Re: Chopper Transient Suppression

The Geckos use a different switching topology; both motor phases are
synchronous meaning both are clocked by a master oscillator running at
22kHz. There is zero noise because both phases operate at the same
frequency and cannot produce any beat frequencies.

This applies at zero or low speeds. All step motors make a
characteristic whine at medium to high speeds. The whine's 'pitch' is
equal to 1/4 the full-step pulse frequency.

It is the 'difference' beat frequency you hear with a constant off-time
chopper; if one phase is running at 19kHz while the other is at 20kHz
then you hear the 1kHz difference. As these frequencies change (and
they do), the difference changes as well, producing those irritating
sounds.

Mariss


--- In CAD_CAM_EDM_DRO@yahoogroups.com, Codesuidae <codesuidae@c...>
wrote:

>
> Mariss Freimanis wrote:
>
> >You are probably using a "constant off-time" switching topology. The
> >screeching, grunting, whistling, hissing, etc. comes for free with
> >that method.:-)
> >
> >
> Do Gecko's make the steppers hiss and screech?
>
> When they run a curve do the steppers make a nice tone?
>
> Dave K
>