Development and design of a new type of multi-powder mica board

With the reform and opening up, in addition to high-voltage large motors, my country has also introduced a variety of motor production technologies, and there is a problem of localization of materials in the process of absorption and digestion.

In addition, the various imported equipments are often equipped with motors. After a period of operation, the motor begins to be damaged and needs to be repaired. Now some powder mica boards cannot fully meet the requirements. For example, the insulation thickness of foreign motors is thin. Therefore, It is required to develop various types of powder mica tapes, such as single or double-sided tapes reinforced with film, powder mica boards reinforced with single-sided glass cloth, etc. Some of these types have been put into production, and some are still in trial production. With the development of the technology, its types and dosages will increase day by day.

In order to develop new types of mica boards, in addition to developing adhesives, new powder mica paper and reinforcing materials should also be developed. At present, 501 powder paper is mainly used in the production of mica boards. In addition to the improvement, new mica paper should also be developed. For example, Hitachi Today has developed two new mica papers, one called M-mica paper, which improves the diameter-thickness ratio of mica paper, so that the layer of mica scales within a unit thickness is improved. When the number of mica flakes is added, the overlapping area of the mica flakes with large diameter is large when they are copied into mica paper, and the adsorption force between the flakes is large, so that the mica flakes are closely attached to each other, and the density is high, and it is easy to make thick mica paper.

The diameter-to-thickness ratio of this kind of paper is more than twice that of traditional mica paper, so it has higher mechanical strength and insulation damage strength; dielectric life characteristics and fatigue resistance are improved. The powder mica and sheet mica are excellent in insulation.

The second type of powder mica paper incorporates a small amount of polyaramid fibers in very fine mica sheet flakes.

Doing so makes the mica paper not easy to break, and can improve the heat resistance of the insulating structure.