... and R McElveen, “InIMPORTANCE OF duction vs permanent magnet motors, ” IEEE now profit from the advantages of PM Ind Applicat Mag., vol 15, no 6, pp 28–35, motors For single-speed applications, ... high motor efficiency when the motor is designed for and operated at 60 Hz instead of 50 Hz The difference in efficiency between 50 and 60 Hz varies with the number of poles and the size of the motor ... 0.1 10 Motor- Rated Power (kW) 100 IE3 Efficiency Levels for 50 Hz IE3 Efficiency Levels for 60 Hz Adapted Ultrapremium Efficiency Levels for 50 Hz Commercial Ultrapremium Efficiency Levels for 60...