Surface · ESP
Step-Up Transformer
A transformer between the drive and the well that raises the low drive voltage to the voltage the downhole motor needs.
What it does
Delivers motor nameplate voltage plus the voltage lost along the cable. Multiple secondary taps let the crew fine tune the surface voltage.
Basics
| Needed when | Supply voltage differs from motor voltage |
| Surface voltage | Motor nameplate voltage + cable voltage drop |
| Rated in | kVA, matched to the drive |
| Variant | Step-down units when the supply is high voltage |
Common failures
- Wrong tap selected, motor runs under or over voltage
- Insulation or oil degradation from heat and overload
Troubleshooting
- Symptom
- Motor current high and running hot after install
- Likely cause
- Surface voltage too low for the cable length
- What to check
- Recalculate cable voltage drop and change the tap