New type of turn insulation for medium-sized, high-voltage electrical machines

A new type of turn insulation for medium-sized electrical machines is described. The insulating material consists of an aromatic polyamide/mica paper, which is folded longitudinally along the enameled conductor, thereby forming an effective corona shield for the enamel. The main feature of the insulation is its space saving, which may increase the output of a high-voltage machine "by some 15% for a given size, or, alternatively, reduce the manufacturing costs by about 10% for a given power rating. The trade name for the new insulation is MICAFOLD®.