ePAC™ Vector Flux Drive Rod Pumping System Automatic Control

The ePAC drive’s embedded programming allows the user to preset limits to customize the control to the application.

These controls are active in all operational modes and include:

• Minimum and maximum SPM
• Gear ratio monitor automatically computes the overall gear ratio between the motor and the crankshaft each stroke of the pump and is used to monitor belt slip. Gearbox torque limits can be preset to limit gearbox stress.
• Rod force limiter reduces rod breaks by limiting the maximum stress that can be placed on the rods and as such increases rod life by reducing fatigue. It also can reduce rod compression damage by controlling the minimum rod force. Maximum and minimum rod forces, and associated rod positions, are captured with each stroke of the pump, and the rod force is adjusted automatically to stay within preset parameters.
• Bridle separation controller uses an internal calculation to detect loss of rod weight on the pump downstroke due to rod fl oat. The separation limiter automatically adjusts downstroke speed to track rod fl oat while maximizing production.
• Pump jack imbalance is displayed to the operator as positive (overbalanced) or negative (underbalanced) crankshaft torque. Imbalance information allows the operator to easily position or change the counterweights to minimize gearbox stress and energy consumption.
• The pump flow monitor uses well parameters and drive information to estimate pump flow. The estimated well production is displayed to the operator in BPD.

ePAC Vector Flux Drive Rod Pumping System Control Monitoring

UEDIT software allows the system to be monitored through one of the ePAC drive’s serial ports. Various screens provide configuration and operational interfaces, including:

• The dynagraph screen can be used to display both surface and pump card.
• Data in the ePAC can be uploaded to an archive as a backup or downloaded to the drive from the archive to restore prior setup information.