Pulse Breakdown of Large Volumes of Mylar in Thin Sheets

Abstract

This work follows that reported by Ian Smith in the notes: “Revision of Breakdown Data concerning Mylar” (SSWA/IDS/6610/102)** and “D.C. and Pulse Breakdown of Thin Plastic Films” (SSWA/IDS/-6610/105).*** These notes were concerned with fairly small volumes of mylar but also suggested that stacks of thin foils might have a significantly greater breakdown strength than thicker single films. This possibility was mentioned in the original note on the “Volume Effect of the Pulse Breakdown Voltage of Plastics”, where it was suggested that for very large areas of thin foil, the intrinsic breakdown field might become independent of the volume since the defects could not be greater in length than the thickness of the foil. Owing to the encouragement (both moral and material) of Dr. Alan Kolb and his group at the Naval Research Group it was decided to investigate the breakdown field of large volumes of mylar to see if there was any sign of this happening. N.R.L. very kindly provided two large rolls of mylar, one of ten thou. and the other of 1/4 thou. thickness, with which the tests were done.

First Printed as SSWA/JCM/673/27 AFWL Dielectric Strength Notes Note 14 30 Mar 1967