Ground and noise problems

[sonosabi]

Hi,

DIY plasma project.

I had this machine (about 1000X500) from previous DIY CNC,
It worked fine.
The project ended and now I am trying to convert it to cut with plasma torch. (I have this simple chinese CUT-50amps no-brand)

I can`t get the steppers to work properly and smoothly while the torch is working.
Sometimes one of the axis stop reacting (mainly Z axis) to commands until I shut down the card and reconnecting it (I have Xylotex driver)

The machine is all metal and all part are connected to each other so there is no isolated parts in the machine.
I`v tried to roll a copper wire over the plasma torch-head cable and ground
it, it helped a little bit but have`nt solve the problem completely.

The motors cables are not shielded - is this a must ? could this be the problem ?

The machine body is connected to the house electric system grounding (base ground - metal-in-the-ground thingy..) by big cable (3 phase motor cable).

I would be glad if someone would share some experience and knowledge and give me some tips with this frustrating situation.

Thanks

[Al_The_Man]

If using a PC based system, although the PC P.S. DC side is grounded in the PC it may pay to take a ground from the P.P. common to a central star point where all the Earth grounds terminate.
Al.

[xalky]

I think your suffering high frequency interference. check out these links: RF Shielding and this one

High Frequency shielding for CNC Plasma time to get familiar with shielding and grounding.

[sonosabi]

I will try recommended solutions,
Thank you very much!

[xalky]

I'm also in the process of shielding and grounding. It's difficult to tell how much shielding is sufficient until you try it out. Plasma makes a lot of electrical noise and it permeates the environment through the air and metal objects in the room act as antennas. My garage is chock full of metal objects, everywhere you look!! I fired my torch a few times and it wasn't pretty. The computer locked up and it might need a new power supply. Ugly ugly stuff.

Sent from my SPH-D700 using Tapatalk 2

[jimcolt]

Correction: Plasma systems that use high voltage, high frequency or other types of high voltage starting produce a fair amount of RF electrical noise that can and will affect sensitive (low voltage) electronic equipment.

Most of the major brand air plasma systems available today use a "blowback start" technology that does not use any of the noise producing starting methods listed above. There are probably 40,000 of these plasma systems operating succesfully on entry level cnc cutting machines worldwide.

Almost all industrial plasma cutting systems (above 130 amps output) continue to use high frequency starting technology.....and virtually all of these plasma systems are integrated to motion control and cnc electronics that are hardened to work with the electrical noise generated. All motor, drive, encoder and computer cables are shielded amd properly grounded, all inputs and outputs of the plasma and electronics and computer are isolated and properly shielded and grounded. All of these machines are installed with dedicated earth ground rods as well.

Jim Colt Hypertherm

[Dave3891]

How much interference does the HPR260XD system with the HD torch produce?
Will this system work with a PC based control?

Dave

[xalky]

Correction: Plasma systems that use high voltage, high frequency or other types of high voltage starting produce a fair amount of RF electrical noise that can and will affect sensitive (low voltage) electronic equipment.

Most of the major brand air plasma systems available today use a "blowback start" technology that does not use any of the noise producing starting methods listed above. There are probably 40,000 of these plasma systems operating succesfully on entry level cnc cutting machines worldwide.

Almost all industrial plasma cutting systems (above 130 amps output) continue to use high frequency starting technology.....and virtually all of these plasma systems are integrated to motion control and cnc electronics that are hardened to work with the electrical noise generated. All motor, drive, encoder and computer cables are shielded amd properly grounded, all inputs and outputs of the plasma and electronics and computer are isolated and properly shielded and grounded. All of these machines are installed with dedicated earth ground rods as well.

Jim Colt Hypertherm

Thanks. I stand corrected