Muzzer,
The spindle has 24000rpm 400Hz on it and has no sensor wires. Having looked on YouTube at a video of one being dissmantled the rotor does look like it's made from laminations so it is probably an induction design as you say.

I use HSMA and do take note of the estimated power. As most of my cutting is done with tools of 6mm diameter or less it's the deflection warning that goes red before the power climbs very high. I've only been getting torque warnings with a 19mm tool I want to use for 'thicknessing' pieces of hardwood but was interested to get the benefit of other peoples experience and knowledge.

It seems like sticking with my fixed torque setting of .85Nm is going to be sensible. I've also set the minimum speed allowed in HSAM to 6000rpm which I've read elswhere on the forum is a speed below which the torque really drops off.

Thanks for all your input.

Kit