Is this thread still active, I've just picked up a at1 2200x (xsy at1) trying to set it up on a 2.2kw watercooled spindle. I'm getting Err 3 - overvoltage protection. Braked voltage is set to 20 (default) which appears to be the recommended overvoltage is set to 255v seeing as it's a 220v power supply.

If anyone has any info. I suspect it's a faulty VFD.