Another consideration is the relationship. between insulation class, temperature rise, and ambient temperature. The insulation. class rating designates the maximum. operating temperature for a winding. The. temperature rise is the difference between the.
China claims it has discovered the world's largest hole, and it's in one of the most dangerous places on the planet. 1  Jul.  Good news: China claims it has discovered the world's largest hole. On Wednesday, state broadcaster CCTV announced that the newly found dragon's hole, a 984-foot (300-meter) cavern in the disputed waters of the South China Sea, is now the world's largest hole.
Photograph by Carsten Peter, National Geographic China's immense Miao Room cavern, hidden beneath rolling hills and reachable only by an underground stream, is the world's biggest cave chamber, an international mapping team reported on Sunday. (Related: China's Supercave..