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.
The USSR had indeed planned since about 1960 to drill deep holes onshore. The Superdeep Number 3 in Kola, Russia, remains the world's deepest hole into the earth, at 12,261m. It took from 1970 to 1984 to get this far.