A 10 000-hp AC Adjustable-Frequency Compressor Drive-The Economics of Its Application

With today's concerted effort to save energy and operating costs in petroleum and chemical processes, much attention is being paid to the study of the economics of constant-versus adjustable -speed motor drives for pumps, compressors, and blowers. A recently installed 10 000-hp compressor drive application is used as an example of such a study. To obtain the required variable flow from the compressor, a case using a constant-speed drive with throttling of the compressor is compared with cases using adjustable-speed drives utilizing a constant-speed motor and hydraulic coupling, an adjustable- frequency drive, and a steam turbine drive. A format is provided for making such a study, and other considerations of constant-versus adjustable-frequency drives are discussed.