A review on the comparison of conventional and corona resistant nanofilled enamels

The low voltage rotating electrical machines, typically based on Type I random/wound windings, are normally controlled by power electronic drives. The power supply voltage waveforms are characterized by fast rise and fall time fronts and in case of resonance and reflection phenomena, overvoltage could appear at the connection terminals of the machine. These overvoltages can incept the partial discharges in the electrical insulation, leading to the total breakdown of the machine. The nanocomposite material used as enamel on the winding wires can lead to increase the performances of the insulating system. In recent years, new class of corona resistant materials based upon nano particles have been characterized. In this work, an overview of the research studies performed by the CMTEST laboratory staff of the University of Genova is presented to summarize the results obtained comparing the behavior of conventional and nano-filled enamels.