Insulation Materials Applications
Electrician commonly used insulating materials according to their different chemical properties, can be divided into inorganic insulation materials, organic insulation materials and mixed insulation materials. Commonly used inorganic insulation materials are: mica, asbestos, marble, porcelain, glass, sulfur, etc., mainly used for motors, electrical insulation winding, switch the bottom plate and insulators. Organic insulating materials are: shellac, resin, rubber, cotton yarn, paper, linen, rayon, etc., mostly used to manufacture insulating paint, winding wire wound insulation and so on. Mixed insulation materials for the above two kinds of materials through the processing of various molding insulation materials, used as electrical appliances of the base, shell and so on.
Application of insulating materials
The role of insulating material is in the electrical equipment to the potential of different charged part of the isolated. Therefore, the insulation material should first have a high insulation resistance and compressive strength, and to avoid leakage, breakdown and other accidents. Second, the heat resistance is better, to avoid long-term overheating and aging deterioration; In addition, there should be good thermal conductivity, resistance to lightning and high mechanical strength and process processing and other characteristics. According to the above requirements, commonly used insulating material performance indicators are dielectric strength, tensile strength, specific gravity, expansion coefficient.
Insulation withstand voltage: the higher the voltage applied across the insulator, the greater the electric field force received by the material, the more prone to ionization collision, resulting in insulator breakdown. So that the minimum voltage breakdown of the insulator is called the breakdown voltage of the insulator. So that 1 mm thick insulation material breakdown, the need to add the voltage kV is called insulation material insulation voltage strength, referred to as the insulation strength. As the insulating material has a certain degree of insulation strength, all kinds of electrical equipment, all kinds of safety equipment (electrical clamp, test pen, insulated gloves, insulation rods, etc.), a variety of electrical materials, factories are required to allow a certain use of voltage, Rated voltage. The voltage to be used shall not exceed its rated voltage, so as to avoid accidents.
Tensile strength: The cross-sectional area of the insulating material can withstand tensile forces, such as glass per square centimeter cross-sectional area can withstand the resistance of 1400 Newton.
Insulation material insulation and temperature are closely related. The higher the temperature, the worse the insulating properties of the insulating material. To ensure the insulation strength, each insulation material has a suitable maximum allowable operating temperature, below this temperature, can be used for long-term safety, more than this temperature will quickly aging. According to the degree of heat, the insulation material is divided into Y, A, E, B, F, H, C and other levels. For example, A-class insulation material of the maximum allowable working temperature of 105 ℃, the general use of distribution transformers, motor insulation materials are mostly A-class.