Natural Frequency test on End Winding:

To assess the mechanical integrity of the Generator end winding, a Natural frequency test is performed in order to determine the natural frequency response of individual loops in the radial and axial directions. If the measured natural frequency values are out of the resonance frequency band 95-100 Hz, it can be declared that the mechanical integrity of the stator end winding is in satisfactory condition. If it is out of resonance frequency, end winding has to be strengthened till the measured frequency values are out of resonance frequency.