Line-to-Line Resistance Fault

What does Er - 04 mean?

This Auto-Tuning fault indicates that the process could not complete within the specified time, or the resistance measurement result fell outside the acceptable parameter range. This typically points to issues with motor wiring, motor integrity, or an active mechanical load during tuning. Inaccurate resistance data will compromise motor control and efficiency.

• Open circuit in one or more motor phases (U, V, W) preventing resistance measurement.
• High resistance connection at motor or Drive output terminals due to loose wiring or corrosion.
• Incorrect motor rated current (P2-02) or rated voltage (P2-05) entered, leading to out-of-range calculations.
• Motor stator winding damage (e.g., burned coil) causing an abnormal resistance value.

Click steps to track your progress.

1. 1

   1. Power down the Drive and disconnect the motor leads from the Drive output terminals (U, V, W).

2. 2

   2. Using a multimeter, measure the resistance between motor phases U-V, V-W, and W-U. All three readings should be balanced and within tolerance (typically a few ohms or less).

3. 3

   3. Check all motor cable connections at both the Drive output terminals and the motor terminal box for tightness and corrosion.

4. 4

   4. Verify that parameter P2-02 (Motor Rated Current) and P2-05 (Motor Rated Voltage) are precisely matched to the motor nameplate.

5. 5

   5. If resistance readings are significantly imbalanced or open, inspect the motor terminal box for internal wiring damage or insulation breakdown.