| dc.description.abstract | Pumps operated with variable and higher speed electric motors provide numerous benefits such as greater range of flow and head, higher head from a single stage, valve elimination, and energy saving. To achieve these benefits, however, extra care must be taken in selecting the appropriate system of pump, motor, and electronic motor driver of VFD for optimum interaction with the process system. Successful pump selection requires knowledge of the full anticipated range of heads, flows, and specific gravities. Motor selection requires appropriate thermal derating and, at times, a matching of the motor’s electrical characteristic to the VFD. VFD selection requires an understanding of the electronic technology employed to determine what effect the VFD may have on the mechanical aspects of the driven equipment train. Despite these extra design considerations, variable speed pumping is becoming well accepted and widespread. In a simple manner, a discussion is presented on how to identify the benefits that variable speed offers and how to select components for trouble free, reliable operation. | en |
