In this paper iron losses are minimized in low wind period by proposing a change of rotor called supplementary rotor as a substitute to main rotor of induction generator. By using either main rotor or supplementary rotor at appropriate period, decided by the monthly average wind speed, the overall yearly electrical power generation can be increased. Eleven (11) numbers of 600 KW wind turbines at a selected site in Muppandal area, India were used for the analysis. The actual generation had been measured on daily basis for the year 2009-2010 for all the eleven numbers of 600 KW wind turbine systems and identified the reference wind turbine corresponding to maximum generated KWH. Subsequently, a comparison of the yearly generation has been made between the existing main rotor mode and the proposed newly designed supplementary rotor mode for reference induction generator under various scenario are analyzed in the context of increased annual generation( in turn the profit growth) and presented. © EuroJournals Publishing, Inc. 2011.