An electrostatic coalescer apparatus for separating water from a crude oil emulsion comprises a vessel housing having a cavity, an inlet for receiving a crude oil emulsion and outlets for water and purified crude oil. First and second pairs of electrodes are positioned in the vessel cavity. A first Scott-T transformer circuit is coupled to the first pair of electrodes and a second Scott-T transformer circuit is coupled to the second pair of electrodes. The first and second Scott-T transformer circuit receive as an input a 3-phase power supply and output a 2-phase high voltage signal pairs of electrodes. The 2-phase voltage generated between the first pair of electrodes is of the same amplitude and phase as the voltage generated between the second pair of electrodes via the respective Scott-T transformer circuits. A method comprises steps performed during operation of the apparatus.