After completion of a long-term thermal-aging program, manufacturers may wish to add new minor components to an EIS. These components may include fastening tapes, tie cords, balancing compounds and other materials commonly used in mechanical applications.
Rather than conducting another long-term thermal-aging program to address the chemical compatibility of these minor components, sealed-tube testing quickly determines if the gaseous degradation by-products of these materials will be detrimental to the major components of the EIS. This sealed-tube test program is aligned with a similar program proposed for inclusion in IEC 61858.
This test is conducted by sealing all tested materials and additional proposed materials in glass tubes. The materials are then aged for two weeks at the established system’s temperature rating, plus 25º C. After aging, dielectric strength testing is conducted on the magnet wire to determine if the new materials have caused any additional degradation.
Sealed-tube conditioning lasts two weeks, but the entire investigation may take up to six weeks to complete.