Current fuse basic knowledge application
The role of the fuse:
1, under normal circumstances, the fuse in the circuit connection circuit role.
2, abnormal (load) cases, fuse as security component in a circuit, by fusing itself safe cut and protection circuit.
Second, the working principle of current fuse fuse:
Fuse when electricity, heat from electricity to melt temperature rise. Normal working current overload current through, or to allow the heat generated by can melt into the surrounding environment, outside shell radiation, heat coming from the way by convection and conduction and heat balance gradually. If the heat generated by the greater than send out quantity of heat, excess heat is gradually accumulated in the melt can be melt temperature rise; When the temperature reaches and exceeds the melting point of the melt, will make can melt melting, fusing and cut off the current, have played an important role in safety protection circuit.
Three, current fuse fuse classification:
1, according to the size of shape can be divided into: phi 2, 3, 4, phi phi phi 5, 6, and others.
2, according to the fusing characteristics into: fast fuse type, medium type delay fuse, time delay fuse type. (can also express, delay).
3, according to breaking capacity is divided into: low grade, high marks broken broken (can also enhance the breaker type).
4, according to the safety standards (or use area) is divided into: UL/cUL (North America) specification, IEC (China, Europe, etc.) specification, MIT/KTL (Japan/South Korea), specifications, etc.
In many electronic devices, cannot leave the FUSE (FUSE). Since the 1890 s, Edison invented the sticky conductor is closed in Taiwan after the first fuse plug in the socket, more and more kinds of fuses, more and more widely used. Here are some fuse parameters, the selection and application of common sense.
Fuse the ratings and performance index is based on the laboratory conditions and acceptance standard determination. Several international authoritative testing and appraisal institutions, such as insurer experimental companies in the United States UL certification, the Canadian standards association cUL certification and the Japan international trade and industry of MTTI ICE certification certification and international electrical technology committee.
1 the fuse involves the choice of factors
A. normal working current.
B. on the applied voltage on the fuse.
C. require fuse disconnect the abnormal current.
D. allow abnormal current shortest and the longest time.
E. the fuse environment temperature.
F. pulse, impact current and surge current, the starting current and circuit transient value.
G. are beyond the special requirements of fuse specification.
H. limited by the size of the installation structure.
I. the requirements of the certification institutions.
J. fuse holder: fuse clip (divided into current fuse clip and auto fuse clip, need to undertake choosing according to the actual situation), box, panel installation, etc.
5, other classification.