800w spindle - noise & controlling remotely

[HankMcSpank]

Oh dear....what is it about the CNC genre?!!!

So I've just hooked up my new VFD to my 800W spindle - the VFD is tripping outwith an overload condition.

I'm figuring it's likely to be the spindle becuase it's of unknown status. I bought the CNC machine in a "needs putting back together" condition ...with a VFD missing. I'm now assuming that a spindle fault perhaps took out the original VFD?

I'm controlling the spindle speed manually with a 10k pot that I've connected up to the VFD, I can get the spindle to turn very, very slowly (without tripping) with the pot at its lowest speed setting but if I turn the pot just a degree or two the VFD goes into an error condition 'overload'....I've checked the VFD settings for tripping out (they're all at default...and nothing seems untoward there)

I don't suppose it's easy to test these water cooled spindles? (I'm seeing just a couple of ohms between pins ...also when the spindle is turning even ridiculously slow, the spindle outer chassis gets warm (not ouch warm, but warm...which is surprising bearing in mind it's turning very slowly ....like 60RPM or so)

Any ideas?