[Guide] During the operation of the motor, the conductive material will affect the motor efficiency, power factor, temperature rise and other performance indicators due to heat. In view of the above reasons, on the one hand, we can control the materials through the selection of suppliers, on the other hand, we can be equipped with the necessary material performance testing equipment to prevent batch quality problems caused by non-conforming raw materials.

Copper and aluminum are the most commonly used conductive materials for motors. Most of the winding wires for motors are copper. Except for some manufacturers' high-efficiency motors that use cast copper and special-purpose motors that use alloy aluminum, most of the cage rotor motors use cast aluminum. And make specific regulations on the purity of aluminum.

For copper electromagnetic wires, the purity of the material can be qualitatively determined by DC resistance detection. The smaller the resistance, the less the impurity content of the material; for aluminum for cast aluminum rotors, the purity is used for requirements and testing, the higher the purity, It is more conducive to the improvement of the performance of the motor; the good aluminum profile has a silver-white cross section and strong reflected light. Because of the high purity of the aluminum ingots used at this time, little or no scrap aluminum is added during casting; if the surface color is dull, it is mostly due to the addition of more scrap aluminum.

During the operation of the motor, the conductive material will affect the performance index of the motor efficiency, power factor and temperature rise due to heat generation. In view of the above reasons, on the one hand, we can control the materials through the selection of suppliers, on the other hand, we can be equipped with the necessary material performance testing equipment to prevent batch quality problems caused by non-conforming raw materials.

Knowledge development of motor materials

1 Classification and

According to its purity, pure aluminum is divided into three types: high-purity aluminum, industrial high-purity aluminum and industrial pure aluminum. The grade of pure aluminum is indicated by the initial "L" of the pinyin "Aluminum" and the number behind it. The purity of high-purity aluminum is 99.996% ~ 99.93%. There are four grades of L01, L02, L03, and L04. The zero in front of the number indicates high-purity aluminum. The higher the number, the higher the purity. High-purity aluminum is mainly used for scientific research and capacitors.

The purity of industrial high-purity aluminum is 99.9% ~ 99.85%, and the grades are represented by L01 and L00. They are mainly used to manufacture aluminum foil, aluminum clad and aluminum alloy raw materials.

The purity of industrial pure aluminum is 99.0% ~ 98.0%. There are five grades of L1, L2, L3, L4 and L5. The larger the number, the lower the purity. Mainly used for preparing aluminum-based alloys and manufacturing wires and cables.

2 Performance advantages of aluminum

● Good electrical and thermal conductivity, second only to silver, copper and gold, ranking fourth. There have been many applications of aluminum magnet wire, but in view of the improvement of the standard of motor efficiency, aluminum magnet wire has been basically eliminated.

● Good plasticity, can be processed by cold or hot pressure to make various profiles, such as wire, wire, rod, tube, etc. This characteristic is related to aluminum's face-centered cubic lattice structure.

● Good resistance to atmospheric corrosion. Because a very dense aluminum oxide film can be formed on the surface of aluminum, it can effectively isolate the contact between aluminum and oxygen, and prevent one-step oxidation of the aluminum surface.

● Aluminum is very light (its density is 2.698g / cm3), about one-third of copper. Aluminum is often used as the basic component of various lightweight structural materials. At present, aluminum alloy materials are widely used in our daily life.

● Intensity variability. Aluminum strength is very low, but the strength can be improved a lot after cold deformation work hardening.

3 Wide application of alloy aluminum

Pure aluminum is a silver-white low melting point light metal and the most abundant metal element in nature. Adding silicon, copper, magnesium, zinc, manganese and other alloying elements to pure aluminum can form various aluminum alloys. Aluminum and aluminum alloys have excellent performance in many aspects, and are the engineering materials widely used only after steel.

4 Purification technology of aluminum

There are two internationally proven purification technologies: three-layer liquid electrolysis and segregation. The three-layer liquid method is now widely used, but compared with the segregation method, the latter has the advantages of power saving, low energy consumption and environmental protection, and can save 6,000 degrees of electricity per ton on average. Moreover, the segregation method uses physical methods. The whole process does not involve any other added substances. No special additional energy is required to promote the solidification and segregation process. In addition to the gas and dust generated by the aluminum smelting itself, it does not produce any toxic substances in the production process. Harmful substances, meet the requirements of environmental protection production