Union Jubilee Clutch.

[Nick]

""Its not only not the cheapest (it has an extra resistor)""

Gosh, an extra 10p, I can't see any other way of getting a 8.31v to 9.93v range from a 10v source cheaper than what refugee suggests.
I would assume Col has tried all the parameters, maybe he has maybe he hasn't? The manual is not very good...Chinglish.

Its not the 5p or whatever That was tongue-in-cheek - its just that that is simply not the way to fix this issue - its a hack, and a bad one at that.

Lets see what the parameter settings are for starters (pun intended) - I'll wager good money its a commissioning issue.

If the frequency range over which the motor can be controlled is small, then PD073 (lowest frequency) and PD072 (highest frequency) would probably be the parameters to change, specifically PD073...

Just for the record, what motor do you have on this lathe - its seems that not all Jubilee motors are suitable for VFD anyway... the actual VFD model number is important too as there may be a jumper to move as well (only on certain models)

EDIT: Apologies if I sounded a bit strident in this thread - I don't mean to, its just that you have a really quite nice (and very common/popular) VFD inverter here whose usage is pretty well documented - these systems really do need proper commissioning for successful use - they are not simple voltage-controlled-oscillators - they are much much more sophisticated than that, and for proper use and long life for your motor AND the controller, they should be set up appropriately...