Rod Lift Variable Speed Drives

General-purpose adjustable-speed drives that vary motor frequency and voltage to set strokes-per-minute on a beam pumping unit. They require a braking resistor or regenerative front end to handle energy returned during the downstroke.

Drives with an active front end that returns braking energy from the downstroke to the utility line rather than dissipating it as heat. They eliminate braking resistors and lower net energy use on cyclic rod-pump loads.

VFD packages bundled with a braking chopper and resistor bank that absorb regenerated energy during deceleration and downstroke. They are used where line regeneration is impractical or the supply will not accept reverse power flow.

Drives using active front ends, 18-pulse rectifiers, or integrated filters to limit input current distortion. They protect weak field grids and shared transformers from harmonic problems caused by many drives on one feeder.

Drives housed in NEMA 3R, 4, or 4X enclosures, often with purge or cooling provisions, rated for wellsite weather and classified hazardous locations. They allow drive installation at the pad without a separate control building.

Combined units that pair speed control with downhole pump-fillage sensing derived from rod load and position. They automatically slow or idle the pump on incomplete fillage to prevent fluid pound and gas interference.

Reduced-voltage starters that limit inrush current and mechanical shock when energizing a fixed-speed pumping unit motor. They protect rods, belts, and gearbox at startup but do not provide continuous speed adjustment.