Factors affecting the electrical strength of insulating plates

1.Sample thickness: When the insulating plate material is very thin, the breakdown voltage is proportional to the thickness, that is, the electrical strength has nothing to do with the thickness. When the thickness of the insulating material increases, it will be difficult to dissipate heat, impurities, bubbles and other factors will make the electrical strength reduce.

2.Temperature: Above room temperature, the electric strength decreases with the increase of temperature.

3.Humidity: Moisture has entered the insulating material. The electrical strength is reduced.

4.Voltage application time: The electrical strength of most organic materials for insulating boards decreases with the extension of the voltage application time. During the test, the boost speed is fast and the electrical strength is high, and the stepwise boost or slow boost voltage has a longer action time, which can better reflect the thermal effect and the existence of defects such as internal air gaps in the material. Therefore, the general test method stipulates that the impulse boost method is not adopted, but the continuous boost or stepwise boost method is adopted.

5.Mechanical stress or mechanical damage: The electrical strength of the insulating material will be reduced after mechanical stress or mechanical damage. Laminate sample processing should avoid strong damage as much as possible, use milling instead of wounds, and control the processing feed to be small.

6.Sample: The sample must not be contaminated, and the thin insulating plate sample must not be wrinkled. Will reduce the breakdown voltage.

7.Water or carbon dust in transformer oil: If the sample is to be tested for breakdown in transformer oil, the transformer oil should meet the standard requirements. Over time, the transformer oil will absorb moisture and have multiple breakdowns of residual carbon powder, which will reduce the breakdown voltage of the sample. Transformer oil should be treated or replaced in due course.

此博客中的热门博文

The polishing treatment methods for alumina ceramics

It has become very common for thick film integrated circuits to use alumina ceramics . Ceramic materials mainly made of alumina (Al2O3) have good conductivity, mechanical strength and high temperature resistance. It is a widely used ceramic at present. However, after the alumina ceramic is sintered and cooled, it does not mean the end of product processing. Some products do not meet the application requirements. Therefore, they need to be processed, such as size correction and polishing. The polishing treatment method of alumina ceramics is as follows: 1. Using laser processing and ultrasonic processing for grinding and polishing. 2. Use Al2O3 powder or diamond paste for grinding and polishing. 3. The method of glazing is required (suitable for products that require high surface smoothness). 4. Use diamond, silicon carbide, etc. harder than alumina to grind step by step from coarse to fine. 5. The surface of the material is processed by ion implantation. Ion implantation...

阅读全文

The solution of bubble issue during injection molding process

According to the causes of bubbles, the countermeasures are as follows: (1) When the wall thickness of the product is large, the cooling speed of its external surface is faster than that of the central plastic part. Therefore, as the cooling goes on, the resin at the central part shrinks and expands towards the surface, resulting in insufficient filling at the central part. This condition is called a vacuum bubble. Solutions mainly include: A) Determine the reasonable gate and gate size according to the wall thickness. Generally, gate height shall be 50% ~ 60% of the wall thickness of the product. B) Until the gate is sealed, a certain amount of supplementary injection material is left. C) The injection time should be slightly longer than the gate sealing time. D) Reduce the injection speed and increase the injection pressure; E) Use materials with high melt viscosity. 2) The bubbles caused by the production of volatile gases are mainly solved as follows: A) Sufficient pre-drying...

阅读全文

The application range of sandblasting treatment

Sandblasting is the process of cleaning and roughening the substrate surface by the impact of high-speed sand flow. Use compressed air as the power to form a high-speed jet beam to spray the blasting material (copper ore, quartz sand, corundum, iron sand, Hainan sand) at high speed on the surface of the workpiece to be processed, so that the appearance or shape of the outer surface of the workpiece surface changes. (1) Workpiece coating and sandblasting before workpiece bonding can remove all dirt such as rust on the surface of the workpiece, and establish a very important basic pattern on the surface of the workpiece (the so-called rough surface). By changing the abrasives with different particle sizes, the roughness of different degrees is achieved, which greatly improves the binding force of the workpiece with coatings and plating materials. Or make the adhesive bond more firm and better quality. (2) The rough surface of the casting, the cleaning and polishing of t...

阅读全文

mold,molding

搜索此博客