Re: Stepper control of spindle / motors and noise

> Jon,
>
> I've been thinking along those same lines. But, instead of removing
> the main drive belt and attaching the stepper's belt, how about an
> electric clutched timimg belt pulley so both belts are always
> engaged. When you wanted the stepper action shut off the main
> spindle motor, activate the clutch and let the stepper do what ever
> spindle rotations are needed. Then everything could happen under the
> CNC's program control. Or maybe both belts could be always engaged
> without the clutch. Then the stepper would be constantly rotated by
> the spindle, wonder if that would be a problem having a stepper
> constantly rotating (with it's driver turned off, of course).
>
> Doug

I think driving the stepper backward that vigorously might produce
some unwanted "generator" effects back up stream at the interface
electronics. I'm being much less ambitious. Treadmill motor in the
back, NEMA 34 stepper in the front. Depending on what "mode" you want
to run in you just move and re-tension the XL belt from one to the other.
I am a little concerned about the effect of the treadmill motor on the
X&Y steppers noise-wise and I expect to be back here before the snow
flies anxiously pleading for info on shielding and isolation strategies
.... hope not ... but I have a bad feeling about it. Not only the
treadmill motor but also the highspeed brush motor for the FOREHAM
rotary tool ... and maybe a dust collection system with two fans
as well :-P ... bad feeling getting worse now .... you can only
make the stepper cables so short without mounting them directly
onto the LPT card.