ČSN EN IEC 61189-2-809

This part of IEC 61189 defines the method to be followed for the determination of the X/Y coefficient of thermal expansion of electrical insulating materials by the use of a thermomechanical analyser (TMA). This method is applicable to materials that are solid of the entire range of temperature used and retain sufficient hardness and rigidity over the temperature range so that irreversible indentation of the specimen by the sensing probe does not occur.