Test cell for electric strength of rubber-epoxy interfaces

Interfaces between solid insulating materials are critical in high voltage apparatus. Here a new test cell for electric strength of rubber-epoxy interfaces was designed and evaluated experimentally. The electrically active part of the interface was about 10 mm long and the interface endpoints were screened. The rubber in the test cell was compressed and the pressure at the rubber-epoxy interface could be varied and measured. The test cell was designed for AC breakdown testing and in 36 out of 39 tested samples the breakdown occurred at the interface.