Turn to turn insulation ageing diagnosis using frequency response analysis

Inverter-fed induction motor applications are very common in many industrial processes. This provides electrical stresses higher than expected when feeding with power frequency. As a consequence, partial discharge activity appears. It has been reported that turn to turn insulation has become the weakest point within an inverter fed motor stator winding, so its ageing condition seems to be an important issue to be studied. This paper presents some promising results in turn to turn insulation ageing diagnosis after applying different electrical stresses by means of dielectric spectroscopy.