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ErrorLib — Industrial Fault Code Library

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31

Power Wiring Error (Adv. Code 1)

Vacon · X4

What does 31 mean?

This fault occurs if an IOC (Internal Overcurrent) fault is detected during the power wiring test, indicating a problem with the drive's power wiring. This signifies a serious wiring discrepancy or an internal component issue that could lead to immediate overcurrent conditions and damage.

Common Causes

  • Short circuit between motor output phases (U, V, W) or from any output phase to ground.
  • Incorrect connection of input power wiring to output terminals (L1, L2, L3 accidentally connected to U, V, W).
  • Damage to the motor cable or motor windings creating a low resistance path detected during the initial self-test.
  • Internal drive hardware fault in the current sensing circuit or IGBTs detected during the pre-charge sequence.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Power down the drive. Disconnect motor wires from drive output terminals U, V, W.

  2. 2

    2. Measure resistance between each drive output terminal (U-V, V-W, U-W) and from each terminal to the drive's protective earth ground, expecting infinite resistance (open circuit).

  3. 3

    3. Verify input power (L1, L2, L3) is correctly connected to the designated input terminals and not accidentally cross-wired to output terminals.

  4. 4

    4. Perform a resistance test on the motor windings (U-V, V-W, U-W) and from each motor lead to its frame ground, ensuring no shorts (expected values typically 0.1-10 ohms).

  5. 5

    5. If all external wiring checks pass and the fault persists without the motor connected, the drive likely has an internal hardware fault and requires replacement.

Browse all codes in this manual (33)
Verified technical data. Last updated: April 2026

Related Faults

1System Fault10Restart Lockout (Adv. Code 0)11Ground Fault (Adv. Code 0)
Source: Vacon X4
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