FUSES
A fuse can be used to protect the electrical circuit against the short circuit failure, it has a thin wire in it, which will burn when excessive current flows and the current rating will be marked in the fuse
TYPES OF FUSES
GLASS CARTRIDGE
This is the earliest type of fuse, it is used to protect the electrical system of automobiles at that time its current ratings from 4 to 30 amperes, some types have clear glass body to view fuse wire between metal caps and the metal caps have fuse rating information
CERAMIC
In this type the fuse wire runs in a groove in the ceramic body, between metal end caps and the fuse rating can be identified by the body color
FLAT BLADE
In this type of fuse, it has a color-coded plastic body with enclosed metal blades and the fuse wire is connected between the metal blades
HRC
It has a high capacity for rupturing it is also called as breaking capacity and the arc is extinguished with the help of quartz sand power
It has heat resistant ceramic body bimetallic element is welded to the end of the brass cap and quartz powder is added to the surrounded space of fuse element and the material will absorb the arc energy and extinguishes it
If there is an excessive current flow the elements melts and vaporizes and the vaporized silver fuses with the quartz and it has high resistance
ADVANTAGES OF HRC FUSE
- It acts fast
- Highly reliable
- It is cheaper when compared to other high current interrupting device
- No maintenance is needed
- High breaking capacity
DISADVANTAGES
- Replacement is needed
- Interlocking is not possible
REWIRABLE OR KIT KAT FUSES
It is simple and cheap and it has a current rating up to 200A they are erratic in operation and their performance deteriorates with time
DROP OUT FUSE
The fuse carrier drops out once the fuse operates
WHAT ARE THE CHARACTERISTICS NEEDED FOR THE FUSE MATERIAL
- Low melting point
- Low ohmic losses
- High conductivity is needed
- Lower rate of deterioration
These are the characteristics needed for the fuse material
FUSE SELECTION FLOW CHART
RELATED TERMS WITH FUSES
FUSING FACTOR
It is the ratio of the minimum fusing current to the rated current
FUSING CURRENT
It is the minimum current at which the fuse melts and it is depended on the material characteristics, length, diameter, fuse element, and the type of enclosure used
RATED CURRENT
It is the maximum current that the fuse can carry without melting