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Why the insulation material of the live body need to take ball pressure test

Mar 30, 2018

blob.pngBall pressure test is the resistance to heat heat test, the main test to support and protect the insulating material of the charged body. The temperature varies depending on the effect of the material. Generally, the temperature requirement for the material supporting the charged body is 125 degrees.

The literal meaning is to use something to press the sample and allow the sample to be tested at unusually high temperatures.

Each different plastic material in direct contact with hazardous voltage shall be baked in the oven for one hour. The temperature shall be set at the temperature of the plastic measured at the temperature rise test +40°C, but not less than 125°C, and the recessed area shall not exceed 2mm in diameter .

The description in IEC 60335-1 cl.30 mainly considers insulating materials. The charged body is required to be 125°C, and the non-charged body is generally 75°C. The normal temperature rise of cl 11.8 and the temperature rise of cl 19 are taken into consideration when thermoplastics are used as additional insulation and reinforced insulation. The diameter of the point after the test is less than 2mm. When doing the ball pressure, it is necessary to wait until the temperature is stable, then put the sample on, mainly to detect the performance of the body material of the fixed carrier fluid.

The ballast test was carried out on the parts of the insulating material necessary to hold the components of the shut-off part and the grounding circuit in the normal position, and the phase and neutral surrounding front part made of a thermoplastic material having a width of 2 mm. If the sample is too large, a small sample of at least 2 mm thick should be cut and tested. The sample to be tested shall be placed on a steel plate of at least 3m in thickness and shall be in direct contact. The sample to be tested shall be placed in a horizontal position and the hemisphere on the test equipment shall be pressed against the surface with a force of 20N. Before the start of the test, the test load and supporting device were placed in a heating chamber to a stable test temperature of 125°C ± 2°C. After 1 hour, the ball was removed from the sample and the sample was immersed in cold water for about 10 seconds to cool to room temperature. The diameter of the resulting impression was no more than 2 mm.

The heat resistance of a material (especially a thermoplastic material) refers to the ability of the material to resist thermal deformation under heat.

The heat resistance of the material is generally verified by ball pressure testing.