Re: current limiting power supply for stepper?

Grant,

Yes, it is done. The linistepper uses this approach, as does Jean
Vachon, with Mel Bartels telescope drive...

Paul Jones, of CNC on a budget, has a circuit for the Vachon current
limiter at the bottom of his homepage. Jean himself can be found
regularly at the "telescope drive" (might be "scope drive") yahoo
group. (Keep in mind that the scope drive guys are pretty much
opposite us: They want SLOOOOOW speed VERRRRRRY smoothly.)

Hope this helps,

Ballendo



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "grantfair2001
<grant.fair@s...>" <grant.fair@s...> wrote:

> Hi Dave-
>
> The power supply I am thinking of using has adjustable voltage and
> current limiting. When the specified current limit has been met the
> voltage lowers (and maximum current remains constant).
>
> (This is from National Semiconductor's datasheet on the LM317, p

14).

>
> So for a given stepper I would adjust the max. current to the max
> current rating for the motor, but use a higher voltage than the
> nominal motor voltage rating. The current would not exceed the

motor's

> max.
>
> I know this is not the way it is usually done, but I am wondering if
> there is any reason not to try it.
>
> Grant
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude
> <davemucha@j...>" <davemucha@j...> wrote:
> > Hi Grant,
> >
> > there is a maximum current you can pump into a motor. voltage is
> > limited(chopped) to keep the power on the upper end of the

curve.

> > current monitoring is how it is done.
> >
> > for reasons why 25 times nameplate is the max as far as voltage

goes,

> > read the white paper at www.geckodrives.com
> >
> > Dave