| Six dielectric liquids have been investigated for the confirmation of the EHD theory of current response to the application of ramped high voltage by using a prebreakdown technique. The conduction current and displacement current were measured and studied individually. Upon plotting conduction current as well as displacement current on a log V -log I scale, two linear portions of the current characteristics were observed in the high stress regime. Thus two separate regimes of the characteristic were found exhibiting current transport in direct proportion to a simple power of the applied voltage, {dollar}rm Ipropto Vsp{lcub}s{rcub}{dollar} (or {dollar}rm I propto Vsp{lcub}g{rcub}{dollar} with respect to displacement current), where s (or g) represented upper s{dollar}sb{lcub}rm u{rcub}{dollar} (or g{dollar}sb{lcub}rm u{rcub}{dollar}) and lower slope s{dollar}sb{lcub}rm l{rcub}{dollar} (or g{dollar}sb{lcub}rm l{rcub}{dollar}) values. The impact of the developments on the relationship between the maximum applied voltage and the power law is discussed. The relationship referred to is one involving both s values merging to 3/2 when the electric field becomes large. A new approach using a computer modelling process for these EHD studies will be presented. Attention will also be given the magnetic field effect observed from the final series of displacement current measurements. A turbulence phenomenon in dielectric liquids has been discovered from a special experiment performed in order to verify the nature of dielectric liquid behaviour under high applied electric field conditions. |
