Re: Voltage to steppers

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "iowaman50212
<stanlass@n...>" <stanlass@n...> wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, JanRwl@A... wrote:
>
> > Jeff:
> >
> > I have forgotten who it was in the group who just asked this
> question, but I
> > see that now and then in other kinda-related groups, as well. It
> is clear
> > most folk do NOT understand that having a DC-SUPPLY voltage

several

> times
> > higher than the motor's "rated coil-voltage" does NOT mean "that
> same
> > [effective] voltage will be applied to the motor"! Well, yes, it
> is, but not
> > "at stand-still". NO MORE than that rated coil-voltage should

be

> applied,
> > "effectively", so that the rated CURRENT does not exceed! This
> concept of
> > the increase of coil-REACTANCE when spinning is something most
> folk "in here"
> > just don't grasp, and this is understandable! (I'm not even sure

I

> do!!!)
> >
> > We need some guru like YOU to explain about how a CHOPPER-drive
> keeps the
> > "effective" current at the proper limit, and why the HIGH voltage
> the drive
> > CHOPS does not cause excessive current (due to DUTY CYCLE of the
> chopping)
> > and that!
> >
> > And how the "old" L/R "six-wire" unipolar system was WASTEFUL and
> > inefficient, and how a power-supply for a CHOPPER system can be
> much smaller
> > than the old L/R system, etc., etc! Do YOU volunteer???
> >
> > Jan Rowland
> >
> >
> Hi,
>
> It occurred to me that if the controller program kept track of the
> steps per second, it could also predict the current needed from the
> power supply.
>
> Also, one could write the controller program to limit the current
> needed from the power supply by limiting the steps per second. When
> the steps per second approached the limit, the program could

stretch

> out the clock period such that the issuing of step pulses to the
> stepper motors is slowed uniformly.
>
> Is this in any controller program?
>
> Newbie Stan

Hmm interesting. The closest I can think of is the HP (agilent)
controller chips HCTL-1100 IIRC, they do have ramp up and ramp down
as well as max velocity and max accelleration on all moves. You can
tell them to move by position or by velocity.