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.