Factors to consider in the application of energy efficient motors

This paper examines the operation of energy efficient (EE) motors in the petrochemical industry with an emphasis on practical operating conditions. These include the effect of the speed difference between EE and standard efficient (SE) motors on efficiency, the effects of higher than rated voltage on efficiency and the important problem of downsizing of motors to improve efficiency. It is shown that the higher operating speed of EE motors reduces the effective efficiency difference between EE motors and SE motors. The higher than rated voltage on the other hand increases the efficiency difference. Finally, the problem of downsizing of motors for more efficient operation is addressed