Re: FS: New 4 axis microstepping driver $45.00 USD

Fred,

Probably very little. Energy stored goes up as the square of RPM, the
purpose for that speed is to simulate what gets stored in the
leadscrew, and to a lesser extent, the mass moved by the screw. The
best way to tell is to run a single drive and scope the supply
voltage under actual running conditions.

I ran some tests using a large NEMA-34 motor spun up to 6,000 RPM
using a 48VDC supply. The stored energy was 35 Joules, of which 22J
were converted back to electrical energy.

The results are available as "Returned Energy.pdf" in the "G201 and
G210" folder in the files section of my Yahoo Group "geckodrive".

Mariss



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Fred Smith" <imserv@v...>
wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mariss Freimanis"
> <mariss92705@y...> wrote:
> > I think regulating the power supply does not address the bigger
> > problem of returned energy and in fact, will make it much worse.
> >
> > Those of you who have scopes may want to try a little experiment
> that
> > could destroy your drive.
> >
> > 1) Place the scope probe across your DC power supply. Set the

input

> > coupling to DC, 10V / div vertical scale, 100 milliseconds / div

on

> > the timebase. Trigger set to AUTO.
> >
> > 2) Spin up a NEMA-23 or NEMA-34 motor to 2,000 to 3,000 RPM.
>
> Maris, this would be 100-150 inches per minute on a Sherline or

Taig

> mill (.050 pitch lead screws) and is not representative of the kind
> of operating conditions that are encountered for these machines.
> What happens to back EMF if the motor spins around 400-600 rpm (20-

30

> ipm) and you stall it?
>
> Fred Smith - IMService
>
> > > >> On Wednesday, Mar 17, 2004, at 17:40 US/Eastern, Fred Smith
> > wrote:
> > > >>>> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Fred Smith"
> > > > <imserv@v... wrote:
> > > >We have a limited edition, 4 axis, microstepping driver
> > > >available for $45. Based on
> > > >the Allegro A3977 chip. The board is rated at 2 amps per axis
> > > >and maximum of 35vdc. This is a promotional item and is

subject

> > > >to prior sale. Quantities are very limited.
> > > >>>
> > > >>> Info at: http://www.cadcamcadcam.com