Transformerboard was developed as the base material for power transformers. The product and term Transformerboard was invented over 80 years ago by Weidmann and is considered the industry standard term today for cellulose based insulating material. Weidmann supplies a wide range of Transformerboard products manufactured using a variety of methods, all meeting the highest quality and international standards.
Transformerboard is used as base insulating material in power, distribution and special transformers. Cut to the requested size, Transformerboard is the base material for components like cylinders, strips, spacers, rings, washers, plates, machine formed and shaped parts, punchings and laminates. To convert Transformerboard to components methods such as sawing, punching, planing, sanding, milling, routing, bending and gluing can be used. Having control over the many steps of the whole process chain from unbleached Kraft pulp to components is advantageous in respect to product quality, customized solutions and creating value in the field of application: insulation of high voltage transformers.
Transformerboard T4 not only exhibits the highest mechanical and electrical strength, but also offers dimensional stability and high compressibility. The unique properties are produced on a board machine with a special hot-press. The latest paper and fiber machine technology allows exact control of CMD and MD profiles in the wet end of the board machine. This ensures excellent flatness of the resulting material. Transformerboard T4 can be shipped in a sheet size of up to 6300 x 3200 mm or, of course, in dimensions tailored to customer requirements.
Basis of Transformerboard T4 is unbleached pulp in pure water. The development and inline installation of a highly sensitive metal detector guarantees board free from metallic particles.
Typical applications of hot-press-dried Transformerboard are strips, cylinders, spacers, plates, washers and supports.
Transformerboard T4 / IEC is manufactured at the Rapperswil plant in Switzerland, the Malyn plant in the Ukraine and the St. Johnsbury plant in Vermont/USA according to standard of IEC 60641-3, type B 3.1. The range of density within this product group starts from a minimum of 1.10 g/cm³ to a maximum 1.30 g/cm³, reflecting the range of thickness from 1.0 mm to 8.0 mm. Transformerboard T4 can be classified as a high-density material.
Transformerboard Grade A is manufactured at the Malyn plant in the Ukraine according to standard of GOST 4194-88. The range of thickness is from 2.0 to 3.0 mm; the density begins from 0.90 g/cm³ to 1.00 g/cm³. Transformerboard Grade A can be classified as a medium-density material.
Transformerboard Grade B is manufactured at the Malyn plant in the Ukraine according to standard of GOST 4194-88. The range of density begins from 0.95 g/cm³ to 1.20 g/cm³, reflecting the range of thickness from 1.0 mm to a maximum of 8.0 mm. Transformerboard Grade B can be classified as a high-density material.
Similar to the manufacturing process for hot-press-dried Transformerboard, unbleached Kraft pulp along with pure water constitutes the basis of calendered board. The special properties of calendered board are produced on a board machine with a hot-air-dryer and sequencing calender. The whole manufacturing process chain from preparation of the pulp, forming and drying of the sheet material is monitored and controlled by modern process control systems. The development and in-line installation of a highly sensitive metal detector guarantees board free from metallic particles.
Typical applications of calendered board are curved pieces like cylinders with small diameters, punchings, stamped pieces and machine-formed parts in power, distribution and special transformers.
Form-Val is manufactured at the St. Johnsbury plant in Vermont/USA. The range of density is from 0.80 g/cm³ to maximum 1.05 g/cm³; the range of thickness from 1.0 mm to 4.0 mm. Form-Val can be classified as a low-density material.
Hi-Val is manufactured at the St. Johnsbury plant in Vermont/USA. The range of density is from 0.90 g/cm³ to maximum 1.15 g/cm³; the range of thickness from 0.8 mm to 5.0 mm. Hi-Val can be classified as a medium-density material.
Laminating of hot-press-dried Transformerboard T4 will result in a higher thickness than 8.0 mm. The range of thickness of laminated Transformerboard T4 is from 9.0 mm to 120.0 mm. Laminated material is, like hot-press-dried Transformerboard T4, dimensionally stable and offers highest mechanical and electrical strength. The adhesives in use are casein and polyester resin glues; casein is aqueous, polyester resin is non-aqueous.
The development and in-line installation of a highly sensitive metal detector guarantees board free from metallic particles.
Typical applications of laminated Transformerboard T4 are press rings, static rings, beams, clamping plates, support strips etc.
Transformerboard T4 / Laminated
Laminated Board is manufactured according to the IEC standard 60763-3-1, Types LB3.1.1 and 3.1.2 at the Rapperswil plant in Switzerland. The resins used are casein and polyester. Casein is an aqueous and polyester resin a non-aqueous glue. We strongly recommend polyester resin glue for thicknesses >30.0 mm. When using casein glue for a thickness >30.0 mm, cracks can appear due to the increased water content. The density of laminated Transformerboard T4 is a maximum of 1.30 g/cm³. The moisture content of Laminated board with casein glue averages 8%, Laminated board with polyester resin glue is controlled at 2% to 6%, depending on the requirements. Laminated board can be classified as a high-density material.
Transformerboard TX2
TX2 is manufactured at the St. Johnsbury plant in Vermont/USA. TX2 meets the requirements of IEC standard 60763-3-1, Type LB3.1.2. The resin used is polyester resin glue, the thickness ranges from 9.0 mm to 120.0 mm. The density of TX2 is a maximum of 1.30 g/cm³; the moisture content is controlled at less than 3.0%. TX2 can be classified as a high-density material.
