Sveba-Dahlen oPF2

What does Sveba-Dahlen oPF2 mean?

The SD-180's Schneider frequency converter has detected a three-phase output anomaly, indicating that the motor is not connected, the supply is insufficient, a contactor or load switch after the drive is open, or there is momentary instability in the motor current. Unlike oPF1 which indicates a single-phase loss, oPF2 reflects a condition where all three phases show abnormal current behavior simultaneously, suggesting a complete disconnection or severe instability in the motor circuit.

Symptoms

• Drive trips with oPF2 on the touchscreen immediately on startup or when a run command is issued
• Motor does not respond at all to run commands, with no rotation or hum
• All three output phase currents read near zero in the drive diagnostics
• Fault occurs after maintenance where motor cables or contactors were disconnected and not fully reconnected
• Intermittent oPF2 trips during operation may indicate a loose connection causing momentary current instability

Common causes

• Motor not connected to the drive output (primary cause per manual)
• Insufficient power supply to the converter causing inability to drive the motor
• Open contactor or load switch installed between the converter output and the motor (primary cause per manual)
• Momentary instability in motor current causing the drive to detect a three-phase anomaly (primary cause per manual)
• All three output phase cables disconnected or severely damaged
• Motor winding failure resulting in an open circuit across all phases

Diagnostic steps

1. 01

   Verify motor is connected to the drive output

   Confirm that the motor supply cable is physically connected to both the drive's output terminals (U, V, W) and the motor terminal box. This is especially important following any maintenance activity where cables may have been removed.

2. 02

   Check for an open contactor or load switch

   If a contactor or load switch is installed between the drive and the motor, confirm it is closed and receiving its control signal. Inspect contacts for wear or failure and verify the contactor coil is energized correctly during the run command.

3. 03

   Measure output phase voltages at the drive terminals

   With the drive issuing a run command and appropriate safety precautions in place, measure the AC voltage at the drive's U, V, and W output terminals. Absent or severely unequal voltages indicate a drive output fault or missing supply to the converter.

4. 04

   Check the drive's input supply voltage

   Measure the input supply voltage at the converter's L1, L2, and L3 terminals. Confirm the supply is within the drive's rated input voltage range as specified in the SD-180 manual; low or absent supply voltage can prevent the drive from delivering sufficient output.

5. 05

   Test motor winding continuity and insulation

   With the motor isolated from the drive, use a multimeter to check phase-to-phase winding continuity and an insulation resistance tester to identify open windings or insulation breakdown. A motor with open-circuit windings must be repaired or replaced before the drive is restarted.

6. 06

   Clear the fault and perform a supervised test run

   After confirming all connections, the contactor state, and motor integrity, clear the oPF2 fault via the touchscreen and perform a supervised test run. Monitor all three output phase currents in the diagnostics to confirm stable, balanced operation.

When to call a professional

Escalate to a licensed electrician or Sveba-Dahlen-authorized engineer if the fault persists after confirming all wiring and contactor conditions are correct, as this may indicate an internal drive output stage fault. Also escalate if the input supply voltage is found to be outside specification, as supply issues require investigation by a qualified electrician. Motor winding faults identified during testing require specialist repair outside the scope of drive servicing.