Motor's expense repaid in savings

This article outlines the designs and some applications of special brushless synchronous motors (SBSMs) with constant exciting current but self-stabilizing cosphiap(1) for oil-field pumps. The study includes the technical and economical reasons for replacing the induction motors (IMs) of distant sucker-rod oil pumps (SRPs) with the SBSM, (as reliable as IM), to save energy and improve stability and reliability while reducing harmful effects on the environment. The practical implementations of the proposed designs in several oilfield experiments and computer-assisted electrodynamic lab model studies are also discussed. The study also determines that the additional manufacturing cost of the SBSM over IM can be recouped in about four to six months