1, insulation resistance and resistivity
The resistance is the reciprocal of the conductance, and the resistivity is the resistance per unit volume. The smaller the conductivity of the material, the greater the resistance, the reciprocal relationship between the two, for the bakelite electrical insulation board, always want the resistivity as high as possible.
2, relative dielectric constant and dielectric loss tangent
Insulation material uses two: electrical network components of the mutual insulation and capacitor medium (energy storage). The former requires a relatively small relative dielectric constant, which requires a relatively large relative dielectric constant, and both require dielectric loss tangent, especially in high frequency and high pressure applications of insulating materials, in order to make dielectric loss is small, require the use of Dielectric loss tangent small insulation material.
3, breakdown voltage and electrical strength
In a strong electric field under the destruction of insulating materials, loss of insulation into a conductive state, known as the breakdown. The breakdown voltage is called the breakdown voltage (dielectric strength). Electrical strength is under the conditions of the breakdown of the voltage and withstand the voltage between the two electrodes, that is, the unit thickness of the breakdown voltage. For insulation cable paper, the general breakdown voltage, electrical strength of the value of the higher the better.
4, tensile strength
Is the maximum tensile stress that the specimen is subjected to in the tensile test. It is the most widely used and most representative test of the mechanical properties of insulating materials.
5, resistance to burning
Refers to the ability of the laminated mica sheet to resist the continued combustion when it is in contact with the flame. With the increasing use of insulating materials, its resistance to flammability is more important, people through various means to improve and improve the flame resistance of insulating materials. The higher the flame resistance, the better the safety.
6, resistant to arc
Under the specified test conditions, the insulation transformer pressboard is resistant to the ability to act along the arc of its surface. Test the use of high-voltage AC current, by high pressure generated between the two electrodes of the arc, so that the surface of the insulating material to form the conductive layer of time required to determine the arc resistance of insulating materials. The greater the time value, the better the arc resistance.
7, the degree of sealing
On the oil quality, water quality isolation is better.
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