I am having trouble getting a new chinese Spindle to turn and I wonder if anyone has suggestions.

Since 2004 I have been building/converting CNC machines and have plenty of experience with VFD's using them as phase converters so I can run larger 3 phase motors from a single phase supply - pretty much always de-rated to 55%. They always work first time and always reliable - failure every decade or thereabouts so happy with technology.

I recently bought a second hand 8x4 router to convert. The old spindle is 8hp/380v. I bought a new smaller but still hefty spindle which is 6hp 220v along with a new 10hp VFD (just outside ideal but thought it would still run). Tried every setting I can think of but cannot get the spindle to turn at all on the inverter - the spindle motor clicks and the VFD trips out with what I think is an overload complaint "OCH" (not actually shown in hand book). Everything I used before has been set to 50 or 60Hz and this is 300Hz which I did set.

The spindle will run on one of the far more expensive Drives Direct Inverters I have even though its only rated at 5.5 hp it starts and runs but is in the boost mode (150% for 30 seconds) so drops out - but proved to me the spindle worked.

I guess since sensibly priced chinese inverters don't seem to be available over 10hp I probably should have bought a smaller spindle? Did I miss a setting perhaps? Is something else different with these spindles that I have not encountered on all the other motors?

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