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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.