For applications that require particularly high reliability and durability (e.g. frequency inverters in wind and solar power systems), good insulating materials such as polyester or PEN may not be sufficient. Particularly in the presence of moisture and heat (e.g. in a control cabinet or box exposed to the elements) additional degradation processes may occur in the insulation material (hydrolysis). Dirt, condensation and contamination on the insulator surface arising from faulty installation reduce the insulating distance. Partial discharges can occur more easily and contribute more quickly to the destruction of the insulator (charring, increased susceptibility to contamination due to rough surfaces).
Overall, tape products such as CMC 75730 (FEP film), CMC 75738 (PTFE film) or CMC 77700 (ETFE film, very low tendency to creep) achieve outstanding service-life ratings, since these types of polymers inherently possess a very high resistance to aging and also deliver a good PD performance (high-PD extinction voltage or low sensitivity to tracking. All versions are easily extensible, allowing a careful layout of the windings and a safe separation from the winding core of the primary to secondary winding (as an alternative to the feathering of, for example, polyester film)
The Kapton® CR (CMC 70300) film from CMC has long been used in high-voltage motor and generator construction. Extensive tests at ABB and Siemens have demonstrated that the glow-discharge resistance is clearly higher than that of "normal" Kapton® HN or polyimide films from other manufacturers.
In case of interest do not hesitate to contact us.