Re: motor sizing vertical slide EDM

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@...> wrote:

> One simple fix is to find a spring that allows the weight to hang with
> the spring partly extended.
> This will put a nearly constant pull on the cable without much inertia
> effect. The cable runs
> over the pulleys, then the weight hangs from the spring.
>
> Jon

You could also make the weight part of closed belt drive so that it
pulled down as well as up?

Is there also the problem that once the weight gets moving upwards
there is nothing to stop it so when the axis moves so it will tend to
bounce?

I needed a brake system for the linear motor z-axis of the scanning
tank I made, I was scared to use weights in the end for that reason
and didn't want to add springs to stop the jumping in case it caused
problems with the tuning. I ended up using a retractable cable with a
very light spring and an electromagnetic brake on the wire drum but
that's a different story.

Graham