Phase U to Gnd

What does F38 mean?

An electrical short circuit has been detected between the drive's output phase U and ground. This could be due to insulation breakdown in the motor winding or the cable connecting the drive to the motor, posing a risk of electrical shock and further equipment damage if not resolved.

• Insulation breakdown in the motor winding for phase U, creating a short circuit path to the motor frame (ground).
• Damaged motor cable insulation between the drive's output terminal U (T1) and the motor, causing a short to conduit or ground.
• Water ingress or conductive contamination (e.g., metallic dust) at the motor's terminal box or drive's T1 terminal.
• Loose conductor strand from phase U at the motor or drive connection touching a grounded enclosure or motor frame.

Click steps to track your progress.

1. 1

   Disconnect motor leads U, V, W from the drive's output terminals (T1, T2, T3). Perform an insulation resistance test (megohm) from each motor phase winding (U, V, W) to the motor frame ground.

2. 2

   Visually inspect the motor cable connected to T1 for signs of damage (e.g., chafing, cuts) along its length.

3. 3

   Using a multimeter, measure resistance from the drive's output terminal T1 to the drive's ground terminal with the motor cable disconnected.

4. 4

   Inspect the motor junction box and the drive's output terminal block T1 for any signs of moisture, conductive debris, or loose wire strands.

5. 5

   If the motor cable is suspected, disconnect it at both ends and perform an insulation resistance test from the cable's U conductor to ground.