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There may be errors in the use of current transformers, which is a normal phenomenon as long as it is within the controllable range. But what are the factors that affect the error of current transformers? Hemei Electronics Current Transformer Company will answer for you. 1. The internal parameters of the current transformer are the main factors affecting the error of the current transformer. (1) The influence of the secondary coil internal resistance R2 and leakage reactance X2 on the error; (2) The influence of the core cross section on the error; (3) The influence of the number of turns on the error. (4) Reduce iron loss and increase magnetic permeability.   2. Current transformer operation error When the current transformer is finalized and its internal parameters are determined, its error size will be affected by the secondary current (or primary current), secondary load, power factor and frequency. These factors are called external factors. The error of the current transformer in operation is mainly affected by these four factors. (1) The influence of the change of current frequency on the error. (2) When the primary current decreases, the magnetic flux density decreases proportionally, but at low magnetic flux density, the decrease in excitation ampere is slower than the decrease in magnetic flux density. (3) The current transformer error has the following characteristics: when the primary current changes within the specified range, the secondary current changes proportionally, and when the secondary load impedance changes within the specified range, the secondary current size is not affected. Therefore, when the secondary load is reduced to the rated range, the magnetic flux density will also decrease. Since the secondary current is constant, the excitation current decreases and the error also decreases. The factory manual of the current transformer generally indicates the rated secondary load impedance value. During operation, the error should be checked according to the secondary load impedance value under the given wiring method. (4) The power factor of the secondary load increases, that is, Rfh increases, Xfh decreases, the angle difference increases, and the ratio decreases.

Permalloy is an iron nickel alloy with high magnetic guidance and low -correction. It is widely used in magnetic materials and electrical elements, such as transformers, transformers, relays, etc. The thermal treatment of the permalloy iron core has a significant impact on its magnetic performance. The following is the specific impact of the thermal treatment system on the performance of the permalloy iron core:   1. Hot treatment temperature   Antuction temperature: Poomo alloy is usually annealing at about 1000 ° C. Excessive or too low annealing temperature will affect the magnetic properties of the iron core. The high annealing temperature can reduce the internal stress, eliminate the cold processing hardening effect, thereby increasing the magnetic guidance and reducing the stubborn force. However, excessive temperature may cause the grain to grow excessively and reduce the magnetic performance of the material.   Antuction time: The appropriate annealing time can ensure fully eliminating the internal stress and forming a uniform micro -tissue. For a long time, it may cause grain to ricate.   2. Cooling speed   Slow cooling: Generally, slow cooling methods, especially in hydrogen or vacuum environments to avoid the introduction of oxidation and internal stress. Slow cold helps to obtain higher magnetic guidance and lower stubborn power.   Fast cooling: Fast cooling may lead to high internal stress, thereby increasing stubborn force and reducing magnetic guidance.     3. Hot treatment atmosphere   Vacuum or hydrogen protection: In order to prevent slope alloys from oxidizing at high temperature, heat treatment is usually performed in the atmosphere of vacuum or hydrogen protection. This helps maintain the purity of the alloy, prevent the formation of oxides, and maintains excellent magnetic properties.   Oxidation atmosphere: If it is treated under the oxidation atmosphere, the surface is prone to form oxides to reduce magnetic performance.   4. Magnetic Antuction   Plus magnetic field: Applying a certain magnetic field (usually called a magnetic field annealing) during thermal treatment can further improve the magnetic properties of the Somo alloy. This process can make magnetic domain arrangement, thereby increasing magnetic guidance and reducing stubborn force.   5. Stress elimination   Stress annealing: During the cold rolling process, the Spoomo alloy may introduce large internal stress, which will affect the magnetic performance of the iron core. Through stress annealing, the internal stress can be significantly reduced, and the magnetic guidance and stability can be improved.   6. Grane size control   Fine grains: Appropriate heat treatment can refine the grains, and small grains help reduce the stubborn force and improve the magnetic guidance.   Gravate grows: an annealing of too long or too high temperature can cause grains to grow, but reduce magnetic performance.

In the field of power electronics, power factor correction (PFC) is one of the key technologies to improve the efficiency of electric energy utilization. With the development of science and technology, amorphous materials have gradually attracted attention due to their superior magnetic properties and low loss, and amorphous PFC constant inductance is an important application. So, what is the working principle of amorphous PFC constant inductance? What application value does it have in modern electronic devices?   1. Technical principle of amorphous PFC constant inductance   Basic concept of amorphous materials   Amorphous materials refer to alloy materials without long-range ordered crystal structure. Compared with traditional crystalline materials, amorphous materials have higher resistivity, lower coercivity and higher magnetic permeability. These characteristics make amorphous materials perform well in the application of inductors, especially in high-frequency applications, which can effectively reduce energy loss.   Concept of PFC (Power Factor Correction)   Power factor (PF) is an indicator to measure the ratio of active power to apparent power in a power system. Ideally, the power factor should be close to 1, which means that almost all the energy in the power system is converted into useful power. In actual applications, due to the presence of inductive and capacitive loads, the power factor is usually lower than 1, which leads to energy waste and reduced equipment efficiency. The PFC circuit improves the power factor by adjusting the phase relationship between current and voltage, thereby improving the utilization efficiency of electric energy.   Principle of amorphous PFC constant inductance   Amorphous PFC constant inductor uses the high magnetic permeability and low loss characteristics of amorphous materials to achieve a constant inductance value. The design of constant inductance ensures that the inductance value changes minimally under different currents and frequencies, thereby maintaining the stability and high efficiency of the circuit. This is especially important for PFC circuits, because a constant inductance value can ensure better power factor correction, reduce harmonic pollution in the power grid, and improve overall system efficiency.   2. Advantages of amorphous PFC constant inductance   High efficiency and low loss   The low hysteresis loss of amorphous materials makes amorphous PFC constant inductance perform well in high-frequency applications. Compared with traditional crystalline materials, amorphous materials can maintain low losses at higher frequencies, reduce the temperature rise of the inductor, and thus improve the efficiency of the overall circuit. This is particularly important for devices that need to run continuously for a long time, such as server power supplies and industrial automation equipment.   Miniaturization and Lightweight   The high magnetic permeability of amorphous materials allows the use of less material at the same inductance value, thereby achieving miniaturization and lightweighting of inductors. This not only reduces production costs, but also reduces the space occupied by the equipment, which is particularly suitable for application scenarios with strict space and weight requirements in modern electronic devices, such as portable devices and automotive electronics.   High Stability and Reliability   The amorphous PFC constant inductor can maintain a constant inductance value under different working conditions, showing extremely high stability. This feature is particularly important in harsh working environments such as high temperature and high frequency to ensure the reliable operation of the equipment. In addition, the corrosion resistance and oxidation resistance of amorphous materials also greatly extend the service life of the inductor and reduce the maintenance cost of the equipment.   The amorphous PFC constant inductor improves the electromagnetic compatibility (EMC) of the equipment by effectively suppressing high-frequency harmonics. In electronic equipment, electromagnetic interference (EMI) is a common problem, and the characteristics of amorphous materials enable it to maintain excellent electromagnetic shielding effect at high frequencies, reduce interference between devices, and improve the reliability of the overall system.   3. Main application areas of amorphous PFC constant inductor   Computer and server power supply   In computers and servers, the power module needs to work stably for a long time and has high requirements for the efficiency of electric energy utilization. Amorphous PFC constant inductor can provide stable inductance value with high efficiency and low loss, ensuring that the power module can still maintain good power factor correction effect under high load and reduce power waste.   Industrial automation equipment   Industrial automation equipment usually needs to handle a large number of power conversion and control tasks, requiring inductors to have high efficiency and high stability. Amorphous PFC constant inductor has been widely used in these devices due to its excellent performance, helping to improve the overall efficiency of the equipment, reduce energy loss during operation, and reduce production costs.   New energy vehicles   In new energy vehicles, the efficiency and stability of the power system directly affect the vehicle's cruising range and performance. Amorphous PFC constant inductor plays an important role in battery management system (BMS), motor controller and on-board charger, helping to improve power factor, optimize power transmission and extend vehicle cruising range.   Renewable energy system   With the popularization of renewable energy, solar power generation, wind power generation and other systems have higher and higher requirements for power factor correction. Amorphous PFC constant inductors can effectively improve the efficiency of power conversion, reduce energy loss and promote the development of green energy in these systems.   Fourth, the manufacturing process of amorphous PFC constant inductors   Production of amorphous materials   The production of amorphous materials is mainly achieved through rapid cooling technology. The molten alloy material is cooled in a very short time so that it cannot form a crystal structure, thus forming an amorphous state. This process has extremely high requirements for cooling speed and temperature control, and requires precise equipment and technical support.   Winding of inductors   After the amorphous material is made into a thin strip, it is wound according to the design requirements to form the core part of the inductor. The number of turns and spacing of the coil need to be strictly controlled during the winding process to ensure the accuracy and consistency of the inductance value.   Assembly and packaging   After the winding is completed, the inductor core is assembled into the inductor shell and packaged. The packaging process must not only consider the heat dissipation and mechanical strength of the inductor, but also ensure the stability of its electrical performance. Finally, the packaged inductor will undergo a series of tests to ensure that it can operate stably under different working environments.

The reasons for abnormal heating of magnetic ring inductor coils may include the following aspects:   Design problems:   Improper inductance selection: The inductance value is too large or too small, resulting in abnormal circuit operation, which causes heating.   Improper core material selection: The saturation flux density and loss characteristics of the core material are not suitable for the operating frequency and operating current, resulting in excessive core loss and heating.   Process problems:   Poor coil winding process: Loose winding and poor interlayer insulation during coil winding lead to increased copper loss.   Improper wire diameter selection: The cross-sectional area of ​​the wire is too small, resulting in excessive current passing through, causing excessive copper loss and heating.   Electrical performance problems:   The operating frequency is too high: At high frequencies, the hysteresis loss and eddy current loss of the core increase, resulting in heating of the core.   Excessive current: Exceeding the maximum current designed for the inductor, resulting in overheating of the inductor.   Heat dissipation problems:   Poor heat dissipation conditions: The ambient temperature around the inductor is high or the heat dissipation measures are improper (such as lack of a heat sink), resulting in the inability to dissipate heat in time.   Magnetic saturation:   Core saturation: The working current exceeds the core saturation current, causing the core to enter the saturation zone, resulting in a sharp increase in core loss.   Problems with inductor use:   Overload use: The inductor is used for a long time under conditions exceeding the rated power, resulting in overheating.   Poor working environment: Environmental conditions such as high temperature and high humidity will accelerate the aging and heating of the inductor.   For these reasons, the following measures can be taken to investigate and deal with them:   Optimize design: Select appropriate inductance value and core material according to actual working conditions.   Improve process: Ensure the quality of coil winding and select appropriate wire cross-sectional area.   Control working parameters: Ensure that the working frequency and working current are within the design range.   Strengthen heat dissipation: Improve heat dissipation conditions, add heat sinks or fans and other measures.   Avoid magnetic saturation: Select appropriate core materials to avoid the working current exceeding the saturation current of the core.

In modern electronic technology, ultra-fine crystal cores have become the core components of many electronic components with their unique electrical properties and efficient working characteristics. So, what is an ultra-fine crystal core? Why is it so important in various applications? This article will explore the characteristics, applications, causes and solutions of abnormal heating of ultra-fine crystal cores from multiple dimensions.   1. Basic Overview of Ultra-fine Crystal Cores   1.1 Definition and Characteristics   Ultra-fine crystal cores refer to magnetic material cores with ultra-fine grain structures. Compared with traditional ferrite cores or silicon steel cores, ultra-fine crystal cores have higher saturation flux density, lower losses and excellent frequency characteristics. These characteristics make it widely used in high-frequency switching power supplies, communication equipment, electric vehicles and other fields.   1.2 Composition and Structure   Ultra-fine crystal cores are usually composed of nano-scale grains, which are formed into a uniform microcrystalline structure through a specific heat treatment process. Common ultra-fine crystal materials include iron-based, nickel-based and cobalt-based alloys, among which iron-based alloys are the most widely used due to their low cost and excellent performance.   2. Main application areas of ultra-microcrystalline cores   2.1 Switching power supply   In switching power supply, ultra-microcrystalline cores are mainly used to make transformers and inductors. Due to its high saturation flux density and low loss, it can maintain excellent electrical performance under high-frequency working conditions, thereby improving the conversion efficiency and stability of the power supply.   2.2 Communication equipment   Ultra-microcrystalline cores are used for filters and chokes in communication equipment. Its excellent frequency characteristics and low loss characteristics can effectively suppress high-frequency interference and improve the quality and reliability of signal transmission.   2.3 Electric vehicles   In the drive system and battery management system of electric vehicles, ultra-microcrystalline cores are used to make high-efficiency inductors and transformers. These components can provide higher energy conversion efficiency and better thermal stability under high-power and high-frequency working environments.   2.4 Industrial automation   Ultra-microcrystalline cores are also widely used in industrial automation equipment. For example, in inverters, servo motors and other equipment, ultra-microcrystalline cores can improve the dynamic response speed and control accuracy of the system.   3. Causes of abnormal heating of ultra-fine crystal cores   3.1 Electromagnetic loss   Electromagnetic loss is one of the main reasons for heating of ultra-fine crystal cores. It includes hysteresis loss and eddy current loss. Under high-frequency working conditions, the hysteresis loop area inside the core increases, and the hysteresis loss increases; at the same time, the eddy current induced in the core also generates heat, which together cause the core to heat up.   3.2 Core saturation   When the working current exceeds the saturation current of the core, the core will enter the magnetic saturation state. At this time, the magnetic permeability of the core drops sharply, resulting in a sharp increase in core loss, which in turn causes heating.   3.3 Excessive operating frequency   Although the ultra-fine crystal core has excellent high-frequency characteristics, its loss will still increase significantly under ultra-high frequency working conditions. Especially when the design frequency range is exceeded, the core heating problem will be more prominent.   3.4 Poor heat dissipation conditions   If the working environment of the ultra-microcrystalline core has poor heat dissipation conditions, such as lack of effective heat dissipation measures or too high ambient temperature, the accumulated heat in the core cannot be dissipated in time, causing heating.   3.5 Manufacturing process problems   The manufacturing process of the core has an important impact on its performance. If the grain structure of the core is uneven or defective during the production process, it will cause its electrical performance to deteriorate, increase losses, and cause heating problems.   IV. Solutions to the heating problem of ultra-microcrystalline cores   4.1 Optimized design   Optimize the design parameters of the core according to the actual working conditions, including selecting the appropriate inductance value, core material and operating frequency range to ensure that the core works under the best conditions.   4.2 Improved heat dissipation measures   Improve the heat dissipation efficiency of the core, such as adding heat sinks, using thermal conductive glue or air cooling, etc., to improve the working environment temperature of the core and prevent overheating.   4.3 Control the working current   Avoid overloading the core, ensure that the working current is within the design range, and prevent the core from entering saturation.   4.4 Improve production process   Improve the production process of magnetic cores to ensure uniform grain structure without defects and improve the electrical performance and thermal stability of magnetic cores.   4.5 Regular maintenance and inspection   Maintain and inspect the magnetic cores regularly to find and deal with potential problems in time to ensure the normal operation and long life of the magnetic cores.

Amorphous (nanocrystalline) materials are all strip materials, so they are very brittle. If they are not wrapped or processed, their force bearing capacity is very poor. To avoid this problem, there are usually two methods: one is surface spraying; the other is to add a protective shell.   Spraying forms a good protective film on the surface of the strip amorphous (nanocrystalline) material, which increases the surface strength and greatly increases its force bearing capacity, so that it can withstand a certain external force. However, spraying only improves the strength of the surface of the amorphous material, and does not change the performance of the matrix, so the magnitude of the force is often limited.   The amorphous sprayed magnetic ring exploded directly during the ring pulling process, which is caused by excessive external force. According to experience, the sprayed magnetic ring can withstand the tension below 0.5mm wire diameter enameled wire, and the good quality can withstand the tension below 0.8mm wire diameter enameled wire. If the wire diameter of the enameled wire exceeds 0.8mm, it is recommended to use a protective shell.   The second is the protective shell solution. In this case, since the magnetic ring is added with a layer of protective shell, the wire diameter is almost unlimited. The main disadvantage is that the shell has a certain thickness, which will increase the volume of the product to a certain extent and reduce the utilization rate of the inner hole of the magnetic ring. However, in terms of reliability, adding a shell is more secure than spraying.   Secondly, amorphous (nanocrystalline) is prone to noise during application. The matrix of amorphous (nanocrystalline) is a strip, and there are certain gaps between the thin sheets. In addition, the differences in the various metal components of amorphous (nanocrystalline) can easily produce magnetostrictive effects, and noise problems will follow.   This puts higher requirements on the quality of the strip. If the strip size deviation is large and the thickness uniformity is poor, resulting in loose winding of the iron core, it will further aggravate the generation of noise.   Third, the production process of amorphous (nanocrystalline) is immature and has poor consistency. Compared with ferrite, the development time of amorphous (nanocrystalline) materials is short, the production process is not very mature, and the scale and automation effects have not been fully reflected. In the application of transformers and inductors, the discreteness of inductance is relatively poor.   Fourth, the price is expensive. Among amorphous and nanocrystalline materials, nanocrystalline is the cheapest. But compared with ferrite, the price is still relatively high. This is related to the raw materials of nanocrystals. The price of the added niobium component is still relatively expensive. Secondly, compared with ferrite, the output of amorphous (nanocrystalline) is limited, and the production process is complicated, which also pushes up the price of amorphous (nanocrystalline) products to some extent.   However, in practical applications, we need to consider the cost comprehensively. The use of amorphous (nanocrystalline) materials will increase the cost of the magnetic core, but greatly reduce the number of winding turns, reduce labor costs, reduce the cost of enameled wires, reduce copper loss and heat generation, and reduce the cost of heat dissipation. Only through comprehensive comparison can we judge whether the amorphous (nanocrystalline) solution is beneficial.

Material selection and processing   The first step in manufacturing Permalloy coils is to select the right material ratio. Typically, manufacturers use an iron-nickel alloy containing 78% to 80% nickel as the base material. These materials are processed through processes such as smelting, rolling, and annealing to ensure that they have ideal magnetic properties.   Coil winding   The winding process of Permalloy coils is very important, and the winding method will directly affect the performance of the coil. Common winding methods include single-layer winding, multi-layer winding, and honeycomb winding. In order to reduce the resistance of the coil and increase its Q value (quality factor), high-precision equipment is usually used during the winding process.   Heat treatment and forming   After winding, the coil usually needs to be heat treated. This process can improve the crystal structure of the alloy and make its magnetic properties better. After the heat treatment is completed, the coil is placed in a special mold for forming and finally made into the desired shape and size.   Testing and quality control   The manufactured Permalloy coil needs to undergo strict testing and quality control. The main test content includes the measurement of parameters such as magnetic permeability, coercivity, and hysteresis loss. Only coils that have passed rigorous testing can be put into use to ensure that they can operate stably in actual applications.

Magnetic ring inductor is one of the commonly used electronic components in the circuit. It can form an LC filter network with capacitor C, form a freewheeling circuit with diode in the step-down circuit, and can also be used in the LC resonant circuit. The following briefly introduces the application of magnetic ring inductor in the circuit.   1. Form LC filter circuit with capacitor Magnetic ring inductor can pass DC and block AC. Since the inductive reactance of magnetic ring inductor is closely related to the AC frequency, the higher the frequency of magnetic ring inductor, the greater the inductive reactance. In the LC filter circuit, the magnetic core inductor is the most common circuit structure of the switching power supply. The inductor and capacitor have a filtering effect. The AC ripple distortion in the circuit will be filtered out by the inductor, and the capacitor C has a filtering effect, which can make the back-end output smoother. This type of magnetic ring inductor is generally used in the application of switching power supply or high-power power supply.   2. Used in DC/DC step-down circuit The input range of DC/DC step-down chip is wide and the conversion efficiency is high, while the DC/DC step-down chip is generally composed of inductor, capacitor, diode, etc. to complete the circuit principle. The magnetic core inductor is a common DC/DC power chip in the DC/DC step-down circuit. The inductor and the diode form a freewheeling function here. When the internal MOS tube is turned on, the inductor stores energy; when the internal MOS tube is turned off, the energy stored in the inductor supplies power to the load. This is also the most common PWM step-down principle at present.   3. Used in LC resonant circuit LC can form parallel resonance or series resonance, which is generally called frequency selection. Among many input frequencies, only those that are consistent with resonance can pass. This type of circuit is often used in applications such as radios and smart TVs. When designing the LC resonant circuit, a lot of calculations must be performed to determine the optimal parameters of the magnetic ring inductor and capacitor.   The magnetic ring inductor is a coil containing a magnetic ring. Because the electromagnetic coil has an inductive reactance to the alternating current after the power is turned on, it forms an electronic component-an inductor. The inductance value of the inductor ranges from a few micrometers to tens of millihenries. Originally, the inductor can be formed by only using coils, but in order to increase the inductance and reduce the volume and line resistance, a ferrite core with little eddy current damage is added. For example, if a 1 microhenry electromagnetic coil is added with a core with a magnetic permeability of 100, the inductance is theoretically increased by 100 times to 100 microhenries. But in fact, how much the actual increase is not only related to the magnetic permeability, but also to the shape of the core. Generally, the core inductance of tens of millihenries is mostly used in high-frequency AC circuits. The inductance in AC circuits under hundreds of Hz will be above hundreds of millihenries. It is no longer suitable to use a core, but it is changed to microcrystal, permalloy, or even silicon steel sheet, which increases the volume and weight. In areas where the inductance quality Q is required to be very high, no iron core is added!

Permalloy, as a material with high magnetic permeability and low coercivity, is widely used in various magnetic components and equipment. Its unique physical properties have attracted much attention for its application in audio transformers. Audio transformer is an important component in audio equipment, which directly affects the sound quality. The following editor will discuss in detail the application of permalloy in audio transformers, analyze its impact on sound quality and its advantages and disadvantages in practical applications.   1. Basic characteristics of permalloy   1. Advantages of high magnetic permeability   One of the most notable properties of permalloy is its high magnetic permeability. This means that at lower magnetic field strengths, permalloy can produce higher magnetic flux densities. This feature is particularly important in audio transformers. Audio transformers need to transmit audio signals over a wide frequency range, and high magnetic permeability can ensure that the transformer can work effectively under low magnetic field strengths, thereby reducing core loss and improving transmission efficiency.   High permeability also means the transformer core can be smaller and lighter. This is especially important for portable audio devices, as reducing weight and volume is an important factor in improving portability and user experience. In addition, high magnetic permeability can also reduce the self-noise of the transformer and provide clearer audio output.   2. Low coercivity and low loss   Low coercivity is another important characteristic of permalloy. Low coercivity means low hysteresis losses, which in audio transformers can significantly reduce signal distortion. During the transmission of audio signals, if the hysteresis loss of the magnetic core is large, it will cause signal distortion and increase noise, thus affecting the sound quality. Permalloy's low coercivity properties allow it to maintain low hysteresis losses, thereby improving the clarity and fidelity of sound quality.   In addition, low coercivity also means that the transformer can respond more quickly at different audio frequencies. This is especially important for high-fidelity audio equipment, because fast response can ensure accurate transmission of audio signals and reduce distortion and attenuation of high-frequency signals.   3. Wide frequency response range   The stable performance of permalloy over a wide frequency range is another advantage in audio transformer applications. Audio signals contain a wide frequency range from low to high frequencies. Traditional magnetic materials may degrade in certain frequency ranges, while permalloy maintains good magnetic permeability and low loss over a wide frequency range.   This characteristic allows permalloy transformers to provide a smoother and more consistent frequency response when transmitting audio signals. This means that whether it is deep sound effects at low frequencies or crisp sounds at high frequencies, they can be accurately transmitted, providing a richer and more realistic sound quality experience.   2. Application advantages of permalloy transformers   1. Improve the clarity of sound quality   A significant advantage of permalloy transformers in terms of sound quality is their ability to improve the clarity of sound quality. Due to permalloy's high magnetic permeability and low coercivity, the transformer minimizes distortion and noise when transmitting audio signals. This significantly improves the overall sound quality of audio equipment, allowing listeners to experience purer and more realistic sound.   Especially in high-fidelity audio equipment, this advantage of permalloy transformers is particularly obvious. Whether it is music playback equipment, professional recording equipment, or high-end sound systems, the use of permalloy transformers can significantly improve the clarity and detail expression of sound quality, allowing listeners to hear more details and layers in music.   2. Reduce distortion and noise   Distortion and noise are common problems in audio equipment. They can seriously affect the sound quality, making the sound blurry and unreal. Permalloy transformers can effectively reduce distortion and noise during the transmission of audio signals due to their low coercivity and low hysteresis loss.   This low-distortion characteristic allows permalloy transformers to maintain higher fidelity during audio signal transmission and reduce sound quality degradation caused by signal distortion. At the same time, the low noise characteristics allow the transformer to provide cleaner and pure sound quality when transmitting audio signals, which is especially important for high-fidelity audio equipment.   3. Advantages of wide frequency response   The stable performance of permalloy transformers in a wide frequency range makes them widely used in audio equipment. Audio signals range in frequency from low to high frequencies, and permalloy transformers are able to maintain good performance across this wide frequency range, providing consistent and stable frequency response.   This advantage of wide frequency response allows permalloy transformers to provide smoother and more accurate sound quality when transmitting audio signals. This is particularly important for music playback equipment and professional recording equipment, which need to provide consistent and high-quality audio output across different frequency ranges.   3. Practical application of permalloy transformer   Music playing equipment   In high-end music playback equipment, permalloy transformers are widely used in signal transmission and sound quality processing. These devices require high-fidelity audio transmission and processing capabilities, and the high permeability, low coercivity, and wide frequency response characteristics of permalloy transformers meet this need and provide superior sound quality.   Whether it is a home audio system, professional recording equipment, or a portable music player, permalloy transformers can significantly improve the sound quality, allowing users to experience more realistic and delicate music effects.   Professional recording equipment   In professional recording equipment, permalloy transformers also play an important role. Recording equipment requires high-precision and low-distortion audio transmission and processing capabilities to ensure the high fidelity and clarity of the recorded audio signals. The low distortion and low noise characteristics of permalloy transformers enable recording equipment to capture and transmit more realistic and high-quality audio signals to meet the needs of professional recording.   High-end sound system   High-end audio systems have extremely high requirements for sound quality, and the characteristics of permalloy transformers make them an ideal choice for such equipment. These sound systems require consistent and high-quality audio output over a wide frequency range, and permalloy transformers meet this need, delivering superior sound quality and listening experience.   Limitations of Permalloy Transformers   Cost issue   A major limitation of permalloy is its relatively high cost. Due to its complex manufacturing process and high material cost, the overall cost of permalloy transformers is high. This may not be ideal for some cost-sensitive application scenarios, where there is a trade-off between performance and cost.   saturation magnetic flux density   Although permalloy has high magnetic permeability, its saturation magnetic flux density is relatively low. This means that in high-power applications, permalloy transformers may be more susceptible to magnetic saturation, affecting their performance and sound quality. Therefore, in applications requiring high power and high flux density, other magnetic materials may need to be considered.   ​Limitations in scope of application   Although permalloy transformers have significant advantages in audio equipment, their application scope is still limited. Due to its high cost and low saturation magnetic flux density, permalloy transformers are mainly used in high-fidelity audio equipment and professional recording equipment. For some ordinary audio equipment and low-cost applications, their use may be limited.

Permalloy metal core: various types of Permalloy materials have their own typical magnetic properties that are superior to silicon steel materials and ferrites, and have higher temperature stability and aging stability.   High initial permeability Permalloy material (IJ79, IJ85, IJ86) cores are often used to make current transformers and small signal transformers; high rectangular Permalloy material (IJ51) cores are often used to make magnetic amplifiers and two-stage pulse transformers; low remanence Permalloy material (IJ67h)   Cores are often used to make small and medium power unipolar pulse transformers   2. Amorphous core:   ⑴ Iron-based amorphous core:   It has the highest saturation magnetic induction intensity (1.451.56T) among almost all amorphous alloy cores, and also has high permeability, low coercivity, low loss, low excitation current and good temperature stability and aging stability.   Mainly used to replace silicon steel sheets, as various forms and different power power distribution transformers, medium frequency transformers, the operating frequency ranges from 50Hz to 10KHz; as the core of high-power switching power supply reactor, the use frequency can reach 50KHz.   ⑵ Iron-nickel based amorphous core:   Medium to low saturation magnetic induction intensity (0.75T), high magnetic permeability, low coercivity, wear resistance and corrosion resistance, good stability. Commonly used to replace Permalloy core as the zero-sequence current transformer core in leakage switch.   ⑶ Cobalt-based amorphous core:   It has the highest magnetic permeability among all amorphous alloy cores, and also has medium to low saturation magnetic induction intensity (0.65T), low coercivity, low loss, excellent wear resistance and corrosion resistance, good temperature stability and aging stability, and impact and vibration resistance. It is mainly used to replace Permalloy core and ferrite core to make high-frequency transformers, filter inductors, magnetic amplifiers, pulse transformers, pulse compressors, etc. in high-end fields (military)   Permalloy is essentially an iron-nickel (FeNi) alloy with very low coercivity, but high saturation magnetic density Bs, magnetic permeability and Curie temperature, close to pure iron. Multi-element Permalloy, the initial relative magnetic permeability can reach 30000~80000, but the resistivity is low, about 10-7Ω-m, it can be processed into extremely thin sheets, so it can be used at working frequencies up to (20~30)kHz. Permalloy thin strips with a thickness of 0.02mm are commonly used in domestic engineering, and there are also 0.005mm thick thin strips, but because the surface of the thin strip must be insulated during the winding process of the magnetic core, its filling factor is greatly reduced, so it is rarely used in engineering. When the application frequency exceeds 30kHz, due to the low resistivity of Permalloy, its loss will increase significantly. High magnetic permeability alloy (Permalloy) High magnetic permeability alloy refers to iron-nickel alloys with high initial and maximum magnetic permeability, and most of the trade names are called "Permalloy".   In addition to high magnetic permeability, Permalloy has relatively low loss, especially good environmental adaptability and stable performance. Although it is expensive, it is still used in power supplies with relatively strict conditions. The main type of Permalloy is iron-nickel alloy, which is composed of nickel (35% to 85%), iron and added molybdenum, copper, tungsten, etc. It was basically finalized in the 1940s and was widely used in the 1970s and 1980s, forming dozens of models, which are generally classified according to the nickel content. Low nickel alloys with a nickel content of 30% to 50% are low nickel alloys, such as China's 1J30, 1J34, 1J50, 1J51, etc. High nickel alloys with a nickel content of 65% to 85% are high nickel alloys, such as China's 1J66, 1J79, 1J80, 1J88, etc. According to the needs of power supplies, various types of Permalloy strips have been developed. There are materials with rectangular, non-rectangular, and linear (constant magnetic conductivity) hysteresis loops. They can be rolled into various specifications with thicknesses from 0.20mm to 0.005mm (5μm). Generally, 0.20mm thick Permalloy is used for 50Hz, and 0.005mm thick Permalloy is used for 500kHz to 1MHz, covering the entire frequency range from industrial frequency to medium frequency to high frequency, and has long broken through the old concept that it can only be used below 20kHz. Like silicon steel and soft ferrites, Permalloy has also been developing rapidly in the past decade. One is to add chromium and other elements to iron-nickel alloys with low nickel content to achieve magnetic conductivity with high nickel content, thereby reducing costs. The reported Ni38Cr8Fe alloy has a magnetic permeability of 100,000 to 300,000 at H=0.4A/m, which is close to the level of high nickel content alloys. What is more outstanding is that in recent years, domestic and foreign companies have successively launched Permalloy products with high initial magnetic permeability of 200,000 to 300,000 and maximum magnetic permeability of 350,000 to 500,000. Another breakthrough is the manufacturing process of Permalloy thin strips, which are rolled into ultra-thin strips with a thickness of 0.01mm to 0.005mm, expanding the frequency application range. When Bm is 0.1T, the loss of 0.126W/g at 500kHz, 0.392W/g at 1MHz, 6.79W/g at 5MHz, and 23.1W/g at 10MHz for 0.005mm thick Ni80Mo5 Permalloy ultra-thin strips. It can be used in power transformers above 1MHz.   Powder cores   1. Magnetic powder cores   Magnetic powder cores are a kind of soft magnetic material made by mixing ferromagnetic powder particles and insulating media. Since the ferromagnetic particles are very small (0.5 to 5 microns for high frequency) and separated by non-magnetic electrical insulating film materials, on the one hand, eddy currents can be isolated and the material is suitable for higher frequencies; on the other hand, due to the gap effect between particles, the material has low magnetic permeability and constant magnetic permeability characteristics; and because the particle size is small, skin phenomenon basically does not occur, and the change of magnetic permeability with frequency is relatively stable. It is mainly used for high-frequency inductance. The magnetic and electrical properties of magnetic powder cores mainly depend on the magnetic permeability of the powder material, the size and shape of the powder, their filling factor, the content of the insulating medium, the molding pressure and the heat treatment process.   Commonly used magnetic powder cores are iron powder cores, Permalloy powder cores and Sendust powder cores.   The calculation formula for the effective magnetic permeability μe and inductance of the magnetic core is: μe = DL/4N2S × 109   Where: D is the average diameter of the magnetic core (cm), L is the inductance (share), N is the number of winding turns, and S is the effective cross-sectional area of ​​the magnetic core (cm2).   (1) Iron powder core   Common iron powder cores are made of carbon-based ferromagnetic powder and resin carbon-based ferromagnetic powder. The price is the lowest among powder cores. The saturation magnetic induction value is about 1.4T; the magnetic permeability ranges from 22 to 100; the initial magnetic permeability μi has good stability with frequency; the DC current superposition performance is good; but the loss is high at high frequency. Changes in the initial magnetic permeability of the iron powder core with the DC magnetic field strength Changes in the initial magnetic permeability of the iron powder core with frequency   (2) Permalloy powder core   Permalloy powder cores mainly include molybdenum permalloy powder cores (MPP) and high flux powder cores (High Flux).   MPP is composed of 81% Ni, 2% Mo and Fe powder. The main features are: saturation magnetic induction value is about 7500Gs; the magnetic permeability range is large, from 14 to 550; it has the lowest loss among powder cores; it has excellent temperature stability and is widely used in space equipment, open-air equipment, etc.; the magnetostriction coefficient is close to zero, and no noise is generated when working at different frequencies. Mainly used in high-quality Q filters below 300kHz, inductive load coils, resonant circuits, LC circuits with high temperature stability requirements, output inductors, power factor compensation circuits, etc., commonly used in AC circuits, and the most expensive among powder cores.   High flux powder core HF is composed of 50% Ni and 50% Fe powder. The main features are: saturation magnetic induction value is around 15000Gs; magnetic permeability ranges from 14 to 160; it has the highest magnetic induction intensity and the highest DC bias capability among powder cores; and the core size is small. Mainly used in line filters, AC inductors, output inductors, power factor correction circuits, etc., commonly used in DC circuits, and is more used in high DC bias, high DC and low AC. The price is lower than MPP.   (3) Kool Mμ Cores   Kool Mμ Cores are composed of 9% Al, 5% Si, and 85% Fe powder. It is mainly used to replace iron powder core, with 80% lower loss than iron powder core, and can be used at frequencies above 8kHz; saturation magnetic induction is about 1.05T; magnetic permeability ranges from 26 to 125; magnetostriction coefficient is close to 0, no noise is generated when working at different frequencies; it has higher DC bias capability than MPP; and has the best performance-price ratio. It is mainly used in AC inductors, output inductors, line filters, power factor correction circuits, etc. Sometimes it is also used as a transformer core instead of air-gap ferrite.   II) Tape-wound core   1. Silicon steel sheet core   Silicon steel sheet is an alloy. The iron-silicon alloy formed by adding a small amount of silicon (generally below 4.5%) to pure iron is called silicon steel. This type of core has the highest saturation magnetic induction value of 20000Gs; because they have good magnetoelectric properties, are easy to mass produce, cheap, and have little mechanical stress, they are widely used in the power electronics industry, such as power transformers, distribution transformers, current transformers and other cores. It is the material with the largest output and usage among soft magnetic materials. It is also the material with the largest usage among magnetic materials for power transformers. It is especially suitable for low frequency and high power. Commonly used are cold-rolled silicon steel sheet DG3, cold-rolled non-oriented electrical steel strip DW, and cold-rolled oriented electrical steel strip DQ, which are suitable for medium and small power low-frequency transformers and chokes, reactors, and inductor cores in various electronic systems and household appliances. This type of alloy has good toughness and can be processed by punching, cutting, etc. The core has stacked and wound types. However, the loss increases sharply at high frequencies, and the general use frequency does not exceed 400Hz. From the application point of view, the selection of silicon steel should consider two factors: magnetism and cost. For small motors, reactors and relays, pure iron or low silicon steel sheets can be selected; for large motors, high silicon hot-rolled silicon steel sheets, single-oriented or non-oriented cold-rolled silicon steel sheets can be selected; single-oriented cold-rolled silicon steel sheets are often used for transformers. When used at power frequency, the thickness of the commonly used strip is 0.2~0.35 mm; when used at 400Hz, 0.1 mm is often selected. The thinner the thickness, the higher the price.   2. Permalloy   Permalloy often refers to an iron-nickel alloy with a nickel content in the range of 30~90%. It is a widely used soft magnetic alloy. Through appropriate processes, magnetic properties can be effectively controlled, such as an initial magnetic permeability of more than 105, a maximum magnetic permeability of more than 106, a coercive force as low as 2‰ Oersted, and a rectangular coefficient close to 1 or close to 0. Permalloy with a face-centered cubic crystal structure has good plasticity and can be processed into 1μm ultra-thin strips and various usage forms. Commonly used alloys include 1J50, 1J79, 1J85, etc. The saturation magnetic induction intensity of 1J50 is slightly lower than that of silicon steel, but the magnetic permeability is dozens of times higher than that of silicon steel, and the iron loss is 2~3 times lower than that of silicon steel. Made into a transformer with a higher frequency (400~8000Hz), the no-load current is small, and it is suitable for making small higher frequency transformers below 100W. 1J79 has good comprehensive performance and is suitable for high-frequency low-voltage transformers, leakage protection switch cores, common-mode inductor cores and current transformer cores. The initial magnetic permeability of 1J85 can reach more than 100,000 105, which is suitable for low-frequency or high-frequency input and output transformers, common-mode inductors and high-precision current transformers for weak signals.   3. Amorphous and Nanocrystalline Soft Magnetic Alloys   Silicon steel and Permalloy soft magnetic materials are both crystalline materials. The atoms are arranged regularly in three-dimensional space to form a periodic lattice structure. There are defects such as grains, grain boundaries, dislocations, interstitial atoms, and magnetocrystalline anisotropy, which are not conducive to soft magnetic properties. From the perspective of magnetic physics, the amorphous structure with irregular atomic arrangement and no periodicity and grain boundaries is very ideal for obtaining excellent soft magnetic properties. Amorphous metals and alloys are a new material field that came out in the 1970s. Its preparation technology is completely different from the traditional method. Instead, it adopts ultra-rapid cooling and solidification technology with a cooling rate of about one million degrees per second. From molten steel to thin strip finished products, it is formed in one step, which reduces many intermediate processes compared to the general cold-rolled metal thin strip manufacturing process. This new process is called a revolution in traditional metallurgical processes. Due to ultra-rapid cooling and solidification, the atoms do not have time to arrange and crystallize in an orderly manner when the alloy solidifies. The solid alloy obtained is a long-range disordered structure without the grains and grain boundaries of crystalline alloys. It is called an amorphous alloy and is called a revolution in metallurgical materials. This amorphous alloy has many unique properties, such as excellent magnetism, corrosion resistance, wear resistance, high strength, hardness and toughness, high resistivity and electromechanical coupling performance. Due to its excellent performance and simple process, it has become the focus of research and development in the material science community at home and abroad since the 1980s. At present, the United States, Japan, and Germany have a complete production scale, and a large number of amorphous alloy products have gradually replaced silicon steel, Permalloy and ferrite to flood the market.

Permalloy and pig iron are both important iron-based materials, but they have significant differences in composition, properties and uses. Here is a detailed comparison of permalloy and pig iron:   Properties of Permalloy Element Main ingredients: Permalloy is mainly composed of about 80% nickel (Ni) and 20% iron (Fe), sometimes also containing a small amount of molybdenum (Mo), chromium (Cr) or other elements to optimize its Magnetic properties.   Magnetic properties High magnetic permeability: Permalloy has extremely high initial magnetic permeability and maximum magnetic permeability, allowing it to achieve high magnetic induction intensity even under low magnetic field intensity.   Low coercivity: Permalloy has a very low coercivity, which means less loss during magnetization and demagnetization, making it suitable for applications that require rapid response to changing magnetic fields.   Low losses: In high-frequency applications, permalloy has low hysteresis losses and eddy current losses, making it excellent in high-frequency electromagnetic equipment.   Magnetic stability: Permalloy can maintain stable magnetic properties over long periods of use.   use Communication equipment: Transformers and filters used for telephone lines and data lines to improve signal transmission quality.   Power electronic equipment: used in high-frequency transformers and inductors to improve the energy efficiency and performance of equipment.   Medical equipment: Used in magnetic shields and inductors in magnetic resonance imaging (MRI) equipment to improve image quality and diagnostic accuracy.   Aerospace and military: used in navigation systems, radar and communication systems to ensure that equipment works efficiently and stably in complex environments.   Characteristics of pig iron Element Main components: Pig iron is mainly composed of iron (Fe) and a higher carbon (C) content, usually between 2.0% and 4.5%. Pig iron also contains impurities such as silicon (Si), manganese (Mn), phosphorus (P) and sulfur (S).   Mechanical properties High hardness and brittleness: Due to the high carbon content, pig iron has high hardness and brittleness, low tensile strength and is easily broken.   Low ductility: Pig iron has little ability to plastically deform and cannot be processed by forging or rolling.   Lower melting point: Pig iron has a lower melting point than pure iron and steel, making it easy to cast into complex-shaped castings.   use Casting parts: Pig iron is widely used to cast various complex-shaped parts, such as pipes, valves, pump casings and machine beds.   Raw material: Pig iron is the raw material for steelmaking and is converted into steel through the steelmaking process.   Wear-resistant parts: Due to its high hardness, pig iron is used in the manufacture of wear-resistant parts such as wear plates and grinder liners.   The main differences between permalloy and pig iron Composition and structure Composition: Permalloy is mainly composed of nickel and iron, while pig iron is mainly composed of iron and carbon and contains other impurities.   Structure: Permalloy is an alloy with high magnetic permeability, while pig iron is an iron-based material with high carbon content.   Magnetic and mechanical properties Magnetic properties: Permalloy has excellent magnetic properties such as high permeability, low coercivity and low losses, making it suitable for high-frequency and high-efficiency magnetic applications. Pig iron has no significant magnetic properties.   Mechanical properties: Permalloy has moderate mechanical properties and is suitable for processing into thin sheets and complex-shaped cores. Pig iron has high hardness and brittleness and is mainly used for casting wear-resistant parts and complex castings.   use Permalloy: widely used in high-frequency transformers, inductors, communication equipment, medical equipment and military fields.   Pig iron: Mainly used for castings, steelmaking raw materials and manufacturing wear-resistant parts.   It can be seen from the above comparison that permalloy and pig iron have significant differences in composition, properties and uses, and each plays an important role in different application fields.

Permalloy is a nickel-iron alloy with high magnetic permeability, which is usually used to make magnetic shielding materials. The magnetic shielding performance of Permalloy is related to its thickness, alloy composition and magnetic field frequency. Generally speaking, increasing the thickness of Permalloy can improve its magnetic shielding effect, but the specific strength of the shielding magnetic field should also consider the following factors:   1. Thickness: The thicker the Permalloy is, the better the shielding effect. The thickness of Permalloy sheets usually used for shielding ranges from 0.1 mm to several millimeters.   2. Magnetic permeability: The higher the magnetic permeability of Permalloy, the better the shielding effect. The magnetic permeability of Permalloy can reach several thousand or even higher.   3. Magnetic field strength: The shielding effect is related to the strength of the external magnetic field. In weak magnetic fields, Permalloy has a better shielding effect, but in strong magnetic fields, its shielding effect may be weakened.   4. Frequency: Permalloy has a good shielding effect on low-frequency magnetic fields (such as DC magnetic fields and power frequency magnetic fields), but a relatively poor shielding effect on high-frequency magnetic fields.   The calculation of the specific shielding magnetic field strength needs to take these factors into consideration, and may require experiments to determine the best shielding effect. If there are specific application scenarios or parameters, more detailed information can be provided to obtain more accurate calculations or suggestions.