Due to its high mechanical strength, it is possibleto use cylinders directly on the winding mandrel as supporting cylinders for coils,even for limited-rating transformers. These cylinders can be impregnated completly without difficulty. The danger of air or water insulations, cannot be avoided with hard paper cylinders.

Although cylinders of TRANSFORMERBOARD behave similarly to soft paper insulation with regard to dielectric properties, they are dimensionally stable and can be loaded without mechanical problems.

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