Views: 7 Author: Site Editor Publish Time: 2022-06-10 Origin: Site
The main indicators affecting the performance of insulating materials are as follows:
1. Insulation resistance and resistivity
Resistance is the reciprocal of conductance, and resistivity is the resistance per unit volume. The smaller the conductivity of the material, the greater the resistance. The relationship between the two is reciprocal. For insulating materials, the resistivity is always expected to be as high as possible.
2. Relative dielectric constant and r-mass loss tangent
Insulating materials are used for two purposes: mutual insulation of various parts of electric network and dielectric (energy storage) of capacitor. The former requires a small relative dielectric constant, while the latter requires a large relative dielectric constant, while both require a small dielectric loss tangent, especially for insulating materials applied under high frequency and high voltage. In order to reduce the dielectric loss, insulating materials with a small dielectric loss tangent are required.
3. Breakdown voltage and electrical strength
In a strong electric field, the insulating material is damaged, loses its insulating property and becomes conductive, which is called breakdown. The voltage at breakdown is called breakdown voltage (dielectric strength). Electrical strength is the quotient of the voltage when breakdown occurs under specified conditions and the distance between the two electrodes bearing the applied voltage, that is, the breakdown voltage borne by the unit thickness. For insulating materials, the higher the breakdown voltage and electrical strength, the better.
4. Tensile strength
Is the maximum tensile stress borne by the specimen in the tensile test. It is the most widely used and representative test of mechanical properties of insulating materials.
It refers to the ability of insulating materials to resist combustion when contacting the flame or to prevent continued combustion when leaving the flame. With the increasing application of insulating materials, the requirements for their flammability become more and more important. People improve and improve the flammability of insulating materials through various means. The higher the flammability, the better the safety.
6. Arc resistance
The ability of the insulating material to withstand the action of arc along its surface under the 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 a conductive layer on the surface of the insulating material due to the arc effect generated by the high voltage between the two electrodes. The greater the time, the better the arc resistance.
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