An electrocyclone designed with a central discharge wire was built and used to investigate the performance factors affecting its particle collection efficiency by varying the operational conditions and parameters in the particle size range of 0.5 to 10 w m. A voltage of 0 to 9 kV was applied to the discharge wire varying in terms of diameter and length. Two types of vortex finder materials, aluminum and acryl, in three lengths, 2.5, 3.5, and 4.5 cm, were employed to examine the effects of electrostatic force. An increase in applied voltage and a decrease in wire diameter were found to boost collection efficiency, particularly at low flow rates for small particles. Many small particles induced in the cyclone were collected at the bottom of the cyclone cone and in the vortex finder that was situated close to the discharge wire. It was also found that the aluminum vortex finder yields higher collection efficiency than the acryl vortex finder and that the length of vortex finder plays a more important role in...