Re: [CAD_CAM_EDM_DRO] 2 steppers-one axis?

Jon,

I know it's possible, as the super-tech site does it. I agree, they
must be "in step". If not, terrible things happen ;>) If the drivers
take PH1 - PH4 to drive them, that might simplify the sync. I don't
remember if super-tech relies on having the "4-phase" drive signals
common, I think so (Dennis, are you there?). I do recall that
super-tech runs TWO separate limit switches, one for each "Y". I think
I'd study what super-tech has already worked out.

Terry, any further thoughts? Try it yet?

Alan

> Jon Elson wrote:
>
> Alan Marconett KM6VV wrote:
>
> > Terry,
> >
> > There should be no problem, just feed the extra Y driver with the SAME
> >
> > pulses as the current Y (or whatever) you want to duplicate (wire
> > motor
> > for the same effective rotation).
>
> The problem is you need to keep the motors synchronized. If they are
> run
> off the same driver, then at least they will always be on the same phase
>
> at the same time. Then, you could tighten the shaft couplings with the
> driver turned on, and the motors would be happy to make a pair. If
> you use separate step and direction drivers, then there is only a 25 %
> chance that they will maintain the same phase relationship as when the
> shafts were coupled together the first time. If the coupling is fairly
> stiff, and the phasing is different, then the motors will be severely
> fighting each other, and neither will be near its resting position for
> that
> step, but somewhere 1 or 2 steps leading or lagging. This will cause
> HORRIBLE loss of torque, and much rattling and stalling. I really
> think the results will be much worse that one motor properly driven,
> or two motors driven off a driver that can support both.
>
> One other possibility is if you have one step-to-phase converter
> driving two phase-input drivers and motors. Then, the motors
> would again always have the same electrical phases active.
>
> Jon
>
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