High voltage rotating machines are widely used in the power stations, sugar mills, steel mills, cement mills etc. Insulation is an essential component for proper operation of electrical machines without any fault and the condition of insulation of an electrical machine mainly determines its life period. The economic aspects of its periodic maintenance like the loss in production due to breakdown and the investment cost due to frequent replacement with a new machine is huge. The insulation condition of the machine can be assessed by measuring the various parameters like insulation resistance, polarization index, leakage current, capacitance, dissipation factor, partial discharge magnitude and surge voltage withstanding strength. To assess these parameters of the stator winding insulation used in high voltage rotating machines, a number of measurements have been made on actual stator coils of machines. For various test voltages, the leakage current, capacitance and dissipation factor are measured and correlated as a function of test voltages. By using artificial neural network algorithm we going to predict, status of the insulation of the AC machines.