[sevilla]

Hi,

We had manufactured an automated TIG welding system; all its control is done with electronics. It works ok when we have the high frequency off but as soon as we activate it the system stops and resets.

We have tried everything, i.e. all controls are in metallic cabinets with wires over 4m, earth of machine and control are different, our power source for welder and control are different, etc.

This problem happens with our new Syncrowave 250 but doesnt happen if we use our old welder (80's). As we have seen the old welder have less high frequency power, tugnsten almost must be in contact to part that it is welded but in the Syncrowave 250 can weld with distances over 1cm.

Any idea?
a) We dont know if Sycrowave 250 hase some kind of potentiometer (internally because outside you cant control power of high frequency) or some way to increase/decrease high frequency.
b) How can we protect our electronic system from HF, protect them in metallic cabinets (grounded), to have independent earths for welding and electronics, have all system including earths in less than 15meters, to have all wires with out any connection and have them connected directly... all this has been done and it improves performance but we cant get a complete cycle, we can finish one and system is reset, later we cant complete 15 cycles and later we can finish 2 cycles, etc. etc.

I really will apreciate your help, we have done everything and we have better results but we cant reach more than 10% of cylces properly finished.

Regards,
Sevilla

[ogorir]

first thing I would do is look at the circuits your controls and the welder are on. they should be on different breakers. next, I'd look into powerline conditioning for your control system.
you will need to make sure that your workpiece ground and the control box are completely isolated. if they're electrically connected (aside from the motors) that's likely your problem.
also, I'd look at what kind isolation there is between the computer bits and the actual motors, if any.

I need a little more information on your system to give more pointed advice. also, what electrical measurement tools and knowledge do you have on hand? an oscilloscope would be a boon in tracking down where you're getting interference.

my guesses though, as I said, are through the mains or through a shared ground plane.

[Polaris_Dave]

Investigate copper shielding around your electronics (Faraday cage).
Here's a similar thread:
http://www.millerwelds.com/resources/co ... with-my-tv

And another:
http://plasmaspider.com/viewtopic.php?f=45&t=1442

[ogorir]

also, if you haven't looked into it yet, put ferrite beads on all your inputs and outputs to your control modules, including the mains.