Trusted Insulation Partner for
Power Transformers
Since 1937, setting the global standard for high-performance cellulose and synthetic-based insulation. Engineered to optimize dielectric safety, lifespan, and thermal endurance.
World-Class Insulation Technologies
We supply the full spectrum of high-quality electrical insulation materials — from raw boards and papers to custom-engineered preformed parts and sensor systems.
Transformerboard T4
High-Density Cellulose Board
The global benchmark for insulation pressboard. Offers unparalleled mechanical rigidity, high dielectric strength, and excellent oil adsorption.
Low Density Board
Flexible Moldable Board
Lower density board engineered with enhanced elasticity and faster oil impregnation (grades: Form-Val, Hi-Val). Suited for barriers and cylinders.
Laminated Board
Heavy Duty Structural Board
Laminated layers of high-density T4 board bonded with premium casein or polyester adhesive. Designed to withstand massive clamping force.
Nomex® Board
High-Temp Pressboard
Aramid-fiber pressboard for high-temperature and hybrid systems (Class F & Class H). Maintains superior dielectric properties at continuous 220°C.
Transformerboard T7
High-Ductility Pressboard
Specially engineered for applications requiring high ductility and elasticity, such as bending around tight radii without crack failure.
Kraft Flat Paper
Pure Wood Pulp Insulation
Electrical-grade (E-grade) unbleached kraft paper for wire wrapping and layer barriers. High chemical purity and mechanical strength.
Thermally Upgraded
Chemically Modified Paper
Kraft paper treated with nitrogenous compounds to resist thermal aging, increasing transformer load capability and service life.
Creped Kraft Paper
High-Elongation Wrapping
Elastic crepe insulation paper offering high tensile elongation and flexibility. Ideal for wrapping exit leads, busbars, and complex joints.
INSULutions® DPE
Diamond Pattern Coated Paper
Cellulose-based insulating paper printed with epoxy resin dots. Cures during winding baking to bind turns against short-circuit forces.
Nomex® Aramid Paper
High-Temp Polyamide Paper
Polyamide aramid paper with exceptional long-term thermal resistance. Suited for dry-type wraps, barrier wraps, and slot liners.
Aramid-Mica Hybrid
Corona-Resistant Wrap
Composite paper combining aramid fiber with mica flakes. Delivers premium partial-discharge resistance under high voltage transients.
Cellulose-Based Insulation Components
Machined and molded components manufactured from high-density T4 Transformerboard and pure electrical kraft pulps.
Machine-Moulded Rings
Standardized End Insulation
Machine-molded angle rings and caps designed to form strong end barriers, optimizing field stress and reducing size.
Hand-Molded Sectors
Custom Shape Sectors
Hand-molded sectors fabricated from wet sheets, custom shaped to fit tight small-radii tolerances down to 60 mm.
Drawn Rings & Caps
Nut & Bolt Insulators
Small drawn caps and rings produced with specific molds, ideal for small transformers and metal nut insulation protection.
Pressed Sectors
Power Transformer End Insulation
Semi-automatically pressed sectors for large power transformers. Offers large diameters and edge radii up to 40 mm.
Flexible Crepe Angles
Distribution Winding Caps
90° flexible crepe angles made of 4 laminated layers of crepe paper. Designed specifically for distribution grid transformers.
Laminated Crepe Rolls
Formable Joint Wrap Rolls
Laminated Rolls built with 4 layers of 200% elongation crepe. Easily formed to required shapes during transformer assembly.
Clamping Rings
High-Pressure Rings
Laminated, high-density pressboard rings designed to distribute axial clamping forces uniformly across structures.
Cylinders
Winding Core Cylinders
High-strength winding cylinders providing structural support for coils and forming critical oil gap barriers.
Edge Protection
Coil Shielding Profiles
Molded cellulose profiles protecting winding edges and cable connections from high electrical stress and wear.
End Rings
Machined Support Blocks
High-density machined block components designed to support and locate coil packages securely at clamping points.
Fixation Elements
Machined Wedges & Guides
Machined guides, keys, blocks, and wedges securing coils and leads against high axial short-circuit forces.
Lead Exit Systems
HV Lead Exit Barriers
Pre-assembled fluid-dynamic barrier structures providing safe routing for high-voltage winding leads to bushings.
Shielding Elements
Electrostatic Shield Rings
Molded caps coated with conducting or shielding papers to control electric field lines at potential borders.
Snouts & Flanges
Inter-Coil Barriers
Flanged tubes and molded snouts providing insulation barriers at connection nodes between phase blocks.
Spacing Elements
Cooling Duct Spacers
Machined strips, keyways, and blocks defining vertical cooling ducts for transformer oil circulation.
Insulating Tubes
Bolt Sleeves & Duct Barriers
Wound and pressed cellulose tubes used as duct barriers or sleeves around structural metal bolts.
Insulating Washers
Collar Press Washers
Machined disc rings separating winding blocks and distributing clamping forces across core discs.
Winding Package
Complete Insulation Kit
A pre-packaged, fully engineered bill of preformed materials and barriers customized to a specific power rating.
High-Temperature Insulation Components
High-performance synthetic aramid components manufactured from Nomex® fibers, designed for hybrid and dry-type transformers.
Nomex® Angle Rings
Class H Molded Rings
Molded aramid components for high-temperature hybrid transformers. Capable of continuous operation up to 220°C.
Nomex® Cylinders
Dry-Type Core Cylinders
Synthetic Nomex® cylinders providing high mechanical strength, thermal stability, and low moisture absorption.
Nomex® Edge Prot.
High-Temp Protective Profiles
Flexible molded aramid profiles protecting dry-type coils against core edge sparks and mechanical wear.
Nomex® Shields
Aluminium-Aramid Shielding
Laminated shielding elements combining aramid paper with reflective aluminium layers for heat radiation screening.
Nomex® Spacers
Dry-Type Cooling Wedges
Machined Nomex® spacing elements defining cooling air ducts for wind power and traction transformer packages.
Nomex® Washers
High-Temp Press Washers
Nomex® aramid washers providing electrical isolation and support between dry-type winding phases.
Cooling & Fluid Valves
Leak-Free Drain Valves
Bronze, ductile iron, and steel sampling and drain valves engineered for high pressure-tight sealing in fluid-filled systems.
HV Connections
High-Voltage Lead Contacts
Specialized shielding contacts, terminals, and bushings providing robust, corona-free high-current connections inside transformer systems.
Core Accessories
IsoTek Cooling Channel Spacers
Cellulose clamping plates and shielding components that optimize cooling fluid circulation and reduce magnetic stray losses.
LAE Winding Machinery
Core Winding Tools
Production winding machines, core cutting systems, and assembly tooling designed to automate high-precision coil manufacturing.
Surge Arresters
Grid Overvoltage Protection
Zinc-oxide surge arresters protecting the transformer systems from high lightning impulses and switching overvoltage surges.
Material Compatibility Matrix
A technical guide to matching high-performance insulation grades with specific transformer profiles.
| Insulation Grade | Material Class & Description | Liquid-Immersed Utility Power |
Dry-Type Grid Data Centers |
Traction Power Locomotives |
Offshore Wind Renewables |
Instrument & Current/Potential |
|---|---|---|---|---|---|---|
| Transformerboard T4 | High-density cellulose pressboard for cylinders, shields, and spacers. | — | — | |||
| Crepe Paper | High elasticity crepe wrapping for lead exit connections and winding wires. | — | ||||
| Diamond Dot Paper | Epoxy dot coated flat paper. Heat cures to lock winding coils mechanically. | — | ||||
| Nomex® Board | Aramid pressboard sheets. Maintains physical/dielectric strength at 220°C. | — | ||||
| Angle Rings & Caps | Press-formed insulation caps for high electrical stress areas. | — | — | |||
| Fiber Optic Sensors | Real-time hot-spot monitors embedded directly within the windings. | — |
Insulation Selection Wizard
Input your transformer rating specifications to dynamically generate recommended solid/liquid insulation bills of materials.
1. Select Transformer Cooling & Medium
Choose the primary cooling medium used inside the active core and winding tank.
2. Select Transformer Voltage Class
Specify the maximum operating winding voltage (primary line voltage).
3. Select Operating Temperature / Winding Class
Specify the maximum hot-spot thermal limits required by the design standard.
Recommended Winding Wires & Insulation Package
Based on your parameters, we recommend specifying the following materials:
Latest Winding & Grid Case Studies
Read about how TransformerInsulation.com engineers partner with utility providers to optimize performance, lower materials weights, and protect grid connections globally.
Partnering
with us
For over 140 years, we have set the global standard in electrical insulation. We develop high-technology, solution-based insulation systems, custom-engineered components, and advanced diagnostics. Our engineering partnerships enable transformer manufacturers and utilities worldwide to optimize design clearances, maximize thermal efficiency, and guarantee grid reliability under the most demanding high-voltage operations.
Technical Catalog
Download our comprehensive corporate presentation and technical specifications catalog.
Request Technical Pricing
Submit your design insulation bill of materials to our engineering staff. Get a custom B2B quotation within 24 hours.
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