I have been running my Chine's VFD/spindle since 2021. Today at the end of my last cut the spindle didn't fully stop but continued at a low RPM for a few extra seconds. Enough to be noticeable. Anyhow when I started my next cut the spindle did not start. The error was E.L.u.S. The manual for these and support is low support but both the errors I listed say low voltage. There are some Threads out there that point to factory reset but since I have been running for a few years now I suspect this is unlikely. After trying a different power source with no success I did factory reset just to appease the internet. I know this is not official Huanyang support line but we are all makers here that have seen different things in our days. Maybe someone here has an Idea for me.
LU is usually Low Voltage, so check input mains cabling. High resistance connection / loose terminal screw etc causing voltage drop under load. Otherwise, time for a replacement - internal faults can show up as external errors