Iron losses in electrical machines excited by nonsinusoidal voltages

Optimisation of system efficiency is a challenge for magnetic material producers, motor designers and end users to optimise the performance of machine cores under complex magnetisation conditions. In many cases the material manufacturer does not know the magnetising conditions in a machine core, hence the best material might not be identified and neither manufacturers nor users know the characteristics of magnetic materials under highly distorted flux waveforms. This paper illustrates state of the art magnetic testing under distorted flux waveforms and presents comparisons of performance of different motor lamination steels under such waveforms. This leads on to highlight a fundamental difference of approach to test reference conditions, which under distorted flux waveforms can lead to misunderstanding in performance predictions.