Insulation material is one of the key factors to determine the technical and economic indicators of motor and electrical appliances, because in the operation of motor and electrical appliances, it is inevitable to be affected by temperature, electrical and mechanical stress and vibration, harmful gases, chemicals, humidity, dust and radiation and other factors. However, insulation material is more sensitive to these factors, which is easy to deteriorate, resulting in electrical equipment failure Therefore, we should pay attention to the factors that affect the performance of insulating materials.

&1. Resistance and resistivity

&The resistivity is the resistance per unit volume, and the resistance is the reciprocal of the conductivity. The smaller the conductivity of a material is, the greater the resistance is. For insulating materials, the higher the resistivity is.

&Relative permittivity and dielectric loss tangent properties

        Purpose of insulating material: it is used for mutual insulation of various parts of electric network and dielectric (energy storage) of capacitor. The former requires small relative permittivity, while the latter requires large relative permittivity. Both require small dielectric loss tangent, especially for insulating materials applied under high frequency and high voltage. In order to reduce dielectric loss, it is required to use insulating materials with small dielectric loss tangent.

&3. Breakdown voltage and electrical strength

&Under a certain strong electric field, the insulating material will be damaged, lose its insulating property and become conductive state, which is called breakdown. The breakdown voltage is called breakdown voltage (dielectric strength). Electrical strength is the quotient of the voltage when breakdown occurs under specified conditions and the distance between two electrodes that bear applied voltage, that is, the breakdown voltage per unit thickness. For insulating materials, the higher the breakdown voltage and electrical strength, the better.

&4. Tensile strength

&The tensile stress of the specimen in the tensile test. It is a widely used and representative test of mechanical properties of insulating materials.

&Combustion resistance

&Nbsp; & nbsp; & nbsp; & nbsp; refers to the ability of an insulating material to resist combustion when it comes into contact with a flame or to prevent further combustion when it leaves the flame. With the expansion of the application of insulating materials, the requirement of its combustion resistance is more important. People improve and improve the combustion resistance of insulating materials through various means. The higher the combustion resistance, the better the safety.

&6. Arc resistance

&The ability of an insulating material to withstand the action of an arc along its surface under specified test conditions. During the test, AC high voltage and small current are used to judge the arc resistance of the insulating material by the time required for the formation of conductive layer on the surface of the insulating material due to the arc action between the two electrodes. The larger the time value is, the better the arc resistance is.

&Sealing degree: it is better to seal and isolate oil quality and water quality.