Despite the advancement of re-settable circuit protection devices, fuses are here to stay. In some applications, fuses are irreplaceable particularly in high current limiting or fast fault-current interruption applications.
Fuses offer a combination of advantageous features.
- High breaking capacity or high current interrupting rating.
- Complex short-circuit calculations not required.
- Easy and inexpensive system upgrade to suit increased system fault currents.
- High current limiting.
- Fault elimination required before re-energizing circuit.
Fuses cannot be reset, fault need to be fixed before re-energizing the circuit.
No mechanical parts, fuse replacement ensures protection is restored to its original level.
- Cost effective protection.
Compact size offers low cost overcurrent protection at high short-circuit levels.
- No damage for starters and contactors (type 2 protection - IEC 60947-4-1).
Current limiting characteristics, suitable for type 2 protection in motor circuits.
- Safe, silent operation.
No emission of gas, flames, arcs or other materials when clearing the highest levels of
- Easy coordination.
Standardized fuse characteristics and a high degree of current limitation ensure effective
- Standardized performance
Standard fuse-links design and manufactur ensure availability of replacements.
- Improved power quality.
Fast fault current interruption minimize dips or sags in system voltage.
Fuses cannot be modified or adjusted thus preserving their level of performance and avoiding malfunction.
- No maintenance.
Fuses require no maintenance, adjustments or recalibrations.
|gM||Motor circuit protection|
|aM||Short-circuit protection of motor circuits|
|gN||North American general purpose for conductor protection|
|gD||North American general purpose time-delay|
|gR, gS||Semiconductor and conductor protection|
|gU||General purpose for conductor protection|
|gL, gF, gI, gII||Former types of fuses for general purpose (replaced by gG type)|
Source: IEC 60269-5
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