T4 Electrical Pressboard：Key Applications and Advantages in Transformer and Motor Insulation

Electric power is a vital foundation for modern life and technology. In the power transmission and distribution network, T4 electrical pressboard plays a crucial role.

T4 electrical pressboard is a specialized insulating material used inside transformers. It is made from pure sulfate wood pulp, processed through special chemical and physical treatments to form a rigid fiberboard. This material features high density, uniform structure, and excellent insulating properties, meeting the stringent requirements of both IEC and GB.

Designed specifically for high-performance electrical applications, T4 electrical pressboard effectively prevents current leakage, ensures the current flows along the intended path, and guarantees safe and stable transformer operation under high-voltage and high-current conditions.

Specific Applications of T4 Electrical Pressboard in Transformers and Motors

T4 electrical pressboard serves multiple functions and plays an irreplaceable role in several key parts of electrical equipment:

1. Interturn and Interlayer Insulation

In transformer windings and motor coils, reliable insulation between conductors and between different winding layers is essential to prevent short circuits. T4  insulation pressboard, precisely cut into spacers, strips, or rolls, is used to separate these components, ensuring a uniform electric field distribution and preventing partial discharge.

2. Insulating Barriers and Spacers

In large oil-immersed transformers, T4 pressboard is used as the main insulating barrier between windings and as spacers that form oil cooling ducts. It provides excellent electrical insulation while maintaining strong mechanical strength to withstand electromagnetic forces and operational vibrations, thereby ensuring structural stability.

3. End Insulation and Padding Blocks

The ends of coils are subjected to high electric field intensity and require reinforced insulation protection. Components made from T4 pressboard—such as angle rings, end rings, and padding blocks—effectively control the electric field at the coil ends, prevent surface creepage, and reduce the risk of dielectric breakdown.

4. Slot Insulation and Liners

In electric motors, T4 pressboard is commonly used for slot insulation and as liner material beneath slot wedges in stator slots. It protects the coil windings from mechanical abrasion caused by the iron core and from electrochemical corrosion, ensuring long-term safe and reliable operation of the equipment.

Five Key Advantages of T4 Electrical Pressboard

Choosing T4 electrical pressboard brings the following core benefits to electrical equipment:

1. Excellent Electrical Insulation Performance

T4 insulation pressboard offers extremely high dielectric strength and volume resistivity. It can withstand high electric fields and transient overvoltage surges, effectively reducing the risk of dielectric breakdown and ensuring operational safety of the equipment.

2. Outstanding Mechanical Strength and Toughness

Its high-density structure provides excellent tensile strength, tear resistance, and toughness. During processing, assembly, and long-term operation, it maintains dimensional stability, resists deformation or damage, and can withstand the strong electromagnetic forces generated during transformer operation.

3. Superior Thermal Stability and Aging Resistance

Through special treatment, T4 electrical pressboard achieves excellent thermal resistance, typically classified as Class A or Class E insulation. It can operate stably for extended periods in transformer oil and at temperatures around 105°C, offering strong anti-aging properties that significantly extend equipment lifespan.

4. Excellent Oil Compatibility and Permeability

In oil-immersed equipment, T4 insulation pressboard can be quickly and thoroughly impregnated with transformer oil, eliminating internal air gaps and preventing partial discharges. This enhances overall insulation performance and improves heat dissipation efficiency.

5. Eco-Friendly and Easy to Process

Made from natural wood cellulose fibers, T4 insulation pressboard is environmentally friendly and biodegradable. It is also easy to process—suitable for punching, cutting, and laminating—allowing engineers to fabricate components of various complex shapes. Considering its performance and longevity, it offers an exceptional cost-performance ratio.

In the modern power equipment industry, T4 electrical pressboard is an indispensable base material in transformer and motor insulation systems. Combining excellent electrical, mechanical, and thermal properties, it provides engineers with a reliable insulation solution. Whether used in the design and manufacture of new equipment or in maintenance and refurbishment of existing systems, choosing high-quality T4 electrical pressboard ensures stable equipment operation and a safe, reliable power grid.