METHOD AND MEANS FOR CONTROLLING LONG STROKE PUMPING UNITS

摘要

METHOD AND MEANS FOR CONTROLLING LONG STROKE PUMPING UNITS of the Invention In a rotating drum or winch type long stroke pumping unit in which the motor which powers the pumping unit operates only during the central portion of the pumping stroke, the motor is energized at the point of maximum load upon the pumping string during the upstroke and the point of minimum load on the downstroke. By precisely coordinating the energization of the motor with the load upon the pumping string detrimental oscillations in the pumping string are damped out.