It appears that current sense resistors aren’t (weren’t?) used, and that the Overcurrent Protection threshold is (was?) set to 8.8 +/- >20% Amps.
@mikep, @Tshulthise Here’s a 300 Watt water cooled HF spindle with a 0 - 60,000 RPM speed range that might be a nice upgrade for the Nomad. And, using the right VFD with it would enable direct monitoring of current.