Earth leakage

What does A2B3 mean?

The drive generates a warning when an earth fault or current unbalance is detected in the motor or motor cable. This indicates a potential insulation degradation or leakage current to ground, which requires investigation to prevent a full fault trip or safety hazard.

• Degradation of insulation in the motor cable (e.g., due to aging, moisture, mechanical abrasion) leading to leakage current to ground.
• Moisture ingress or contamination (e.g., oil, conductive dust) at the motor terminal box or cable glands.
• Partial insulation breakdown within the motor windings, allowing small currents to flow to the motor frame (earth).
• Improper grounding of the motor frame or the drive, creating an undesired earth path or ground loop.
• High frequency common mode currents finding a path to ground through the motor cable shielding due to poor EMC installation.

Click steps to track your progress.

1. 1

   1. Disconnect the motor cable from the drive. Perform an insulation resistance test (Megger, e.g., 500VDC) on each motor phase cable (U, V, W) to ground (PE).

2. 2

   2. Inspect the motor terminal box for signs of moisture, corrosion, or contamination and ensure all cable glands are properly sealed.

3. 3

   3. Inspect the entire length of the motor cable for visible damage to the outer jacket or signs of wear.

4. 4

   4. Verify the integrity of the ground connection from the motor frame to the machine frame and back to the drive's PE terminal.

5. 5

   5. Check for proper termination of the motor cable shield at both the drive and motor ends, ensuring it is grounded correctly.