Temperature-controlled fuses are widely used in microwave ovens, drinking fountains, disinfection cabinets, electric irons, toasters, barbecue machines, coffee machines, hot water kettles, clothes dryers, electric freezers, electric water heaters and other electrical equipment.
Chinese name: temperature control fuse mbth: thermal link, also known as temperature controller mbth: thermal control belongs to: temperature fuse device category: organic heat-sensitive particles are heat-sensitive materials. It can detect the abnormal temperature rise of household or industrial electrical products, and cut off the circuit quickly and timely to prevent fire burning. Temperature fuse Temperature control fuse, also known as fuse, is a disposable component connected to the circuit to protect the circuit. When the current on the circuit is too large, the metal wire or chip inside will be blown off by high temperature, causing an open circuit and interrupting the current, thus protecting the circuit from damage. After the old fuse is blown, it is necessary to manually replace the new fuse to restore the operation of the circuit. The basic introduction of temperature fuse is that after the current exceeds the specified value for a period of time, the melt is melted by the heat generated by itself, thus breaking the circuit; Current protector based on this principle. Fuses are widely used in high and low voltage distribution systems, control systems and electrical equipment. As protectors of short circuit and overcurrent, they are one of the most common protective devices. The fuse is an overcurrent protector. Fuse is mainly composed of melt, melting tube and additional filler. When in use, the fuse is connected in series in the protected circuit. When the current of the protected circuit exceeds the specified value, and after a certain period of time, the heat generated by the melt itself melts the melt and disconnects the circuit, thus playing a protective role. A metal conductor is used as an electrical apparatus for breaking the melt, which is connected in series in the circuit. When overload or short-circuit current passes through the melt, the melt itself will heat and fuse, thus playing a certain protective role for power system, various electrical equipment and household appliances. It has the characteristics of reverse delay, and the fuse time is long when the overload current is small; When the overload current is large, the fuse time is short. Therefore, in a certain range of overload current, until the current returns to normal, the fuse will not blow and can continue to be used. Fuse is mainly composed of melt, shell and bracket, in which melt is the key factor to control fuse characteristics. In the import and export tariff, it is classified as 8535 or 8536. Working principle: Metal conductor is connected in series in the circuit as a melt. When an overload or short-circuit current passes through the melt, it will fuse due to its own heat, thus breaking the circuit. Fuses are simple in structure and easy to use, and are widely used as protection devices in power systems, various electrical equipment and household appliances. The rated current of characteristic melt is not equal to the rated current of fuse. The rated current of the melt is selected according to the load current of the protected equipment, and the rated current of the fuse should be greater than the rated current of the melt, which should be determined in coordination with the main electrical appliance. Fuse is mainly composed of melt, shell and bracket, in which melt is the key factor to control fuse characteristics. The material, size and shape of the melt determine the melting characteristics. Melt materials are divided into two categories: low melting point and high melting point. Low melting point materials, such as lead and lead alloys, are easy to melt because of their low melting points. Because of their high resistivity and large cross-sectional size of melt, they produce more metal vapor when melting, and are only suitable for fuses with low breaking ability. High-melting-point materials, such as copper and silver, have high melting points and are not easy to fuse, but because of their low resistivity, they can be made into smaller cross-sectional dimensions than low-melting-point melts and produce less metal vapor when fusing, so they are suitable for fuses with high breaking capacity. The shape of melt can be divided into two types: filiform and ribbon. Changing the shape of variable cross-section can significantly change the fusing characteristics of fuze. Fuses have the characteristics of inverse time limit, that is, when the overload current is small, the fusing time is long; When the overload current is large, the fuse time is short. Therefore, in a certain range of overload current, when the current returns to normal, the fuse will not blow and can continue to be used. Fuses have various fuse characteristic curves, which can meet the needs of different types of protected objects. It is installed in the circuit as an electrical component to ensure the safe operation of the circuit. When the circuit breaks down or is abnormal, with the current rising, some important or valuable devices in the circuit may be damaged, the circuit may be burned, and even a fire may be caused. If the fuse is properly placed in the circuit, when the current rises abnormally to a certain height, the fuse will blow itself to cut off the current within a certain period of time, thus protecting the safe operation of the circuit. The fuse cuts off the current, thus protecting the safe operation of the circuit. [1] Inter-level cooperation In order to prevent super fuses and expand the scope of accidents, there should be good cooperation between upper and lower fuses (that is, power supply trunk lines and branch lines). When selecting, the rated fuse current of the superior (power supply trunk) fuse should be 1 ~ 2 higher than that of the subordinate (power supply branch). Commonly used fuses include tube fuse R 1 series, spiral fuse RLl series, package closed fuse RT0 series and quick fuse RSO and RS3 series. Brief introduction to the use and maintenance of fuse in low-voltage distribution system fuse is a kind of electrical appliance with safety protection function. Fuses are widely used in power grid protection and electrical equipment protection. When the power grid or electrical equipment is short-circuited or overloaded, it can automatically cut off the circuit to avoid the damage of electrical equipment and prevent the spread of accidents. Fuse consists of insulating base (or bracket), contact, melt, etc. Melt is the main working part of fuse, which is equivalent to a special wire connected in series in the circuit. When the circuit is short-circuited or overloaded, the current is too large and the melt melts due to overheating, thus cutting off the circuit. Melt is usually made into filaments, meshes or sheets. Melt material has the characteristics of low relative melting point, stable characteristics and easy melting. Generally, lead-tin alloy, silver-plated copper sheet, zinc, silver and other metals are used. In the process of melting and cutting off the circuit, an arc will be generated. In order to extinguish the arc safely and effectively, melt is generally installed in the fuse shell, and measures are taken to extinguish the arc quickly. Fuses have the advantages of simple structure, convenient use and low price, and are widely used in low-voltage systems. Precautions (1) Precautions for fuse use: (1) The protective characteristics of the fuse should be adapted to the overload characteristics of the protected object. Considering the possible short-circuit current, the fuse with corresponding breaking ability should be selected. (2) The rated voltage of the fuse should be suitable for 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 fuses at all levels in the line should be matched accordingly, and the rated current of the upper level must be greater than that of the lower level. (4) Fuse melts shall be matched as required, and it is not allowed to add melts at will or replace melts with other conductors. (2) Patrol inspection of fuses: (1) Check whether the ratings of fuses and melts match the protected equipment. (2) Check whether there is any damage and deformation on the fuse appearance, and whether there is any flicker discharge trace on the insulating part of porcelain insulator. (3) Check whether the fuse contact points are in good condition, with close contact and without overheating. (4) The fuse signal indicates that it is normal. (3) Use and maintenance of fuse: (1) When the melt melts, carefully analyze the melting reason. Possible reasons are: 1) short circuit fault or overload operation and normal fuse. 2) If the melt is used for a long time, it will be broken by mistake because of oxidation or high temperature during operation. 3) When the melt is installed, there is mechanical damage, which reduces its cross-sectional area and causes misoperation. (2) When replacing the melt, the requirements are: 1) Before installing a new melt, find out the cause of melt melting. If the cause of melt melting is uncertain, do not replace the melt for trial delivery. 2) When replacing a new melt, check whether the rating of the melt matches the protected equipment. 3) When replacing the new melt, check the internal burn of the melting tube. If there are serious burns, replace the fuse tube at the same time. When the porcelain fused tube is damaged, it is not allowed to replace it with other materials. When using filler fuse instead of melt, attention should be paid to filling filler. ③ The fuse should be repaired at the same time as the power distribution device: 1) Clean the dust and check the contact conditions of the contacts. 2) Check the fuse appearance (remove the fuse tube) for damage and deformation, and check whether there are any discharge flicker marks on the porcelain bottle. 3) Check whether the fuse and melt match the protected circuit or equipment, and investigate in time if there are any problems. 4) Pay attention to check that fuses are not allowed to be used on the N line of TN grounding system and the grounding protection line of equipment. 5) When repairing and checking the fuse, cut off the power supply according to the requirements of safety regulations, and do not take the fuse tube with electricity. 4. Fuse adapter The fuse adapter includes a base, a micro indicator switch and a radiator. Users can negotiate with fuse manufacturers according to their own needs. The difference between them and circuit breakers is that they can realize short-circuit protection. The principle of fuse is that the conductor will be heated by the current flowing through it, and the conductor will melt after reaching the melting point of the conductor, so the electrical appliances and lines used for circuit protection will not be burned out. It is the accumulation of heat, so overload protection can also be realized. Once melted, it should be replaced. Circuit breakers can also realize short-circuit and overload protection of lines, but the principle is different. It realizes open circuit protection through the bottom magnetic effect of current (electromagnetic trip) and overload protection through the thermal effect of current (no fuse, no need to replace devices). In practice, when the power load in the circuit is close to the load of the fuse used for a long time, the fuse will gradually heat up until it blows. As mentioned above, fuse blowing is the result of the combined action of current and time, which plays a role in protecting the line. This is disposable. Circuit breaker is a circuit whose current suddenly increases. When it exceeds the load of the circuit breaker, it will automatically disconnect. It is the protection of the circuit against the increase of instantaneous current, such as when the leakage is large, or when it is short-circuited, or when the instantaneous current is large. When the reason is found out, it can be closed for further use. As mentioned above, fuse blowing is the result of the combined action of current and time, and the circuit breaker will trip as soon as the current passes its set value, and the time effect can be almost ignored. Circuit breakers are commonly used components in low-voltage power distribution. There are also some places where fuses are suitable. Select and classify (1) spiral fuse RL: the fuse tube is filled with quartz sand and the melt is buried in it. When the melt melts, the arc is sprayed on the quartz sand and its gap, which can be quickly cooled and extinguished. In order to facilitate monitoring, one end of the fuse is equipped with a color point, and different colors indicate different melt flows. When the melt melts, the color point jumps out, indicating that the melt has melted. The rated current of spiral fuse is 5 ~ 200 A, which is mainly used for short-circuiting branches with large current or places with combustible gas. ⑵ Inflatable tube fuse RT: Inflatable tube fuse is a current-limiting fuse. It consists of porcelain fused tube filled with quartz sand, contact and silver-plated copper grid melt. The filled tube fuse is installed on a special base, such as a base with an isolation knife switch or a base with a fuse as an isolation knife, and is operated by a manual mechanism. The rated current of packaging tube fuse is 50 ~ 1000 A, which is mainly used in circuits with large short-circuit current or places with combustible gas. ⑶ Empty tube fuse RM: The fuse tube of empty tube fuse is made of fiber. The melt used is a zinc alloy plate with variable cross section. When the melt melts, some fibers in the fused fiber tube are decomposed by heat, producing high-pressure gas, which makes the arc extinguish quickly. Filler-free tube fuses have the characteristics of simple structure, good protection performance and convenient use, and are generally used in conjunction with knife switches to form fuses and knife switches. ⑷ Filled closed tube quick fuse RS: Filled closed tube quick fuse is a kind of quick action fuse, which consists of fuse tube, contact seat, action indicator and melt. The melt is in the form of silver strip or mesh, which can be used once and cannot be replaced by itself. Because of its quick action, it is generally used as the protection of semiconductor rectifier elements. 5] Fuses can be divided into high-voltage fuses and low-voltage fuses according to the use voltage. According to the protection objects, it 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 elements, fuses for protecting motors and fuses for protecting household appliances. According to the structure, it can be divided into open fuse, semi-closed fuse, tube fuse and jet fuse. [6] The surface-mounted fuse is simple in structure, the melt is completely exposed to the air, supported by porcelain columns, and there is no bracket, so it is suitable for low-voltage outdoor use. When the current is interrupted, it will produce huge sound and light in the atmosphere. Once, put the melt of the semi-closed fuse on the porcelain frame and insert it into the porcelain box with metal sockets at both ends, which is suitable for low-voltage indoor use. When the current is cut off, the sound and light produced are blocked by the porcelain box. The tube fuse is fused in the fuse body. Then plug it into the bracket or connect it directly to the circuit for use. The fuse is a completely sealed insulating tube with metal caps or contact knives at both ends. If the insulating tube of this fuse is filled with quartz sand, the current will be limited when breaking current, which can greatly improve the breaking capacity, so it is also called high breaking capacity fuse. If a vacuum tube is vacuum, it is called a vacuum fuse. If the tube is filled with SF6 gas, it is called SF6 fuse, and its purpose is to improve the arc extinguishing performance. Because quartz sand, vacuum and SF6 gas all have good insulation performance, this fuse is suitable for not only low voltage but also high voltage. Pet-name ruby jet fuze is to put the melt in an insulating tube made of solid gas-producing materials. The solid gas-producing material can be electrical white cardboard or plexiglass material. When the short-circuit current passes through the melt, the melt melts to generate an arc, and the high-temperature arc quickly decomposes the solid gas-producing substances to generate a large amount of high-pressure gas, so that the ionized gas is sprayed at both ends of the tube as an arc, giving off a huge sound and light, and the arc-breaking current is extinguished when the alternating current crosses zero. Insulating tubes are usually installed on insulating brackets to form a fuse as a whole. Sometimes the upper end of the insulating tube can be moved, and then the current will break away and fall off. This kind of jet fuze is usually called drop fuze. Generally suitable for outdoor occasions with voltage higher than 6 kV. In addition, fuses can be divided into general fuses, standby fuses and full-range fuses according to the breaking current range. The breaking current range of universal fuse 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. The breaking current range of standby fuse refers to the range from overload current greater than 4 ~ 7 times the rated current to the maximum breaking current. This fuse is often used in series with the contactor. When the overload current is less than 4 ~ 7 times the rated current, the contactor will realize breaking protection. Mainly used to protect the motor. With the development of industry, special fuses, such as electronic fuses, temperature fuses and self-reset fuses, have been manufactured. Functional fuse is a simple and effective protective appliance. It mainly plays a short-circuit protection role in the circuit. Fuse is mainly composed of melt and insulating tube (insulating seat) for installing melt. When in use, the melt is connected in series in the protected circuit, and when the circuit has a short circuit fault, the melt melts instantly, thus disconnecting the circuit, thus playing a protective role. The function of fuse is: when the circuit fails or is abnormal, the current will rise continuously, and the rising current may damage some important devices or valuable devices in the circuit, burn the circuit and even cause a fire. If the fuse is properly placed in the circuit, when the current rises abnormally to a certain height, the fuse will blow itself to cut off the current within a certain period of time, thus protecting the safe operation of the circuit. The earliest fuse was invented by Edison over 100 years ago. Because the industrial technology at that time was underdeveloped and incandescent lamps were expensive, they were originally used to protect expensive incandescent lamps. Low-voltage tube fuse classification 1) used in residential and similar occasions, gG type; 2) Used in industrial occasions, gG, gM or aM type. The first letter indicates the fusing range: * "G" indicates a fuse with full fusing capability; * "A" indicates a fuse with partial fuse capacity. The second letter indicates the category of application and accurately describes the characteristics of time and current, conventional time and current. For example: * "gg" stands for universal fuse with full fuse capacity; * "GM" denotes a fuse for protecting the full-range fusing ability of the motor circuit; * "AM" indicates the fuse used to protect the fuse capacity of the motor circuit. Some fuses have a "fuse blown" mechanical indicator. When the current flowing through the fuse exceeds a given value for a certain time, the fuse device cuts off the circuit through the fuse. The current/time relationship is given by each type of performance curve. The standard defines two types of fuses: * for residential use, box type, rated current 100A, and specified type gG (IEC60269- 1 and 3). * Used in industrial occasions, cylinder, gG type (universal); GM, aM (for motor circuits), IEC60269- 1 and 2. Classification of fuse temperature: according to the material, it can be divided into metal shell and plastic shell. According to the temperature, the oxide film shell can be divided into 73 degrees 99 degrees 77 degrees 94 degrees 1 13 degrees 12 1 33 degrees 142 degrees 157 degrees/kloc-0. 1 10 degree 1 15 degree 12 1 28 degree 130 degree14/kloc-. 085 degrees 192 degrees 2 16 degrees 227 degrees 228 degrees 240 degrees 250 degrees 280 degrees 320 degrees Selection of rated melt current Because all kinds of electrical equipment have certain overload capacity, they are allowed to run for a long time under certain conditions; When the load exceeds the allowable value, it is required to protect the melt from melting within a certain time. There are also some devices with large starting current but short starting time, so the protection characteristics of these devices are required to meet the needs of equipment operation, and the fuses are required not to blow when the motor is started, and can be reliably blown under the action of short-circuit current and when the allowable overload current is exceeded, thus playing a protective role. The rated current of melt is too large, and the load cannot be blown in time when it is short-circuited or overloaded for a long time; If it is too small, it may fuse under the action of normal load current, which will affect the normal operation. In order to ensure the normal operation of the equipment, the rated melt current must be reasonably selected according to the load nature. (1) The rated current of the lighting circuit melt is greater than or equal to the sum of the working currents of all lighting appliances on the protected circuit. ⑵ Motor: ① The rated melt current of a single direct start motor = (1.5 ~ 2.5) × the rated motor current. (2) The rated current of the total protective melt of multiple direct-start motors = (1.5 ~ 2.5) × the sum of the currents of each motor. (3) rated melt current of step-down starter motor = (1.5 ~ 2) × rated motor current. (4) The rated melt current of the wound motor = (1.2 ~ 1.5) × the rated motor current. (3) Rated current of distribution transformer low-voltage side melt = (1.0 ~ 1.5) × rated current of transformer low-voltage side. (4) The rated melt current of shunt capacitor bank = (1.43 ~ 1.55) × rated current of capacitor bank. 5] rated current of welding machine melt = (1.5 ~ 2.5) × load current. [6] Rated current of electronic rectifier component melt ≥ 1.57× rated current of rectifier component. Note: the numerical range of rated current of melt is to adapt to the rated value of melt standard parts. The action of ampere-second characteristic fuse is realized by melting the melt. When the current is large, the time required to melt the melt is short. When the current is small, it takes a long time for the melt to melt, or even not to melt. Therefore, for the melt, its action current and action time characteristics, that is, the ampere-second characteristics of the fuse, are inverse time characteristics. Each melt has a minimum melting current. The minimum melting current is different according to different temperatures. Although the current is influenced by the external environment, it can be ignored in practical application. Generally, the ratio of the minimum melting current of the melt to the rated current of the melt is defined as the minimum melting coefficient. The melting coefficient of common melt is greater than 1.25, that is to say, the melt with rated current of 10A will not melt when the current is lower than12.5a. See Table 1-2 for the relationship between the melting current and the melting time. Thus, the fuse can only play a short-circuit protection role, but not an overload protection role. If it really needs to be used in overload protection, the rated current must be reduced. For example, in 10A circuit, 8A melt is used for short-circuit protection and overload protection, but the overload protection characteristics at this time are not ideal. The choice of fuse mainly depends on the protective characteristics of load and the size of short-circuit current. For motors and lighting branch lines with small capacity, fuses are often used as overload and short-circuit protection, so it is hoped that the melting coefficient of melt will be appropriately small. RQA series fuses of lead-tin alloy melt are usually selected. For motors and lighting trunk lines with large capacity, short-circuit protection and breaking capacity should be considered emphatically. RM 10 and RL 1 series fuses with high breaking capacity are usually selected; When the short-circuit current is large, the rated current of RT0 and RTl2 series fuses with current limiting function should be selected as follows: 1) When protecting stable loads without starting process, such as lighting circuits, resistors, electric furnaces, etc. The rated current of the melt is slightly greater than or equal to the rated current in the load circuit. 2) The melt current for protecting a single motor from long-term operation can be selected according to the maximum starting current or the following formula: IRN ≥ (1.5 ~ 2.5), where IRN is the rated melt current; Rated current of motor. If the motor starts frequently, the coefficient in the formula can be appropriately increased to 3 ~ 3.5 according to the actual situation. 3) Protect multiple motors (power supply trunk lines) working for a long time: the maximum rated current of a single motor with the largest capacity is max≥( 1.5 ~ 2.5)in+σ. σ is in the rest. Sum of rated current of motor. Working temperature range: SF type is 73℃ ~240℃, SM type is 76℃ ~ 187℃. There are various products with rated current of 0. 5A ~ 15A。 Safety certification includes: UL, CSA, VDE, BEBA, PSE, JET, CQC… certificates, which meet the requirements of EU ROHS environmental protection directive. NEC temperature fuse has the function of detecting abnormal temperature and cutting off the circuit. It can detect the abnormal temperature rise of household or industrial electrical products, and cut off the circuit quickly and timely to prevent fire burning. NEC temperature fuse is a very reliable over-temperature protection element. It has the advantages of small size, large overcurrent, no need to reset, stable performance, convenient installation, and a certain range of humidity setting and tolerance to choose from, which meets the application needs of customers. Products are widely used in: various motors, copiers, fax machines, HID ballasts, fluorescent lamp ballasts, transformers, chargers, battery packs, heating appliances, electric irons, hair dryers, electric stoves, rice cookers, electric kettles, coffee machines, ventilator fans, electric sewing machines, water heaters, power converters, power plugs, freezers, air conditioners, car air conditioners and instruments. Product function editor SEFUSE temperature fuse installation notes: 1. When the wire is bent, it should be bent from the part more than 6 mm away from the root; When bending, the roots and leads shall not be damaged, and the leads shall not be forcibly pulled, pressed or twisted. 2. When the thermal fuse body is fixed with screws, rivets or terminals, it should be able to prevent mechanical creep and poor contact. 3. The connector should be able to work reliably within the working range of electrical products and will not be displaced due to vibration and impact. 4. During the lead welding operation, the heating humidity should be limited to a minimum, and care should be taken not to increase the high temperature of the thermal fuse; Do not forcibly pull, press or twist thermal fuses and wires; Immediately after welding, it should be cooled for more than 30 seconds. 5. Thermal fuses can only be used under the specified rated voltage, current and specified temperature conditions, and special attention should be paid to the maximum continuous bearing temperature of thermal fuses. Remarks: Nominal current, lead length and temperature can be designed according to customer's requirements. Excellent temperature response speed.
Very sensitive to ambient temperature
The heat conductor is made of copper alloy to ensure that the environmental heat energy is quickly transferred to the fuse link.
Copper alloy is selected as the heat conductor to ensure high performance of thermal response. Reliable and accurate action, stable and accurate operation, high sensitivity temperature sensor to ensure that every Alin? The working temperature error of F00/F0 1/F00-V series temperature fuses is within the range of rated temperature +0℃/ -5℃. We choose high-quality chemicals to ensure that we always work at the rated temperature of +0℃/-5℃. One-time action cuts off the current single operation 4. Longer service life: Can high-temperature series fuses above 200℃ last longer at room temperature? The hot connecting rod (TF > 200℃) has good working life performance, and can only act once and cannot be reset. F00/F0 1/F0X series thermal fuses are widely used for thermal protection of equipment to prevent parts from reaching dangerous high temperature locally under fault conditions. Arlene. F00/F0 1/ F0X series is a compact and reliable one-time thermal link, which is designed to protect various electrical appliances from high temperature or other risks. Structure and working principle F series products are temperature fuses with metal as shell and heat sensitive particles (organic chemicals) as heat sensitive body. High-quality silver is used as the contact material, which makes it have extremely low internal resistance and good current resistance. F-series thermal disconnectors use metal as shell and heat-sensitive particles (organic chemicals) as thermal sensors. Because solid alloy material is used as contact material, F series thermal disconnectors have very low internal resistance and very good electrical durability. Precautions for installing size temperature fuse: 1. When the wire is bent, it should be bent from the part more than 6 mm away from the root; When bending, the roots and leads shall not be damaged, and the leads shall not be forcibly pulled, pressed or twisted. 2. When the thermal fuse body is fixed with screws, rivets or terminals, it should be able to prevent mechanical creep and poor contact. 3. The connector should be able to work reliably within the working range of electrical products and will not be displaced due to vibration and impact. 4. During the lead welding operation, the heating humidity should be limited to a minimum, and care should be taken not to increase the high temperature of the thermal fuse; Do not forcibly pull, press or twist thermal fuses and wires; Immediately after welding, it should be cooled for more than 30 seconds. 5. Thermal fuses can only be used under the specified rated voltage, current and specified temperature conditions, and special attention should be paid to the maximum continuous bearing temperature of thermal fuses. Remarks: Nominal current, lead length and temperature can be designed according to customer's requirements. The printing temperature fuse is clearly printed with environmentally friendly ink, and its trademark and LOGO are printed according to customer requirements. F00/F0 1 series