Comparative Analysis of High Voltage Insulating Materials

1. Definition of insulating materials

  Broad definition: materials that can stop current flowing through, commonly known as non-conductive materials.

  Scientific definition: the insulation resistance coefficient of substances that can establish a strong electric field should be more than 10 ^ 7 ohm • cm. Such substances are called dielectrics or insulating materials.

2. Classification of insulating materials

  According to the unified standards of the national mechanical and electrical industry, insulating material products are divided into eight categories according to their morphological structure, composition or production process characteristics, which are represented by one Arabic numeral.

1 represents insulating paint, polymerizable resin and glue;

2 represents resin impregnated fiber products;

3 represents laminated products, winding products, vacuum pressure dipping products and drawing products;

4 represents molding materials;

5 represents mica products;

6 represents film, adhesive tape and soft composite materials;

7 represents fiber products;

8 stands for insulating liquids.

  The first category of laminated products includes: laminates, laminated rods and laminated tubes. 3240 epoxy sheet (full name) currently used by our company

3240 epoxy phenolic glass cloth laminate) belongs to the laminate of laminated products.

Naming and indication of insulation material model

Product name=resin+base material+form (can also be modified)

For example: phenolic paper laminate, epoxy glass cloth laminate, high-strength phenolic cotton cloth laminate, phenolic cotton cloth laminate, etc

  Model designation and indication content (the model is usually represented by four digits.

  The first digit: indicates the category of insulating material, for example, "3" indicates the category of insulating layer pressing

  The second digit: indicates the code of small category products (0 ^ 8 digits)

0 - Organic reinforcing material laminate (paper, cotton cloth, such as 3021 cardboard, 3025 cotton cloth board)

1 - Vacuum pressure impregnated products (formerly asbestos laminates)

2 - Inorganic reinforcing material laminate (glass cloth, 3240 epoxy glass cloth)

3 - Empty number

4 - No

5 - Laminated tubes of organic reinforcement materials (paper, cotton cloth, etc., such as 3520 paper tubes and 3526 cotton cloth tubes)

6 - Laminated pipes made of inorganic reinforcement materials (glass cloth, 3640 epoxy glass cloth)

7-Laminated rods of organic reinforcement materials (paper, cotton cloth, etc., such as 3721 phenolic cotton cloth rod)

8 -- Inorganic reinforcing material laminated bar (glass cloth, 3840 epoxy glass cloth bar, etc.)

The third digit: refers to the reference working temperature and resistance

  For example, our 3240 epoxy board has a temperature resistance grade of F, with reference to the working temperature of 155 ° C, and the number is 4.

  The fourth digit indicates the crystallization sequence of the same category, the same subcategory and the same reference temperature

For example: phenolic cotton laminate: 3025, 3026, 3027, 3028

  The additional fifth digit or letter is generally added by the manufacturer to indicate some characteristics or features of the product

  For example, 3240-1 represents 3240 economic type board (Furunda)

  3025-CS indicates that the economic plate well of 3025 has wear resistance (Furunda)

3. Common insulating materials for high-voltage inverter

  Introduction to insulating laminated products

  Phenolic resin is a kind of resin with different properties produced according to different molar ratio [molecular weight ratio] of phenol and formaldehyde;

  Detailed specification definition of cotton cloth:

  a. Yarn count: refers to the unit of yarn fineness, i.e. the ratio of yarn length to yarn weight

  British lower cotton yarn weighs one pound, and 840 yards is a piece of yarn. Converted to metric unit, it is 1kg cotton cloth meter

  It is a piece of yarn.

  b. Density: the number of yarns within a certain length, the density in warp and weft direction, generally measured as the number of yarns with a length of 10mm.

  C. Width: the transverse width of cotton cloth, generally expressed in mm.

  d. Organizational form: according to the different methods of warp and weft yarn interweave, plain, folded, twill, unidirectional, etc. are formed

Basic organization form. The insulating laminated products usually use plain weave.

  b. Phenolic paper laminate (Grade E)

  Processing: It is a hard board insulating material made of electrical insulating impregnated paper dipped in phenolic resin paint, baked and hot pressed.

Type and use:

  PFCP201 - mechanical, higher mechanical strength and worse electrical performance than other PFCP types. Suitable for mechanical equipment

Structural components of.

  PFCP202-PFCP has the best electrical performance.

  PFCP203 - It is suitable for insulating structural parts for motors and electrical equipment with high mechanical performance requirements,

It can also be used in transformer oil.

  PFCP204, 206 are for mechanical and electrical use. They have good electrical performance at high temperatures and are also suitable for hot stamping.

  PFCP207 - similar to PFCP201, but with improved punching characteristics at lower temperatures.

  PFCP308 - similar to PFCP206, but flame retardant.

c. Phenolic cotton laminate (Class E)

  Processing: It is made of industrial cotton cloth dipped in phenolic resin paint, dried and hot pressed hard board insulation material.

Type and use:

  3025, PFCC201, F850 - mechanical, poor electrical performance (coarse cloth). Low cost of 3025B and 3025C, but the mechanical property is worse than 3025.

  3027, PFCC202, F851 - mechanical and electrical (coarse cloth), with higher electrical property than group 3025

  3028, PFCG204, F853 - mechanical (fine cloth), with higher comprehensive performance than group 3027.

  d. Epoxy glass laminate

  Processing: pressing alkali free glass cloth (EW-140) with low molecular weight liquid epoxy resin e44 as curing agent

  Application: With high mechanical strength and good electrical performance, it is suitable for use as insulation structure in motors and electrical equipment

  Parts and components, well can be used in humid environment and transformer oil.

  3240 epoxy sheet - lower level, with high mechanical strength, good electrical performance, heat resistance, water resistance, and stable electrical performance after immersion. It is suitable for insulating structural parts requiring high mechanical strength, high dielectric property and good water resistance. It can work in oil.