ERT™ Power Section Specification
700ERTcr7857
7" 7:8 Lobes 5.7 Stages
Rotor Specifications
Overall Length 251.88 in
Avg. Diameter 4.151 in
Contour Length 244.88 in
Eccentricity 0.246 in
Major Diameter 4.643 in
Head Diameter 4.000 in
Head Length 7.00 in
Weight 915 lb
Thread Form 2 7/8" API Reg
Stator Specifications
Overall Length 260.00 in
Tube OD 7.00 in
Contour Length 243.50 in
Tube ID 4.855 in
Rubber Cut-back
Side 1: 8.25 in
Side 2: 8.25 in
Weight 1251 lb
Material Alloy Steel
Performance Specifications
Flow Range 300-750 GPM
Rev per Unit Volume 0.23 Rev/Gal
Speed Range 69-173 RPM
No Load Pressure Loss 253 psi
  POB XTH
Max Rec Press 1,580 psi 1,690 psi
Torque @ Max Press 17,950 ft-lbs 19,200 ft-lbs
Stall Pressure 2,890 psi 3,090 psi
Stall Torque 32,930 ft-lbs 35,220 ft-lbs
Stator Minors and Fit (in) at 70°F
  XTH POB
Group Minor Fit Minor Fit
C 4.143 0.008 4.145 0.006
0 4.150 0.000 4.153 -0.002
1 4.162 -0.011
2 4.164 -0.013 4.163 -0.013
5 4.175 -0.024
 
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 1,000 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 Speed (RPM) 0
Mechanical Power
Differential Pressure (psi) 0 1,000 2,000 Mechanical Power (hp) 0
Torque
Differential Pressure (psi) 0 500 1,000 1,500 2,000 2,500 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 0.05
Speed
300 GPM 525 GPM 750 GPM Differential Pressure (psi) 0 500 1,000 1,500 2,000 2,500 Speed (RPM) 0 50 100 150 200
Mechanical Power
300 GPM 525 GPM 750 GPM Differential Pressure (psi) 0 500 1,000 1,500 2,000 2,500 Mechanical Power (hp) 0 200 400 600
©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.