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Method and apparatus for matching the power output of a high slip motor to the demand requirement of a pumpjack unit. The stators of the high slip motor are automatically connected in various different configurations to provide the optimum torque as required by the pumpjack unit due to the downhole

Method and apparatus for matching the power output of a high slip motor to the demand requirement of a pumpjack unit. The stators of the high slip motor are automatically connected in various different configurations to provide the optimum torque as required by the pumpjack unit due to the downhole pumping conditions. A novel control circuitry is connected between the motor starter and the motor stators. The control measures the power drawn by the stators and selects the most optimum configuration thereof for the load required by the pumpjack. This selection operates the motor in the lowest possible torque mode, which is considered the best electrical and mechanical operation of the pumpjack apparatus.

대표청구항 ▼

A motor control unit for automatically controlling the torque output of a high slip motor powering a pump jack unit for stroking a downhole pump, said motor including motor starter means connected to motor stater windings and circuit means for altering the electrical configuration of said stater win

A motor control unit for automatically controlling the torque output of a high slip motor powering a pump jack unit for stroking a downhole pump, said motor including motor starter means connected to motor stater windings and circuit means for altering the electrical configuration of said stater windings, said motor control unit comprising: sensor means for detecting the magnitude of the average current flow through said starter windings during a multiplicity of pump strokes; said stater windings being electrically connected in a first electrical configuration for a relatively lower motor torque output; first overload means responsive to said sensor means for automatically altering the electrical configuration of said motor windings from said first electrical configuration to a second electric configuration when said average current flow exceeds a first preselected value to increase said motor torque output; first timing means for sensing the time period said stater windings are connected in said second electrical configuration and automatically altering said motor stater windings from said second electrical configuration to another electrical configuration to reduce said motor torque output after a preselected period of time.