High Density Pre-Compressed Pressboards Manufacturer in India

Features

• Strength and stability: Pre-compression eliminates voids and increases mechanical load-bearing capacity significantly above standard pressboard.
• Versatility: Available in thicknesses from 8 mm to 60 mm and custom sheet sizes for diverse transformer designs.
• Ease of machining: Can be precisely cut, milled, and drilled using standard CNC equipment to OEM drawing specifications.
• Cost-effectiveness: Long service life and dimensional stability reduce replacement frequency and maintenance downtime.
• Excellent dielectric properties: High purity cellulose provides consistent dielectric strength throughout the board thickness.
• Thermal stability: Rated Class A (105°C) for continuous operation in oil-immersed transformer environments.
• Chemical compatibility: Fully compatible with mineral transformer oil and synthetic ester fluids.
• Environmentally responsible: Manufactured from renewable wood pulp with no synthetic binders or hazardous additives.

Key Properties

• High mechanical strength — resists deformation under electromagnetic short-circuit forces
• Superior dielectric performance — consistent breakdown voltage when oil-impregnated
• Excellent dimensional stability — minimal shrinkage or swelling across thermal cycles
• Oil compatibility — wicks and retains transformer oil for enhanced dielectric performance
• Resistance to short-circuit forces — pre-compressed density prevents delamination under fault conditions
• Long service life — typically exceeds 25 years in correctly designed transformer insulation systems

Applications

High density pre-compressed pressboards are widely used in:

• Power and distribution transformer winding spacers
• End rings and insulation barriers between windings
• Structural insulation components and clamping rings
• High-voltage bushings and tap changer insulation
• Reactor and instrument transformer insulation systems

Role in Transformer Insulation Systems

These pressboards provide critical structural and electrical functions within oil-immersed transformer designs:

• Mechanical support to withstand electromagnetic forces during short-circuit events
• Electrical separation between HV and LV windings and between windings and the core
• Dimensional stability during thermal cycling from cold start to full-load operating temperature

Their use significantly reduces the risk of insulation deformation and mechanical failure under fault conditions, extending transformer service life.

Manufacturing Process at ACC Insulations

ACC Insulations follows strict manufacturing protocols to produce pressboards that consistently meet IEC and IS requirements:

• Selection and testing of high-purity cellulose pulp for moisture content and ash content
• Multi-layer sheet formation and precision pre-compression under controlled hydraulic pressure
• Controlled drying and calendering to achieve target density (1.1–1.2 g/cm³)
• Comprehensive electrical and mechanical testing — dielectric strength, tensile, and dimensional checks on every batch

Compliance and Standards

Our high density pressboards comply with:

• IEC 60641-3-1 — Pressboard for transformer insulation
• IS 1576 — Indian Standard for transformer pressboard
• Customer and transformer OEM-specific requirements

Advantages of ACC Insulations Pressboards

• High load-bearing capacity — suitable for the largest power transformer designs
• Consistent quality — every batch tested to the same mechanical and dielectric standard
• Custom machining support — CNC facilities for OEM-specific spacers, rings and barriers
• Reliable long-term performance — proven in India's major transformer manufacturers

Industries Served

• Power transformer manufacturers (up to 765 kV class)
• Distribution transformer manufacturers
• Heavy electrical and switchgear equipment manufacturers

Why Choose ACC Insulations?

With decades of expertise in electrical insulation manufacturing, ACC Insulations supplies high density pre-compressed pressboards to leading transformer OEMs across India and international markets. Our products undergo rigorous dielectric, mechanical, and dimensional stability testing to ensure long-term reliability under high electrical stress conditions.