3.4 Nomex paper

3.4.1 Nomex paper is a heat-resistant synthetic fiber paper produced by DuPont in the United States.Nomex is the trade name of this fiber paper.The main component of Nomex is aromatic polyamide, which has good thermal aging properties.It can be used for a long time at 220°C and is a C-grade insulation material

3.4.2 Characteristics of Nomex paper

3.4.2.1 Inherent dielectric strength

Dense Nomex paper has a lower dielectric constant and a lower dielectric loss factor.

3.4.2.2 Mechanical toughness

Dense Nomex paper has very high strength and good elasticity.Thinner grade products have better flexibility, tear resistance and wear resistance 3.4.2.3 thermal stability

When the temperature of Nomex paper is not higher than 200℃, the electrical and mechanical properties are very little affected.Even at a temperature of 220℃ C continuously, its mechanical and electrical properties can be maintained for a long time for at least 10 years.

3.4.2.4 Low temperature performance

Because Nomex paper has a unique molecular structure, it can be used in a variety of low temperature conditions.

3.4.2.5 Moisture resistance

Nomex paper is in an environment with a relative humidity of 95%, and its dielectric strength is 90% in a completely dry state.

3.4.2.6 Radiation resistance

Even when the intensity of ionizing radiation reaches a very high level, Nomex paper is basically unaffected by it, and after being exposed to multiple radiation, it still maintains its effective mechanical and electrical properties.

3.4.2.7 Non-degree, flame resistance

So far, Nomex paper has not been found to have toxic reactions to humans and animals. Nomex paper does not melt, does not aid combustion, and does not burn in the air.

At present, many transformer factories use Nomex paper with a thickness of 0.05mm as the insulation paper for the turns of H-class dry transformers.Since the H-class dry transformer uses Nomex paper, coupled with vacuum pressure dipping, drying and curing treatment after dipping, it has high mechanical strength and good electrical properties.

3.5 Adhesive paper

Adhesive paper can be divided into three types: single-sided adhesive paper, double-sided adhesive paper and grid-free adhesive paper.The glued paper type is made of 0.07mm winding paper coated with phenolic resin or epoxy resin and then baked and dried.

3.5.1 Single-sided adhesive paper

Single-sided adhesive paper, also known as phenolic adhesive paper, is made of winding paper coated with phenolic resin and then baked, dried and rolled.The product has good insulation and processability.Its heat-resistant grade is E-grade, which is suitable for rolling tape tubes (also known as bakelite tubes) or tape tubes (bakelite tubes with small diameters are also known as bakelite tubes) or tape tubes (bakelite tubes with small diameters are also known as bakelite tubes).

3.5.2 Double-sided adhesive paper

Double-sided adhesive paper is made by winding paper or cable paper coated with phenolic resin, baking, drying and winding.This material replaces phenolic resin glue and is mainly used to suppress insulating laminates.

3.5.3 Rhombic glued paper

Lingge adhesive paper, also known as grid adhesive paper or dispensing paper, is coated with epoxy resin on one or both sides of 0.075mm~0.5mm cable paper, and the thickness of the adhesive layer is 0.0125mm~0.025mm.The curing agent of epoxy resin uses latent curing agent, so the storage period of the adhesive paper is 6 months. Lingge adhesive paper can be used as turn insulation to improve the short-circuit resistance of windings, and is used as layer insulation for foil windings, that is, a layer of aluminum and a layer of grid adhesive paper.It can also be used as a layer insulation for cylindrical windings.

3.5.4 Semi-conductive cable paper

Semi-conductive cable paper is made of 100% natural sulfate wood pulp.Add carbon fiber to it, etc. to control the surface resistivity between 1040~106Q.Semiconductor cable paper is also known as semiconductor paper.There are two kinds of monochrome and two-color.

Semiconductor cable paper is mainly used for shielding high-voltage leads and high-voltage electrical appliances.It can make the electric field uniform.

3.5.5 Metallized crepe paper

It is used for bandaging electrostatic plates, electrostatic screens, end rings, and shielding of leads and heads.The base paper of metallized crepe paper is colored cable paper with aluminum foil on one side.Cable paper and aluminum foil are made of adhesive and wrinkled after sticking.

3.6 Metallized paper

Metallized paper is used for floor screens and electrostatic screens.The base paper is 0.2mm thick insulating paper, and the aluminum thickness is 0.02mm

3.7 Insulated cardboard

It is made of sulfuric acid wood pulp and paper.It is used for oil gap pads, partitions, cardboard tubes, corrugated paper, iron yoke insulation, clip insulation and end insulation winding pressure plates for cake windings.

According to the density, it is divided into low-density cardboard (T3 soft cardboard), medium-density cardboard (T1 cardboard), and high-density cardboard (T4 hard cardboard); according to the cardboard forming process, it is divided into hot-pressed cardboard and calendered cardboard.

3.8 insulated tube

The insulating tubes used in transformers are phenolic tape tubes, epoxy glass cloth tubes, glass fiber reinforced plastic tubes and cardboard tubes.