RE: [CAD_CAM_EDM_DRO] EMI Rehab

HI Abby,

Put the driver/PS in a 19" wide by 9" deep by 7" high rack mount box. Put
the box BESIDE the mill, and put your monitor on top of the driver/PS. Put
the keyboard in front of the box. Computer can go on the floor below the
table.

You might want to consider Geckos. They are a bit more immune to noise.
Also, Jeff has worked out some mods, I think, that will help the Xylotex
board.

No need to partition the inside of the box, unless you're thinking about
putting a PC in it as well.

Alan KM6VV
SherlineCNC list

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Abby Katt
> Sent: Friday, June 24, 2005 4:18 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] EMI Rehab
>
> Hi all,
>
> I'm putting my Sherline/Xylotex setup through some EMI rehab, as the
> mill has been out of use for a little while, but I'm now planning to fix
> it up for either small precision work, or to sell (I'll put it here
> first..) Anyhow...
>
> I decided I want to take the EMI thing rather seriously, so I shall be
> fabbing up a huge metal casing for the whole setup this weekend, here is
> what I'll be doing:
>
> .1 main case around everything
> .Power-supply enclosed in it's own metal case inside of the main case
> .Main case partitioned in two with small holes so the logic/power side
> is separate (with big distance between) from the AC side.
> .I have an EMI filter unit for the AC in
> .Installing capacitors on the Xylotex step lines to ground
>
> So as you can see, I'm very annoyed with random steps/stalls!
>
> Here is what I'm not sure about...
>
> .I have 0.68uF 450V caps for the sherline DC spindle motor, as listed in
> Cletus' EMI solution. But the diagram shows 3 wires going to the motor?
> I was sure the Sherline had only 2 wires as it was a DC motor? How do I
> wire these caps over the motor's brushes to reduce EMI? Or was this
> diagram for an AC motor only? I'm a bit scared to just start soldering
> caps wherever looks good!
>
> .Grounding.. foot bones goes the uh.. leg bone, leg bones goes to the..
> uh uh oh! Okay, so the chassis will be grounded, the EMI filter ground
> is common to the chassis ground (well, it's connected actually) but what
> about the parallel port cable? Do I ground the outer shell of that to
> the chassis, or leave it off? Wouldn't grounding this cause the cable to
> be grounded at both ends (PC and controller chasis) and therefore cancel
> out the effect?
>
> .Is it going to be terrible to mount the sherline on top of this new
> casing? From an EMI point of view? It would seem to be a nice idea to
> have the sherline, with controller, as all one unit.
>
> .Any other tips or morsels of EMI wisdom you want to share?
>
> Rehabs for quitters, anyway. :)
> ~Abby
>