Studies and industrial applications for oil field pumps a special brushless synchronous motors

This paper outlines the designs and the applications experience of special brushless synchronous motors (SBSM with constant exiting current, but self-stabilizing cos/spl Phi/ /spl ap/ 1) for special use in oilfield pumps. The studies begun in the former USSR and covers the following issues: 1) the severe duties and the main demands of mechanisms on the oil and gas industries field equipment; 2) technical and economical substantiation of the replacement of distant sucker-rod oil pumps (SRP) induction motors (IM) with the SBSM, reliable like IM, as a measure for saving energy, improving stability, reliability, while reducing harmful effects on the environment; 3) a peculiar approach during the SBSM design work to get self-stabilizing cos/spl Phi/ /spl ap/ 1 effect under a wide range of cycling torque; 4) supporting the substantiation oilfield experiments and computer-assisted electro-dynamic lab model studies: IM and SBSM dynamic stability analyses in the conditions of supply voltage fluctuations and extensive cyclic moment on the shafts. The calculated SBSM production cost is equal to 130-150% to that of one IM. Despite this the SBSM was recommended oil industry as a replacement for burned or obsolete IM and for new SRP, even if the cost of the SBSM is double of the IM cost. The payback time of the SBSM is determined 4-6 month.