Fuses can be divided into high-voltage fuses and low-voltage fuses according to the voltage used. According to the protection object can be divided into fuses for protecting transformers and general electrical equipment, fuses for protecting voltage transformers, fuses for protecting power capacitors, fuses for protecting semiconductor components, fuses for protecting electric motors, and fuses for protecting household appliances, etc. The structure can be divided into open type, semi-enclosed type, tube type, and spray type fuse.
Open fuse structure is simple, the fuse is completely exposed to the air, supported by the porcelain column, with no support. Suitable for low-voltage outdoor use. Break the current in the atmosphere when the larger sound and light.
A semi-enclosed fuse is mounted on the porcelain frame, inserted into the porcelain box with a metal socket at both ends. Suitable for low-voltage indoor use. When breaking the current, the sound and light generated by the porcelain box are blocked.
Tube fuse body installed in the fuse body. Then inserted in the standoffs or directly connected to the circuit of use. Fuse body is a set of metal caps at both ends or with a contact knife completely sealed insulated tube. This fuse insulating tube is filled with quartz sand, then breaks the current with current limiting effect, can greatly improve the breaking capacity, so also known as high breaking capacity fuse. If the tube is vacuumed, it is called a vacuum fuse. If the tube is filled with SF6 gas, it is called SF6 fuse, the purpose is to improve the interrupting performance. As quartz sand, vacuum, and SF6 gas have good insulating properties, this fuse is not only suitable for low voltage but also for high voltage.
Jet fuse is the melt is installed in the insulating tube made of solid gas-producing material. Solid gas-producing materials can be used to electrician anti-white paper board or plexiglass materials. When the short-circuit current through the melt, the melt then fused to produce an arc, high-temperature arc so that the solid gas-producing materials quickly decompose to produce a large amount of high-pressure gas, which will be ionized gas with an arc at both ends of the tubed spray, emitting a great sound and light, and in the AC current over zero when the arc is extinguished and break the current. An insulated tube is usually mounted on an insulated bracket, forming the fuse as a whole. Sometimes the upper end of the insulating tube is made movable, after breaking the current then disconnected and falls, such as a jet fuse commonly known as a drop fuse. Generally applicable to the voltage higher than 6 kV outdoor occasions.
In addition, the fuse according to the breaking current range can also be divided into general-purpose fuse, backup fuse, and full range fuse. General-purpose fuse breaking current range refers to the range from overload current greater than 1.6 ~ 2 times the rated current, to the maximum breaking current. This fuse is mainly used to protect power transformers and general electrical equipment. Backup fuse interrupting current range refers to the range from overload current greater than 4-7 times the rated current to the maximum interrupting current. This fuse is often used in series with the contactor, as the overload current is less than 4 to 7 times the rated current range, by the contractor to achieve the interrupting protection. Mainly used to protect the motor.
With the needs of industrial development, also manufactured for a variety of different requirements of the special fuse. Such as electronic fuse, thermal fuse, self-repeating fuse, etc.