F13

Ground Fault

Allen-Bradley · PowerFlex 40 Adjustable Frequency

What does F13 mean?

This fault detects a current path from the motor or drive output wiring to ground. This can be caused by damaged motor insulation or faulty wiring between the drive and the motor.

Common Causes

  • Insulation breakdown in the motor windings due to age, moisture ingress, overheating, or physical damage, creating a path to ground.
  • Damaged motor cable insulation between the drive and the motor, creating a current path to ground (e.g., crushed conduit, abrasion).
  • Moisture, conductive dust, or foreign material inside the motor terminal box or drive output terminals (U, V, W) causing a short to ground.
  • Incorrect grounding of the motor frame or cable shielding, leading to an improper ground path.
  • Internal drive output stage component failure leading to a ground fault within the drive itself (less common).

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Disconnect the motor cables (U, V, W) from the drive output terminals. Perform an insulation resistance test (megger) on the motor cable from each phase conductor to ground.

  2. 2

    Perform an insulation resistance test (megger) on the motor windings, checking each phase (U, V, W) to the motor frame (ground).

  3. 3

    Inspect the entire length of the motor cable for visible damage, abrasion, or signs of moisture ingress.

  4. 4

    Check the motor terminal box and drive output terminal area for moisture, conductive debris, or loose wire strands causing a short to ground.

  5. 5

    Ensure proper grounding connections for the motor frame and cable shield (if used) are intact and have low resistance to the main ground bus.

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Verified technical data. Last updated: March 2026

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Source: Allen-Bradley PowerFlex 40 Adjustable Frequency