Re: [CAD_CAM_EDM_DRO] Mill Conversion questions

Hi Chris, Tim,

Tim's points are all correct. I would just add that if you have
aspirations of driving a BIGGER machine at a later date, you might want
to use an enclosure big enough to run 7A per axis. A full sized heat
sink (from Dan) won't cost you that much. A pair of fans is cheap
enough. Leave room for additional transformers and caps that can be
added in parallel, and you can "upgrade" the driver/PS at a later date.
One or two controlled AC outlets will be found to be useful too.

You never know, you might get that bridgeport at a later date!

Alan KM6VV


Tim Goldstein wrote:

>
> As I posted on the Sherline CNC list (you will find that there is a lot
> of people on both lists so the answers are not going to be much
> different) the Gecko's are major overkill for a Sherline. They will work
> great and put a big dent in your wallet compared to using something like
> a Xylotex and will not perform substantially better. But if you have the
> money to spend and don't care if you will not find any performance
> difference, than by all means use the Gecko's.
>
> You do not have to unplug the motors to turn the cranks by hand. Yes
> they act like generators, but you will not be cranking fast enough to
> generate much in the way of a current.
>
> Once again, using Gecko with these motors will put you at such a low
> amperage (they are 2 amp motors) that you will not even need a heat
> sink. There is no need at all to build a cooling tower that would be
> suitable for running the drives at the full 7 amps. If you read the
> G201/G210 manual you will see that heat sinks are not required until you
> go over 3 amps. At 2 amps they will not get much more than barely warm.
> I have run the G210's at full amperage using only a CPU heatsink and fan
> to cool them and they stay very cool. At 2 amps you can do just about
> anything but pack them in insulation and they will not get too hot.
>
> Don't lose site of the size of the machine and what it requires. A
> Sherline is a small machine and it does not gain you anything to build
> the drive system as if it was going onto a Bridgeport. This is not to
> say that there is anything wrong with a Sherline. I own one myself and
> use it regularly. But, it does not require or benefit from using much
> more than a 2 - 2.5 amp drive and cooling is not much of an issue.
>
> Tim
> [Denver, CO]
> Sherline & Taig products at Deep Discount
> Mach1 & DeskCNC with credit card ordering
> www.KTMarketing.com/Sherline
> e-mail me at Timg @ KTMarketing.com for items not yet listed
>
> > -----Original Message-----
> I'm in the process of convertimg my Sherline Mill to CNC. I'm
> > thinking (at the moment) about running Sanyo Denki 232-180-DB
> > motors with Gecko 210 drives.
> >
> > If I mount the handwheels on the rear motor shafts so I can
> > run the mill by hand when I want to, I end up generating
> > voltage when I move the handwheels, assuming that the motors
> > act like generators in this case.
> >
> > Are the 210 drivers sensitive to this voltage, particularly
> > when the system is otherwise unpowered? Do I need to
> > disconnect the drive motor cables, either directly or with a
> > relay, when I use the mill manually? If so, do all of the
> > motor leads need to be disconnected? (That's not a problem if
> > you just unplug it, but would be a design detail if you were
> > going to use a switch or relay)
> >
> > Is there a recommended heatsink for the 210? (I've seen one
> > at the Camtronics site that mounts 4 drivers) I was thinking
> > about using a variation on a heatsink system I once saw on a
> > high power stereo amplifier. The drivers would be mounted
> > vertically on individual heatsinks to form a chimney with
> > fans top and bottom. My idea is to get really good airflow
> > for efficient cooling, putting the air where it it really
> > needed. (In fact, if I used the Camtronics heat sink I would
> > be really tempted to box the back side for the same reason.
> >
> > I asked a question like this on the SherlineCNC group and got
> > some good answers, but not everything I was looking for so I
> > figured I should ask here.
> > Thanks,
> > Chris
> >
>