Output side earth (ground) fault overcurrent at start

Was bedeutet E.GF ?

This fault indicates an output side earth (ground) fault overcurrent detected during inverter startup on the load side. It signifies a critical insulation breakdown in the motor or its connecting cables, posing a significant safety hazard and risk of equipment damage. This protection is configurable via Pr. 249.

• Insulation breakdown between one or more motor phases and the motor frame (ground).
• Insulation damage in the motor cable (U, V, W to motor ground/shield) due to mechanical abrasion or aging.
• Water ingress or contamination in the motor terminal box or cable glands, creating a conductive path to ground.
• Loose ground connection between the motor frame and the main facility ground, leading to spurious ground current detection.
• Internal short to ground within the inverter's output stage (IGBTs) or internal output wiring.

Klicken Sie auf Schritte, um Ihren Fortschritt zu verfolgen.

1. 1

   Disconnect the motor cables (U, V, W) from the inverter output terminals. Attempt to run the inverter without the motor.

2. 2

   Using a megohmmeter (insulation resistance tester), measure insulation resistance from each motor output phase (U, V, W) to motor frame ground (PE). Values should typically be greater than 1 MOhm.

3. 3

   Visually inspect the entire length of the motor cable for any visible damage, cuts, or crushed sections.

4. 4

   Check for moisture or debris inside the motor terminal box and ensure all connections are clean and dry.

5. 5

   Verify the integrity and continuity of the protective earth (PE) connection from the inverter chassis to the motor frame.