PDA

View Full Version : VFD's, CNC and TIG noise



johnc
10-30-2012, 02:40 PM
I've been looking at TIG welders and wondered what you guys do about the high-frequency noise around CNC's and VFD's. A salesman highly recommended a inverter-style unit that had the capability to "lift-start" and turn off the high-frequency starting. How critical is this? Or do you guys just unplug your other machines when you fire up your TIG?
Thanks,
John

lakeside53
10-30-2012, 04:06 PM
It sound like hype. I've never had a problem and can't really see an issue - plenty of filtering on the vfd's etc for power wiring borne noise, and rf isn't going to affect much.

macona
10-30-2012, 05:11 PM
Some older tig machines can cause Cnc machines to crash. Newer tig machines don't have real HF. It's just a HV pulse to start the arc.

Crash like a computer crash. Not the really bad one.

johnc
10-30-2012, 05:28 PM
Thanks guys, The salesman was inferring that the high frequency voltage would pollute anything with a common ground. I don't know much about it but thought it might be wise not to run a machine while tig welding, it never dawned on me that it might affect a machine simply plugged in. Good to hear that he might have been over-conservative.

John Stevenson
10-30-2012, 07:17 PM
My old TiG, 200 amp AC/DC TransTiG with spark gap HF used to stuff everything up electrical when it was running.
To frightened to try it with the CNC but when i was welding and went into the office afterwards the shop computer would have about 15 windows open, some I had never seen before.

This is absolutely true, no joke.

The new Chinese inverter unit is fine though, can weld at the side of the CNC and even pull power from the same spur.

oldtiffie
10-30-2012, 08:46 PM
I've been looking at TIG welders and wondered what you guys do about the high-frequency noise around CNC's and VFD's. A salesman highly recommended a inverter-style unit that had the capability to "lift-start" and turn off the high-frequency starting. How critical is this? Or do you guys just unplug your other machines when you fire up your TIG?
Thanks,
John

If you have a "pace-maker" inserted it may be useful to ask your doctor about it. Modern pace-makers seem to have largely but perhaps not entirely over-come this issue.

http://en.wikipedia.org/wiki/Pacemaker_failure

http://www.google.com.au/#hl=en&sugexp=les%3B&gs_nf=3&cp=12&gs_id=1a&xhr=t&q=pacemaker+failure&pf=p&rlz=1R2IRFC_enAU360&sclient=psy-ab&oq=pacemaker+fa&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=36322ed43c859f1a&bpcl=36601534&biw=1920&bih=855