Do you know different types of insulating material for transformer core?

The following insulation materials are often used in transformer core: laminated sheet, insulation cylinder (tube), binding belt and so on.

1) Laminated sheet: Electrical laminated products are layered structure insulation materials made of paper, cloth and wood veneer as the substrate, soaked (or coated) with different adhesives by hot pressing (or rolling). According to the requirements, laminated products can be made into products with excellent electrical and mechanical properties, heat resistance, oil resistance, mildew resistance, arc resistance and corona resistance. Laminate products mainly include laminated sheet, laminated wood, laminated pipe, rod, capacitor sleeve core and other special profiles. The properties of laminated products depend on the properties of substrates and adhesives and their forming processes.

Depending on the raw material and adhesive, laminated sheet can be divided into insulation laminate (paperboard, used in the oil transformer), phenolic laminated sheet (known as bakelite sheet, cardboard impregnated phenolic resin, used in the oil transformer), phenolic laminated cloth plate (cotton cloth dipped in phenolic resin, used in the oil transformer), epoxy glass cloth sheet (glass fiber cloth with epoxy resin as binder, and can be used for F class dry or oil transformer), modified diphenyl ether glass cloth plate (glass fiber cloth with modified diphenyl ether resin as adhesive, can be used for class H dry transformer), bismaleimide glass sheet (glass fiber cloth with bismaleimide resin as adhesive, can be used for class H dry transformer). Laminated sheets usually have good mechanical strength and insulation performance, and are often used as insulation and external supporting parts for core clamps in transformers.

2) Insulation cylinder (pipe) : The insulation cylinder in the transformer is mainly used between the inner and outer coils, between the coils and the core, as well as the coil lining skeleton. The wire is wound directly on the insulation cylinder. Meanwhile, the insulation cylinder can also be used for the main insulation to increase the number of oil gap of the main insulation and strengthen the insulation. According to different materials, insulation tube typically consists of phenolic paper tube (often used in the oil transformer), epoxy glass cloth tube (often used in the oil transformer or F dry transformer), diphenyl ether modified glass tube (often used in H dry transformer), glass steel cylinder (often used in class H dry transformer), bismaleimide glass cloth cylinder (often used in H dry transformer), etc.

3) Binding belt: Binding belt for transformer often includes cotton belt, tightening belt, reticulated semi-dry weft free belt, glass cloth belt, polyester belt, etc. It is used for binding and tightening of iron core and coil, etc.