its peak, the fuse element melts if a large current flows through it.

The element of the fuse won’t blow off when the fuse is overloaded, but if the condition persists for a long time, a substance like eutectic will dissolve the element and cause it to break. The thin parts of the fuse element with less area will dissolve quickly and smash before the eutectic material when the fuse is in short circuit condition.

HRC Fuses Types

These fuses come in three different types, which are as follows:

NH Fuse

This fuse provides short-circuit and overload protection for low and medium voltage. These fuses protect devices susceptible to overload and short circuits, such as motor starters. These fuses are offered in a solid dimension and a lighter weight.

The Din Type Fuse

These are available in a wide range of rated currents and are used in various fields for various reasons, including their ability to operate at multiple temperatures. These serve to protect the transformer and are accessible at different voltage levels. In addition, this has a remarkable cleaning capacity that works perfectly with the short-circuit act. These are employed in transformers, gas-insulated switchgear, feeder sectionalizing, and air and mining.

Blade-Type Fuse

Other names for this kind of fuse include plug-I and spade. These come with a plastic body and two metal caps that fit inside the socket. These are employed in automobiles to protect against short circuits and wiring and backup protection in motors. In addition, these come in lighter-weight options and have a smaller cutoff current.

Applications of HRC Fuses

These fuses can be used for the following things.

  • In HV switchgear, HRC fuses are used to guard against short circuits.
  • It is used as a backup safety measure. 
  • It safeguards electrical equipment such as motors, transformers, cars, etc.
  • These fuses are used in the motor stators.

Benefits of an HRC Fuses with Tripping Device 

  • When a three-phase system experiences a single-phase fault, the plunger trips the circuit breaker, opening all three phases and stopping the single-phase supply.
  • Circuit breakers must consider the effects of a short circuit to use a less expensive circuit breaker.
  • Small currents can be handled by the fuse-tripped breaker, negating the need to replace the fuse (except for high current).

Conclusion

The main focus of this article has been an overview of the HRC fuse. Based on the information presented above, the material, dimensions, length, diameter, shape, and size of a fuse wire are the main determinants of its capacity to carry current.

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