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Air transportation has certain particularities. To ensure safety, both people and goods need to undergo security checks before boarding. If you carry magnetic materials, such as NdFeB magnets, or if customers are in a hurry to get the goods and hope that the manufacturer will ship them by air, can we bring the magnets on board?   Since weak stray magnetic fields can interfere with the aircraft's navigation system and control signals, the International Air Transport Association (IATA) has classified magnetic cargo as Class 9 dangerous goods, which must be restricted during transportation. Therefore, some air cargo with magnetic materials now needs to undergo magnetic testing to ensure the normal flight of the aircraft. Magnetic materials, audio materials, and other instruments with magnetic accessories must undergo magnetic testing.     Airlines or logistics companies that transport magnetic materials will force customers to undergo magnetic testing and issue an "Air Transport Conditions Identification Report" to ensure the normal flight of the aircraft. Air transport identification can generally only be issued by a qualified professional identification company recognized by the country's civil aviation administration, and it is generally necessary to send samples to the identification company for professional testing before issuing an identification report. If it is inconvenient to send samples, the identification company's professionals will conduct on-site testing and then issue an identification report. The validity period of the identification report is generally for the current year, and it is generally necessary to re-do it after the New Year.   During magnetic testing, customers are required to pack the goods according to air transport requirements. The testing will not damage the packaging of the goods. In principle, the goods will not be unpacked for testing, but only the stray magnetic field of the six sides of each piece of goods will be tested. If the goods fail the magnetic test, special attention should be paid. First, with the consent of the customer, the magnetic inspection staff will unpack the goods for inspection, and then make relevant reasonable suggestions based on the specific situation. If the shielding can meet the requirements of air transportation, the goods will be shielded according to the customer's entrustment, and relevant fees will be charged.  

The internal structure of the neodymium magnetic bar is not just composed of a whole magnet. In fact, the neodymium magnetic bar consists of an internal magnetic core and an external cladding. The magnetic core is the core part of the magnetic bar, usually composed of a cylindrical magnetic block and a conductive magnetic sheet. These magnetic blocks and conductive magnetic sheets work together to generate a strong magnetic field, thereby achieving the adsorption of ferromagnetic materials.   The external cladding plays a role in protecting the magnetic core and enhancing the stability of the magnetic bar structure. At the same time, a good magnetic bar equipment should have a uniform spatial distribution of magnetic induction lines, and the distribution of magnetic induction points should fill the entire magnetic bar as much as possible to ensure that it can provide stable adsorption at all positions.     Therefore, although the magnetic bar contains magnetic components inside, its structure is far more complex than a single magnet, and is the result of the coordinated work of multiple components. This design enables the magnetic bar to efficiently and accurately remove ferromagnetic impurities and improve product quality in the fields of chemical, food, and waste recycling.   As a professional neodymium magnets manufacturer, Huajin provides bulk magnetic rods with high gauss magnet strength that can be customized according to customer requirements.  

Neodymium ndfeb materials have poor thermal stability, and their high temperature coefficient can easily cause irreversible demagnetization (also known as demagnetization) when permanent magnet motors are running.   On the one hand, the eddy current of permanent magnet motors generates heat on the surface of permanent magnets, and the heat dissipation conditions inside the motor are poor, which exceeds the working temperature of permanent magnets, causing permanent magnet demagnetization. Therefore, the temperature stability of permanent magnets is crucial to motor applications.   On the other hand, the unreasonable design of the working point of the permanent magnet motor magnetic circuit is also prone to irreversible demagnetization. When the motor encounters a large demagnetization during starting, reversing and stalling, the working point of NdFeB may drop below the inflection point of the demagnetization curve, causing irreversible demagnetization. Therefore, the working point of the permanent magnet motor magnetic circuit should be designed to be higher than the inflection point of the NdFeB material. When the motor stops running, the residual magnetic induction intensity Br of the permanent magnet material remains basically unchanged.   The design of permanent magnet motors must also understand the actual operating environment of the motor and take necessary measures in assembly to ensure that it is in a stable state without demagnetization at high temperatures. The SH grade NdFeB magnets used in motors that meet the standard requirements cannot guarantee that the motor will not lose magnetism during operation. Only by increasing the intrinsic coercive force and Curie temperature of the NdFeB magnets can the irreversible magnetic loss of the NdFeB magnets be reduced and the temperature stability of the permanent magnets be improved, thereby extending the service life of the permanent magnet motor.   

In daily life, magnets are a very common thing. From various special electronic devices to daily teaching aids and toys, magnets can often be seen.   We know that the main component of magnets is ferroferric oxide. An ordinary small magnet is made of black ferroferric oxide. However, due to the nature of ferroferric oxide itself, its attraction to iron objects is not too strong, and its magnetism will gradually weaken over time. In this case, how can we make a magnet with stronger attraction and less prone to decay? Under this premise, neodymium iron boron magnets came into being.     This kind of magnet with a shiny surface after anti-corrosion treatment is a neodymium boron magnets, and its chemical formula is Nd2Fe14B. The most commonly used neodymium iron boron magnet is made of neodymium, iron, and boron at high temperature sintering, and is the strongest artificial magnet to date. If the core element of traditional ferroferric oxide is iron, then the reason why neodymium iron boron magnets have such strong magnetism is the role of neodymium. The pieces of metal in the picture below are neodymium:     Neodymium is the fourth element of the lanthanide family of rare earth elements. Like iron, cobalt, nickel and the aforementioned gadolinium, it can also be attracted by magnets. In addition, neodymium is the most active of the lanthanide elements, so it is easily oxidized like iron, which is why there is a coating on the surface of the NdFeB magnet. If neodymium is used to enhance magnetism, then the role of boron should not be underestimated.    In the periodic table, boron is located to the left of carbon, so boron chemistry similar to carbon-centered organic chemistry has recently emerged. In NdFeB magnets, boron is the mediator between neodymium and iron. Boron greatly expands the maximum magnetism that a substance can produce while ensuring the stability of its molecular structure, making the neodymium magnetic properties of the entire magnet extremely high, and even allowing it to attract objects equivalent to 640 times its own weight.  

1. What is a motor? A motor is a component that converts battery energy into mechanical energy to drive the wheels of an electric vehicle. 2. What is winding? The armature winding is the core part of the DC motor. It is a coil wound with copper enameled wire. When the armature winding rotates in the magnetic field of the motor, it will generate electromotive force. 3. What is a magnetic field? It refers to the force field generated around a permanent magnet or electric current and the space or range of magnetic force that can be reached. 4. What is magnetic field strength? The magnetic field strength of an infinitely long wire carrying a current of 1 ampere at a distance of 1/2 meter from the wire is 1A/m (ampere/meter, SI); in the CGS unit system (centimeter-gram-second), in order to commemorate Oersted's contribution to electromagnetism, the magnetic field strength of an infinitely long wire carrying a current of 1 ampere at a distance of 0.2 cm from the wire is defined as 10e (Oersted), 10e=1/4.103/m, and the magnetic field strength is usually represented by H. 5. What is Ampere's law? Hold the wire with your right hand, with your extended thumb pointing in the same direction as the current. Then the direction pointed by your bent four fingers is the direction of the magnetic flux lines. 6. What is magnetic flux? Magnetic flux is also called magnetic flux: suppose there is a plane perpendicular to the direction of the magnetic field in a uniform magnetic field, the magnetic induction intensity of the magnetic field is B, and the area of ​​the plane is S. We define the product of the magnetic induction intensity B and the area S as the magnetic flux passing through this surface. 7. What is a stator? The part of a brushless or brushless motor that does not rotate when it is working. The motor shaft of a hub-type brushless or brushless gearless motor is called a stator. This type of motor can be called an internal stator motor. 8. What is a rotor? The part that rotates when a brushed or brushless motor is working. The outer shell of a hub-type brushed or brushless gearless motor is called a rotor, and this type of motor can be called an external rotor motor. 9. What is a carbon brush? A brush is placed on the surface of the commutator in a motor. When the motor rotates, it transmits electrical energy to the coil through the commutator. Since its main component is carbon, it is called a carbon brush and is easy to wear. It should be regularly maintained and replaced, and carbon deposits should be cleaned. 10. What is a brush holder? A mechanical guide that holds and holds the carbon brushes in place in a brushless motor. 11. What is a commutator? Inside a brushed motor, there are mutually insulated strip metal surfaces. As the motor rotor rotates, the strip metal alternately contacts the positive and negative poles of the brushes, achieving alternating positive and negative changes in the direction of the motor coil current, completing the commutation of the brushed motor coil. 12. What is phase sequence? The order in which the brushless motor coils are arranged. 13. What is magnet? It is generally used to refer to magnetic materials with high magnetic field strength. Electric vehicle motors all use neodymium permanent magnets. 14. What is electromotive force? It is generated by the rotor of the motor cutting the magnetic lines of force. Its direction is opposite to that of the external power supply, so it is called back electromotive force.