What is the relationship between the motor and the magnet material magnetic steel

Magnetic steel is actually a very broad meaning of the thing, simply speaking is the permanent magnet, the traditional called magnet, of course, the magnetic steel is relatively weak. After the industrial revolution, through the research of Faraday, Max, Wellorentz and others, electromagnetic transformation has become the driving force leading the development of the times. Then the electromagnetic theory at this time is available, but subject to the process and material problems of permanent magnets, the volume of DC motors has become a bottleneck that cannot be broken through. 9.18 that year, not only did the Japanese enter the northeast, but the Japanese also made a breakthrough in metallurgy: Mishima Deqi made a breakthrough in discovering that proper ratio of aluminum-nickel-cobalt can obtain good magnetic properties, and magnetic steel can

Magnetic steel is actually a very broad meaning of the thing, simply speaking is the permanent magnet, the traditional called magnet, of course, the magnetic steel is relatively weak.
After the industrial revolution, through the research of Faraday, Max, Wellorentz and others, electromagnetic transformation has become the driving force leading the development of the times. Then the electromagnetic theory at this time is available, but subject to the process and material problems of permanent magnets, the volume of DC motors has become a bottleneck that cannot be broken through.
 
9.18 that year, not only did the Japanese enter the northeast, but also the Japanese made a breakthrough in metallurgy: Mishima Deqi made a breakthrough in finding that proper ratio of aluminum-nickel-cobalt can obtain good magnetic properties, and magnetic steel can be made without demagnetization at high temperature (600 degree environment), which also provided an opportunity for the development of strong magnetic steel in the later period, thus bringing about a leap in the miniaturization of DC motors, of course, with the demand of human beings, magnetic steel quickly kept pace with the demand. Therefore, NdFeB rare earth magnetic steel used in electric vehicle motors came out in the early 1970 s and was finalized in 1983. The NdFeB formula standard has continued to occupy the throne of magnetic king until now. Unfortunately, the Japanese also won this honor again.
 
Needless to say, the magnetic properties of NdFeB are the most cost-effective of all magnetic materials, and can release larger magnetic energy products in a small volume, which is also the reason why electric vehicle motors can be popularized on a large scale within ten years. However, the disadvantage of being afraid of high temperature and corrosion is also obvious, so what kind of magnetic steel is a good magnetic steel can also be seen from its technological process: ingredients → smelting ingot/sling → milling → profiling → sintering and tempering → magnetic detection → grinding → pin cutting → electroplating → finished products.
As the saying goes, no matter how good a cook is, he can't make a good banquet with inferior ingredients. The same is true for magnetic steel. The material determines the performance of the product. The so-called temperature resistance of magnetic steel depends first on its material and then on its volume. NdFeB magnet steel is only used in the electric vehicle with four grades of N,M,H and SH, and its performance is from low to high. Among them, N material can only work on the handle because its temperature resistance is too low and only 80 degrees. M material has a temperature resistance of 100 degrees, which has become the first choice for electric vehicle motors. H material has a temperature resistance of 120 degrees and is suitable for motors with relatively high power. As for SH material with a temperature resistance of 150 degrees, after 11 years of magnetic steel prices basically disappeared in the electric car industry.
 
So is there any difference between magnets of the same brand? People have 369 grades, meat is divided into five flowers and three layers, and products of the same brand are also different. First is consistency. The number of magnetic steel in a motor is 40 at every turn. The magnetic steel factory can stabilize it within a certain range of values to form a uniform magnetic field. Only in this way can the motor have high efficiency. Otherwise, it will fall into a vicious circle of: uneven magnetic field-large power consumption-heating temperature rise-demagnetization of magnetic steel-further uneven power consumption-further increase of temperature rise.
The second is the problem of dysprosium content. Dysprosium plays a role in magnetic steel like monosodium glutamate, adding a small amount but has a decisive significance: temperature resistance. The so-called temperature resistance here refers to that the demagnetization of magnetic steel in the hub environment shall not exceed the specified value within 2 hours at the test temperature. Generally, this value is not more than 3%, and this demagnetization is irreversible. The demagnetization coefficient of materials of the same brand is much worse than that of dysprosium. It happens that the current price of this product is nearly 7 million/ton, therefore, in order to reduce costs, various magnetic steel mills basically make ideas on the amount of dysprosium. This is the main reason why many people's motors feel slower and slower after riding for a few years and consume more and more electricity.
 
Next, some people will ask, we can't see these so-called technological processes at all, and we can't determine whether the manufacturer can process with quality and quantity. What should we do?
The method is very simple. Most chip factories cannot confirm the sintering process and ingredients of the previous process, but they can master your test data to determine whether it is qualified. Then the test data used by consumers to judge whether it is qualified is the warranty period. Brushless DC motors have appeared on electric vehicles for nearly 20 years today, and the warranty period of electronic components has corresponding regulations: three years for the motor, one year for the controller battery, and three months for the transfer. The three-year warranty of this motor is a hard and fast rule, because if your material is qualified and the design is reasonable, there will be no problem in normal operation within three years; if the warranty is less than three years, it can basically be judged that it is cutting corners, otherwise it is the process. Great irrationality.