A substrate support comprises an electrode and a dielectric layer covering the electrode, the dielectric layer having a surface to receive a substrate. The article supporting device includes a horizontal supporting component, an article supporting fixture fixed to the front end of the horizontal component, and a pair of spaced posts fixed to the rear end of the horizontal component. An impeller shaft is mounted directly to the camshaft so as to be concentrically rotatably driven thereby. Two-phase operation generates an increased-magnitude output voltage of a negative polarity and another two phases of operation generate an increased output voltage of a positive polarity.