The coil is the key to motor manufacturing. The quality of the coil depends on the quality of the electromagnetic wire on the one hand, and on the processing technology of the coil on the other hand, which mainly includes winding, molding and insulation. Due to factors such as voltage capacity, voltage level and use environment, as well as differences in equipment conditions and production batches, although the coil manufacturing methods are quite different, their common requirements can be summarized as follows.

The error of the number of turns will affect the change of electromagnetic parameters and the difficulty of embedding. The error of the number of turns is easy to occur in the case of loose-embedded windings with a large number of turns. Therefore, necessary turn counting and detection methods should be used when winding such coils. The more common ones used by motor manufacturers are turn measuring instruments. For multi-turn winding, the first turn is generally measured manually and with turn counting equipment. In most cases, the subsequent winding inspection of the same coil uses weight comparison method.

When using the weight comparison method, the correctness of the sample coil data must be guaranteed, followed by the consistency of the winding process control, such as tightness requirements, length control of the head, etc. For continuously wound coils, the correctness of each coil data must also be guaranteed. Someone once did an experiment. For the same coil, due to the inconsistency of the operator's hand strength, the weight of the coil is quite different when the number of turns is the same. For example, the coils wound by men and women are quite different. In comparison, the coils wound by men are neat, which is more conducive to the later embedding, while the coils wound by women are scattered and irregular due to the relatively weak strength, which is not conducive to the later embedding.

For motor manufacturers that have adopted automatic winding machines, both the number of turns control and consistency issues can be easily solved.

The shape of the coil is based on the compliance of the theoretical size. It is very important to ensure the shape of the coil for the formed coil. Otherwise, the subsequent wire embedding cannot be completed, or the coil insulation is damaged after forced operation, or the forming effect is not good, which affects other performances of the motor.

The distance between the two edges of the formed coil and the angle formed must be accurate, otherwise it will cause difficulty in embedding or direct damage to the insulation. Another thing is the length of the straight side. If it is too short, it cannot be embedded. If it is too long, the winding end will be too long, affecting the installation of the motor and other parts (such as the windshield), and even causing the creepage distance to be inconsistent. What's more, it will affect the loss value of the motor.

The insulation between turns and to the ground of the coil must be good and reliable. For high-voltage motor coils, in addition to having sufficient electrical strength, they must also have low dielectric loss and good anti-corona ability. In the actual production and processing process, due to improper post-processing control, the outer insulation layer or anti-corona belt of the coil is damaged, which has a great quality risk to the motor performance.

The inter-turn insulation in multi-turn coils is the weak link in the winding insulation structure. Therefore, on the one hand, it is necessary to select suitable electromagnetic wires, and on the other hand, it is necessary to select suitable processing technology and tooling to prevent damage to the inter-turn insulation; measures should be taken to remedy the situation of inter-turn insulation defects, otherwise it will lead to a devastating disaster for the motor. For this work, most motor manufacturers will conduct a one-by-one inspection through an inter-turn withstand voltage instrument during the semi-finished product test; if no inspection is carried out, it can only be verified after the motor is tested as a whole or put on the market, and the losses caused, especially for customers, will be immeasurable.

For water-cooled coils, it is also required that after processing, the flow resistance to the internal cooling liquid should not increase too much, and there should be no cracks or pinholes to prevent the internal cooling liquid from penetrating and damaging the insulation.

The materials selected for the coils should be easily available and reasonably priced. Oversaturated materials should not be selected in pursuit of reliability. In terms of processing technology, necessary process improvements should be made to meet quality requirements and improve work efficiency. It should be emphasized that the operability of the coil production process is very important, and the safety of the workers' operation process should be taken into account. In order to meet this requirement, there are many details that need to be refined. Ms. will communicate and exchange with you at the meeting at an appropriate time.