Surface · Rod Pump
Gear Reducer
The gearbox at the back of the pumping unit that turns the crank.
What it does
Converts the high speed, low torque power of the prime mover into the low speed, high torque the pumping unit needs.
Basics
| Input | High speed, low torque |
| Output | Low speed, high torque to the crank |
| Sized by | Peak crank torque (API TR 11L method) |
Common failures
- Gear and bearing damage from fluid pound shocks
- Overload from poor counterbalance
- Oil leaks and contamination
Troubleshooting
- Symptom
- Knocking in the gearbox each stroke
- Likely cause
- Fluid pound
- What to check
- Confirm on the dynamometer card; slow down or add pump-off control
- Symptom
- Gearbox running hot
- Likely cause
- Overload or low oil
- What to check
- Check counterbalance and oil level