Cause: Motor ground fault comes when motor suddenly starts running at high speed upon power-up, and the drive detects a ground fault.

E23.09 fault on an Inovance IS580 drive is a Motor Ground Fault, just like E23.00, but it is a special condition fault triggered during power-on or auto-start scenarios — specifically when the motor suddenly starts running at high speed upon power-up, and the drive detects a ground fault.

• Check motor insulation resistance (most important).
• Disconnect motor and power up drive.
• Inspect motor wiring and terminal box.
• Inspect drive output terminals: Look at U/V/W terminals for arcing or contamination.