ERT™ Power Section Specification
725ERT7872
7.25" 7:8 Lobes 7.2 Stages
Rotor Specifications
Overall Length 252.00 in
Avg. Diameter 4.489 in
Contour Length 240.00 in
Eccentricity 0.267 in
Major Diameter 5.024 in
Head Diameter 4.750 in
Head Length 12.00 in
Weight 1453 lb
Thread Form 3.688 XDV
Stator Specifications
Overall Length 260.00 in
Tube OD 7.25 in
Contour Length 237.50 in
Tube ID 5.094 in
Rubber Cut-back
Side 1: 9.00 in
Side 2: 13.50 in
Weight 1165 lb
Material Alloy Steel
Performance Specifications
Flow Range 500-800 GPM
Rev per Unit Volume 0.25 Rev/Gal
Speed Range 125-200 RPM
No Load Pressure Loss 228 psi
  POB XTH
Max Rec Press 1,990 psi 2,130 psi
Torque @ Max Press 20,880 ft-lbs 22,370 ft-lbs
Stall Pressure 3,640 psi 3,900 psi
Stall Torque 38,200 ft-lbs 40,930 ft-lbs
Stator Minors and Fit (in) at 70°F
  XTH POB
Group Minor Fit Minor Fit
2 4.494 -0.005 4.494 -0.005
 
Reline Lengths (in) Max 260 Min 254
Alt. Stator OD (in)   -   -
Alt. Rotor Diameter (in) - - - -

Max DP for reliable operation will vary based on
operational conditions. Refer to ERT Operational
Guidelines for guidance.

Torque
Differential Pressure (psi) 0 2,000 Torque (ft-lb) 0
Fit Increase
Change in Temperature (°F) 0 100 200 300 Fit Increase (in) 0
Speed
Differential Pressure (psi) 0 1,000 2,000 3,000 Speed (RPM) 0
Mechanical Power
Differential Pressure (psi) 0 2,000 Mechanical Power (hp) 0
Torque
Differential Pressure (psi) 0 500 1,000 1,500 2,000 2,500 3,000 Torque (ft-lb) 0 10,000 20,000 30,000
Fit Increase
Change in Temperature (°F) 0 50 100 150 200 250 300 Fit Increase (in) 0 0.01 0.02 0.03 0.04
Speed
500 GPM 650 GPM 800 GPM Differential Pressure (psi) 0 500 1,000 1,500 2,000 2,500 3,000 Speed (RPM) 0 100 200 300
Mechanical Power
500 GPM 650 GPM 800 GPM Differential Pressure (psi) 0 500 1,000 1,500 2,000 2,500 3,000 Mechanical Power (hp) 0 200 400 600 800 1,000
©2026 NOV. All rights reserved. Except as noted, all trademarks referenced in this document are trademarks of NOV. Performance curves describe theoretical performance with 175°F (79°C) water and are for reference only. Operational fit and drilling conditions will affect performance. Operation above maximum recommended limits will reduce life. Specification data are subject to change without notice.
PS App v.