Re: Power supply question

Joachim,

I use at least 2000uf per amp for 297/298 designs. Although the gecko
white paper says it is okay to use less for GECKO drives, I have
found that these particular chips "prefer" a smoother DC.

(I'm sometimes a bit confused when a paper written with the needs of
a particular drive is presented as the "truth" for ALL drives.
Admirably, Mariss, who wrote the paper(s) does not do this. So
although some parts of the Gecko White papers are of general use,
don't forget that they are written from a "gecko" perspective. And
although Mariss is a genius in drives, IMO; he's still selling his
product.)

Hope this helps,

Ballendo

P.S. Offlist, could you tell me where you got your transformer?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Joachim Reif
<joachim.reif@t...>" <joachim.reif@t...> wrote:

> What kind of quality current does a stepper motor need?
>
> I have a transformer that gives 300VA and 18 Volts and I am trying
> to estimate the ripple in order to calculate the capacitor. First I
> wanted the ripple to be 2.5% but it makes the capacitor rather big.
>
> My driver is a chopper type build around the L297 and the L298.
> Should I take a higer procentage of ripple to keep the kapacitor
> smaller (and cheaper)?
>
> Any ideas friends???
>
> Joachim Reif
>
> Gothenburg, Sweden