Insulating Composite Materials - Electrical
With over 80 years of experience in the electrical industry, our paper based phenolic, fine weave cotton epoxy, and woven glass epoxy grades all possess excellent dielectric strength in the most demanding environments.
Paper based phenolic grade
Originally developed for use as a superior rigid electrical insulation material in heavy duty switchgear in the 1920’s, our famous Kite Brand Tufnol is still manufactured today in large quantities to satisfy the requirements of today’s modern electrical industry.
It is the most widely used of all Tufnol phenolic paper grades and is put to use in a multitude of different applications including busbar supports, coil formers, insulating sleeves, mounting panels, insulated enclosures and a myriad of punched parts.
High insulative resistance
Outstanding electrical strength
Low water absorption
Excellent dimensional stability
Fine weave cotton epoxy grade
Our superior epoxy cotton laminate, Tufnol Grade 6F/45, has a unique combination of properties.
Using a specially modified epoxy resin system, this material possesses high insulation resistance and electrical strength and an exceptional resistance to surface electrical tracking.
This versatile grade is mechanically strong, has low water absorption and excellent dimensional stability which enables it to be machined to a superb finish and very close tolerances – not surprising therefore that it is generally regarded as the ‘Rolls-Royce’ of cotton laminates!
Dangers of Electrical Tracking or ‘Treeing’
Insulator tracking refers to partial electrical breakdown along the surface of an electrical insulating material, and the formation of permanent partially-conductive paths (“tracks”) across a portion of the insulator surface. Tracking typically occurs across an insulating surface that has been subjected to prolonged high-voltage stress without the correct selection of insulating material. As these tracks develop, they often resemble ‘tree’ patterns on the insulation material
Over time this tracking can lead to an electrical arc between conductors which can cause catastrophic failure of equipment and likely result in a fire. Thus it is vital that materials used for electrical insulation are appropriate for the equipment.
Woven glass epoxy grade
The woven glass epoxy grades in the Tufnol range are truly high performance in terms of electrical strength. Using a variety of advanced resin formulations, our group of materials in this range are characterised by very high strength properties and dimensional stability.
The range includes grades with exceptional temperature resistance, first class dielectric properties, good resistance to surface tracking, assessed flammability and superb structural strength and toughness. These high performance materials are used in applications such as insulation in large turbine generators, components in cryogenic superconducting magnets, jigs for electrochemical machining, rail/fishplate insulation, and structural insulation for electronic equipment.