Electric Field and Heat at the CAT-SG Coatings Interface Under Fast Rise Pulses

PWM voltages modify the performance of the stress grading coatings at the end winding region of rotating machines. The electric field and heat in these layers become intensified under this type of waveforms. Under this condition, the design of the stress grading and the conductive armor coatings can become difficult and modeling has resulted in a useful tool in understanding the influence of the various design parameters. In this work, optical micrographs of the overlapping area are obtained from form-wound coils to observe the topology of the interface between conductive armor and stress grading tapes. The interface geometries observed in the images are used to simulate the electric field and heat under fast rise time pulses, and the results are compared with those obtained with the typical interface topology used in simulations.