Hum ...
ESS, Baldor DC servo motor for spindle, Index line encoder, SMPS driver - I trust it down to about 100 RPM. Below that it seems a bit wobbly.
Granted, that is a DC motor, not a VFD, and that has only an open loop control. The index pulse is used for threading, which works very well. I have never tried the motor with a servo driver like a Gecko 320.
Hum again - but the XYZ axes are also DC servo motors with 512 line encoder FB and Gecko 320 drives. I am not sure that I could get them up to 6,000 RPM though - maybe 4000 RPM. Not a lot of torque at high RPM.
Ah - Mach3 does not support positioning on the spindle. Maybe that is why I never bothered?
OK, thinking about all this. Thank you.
Cheers
Roger