Originally Posted by mulligan  The only change this time was I fired the cutter with the tip touching the table and the torch ground clamp was left hanging on the plasma cart...  |
That will cause you problems nearly every time.
Something to remember with anything electrical is that the current is trying to get to ground as fast as possible.
So when you left the plasma ground lead off your cutting table the current found another way to ground. It just happen to be through your drive motors to the controllers.
What you are planning on doing to improve your system looks good.
This is my thoughts.
Originally Posted by mulligan 1. Earth ground attached to torch chasis and driven 4' into the ground. (Have done this already, BUT this ground rod is within 3' of electrical panel rod) |
Originally Posted by mulligan Originally Posted by Ajax-oz View Post
Is your cutting bed, part of the CNC gantry
Yes. I have the typical 5/16 roller blade bearings for the gantry rollers. |
Excellent
attach ground to the your cutting table.
The Gantry concerns me may need to have a ground connected to it as well. It would depend on the design.
Cable the that same size (or larger) as the earth on your plasma unit would do. I like using the flat braid for earths but they aren't convenient to use over longer distances.
Remember you still need to connect your earth from your plasma unit to the cutting table. The extra earths protect your electronics and you form being fried.
Originally Posted by mulligan 2. Wire sheathing covering the torch lead from chasis all the way to handle on the gantry. |
Excellent
Helps reduce RF
Originally Posted by mulligan 3. Move all my electronics (drives, power supply, Print port protecter, etc) into a steel weather proof enclosure. Should this be case be earth grounded also? Currently and I am ashamed to say, everything is mounted on a temp sheet of plywood... |
Excellent
Mount your steel weather proof enclosure to your chassis if you like.
Yes it should be earthed
I normally have a braided earth strap from the enclosure to the chassis, even if it is directly bolted.
Remember to remove the paint for the earth
Originally Posted by mulligan 4. Rubber mount my motor mounts on my table. Since I have a timing belt setup, will this be sufficent for isolation? |
Not needed in my opinion
Motors need to be grounded as well.
Originally Posted by mulligan 5. Ensure that ALL grounds terminate with my power supply ground. |
If you do as you said in number 3 this will be done in your steel weather proof enclosure.
Originally Posted by mulligan 6. Ground only one end of the wire shields. |
excellent
Originally Posted by mulligan 7. Enclose torch case in a steel box if necessary?? The torch has its pilot arc in its case unlike my Hypertherm 600 which has it at the torch tip.
Should I switch to the hypertherm cutter?? |
I think it will most likely not be needed, but I could be wrong.
I work on the Hyperthem & Kaliburn (Inner Logic) 200A + units, so I don't now anything about the models you are talking about.
Here is a link to some of the equipment I work on
http://www.profilecuttingsystems.com/pcsproducts.html
Originally Posted by mulligan I have an aluminum block the compresses around the ceramic cup on my torch handle for a torch mount. This block is mounted to a piece of HIWIN rail and then to HIWIN bearing blocks. |
It sounds like your torch is isolated nicely.
hope this helps
AJ