electromagnetic interference

[alehman]

I have a client who has non-specific concerns about potential for EMI from electric welding of building structural elements in proximity to operating data processing equipment. Does anyone know of any standards pertaining EMI mitigation for electric welding?

 

[MintJulep]

You just gotta love those non-specific concerns.

If he can't give you field strength levels that you have to stay below, there really isn't much you can do is there?

This IEEE paper might be a starting point for you:

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/7008/18935/00874705.pdf

 

[alehman]

Thanks for the reply. I'm following up on that article. I inquired with Lincoln Electric and they know of no standard either. They provided some general suggestions:

Avoid high frequency TIG welding. Route welding cables away from electronic equipment and cabling. Connect the work cable to the work piece as close as possible to the area being welded. Route the electrode and work cables together and secure together with tape if possible.

That may have to be good enough.

 

[Pressed]

Had a similar issue once and had no real evidence/info to act on but these links below are good to read.

[URL unfurl="true"]http://www.intermark-usa.com/products/EMC/Cable/MT.shtml[/URL]
[URL unfurl="true"]http://www.dtbtest.com/EMI-EMC-electric.aspx#shielding[/URL]
[URL unfurl="true"]http://www.magnetic-shield.com/products/cables.html[/URL]

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http://mech.e.tripod.com

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http://www.tailofthedragon.com

 

[unclesyd]

This is just empirical evidence concerning one of our our processes and their computer controls. We have DC fields surrounding our control room which consist of 12 Provox consoles. The DC power cables go up 2 sides and over the control room. There hasn't been any problem than I can remember. I do remember that when changing from pneumatic to Provox there were a some concerns but these were quickly laid to rest. The control room also sits over the motor generator room, initially there were 16 sets in operation but has since been cut to 8.

Also we use the building steel for the welding grounds as all welding machines are in auxiliary buildings. We snake the hot leads in and around all the process transmitters.