End turn corona suppressing coatings their composition and effect

Abstract

Many techniques have been p roposed for the elimination of the ring of corona which can occur just outside the slot of high voltage stator coils. The aim of this work was to evaluate these voltage grading methods to determine t he most prac tical methods of accomplishing this objective for machines rated above and below 16 KV . For operating voltages up to 16 KV a single semiconducting silicon carbide paint system of 2.5" or longer provides excel l ent corona protection. For highe r voltag es a multiple paint system or a system composed of two layers of pa int separated by insulation is required.

Applications

“…Day et al (135) deal with stress-grading at the slot exits of high-voltage stator coils by silicon carbide coatings. They find 63 rnrn long single layers satisfactory up to 16 kV rating.…”