Re: [CAD_CAM_EDM_DRO] Re: Power Supply Box's

>>
> I think you are asking for a long frustrating project. The more you
> can do to separate low level logic systems and high power circuits
> the better. It may work with no problem. It may reset your
> computer everytime the motors get under load or it may just wait
> until you have expensive project 80% done and ruin it.
>
> Grounding/shielding for minimum RFI and EMI interference is the
> subject of entire books (I know because I have one). It CAN be done
> but it takes a lot of testing and understanding of how HF signals
> are propagated across common connections and through the air.
> Putting signals inside a cabinet helps keep them from transmitting
> to the world. Put two systems into the same case actually works
> against you since the crosstalk in the cabinet is greater.
>
> We could design a switching power supply in a few hours. It then
> took days to minimize the noise so the control electronics would not
> pickup the PWM power spikes.
>
> If you want to move the PC out close to the controller, consider
> either having two separate metal compartments for each side. You
> power supply and motor drives in one side and your computer and
> breakout card in the other.
>
> Any wire over 12" long becomes an antenna for RFI. Running them in
> close proximity lets them more easily "talk" across. The inverse
> square law applies to RFI where the strength of the field is 1/4 if
> the distance is doubled. That is in open air. Closed insde
> a "faraday shield" the calculations are much more complex

Thanks for taking the time to reply and bring questions to light.

Reading your note, it would appear I have a bit of a excercise on my hands
:-). If I was to build my entire box so as to have each level of
control/power/function in its own partitioned section, would this help?
What I wanted to do was have the computer part, the mobo, drives, keyboard,
screen etc all in the top compartment, the screen is one of those
industrial flush panel mount touch screens [not sure if touch screen's are
worse for RF emissions or not]. Then below that is the control compartment.
The control compartment would house the G100, and motor drives. The
compartment below that would be the power supply compartment, it would have
the motor power supply as well as [possibly] the computer UPS. Then the
final compartment below that would house the VFD. Every single power,
control or sensor wire in every compartment will be sheilded and star
ground to a single point [most likely in the power supply compartment].
Each 'compartment' would be seperated from its neighbouring compartment by
a 20ga steel panel, these panels would be as tight fitting as is possible,
however this would be openings as needed for cables to pass through.

Does this still sound as bad as first thought?.

The reason I'm going to all this is because I want a control box which
moves along the machine. My machine is 20ft long and i'd like to be able to
position the control box anywhere along the length of the unit just by
sliding it down. The entire box will ride on its own set of rails mounted
to the outside of the machine. This should save me from walking 20-40 feet
each time I want to access the control. I do plan to use a pendant, but
that doesn't preclude someone from having to move back and forth to the
control unit.

Totally open to suggestions! [and thank you to all who have already posted]

Sincerely
Jarrett