Surface · PCP
Drive Head
The surface unit that turns the whole rod string. A motor drives it through belts or a gearbox, usually at a few hundred rpm.
What it does
Rotates the rods and rotor, carries the axial load of the string, and holds the backspin brake that releases stored rod torque safely when the well stops.
Basics
| Drive | Electric motor, belts or gearbox |
| Typical speed | 100 to 500 rpm |
| Key safety part | Backspin (anti-reverse) brake |
| Sits on | Wellhead, above the stuffing box |
Common failures
- Backspin brake not holding when the well stops
- Belt slip or worn belts
- Gearbox or bearing failure, oil leaks
- Motor overload from high downhole torque
Troubleshooting
- Symptom
- Rods spin back hard after shutdown
- Likely cause
- Backspin brake worn or not engaging
- What to check
- Test the brake before any restart; never work on the head while torque is stored
- Symptom
- RPM below setpoint, belts squeal
- Likely cause
- Belt slip from wear or low tension
- What to check
- Belt tension and wear, sheave alignment
- Symptom
- High motor amps, low flow
- Likely cause
- Downhole problem: swollen stator or rotor tagging
- What to check
- Torque trend, space-out, fluid compatibility