Re: [CAD_CAM_EDM_DRO] Motor Noise?

Hi Sven,

Sorry, I didn't to "loose" you in my comments. Since you are working
with what is basically an "HF" transmitter, then I'd suggest checking
out "transmitter shielding", again, it's in the A.R.R.L handbook (for
ham radio).

That sounds like a pretty rough environment for a PLC! Shielded boxes,
with feed-throughs for power and control lines are probably in order.

Alan KM6VV


"Sven Peter, TAD S.A." wrote:

>
> Hello Alan,
> my ears cling. If at all I understood a forth of your post!
> Here my application:
> I have a centrifuge for chrome-colbalt casting that works with
> pulsed (1,3 to 1,5Mhz) induction current (4500VDC)
> for to melt the metal.
> (Brand german Dentaurum, type Megapuls D100)
> The trouble with it is that the induction sparks and the high humidity
> in Costa Rica turn this thing, that never fails in Europe into
> a nerve killing trouble maker. The secretary of that odontologic
> laboratory calls me: "911"
> My plan is to use a Siemens LOGO mini-PLC (120VAC, currents in mA area)
> for control tasks and put together to the main contactor a few solid state relays.
> These STR will eliminate the damn sparks of the 4KW-transformer
> and by the way I can supervise all elementary functions.
> Sven Peter
>
> Alan Marconett KM6VV wrote:
>
> > Hi Sven,
> >
> > Yeah, you need either sintered or ferrite. Oftentimes you can keep RF
> > out of stuff by getting an old TV deflection yoke, and wrapping turns
> > around that!
> >
> > Lets see, if you're trying to "keep the RF in", then one can usually
> > turn on a TV or radio, and see what "works" (add a few beads, try a few
> > toroids). To keep RF out of a circuit is a little tougher. What wires
> > go into/out of the "box"? DC power lines can be bypassed with caps,
> > beads/toroid chokes can be added, and then you somehow need to get a
> > 'scope probe in to see if RF is getting in. A little harder. Perhaps a
> > bulkhead BNC, with a short wire "probe" antenna INSIDE the box; to
> > couple out some signal to a 'scope. Check out the "ARRL handbook",
> > there are chapters on shielding and filtering, and probably some
> > suggested values of parts.
> >
> > If you have the power supply inside the box, then try a CORCOM filter on
> > the AC leads.
> >
> > There should be some data sheets on the Amidon products on the web
> > sites, these will give you the freq. ranges for the various beads and
> > toroids. Or call them!
> >
> > Hope this helps!
> >
> > Alan KM6VV
> >
> > "Sven Peter, TAD S.A." wrote: