Application of Surface PM Motor Drive for Sucker Rod Pumps

For decades standard V-belt transmission with an asynchronous motor has been a traditional method to drive beam pumping units. This study describes a new approach based on the use of a Permanent Magnet Motor with no transmission. Non-transmission drive integrates a permanent magnet motor (PMM) and smart variable frequency drive. Since rotor is mounted directly on the gearbox input shaft, with stator being mechanically attached to the gearbox housing, the technology eliminates the need for conventional V-belt transmission between the motor and the gearbox. Variable Speed Drive (VSD) can provide a more advanced control for the permanent magnet motor, embedding mathematical models with a number of options for motor speed and rod load control, operation monitoring, failure risk mitigation, and production optimization. Application results revealed unique features of the system, that cannot be reached with a standard application. Elimination of V-belt transmission allows for safe and environmentally friendly operation with enhanced reliability and reduced non-productive time as no maintenance is required. High-efficient PM Motor (with no losses in the transmission) improves power consumption and practically demonstrate total power savings of 15-35 % if compared to the previously installed systems. The PMM system is easy to install, with installation time being less than 1 hour. PM Motor principles of operation provide a number of options for its control through smart VSD algorithms requiring no additional sensors. Real-time up-stroke / down-stroke speed adjustment, torque control, operating trips detection and many other features can potentially improve production and expected runlife of downhole and surface equipment. The results of this study are intended to demonstrate an effective and efficient alternative for oil production with Sucker-Rod Pumps (SRP). Application of the new type of surface drive has proved its high potential for production optimization and power consumption improvement with minimized risk of failures.