Pump · ESP
ESP Motor
An oil filled, three phase electric motor at the bottom of the string that drives the seal and the pump through a common shaft.
What it does
Turns electrical power into shaft power. It is cooled by well fluid flowing past it, so it is normally set above the perforations or fitted with a shroud.
Basics
| Types | Induction (2 pole, three phase, squirrel cage) or permanent magnet |
| Speed | About 3,500 rpm at 60 Hz for 2 pole induction; above 5,000 rpm possible with a VSD |
| Typical voltage | About 460 to 4,200 V at 60 Hz |
| Power range | From about 7.5 kW to more than 750 kW |
| Filled with | High dielectric synthetic oil |
| Cooling | Fluid velocity past the housing |
Common failures
- Overheating from low fluid velocity past the motor
- Winding insulation failure (burnt motor)
- Contamination from a failed seal or pothead
Troubleshooting
- Symptom
- Motor temperature climbing
- Likely cause
- Low flow past the motor, set below perforations or pump off
- What to check
- Check setting depth, flow rate and shroud
- Symptom
- Phase to ground fault
- Likely cause
- Insulation failure in motor, pothead or cable
- What to check
- Test from the junction box section by section