What are the common types of quick-blow fuses? Classification of fast fuses and their respective characteristics
The fast fuse is a kind of fuse, which is often used in various protection circuits. The appearance of the fast fuse is small, but it has many components. It is made up of magnetic shell, conductive plate and melt. It consists of six parts, such as quartz sand, arc extinguishing agent and indicator. It has the characteristics of outstanding current limiting characteristics, strong breaking capacity and small impact energy of load equipment. There are also many types of fast-blow fuses. According to market statistics, there are at least 500 models of fast-blow fuses, but there are only a few commonly used models. Today, Xiaobian will introduce the common models of fast-acting fuses.
What are the commonly used fast fuse models?
XRNT fast fuse
The main features of XRNT fast fuses are
1. High breaking capacity, breaking current up to 63KV.
2. Low power consumption and low temperature rise.
3. The action is particularly fast, and the characteristics of the one second are faster than those of the similar products currently produced in China. For example, the fuse with a rated current of 100A is connected to the expected current of 1000A, and the time before the arc is not more than 0.1S.
4. The characteristic error of the second is less than ±10%.
5. It is equipped with a spring type impactor, which has the characteristics of large contact surface and small pressure. Therefore, when the switch interlocking action is pushed, there is no occurrence of breakage or breakdown of the contact surface of the switch and the striker. .
6. Product performance in line with GB15166.2 national standards and IEC60282-1 international standards.
7. It can reliably break any fault current between the minimum breaking current and the rated breaking current, and it is safer to use. So this type of fast fuse is also the best choice for industrial fuses.
RT14-20 fast fuse
This type of quick-blow fuse is specially constructed. It consists of a fuse body and a fuse base. The fuse-link is made of a pure copper sheet and is melt-packed in a melt tube made of high-strength porcelain. The fusion tube is filled with chemically treated high-purity quartz sand as an arc extinguishing medium, and the two ends of the melt are firmly connected with the end cap, and both sides of the fuse are in contact with the copper, commonly known as a double cover, forming a cylindrical hat structure. . The fuse base is made of resin or plastic pressed housing with contacts and load carrying parts, or riveted connection, which can be used as a support for the corresponding size fuse. Therefore, this type of fast-blow fuse has the characteristics of small size, convenient installation, safe use and beautiful appearance, and has been welcomed by the majority of users.
SP10M10 fast fuse
The SP10M10 fast-blow fuse has the following features:
1. SP10M10 fast fuse has a very wide operating temperature range, the upper limit can reach 90 ° C, and the lower limit can reach -50 ° C.
2. Has good breaking ability, the maximum breaking capacity reaches 35KA, and the breaking time constant is 1-3ms.
3. Excellent fusing characteristics: SP series DC fuses are blown within 1 hour when the actual working current reaches 1.13 times of the rated current; when the actual current reaches 1.45 times of the rated current, it is blown within one hour. This feature is especially suitable for the changing output current of photovoltaic power plant panels.
4. With ultra-low contact resistance, the two-head contact cap of SP10M10 fast-acting fuse adopts Japanese NGK beryllium copper, which has the characteristics of high strength, high electrical conductivity, fatigue resistance, high thermal conductivity and corrosion resistance.
Fast fuse common types
Plug-in fuse: It is commonly used at the end of lines with voltage ratings of 380V and below, as short-circuit protection for distribution lines or electrical equipment. Spiral fuse: The upper end cap on the melt has a fuse indicator. Once the melt blows, the indicator pops up immediately and can be seen through the glass hole in the porcelain cap. It is commonly used in machine tool electrical control equipment.
Spiral fuse. It has a large breaking current and can be used for short-circuit protection in circuits with voltage levels of 500V and below and current levels below 200A.
Enclosed fuses: Closed fuses are divided into two types: filler fuses and non-filled fuses. Packed fuses are generally made of square ceramic tubes with built-in quartz sand and melt. They have strong breaking capacity and are used for voltage levels below 500V. In circuits with current levels below 1KA. The non-filled sealed fuses are used to load the melt into a closed cylinder with a slightly smaller breaking capacity for use in power grids or power distribution equipment below 500V and below 600A.
Fast-acting fuses: Fast-blowers are mainly used for short-circuit protection of semiconductor rectifying components or rectifiers. Due to the low overload capability of semiconductor components. It can only withstand large overload currents in a very short time, so short circuit protection is required to have a fast blown capability. The structure of the quick-blow fuse is basically the same as that of the filled-closed fuse, but the melt material and shape are different, and it is a variable-section melt with a V-shaped deep groove punched by a silver sheet.
Self-resetting fuse: using sodium metal as the melt, it has high conductivity at normal temperature. When a short-circuit fault occurs in the circuit, the short-circuit current generates a high temperature to rapidly vaporize the sodium, and the vaporous sodium exhibits a high-resistance state, thereby limiting the short-circuit current. When the short-circuit current disappears, the temperature drops and the metal sodium returns to its original good electrical conductivity. Self-resetting fuses can only limit the short-circuit current and cannot really break the circuit. The advantage is that the melt does not have to be replaced and can be reused.
Precautions
Due to its excellent short-circuit protection performance, the fuse is widely used in high and low voltage power distribution systems and control systems as well as in electrical equipment. As a protector for short-circuit and over-current, it is one of the most common and important protection devices. In the application, we must pay attention to the use of fuses, daily inspections and maintenance. Fuse use precautions:
1. The protection characteristics of the fuse should be compatible with the overload characteristics of the protected object. Considering the short-circuit current that may occur, the fuse with the corresponding breaking capacity is selected.
2. The rated voltage of the fuse should be adapted to the line voltage level, and the rated current of the fuse should be greater than or equal to the rated current of the melt.
3. The rated current of the fuses of all levels of fuses in the line should be matched accordingly, and the rated current of the first stage melt must be greater than the rated current of the next stage.
4. The melt of the fuse should be used with the matching melt as required. It is not allowed to increase the melt arbitrarily or replace the melt with other conductors.
Fuse inspection inspection:
1. Check that the fuse and melt ratings match the protected equipment.
2. Check the appearance of the fuse for damage or deformation, and whether there is any flashing discharge mark on the porcelain insulation part.
3. Check whether the contact points of the fuse are in good condition, the contact is tight, and there is no overheating.
4. Is the fuse signal indicator of the fuse normal?
Fuse maintenance:
1. When the melt is blown, the cause of the fuse must be carefully analyzed. The possible causes are: 1) short-circuit fault or overload operation and normal fuse; 2) the melt is used for too long, and the melt is subjected to oxidation or high temperature during operation. The melt characteristics are changed and mistakenly broken; 3) There is mechanical damage during the melt installation, so that the cross-sectional area becomes small and causes a break in operation.
2. When disassembling the melt, it is required to: 1) Before installing the new melt, find out the cause of the melt blow, determine the cause of the fuse, do not replace the melt test; 2) When replacing the new melt, Check that the melt rating matches the equipment to be protected; 3) When replacing the new melt, check the internal burn of the fuse tube. If there is severe burn, replace the melt tube at the same time. When the porcelain melt pipe is damaged, it is not allowed to replace it with other material pipes. When filling the fuse with a filler fuse, pay attention to filling the packing.
3. The fuse should be repaired at the same time as the power distribution device: 1) clean the dust and check the contact point contact; 2) check the appearance of the fuse (remove the fuse tube) for damage, deformation, and whether the porcelain is flashing or not. Traces; 3) Check fuses, whether the melt is matched with the circuit or equipment to be protected, and investigate if there is any problem; 4) Pay attention to check the N line in the TN grounding system, the grounding protection line of the equipment, and do not allow the fuse to be used. 5) When maintaining and inspecting the fuse, the power supply must be cut off according to the safety regulations. It is not allowed to take the fuse tube with power.
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