33

Single Phase Overload

Vacon · X4

What does 33 mean?

This fault occurs when the drive is configured for single-phase operation (parameter 517), and the DC bus voltage ripple exceeds the drive's allowable limits. This indicates the input power demand is too high for the drive's capacity in single-phase mode. This can lead to drive instability and potential damage if overloaded.

Common Causes

  • Drive operating in single-phase mode (P5-17 = 1) with an output load current exceeding the drive's derated capacity for single-phase input.
  • Input line impedance too high for the single-phase supply, causing excessive voltage drop and increased DC bus ripple under load.
  • Failure of internal DC bus capacitors, reducing their filtering capacity and increasing ripple voltage.
  • Unbalanced loading on the single-phase input leading to high RMS current draw on the active phases.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Verify Parameter P5-17 (Input Phase Configuration) is correctly set to '1' for single-phase operation.

  2. 2

    2. Reduce the motor load or operating current (monitor P0-01) to stay within the drive's derated current capacity for single-phase input.

  3. 3

    3. Check input voltage stability at L1 and L2 (or L1 and L3) terminals under load using a true RMS multimeter, ensuring it remains within specified limits.

  4. 4

    4. Ensure input power wiring gauge is adequate for the current draw, minimizing voltage drop to the drive.

  5. 5

    5. If supported, consider adding an input line reactor to reduce input current harmonics and DC bus ripple.

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Verified technical data. Last updated: March 2026

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