Abstract: An oil separator for pressurized systems having flowing vapor with entrained oil particles, the separator including an electrically conducting enclosure having an inlet for the oil bearing vapor and a first outlet for the vapor and a second outlet for the separated oil, an electrically conductive screen positioned within the enclosure to receive the entire flow from said vapor inlet, said screen being electrically insulated from the inlet and enclosure, and a high voltage mono-polarity source connected between the screen and the enclosure. A needle-like electrode at the same potential as the enclosure is positioned at the vapor inlet to accentuate the electric field, thereby improving separation.