E.UP fault in KEB COMBIVERT F5 Drive indicates an Under Voltage. This means the internal DC bus voltage dropped below the minimum operating threshold, often caused by a phase loss or low input mains.
Cause:
DC bus voltage drop. Common sources include:
- Input voltage too low or unstable.
- One phase of the line input is missing.
- Line input phases are imbalanced (the phase-to-phase voltage imbalance should not exceed 2%).
- Undersized or incorrectly wired isolation transformer.
- Faulty DC bus voltage measurement circuit.
Remedy:
- Verify the input voltage and wiring. The DC bus should measure approximately 1.41 x AC Input phase-to-phase, and should match the DC bus measurement read by the drive in the Diagnostics Menu.
- Measure the DC bus directly and verify against the DC bus voltage read from the Diagnostics screen.
Note: A 460V drive can operate on a 230V, single phase power supply if programmed for UPS mode operation.
