21 June 2019
Transformerboard is manufactured in accordance to IEC standards, in a single sheet and in a thickness of up to 8 mm. The thickness range can be extended up to 150 mm by laminating Transformerboard T4. In America and Europe Weidmann use liquid adhesives, usually polyester, however depending on the customer specification, may also use casein.
Since the 1940s, laminated Transformerboard has been used for clamping rings and other pressure elements, winding lead supports, end rings and strips of S > 8 mm. It is also the base for Barrierboard and Faltenbalg rings, and therefore must meet the highest mechanical and electrical requirements. These high standards are achieved thanks to its homogenous structure and high purity. A sophisticated and well monitored process guarantees the absence of any voids in the glue and provides a board free of partial discharge.
The nature of the material and its purity also returns long term dividends in comparison with laminated wood in its environment under oil at operating temperature. Laminated board is free of any acidic components which may affect the quality of the oil. Furthermore, the degradation of mechanical strength as a result of material ageing is also significantly delayed in comparison to plywood. Therefore, the higher initial purchasing cost of laminated Transformerboard is recouped in the form of a higher residual safety in the long run. This must be taken into account when considering the increased expectations regarding the service life of a transformer.