Accurate Rotational Speed Measurement for Determining the Mechanical Power and Efficiency of Electrical Machines

Accurately measuring the mechanical power of electrical machines is essential for determining their efficiency. Conventionally, the machines' rotational speed is measured over a short time interval with a high measurement uncertainty. In this paper, we propose a rotational speed determination based on the angle covered within a longer time interval. This method is shown to achieve a higher accuracy for the determination of mechanical power and total efficiency with negligible systematic effect.