Patent ID: 6592332
Filing Date: 2003-07-15
Classification: E21B,F04B

Abstract:
A pump-off control system for use in conjunction with an electric motor driven beam pumping unit including a polished rod attached by a wire-line carrier and hangar assembly to a horse head of the beam and to a down hole sucker rod pump comprising:(a) an electrical power source; (b) an interlocking pair of normally open relays wherein the first relay of said pair must be dosed before the second relay of said pair can close; (c) a first electrical circuit connected to the power source for energizing the first relay after a pre-determined time delay; (d) a control device attached to the polished rod as a component of said first electrical circuit, the control device momentarily de-energizing the first relay upon incurring fluid pound; (e) a second electrical circuit connected to the power source for energizing the second relay when the first relay is energized; and (f) a motor controller connected to the power source for starting and stopping the electric motor, the motor controller starting the electric motor in response to the second relay being energized and stopping the electric motor in response to the second relay being de-energized.