Measurement of electrical pressures in insulating liquids under direct applied voltages

The application of high electrical fields to a liquid dielectric induces internal pressures. In this new technique, a bubble of known size was injected via a sphere electrode through a hole at the apex of the sphere; the sphere electrode being immersed in the liquid dielectric. The bubble injection system was connected to a pressure monitoring and measuring system. Thus it was possible to monitor and measure the internal pressure of the injected bubble at different test conditions. The same technique has been used in the present work, with direct high voltages of either polarity applied to the sphere electrode.