In this paper,diagnosis for 85 high voltage induction motors which have operated for more than 20years
in 18 wide area water supply offices were applied and the results of diagnosis were analysed.
Furthermore, main factors that would be affecting rotor defects were selected and correlations between dependent variables which was magnitude for sideband frequency on currentduring operation and independent variables such as starting characteristic, operating time, number of operation, load factor, maker, rotation speed, capacity wereanalysed. It was clear that factors including starting characteristic, number of operation, maker, rotation speed caused break by correlation analysis. From this, regression equation was deduced through regression analysis. Based on suggested regression equation, it is applied usefully that we can estimatethe condition of rotor without on site diagnosis and plan the schedule of diagnosis.
