A 10000-hpAC Adjustable-Frequency Compressor DriveTheEconomics ofItsApplication RONALD A.GUTZWILLER,SENIORMEMBER, IEEE,R.JOHNGERHART,AND HERBERTN.HICKOK,MEMBER,IEEE

With today's concerted effort tosaveenergy andoper- ating costsinpetroleum andchemical processes, muchattention is beingpaidtothestudyoftheeconomics ofconstant- versusad- justable-speed motordrives forpumps,compressors, andblowers. A recently installed 10000-hp compressor drive application isusedasan example ofsuchastudy. Toobtain therequired variable flowfromthe compressor, acaseusing aconstant-speed drive withthrottling ofthe compressor iscompared withcases using adjustable-speed drives uti- lizing aconstant-speed motorandhydraulic coupling, anadjustable- frequency drive, andasteamturbine drive. A format isprovided for makingsuchastudy, andotherconsiderations ofconstant- versus adjustable-frequency drives arediscussed.