A method of saving energy for a pump jack (30'; 308) with a counterweight disposed within a well, comprising the steps of: connecting a closed loop motor controller to an electric motor (3; 6'; 306) connected with the pump jack, said motor controller having switching devices; supplying a line voltage and current to said motor that rotates the pump jack counterweight for a plurality of pumping cycles (316, 318, 320); observing a phase angle between the voltage and current supplied to said motor with said motor controller; comparing the observed phase angle with a threshold phase angle; characterised in that the method further comprises: in a first state, adjusting the supply voltage upon reaching said threshold phase angle using a firing angle of said switching devices to maintain the observed phase angle at a value no greater than a target phase angle; reinstating the full supply voltage to said motor (3, 6'; 306) when the firing angle falls below a threshold firing angle; identifying time periods during the plurality of pumping cycles that the supply voltage is adjusted; comparing said time periods and determining whether said time periods have a close correlation to establish predetermined turn-off time periods for switching off the supply voltage; wherein the method further comprises: in a second state, after the step of comparing said time periods, switching off the supply voltage to the motor during said predetermined turn-off time periods (OFF#1, OFF#2); and switching on the supply voltage during said the other time periods, the other time periods being predetermined turn-on time periods. connecting a closed loop motor controller to an electric motor (3; 6'; 306) connected with the pump jack, said motor controller having switching devices; supplying a line voltage and current to said motor that rotates the pump jack counterweight for a plurality of pumping cycles (316, 318, 320); observing a phase angle between the voltage and current supplied to said motor with said motor controller; comparing the observed phase angle with a threshold phase angle; characterised in that the method further comprises: in a first state, adjusting the supply voltage upon reaching said threshold phase angle using a firing angle of said switching devices to maintain the observed phase angle at a value no greater than a target phase angle; reinstating the full supply voltage to said motor (3, 6'; 306) when the firing angle falls below a threshold firing angle; identifying time periods during the plurality of pumping cycles that the supply voltage is adjusted; comparing said time periods and determining whether said time periods have a close correlation to establish predetermined turn-off time periods for switching off the supply voltage; wherein the method further comprises: in a second state, after the step of comparing said time periods, switching off the supply voltage to the motor during said predetermined turn-off time periods (OFF#1, OFF#2); and switching on the supply voltage during said the other time periods, the other time periods being predetermined turn-on time periods. in a first state, adjusting the supply voltage upon reaching said threshold phase angle using a firing angle of said switching devices to maintain the observed phase angle at a value no greater than a target phase angle; reinstating the full supply voltage to said motor (3, 6'; 306) when the firing angle falls below a threshold firing angle; identifying time periods during the plurality of pumping cycles that the supply voltage is adjusted; comparing said time periods and determining whether said time periods have a close correlation to establish predetermined turn-off time periods for switching off the supply voltage; wherein the method further comprises: in a second state, after the step of comparing said time periods, switching off the supply voltage to the motor during said predetermined turn-off time periods (OFF#1, OFF#2); and switching on the supply voltage during said the other time periods, the other time periods being predetermined turn-on time periods.