Re: [CAD_CAM_EDM_DRO] HELP ! on Westamp servo drives.

"Ward M." wrote:

>
> Yes, I have a scope and will be giving the tune-up a try soon. I'm still
> hoping for a schematic or parts layout so the test points are more clear. I
> can remove the amp from the lathe and trace out the circuit and make a
> schematic but I am trying to avoid this. Prior to opening my machine shop,
> I was working as an electrical engineer designing servo and video systems.
> Unfortunately, I no longer have access to the frequency and network analysis
> tools I once used.

Glad to hear you have this experience, as it will be extremely helpful
in understanding the results.

> I suppose I could run a rough closed loop disturbance
> analysis using a sweep generator and input a low level signal in the loop.
> The results might be somewhat harder to interpret from a scope screen as
> opposed to a frequency and phase domain system. What do you think?

I actually managed to pick up a gain and phase analyzer in a scrapyard, and
repaired it with a new vacuum fluorescent display module. I really can't
say it told me a whole lot more than I knew without it. I did already have
a digital scope that I used to dope out most of the response.

> Maybe I should just tune it as you have kindly suggested. This will no
> doubt get it where it needs to be without the extra trouble and analysis.

Without detailed info on all the components, both electrical and mechanical,
it would be pretty hard to do an analytical solution. Observing the response
to transients is pretty effective at gauging the total response.

Jon