pat nos 4 220 440 taylor and 4 695 779 yates and or can be coupled to an overload underload controller including a processor and timing means as in u s pat no 4 767 280 markuson et al each of which patents is incorporated herein by reference according to the invention a controller 50 of this general type is arranged to calculate the values of process variables from the electric power applied to the pump motor 40 as a result well and pump performance monitoring data is obtained and decisions can be made for controlling operation of the pump 20 with no or minimal reliance on sensors for detecting tension compression flow rate pressure and other similar variables that might otherwise be used to assess the pumping operation referring to fig2 the controller 50 is coupled to a transducer 54 operable to sense the instantaneous electric power level drawn from the power line 66 by the electric motor 40 operating the well pump 24 in the embodiment shown the controller 50 comprises a digital processor 56 and the transducer 54 comprises a watt transducer that produces a voltage output proportional to the instantaneous power level the voltage output is sampled using an analog to digital converter 58 clocked periodically by the controller 50 at a frequency substantially higher than the frequency of cyclic pump operation e g several times per second the watt transducer 54 averages the.