Hi All,

I bought myself a new motor (0.55kw, dual voltage, 4 pole) for my Myford lathe and to test it I thought I'd hook it up to my Chinese 2.2kw VFD that I bought for my CNC router. I have used the VFD with router spindle and it works fine so I know that the VFD is functional. I swapped the links in the motor to make it delta configuration and wired up U,V,W and Earth to the VFD and powered up.

On the VFD I pressed the Run button and slowly started to increase the frequency. The motor started to turn slowly but as I increased the Hz the shaft slowed and eventually stopped turning altogether. The thing I found most wierd was that the motor sounded like it was getting faster as I increased the Hz on the VFD but the shaft speed didn't reflect that. I would say that it reaches about 50-60 RPM (not Hz) before the shaft speed drops off again.

The VFD is completely unaltered from new, I haven't changed any of the parameters. I have looked through the manual and I can't see that any of the parameters would have an effect on the symptoms that I am experiencing - but I'm certainly not sure of that. I have tried swapping a couple of the phase wires around, rechecked all my connections, turned it off and back on again (a 25 year career in IT - can you tell?), checked the ribbon cable to the VFD's control panel, and re-wired it all up again in case I had a brain-fart but I am still getting the same result. Anyone know where I might be going wrong - am I doing something properly daft? Or could I have a duff motor?