The Ronk ECONO-PHASE® Shifter is a cost effective, high efficiency power converter for use in pump jack application where design D high slip pump jack motors are used. Electric pumping start up costs on smaller wells can be reduced significantly using this unit. 1-phase oil well motors are limited in size and availability, as well as being more expensive initially and in operation. This unit makes it possible to utilize standard three phase motors, which are available in ratings that single phase motors are not. ECONO-PHASE® Shifter uses heavy components matched to oil well requirements for surging loads and the ability to operate continuously, if needed. Special capacitors are used to handle the high peak voltages that can occur when the motor runs over-speed in the down stroke and acts as a generator. Because of the run capacitor design in the ECONO-PHASE® converter, they will generally operate most motors at full load as needed and provide 3/4 load on a continuous basis.