Silicone waterproof seals are solids used to isolate different electrical conductors. Solid insulating materials are also generally required to have a supporting effect. Solid insulating materials have a much higher breakdown strength due to higher density, and the insulating resistance, dielectric constant and the range of dielectric insulating materials vary widely.
Solid insulating materials can be divided into two major categories, inorganic and organic.
Inorganic solid insulation materials: mainly powder mica and mica products, glass, glass fiber and its products, as well as electric porcelain, aluminum oxide film and so on. They are resistant to high temperatures, are not susceptible to aging, and have considerable mechanical strength. Some of these materials, such as those, have low cost and occupy a certain position in applications.
The glass process is simpler than ceramic and can be used to manufacture. Glass fiber can be made into silk, cloth and tape, has much higher heat resistance than organic fiber, and plays an important role in the development of insulation structure to high temperature.
Organic solid insulation material: mainly natural in the 19th century, such as paper, cotton, silk, and curable vegetable oil. These materials are flexible, meet the application process requirements, and are readily available.
The silicone resin is combined with a low-alkali glass cloth to greatly improve the heat resistance level. Polyethylene formal is a paint-based enameled wire that opens up a broad prospect for enameled wire, replacing the wire and yarn envelope. The thickness of the polyester film is only a few tens of micrometers, and it is used to replace the original paper and cloth, so that the technical and economic indicators of the motor and the electric appliance are greatly improved. The aramid fiber paper, the polyester film, and the polyimide film are used to make the heat resistance level of the motor slot insulation F grade and H grade, respectively. Similar developments have been made with elastomeric materials such as heat resistant silicone rubber, oil resistant nitrile rubber, and subsequent fluoroelastomers, ethylene propylene rubber, and the like.