A fuse tube is also called a fuse, and a fuse is also known as a fuse. The IEC127 standard defines it as "fuse-link". It is an electrical component installed in the circuit to ensure the safe operation of the circuit. The function of the fuse is that when the circuit fails or abnormal, the current increases with the current, and the rising current may damage some important devices or valuable devices in the circuit, and may also burn up the circuit and even cause the fire. If the fuse is properly installed in the circuit, the fuse will break off the current when the current is raised to a certain height and a certain time, so that the protective circuit can operate safely. Fuse tube
Classification of fuse tubes:
According to the scope of use, the fuse pipe can be divided into: electric fuse, machine fuse, electrical instrument fuse (electronic fuse), automobile fuse.
The fuse pipes can be divided into large, medium, small and miniature parts. According to rated voltage, it can be divided into: high voltage fuse, low voltage fuse and safety voltage fuse.
According to the breaking capacity, the fuse can be divided into high and low breaking capacity fuses.
Fuse pipe according to shape, can be divided into: flat pipe fuse (also can be divided into internal welding fuse and external welding fuse), sharp pipe fuse, cutter type fuse, spiral fuse, insert type fuse, flat type fuse, wrapped type fuse, patch type insurance silk.
The fuse pipe can be divided into: special slow fuse (generally used in TT), slow fuse (generally expressed in T), medium speed fuse (generally expressed in M), fast fuse (generally expressed in F), andspecial fast fuse (generally expressed in FF).
According to the brand, the fuse can be divided into: Sheng Ming fuse, power fuse, Hua De fuse
According to the standard, the fuse pipe can be divided into: VDE, UL and PSE.
The fuse tube can be divided into size, 3.6X10, 3X10, 5X20, 6X30, 6X32, 6X25, 10*38, 2.4X7, 2.5X6, 3X8, 2.5X9, 8.5X8, 6X30 / > Fuse can be divided into 32mA, 63ma, 100mA, 150mA, 200mA, 250mA, 300mA, 400mA, 500mA, 600mA, 800mA, 1A. 5A, 6A, 7A, 8A, 9A, 10A, 12A, 15A, 20A, 25A, 30A
The fuse tube can be divided into: glass current fuse, ceramic current fuse
Type selection of fuse pipe:
A) determine the safety mark: according to the market requirements that the product will sell, the safety certification mark and safety standard of the fuse tube (UL standard or IEC standard fuse tube) are selected.
B) determine the external dimensions: choose the dimensions of the fuse tube according to the installation space and the specified safety certification mark and safety standard.
C) determine the type: according to the current characteristics of the protected circuit, select the model of the fuse tube. For example, the current characteristic of the protected circuit is a constant current, then a fast fuse type is adopted.
D) determine the rated voltage: determine the rated voltage of the fuse tube according to the input voltage and the usage requirement of the protected circuit. For example, the input voltage of the protected circuit is 220V, and the fuse tube with rated voltage above 220V is selected, and 250V, 300V, 350V and so on are optional. But considering the cost factors, it is not necessary to choose the high rated voltage.
E) determine the minimum rated current: initially determine the rated current of the fuse tube according to the steady working current of the protected circuit and the related loss factor. For example, the stable working current of the protected loop is 1A, and the UL standard time delay fuse tube is selected. The working environment temperature is about 80 degrees C, and the rated current of the fusetube is selected as 1A x 1.25 0.5=2.5A.
F) determine the minimum I2T of the fuse tube: determine the I2T of the fuse tube according to the surge I2T of the protected circuit. For example, the surge I2T of the protected loop is 1 (A2S), to ensure that the fuse tube can withstand more than 100 thousand times of impact, the fuse tube's I2T should be greater than: 1 0.2=5 (A2S).
G) determine the rated current of the fuse tube: according to the minimum rated current and minimum I2T value, check the corresponding model specifications in the product catalogue, take the primary rated current, which is greater than the minimum rated current value and its I2T value is also greater than the minimum I2T value, to select the rated current of the fuse tube. For example, according to the minimum value above,
(1) if the rated current 2.5A I2T is 4.3A2S and the 3A I2T is 5.4A2S, then 3A is chosen as the rated current of the fuse tube;
(2) if the rated current 2A I2T is 5.3A2S and the 2.5A I2T is 7.6A2S, then 2.5A is chosen as the rated current of the fuse tube.