Better to be Lucky Than Good

This paper describes various factors that are to be considered in selecting a variable speed drive and a steam turbine for any process equipment. To better illustrate the process of selecting a drive from both VFD and turbine options, two example cases were created that represented actual applications already installed and operating. The specific applications are a boiler feedwater pump (BFW) and an FD fan. It is necessary to consider and include all the costs for either type of drive system. The VFD and motor costs were obvious but the existing surplus distribution and transformer capacity, had it not been available, would have altered the economics considerably. Similarly, the cost of steam piping and lube oil supply, cooling, and filtration, which was available at the BFW pump but not at the FD fan, was not discussed but could have had significant cost impact.