Low heat level to determine system Insulation Rating

Heat insulation dry-type transformers and the determination of other solid insulation of electrical devices, is composed of different solid dielectric composite  Air circuit breaker with air insulation system, how to determine the system's thermal insulation levels, is an issue of great concern to the user. Dry type transformer coils, for example, we believe that the most close to a heat source (heating element) of  air circuit breaker  to determine the minimum level of heat insulation rating system is more scientific, then the dry-type transformers, most close to the wire heating undoubtedly the strands body interturn insulation and insulation, of course, should also include a layer of pressure foil coil insulation.