A new mica-free turn insulation for rotating HV machines

A new mica-free turn insulation for rotating HV machines has been developed. The insulation consists of a high temperature resistant wire-enamel coated with a chromium oxide-binder layer. The chromium oxide acts as a PD resistant coating protecting the wire enamel from degradation. By accelerated aging tests it is shown that the chromium oxide coating is well as good as the normally used mica. The main advantages of the new insulation are the possibilities of a rapid production process and its space saving performance.<>